Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 16

» Secure and Energy-Efficient Beamforming for Simultaneous Information and Energy Transfer
Abstract:
Some next-generation wireless networks will likely involve the energy-efficient transfer of information and energy over the same wireless channel. Moreover, densification of such networks will make the physical layer more vulnerable to cyber attacks by potential multi-antenna eavesdroppers. To address these issues, this paper considers transmit time-switching (TS) mode, in which energy and information signals are transmitted separately in time by the base station (BS). This protocol is not only easy to implement but also delivers the opportunity for multi-purpose beamforming, in which energy beamformers can be used to jam eavesdroppers during wireless power transfer. In the presence of imperfect channel estimation and multi-antenna eavesdroppers, the energy and information beamformers and the transmit TS ratio are jointly optimized to maximize the worst-case user secrecy rate subject to energy constrained users’ harvested energy thresholds and a BS transmit power budget. New robust path-following algorithms, which involve one simple convex quadratic program at each iteration are proposed for computational solutions of this difficult optimization problem and also the problem of secure energy efficiency maximization. The latter adds further complexity due to additional optimization variables appearing in the denominator of the secrecy rate function. Numerical results confirm that the performance of the proposed computational solutions is robust against channel uncertainties.
Autors: Ali Arshad Nasir;Hoang Duong Tuan;Trung Q. Duong;H. Vincent Poor;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7523 - 7537
Publisher: IEEE
 
» Secure Degrees of Freedom for the MIMO Wire-Tap Channel With a Multi-Antenna Cooperative Jammer
Abstract:
In this paper, a multiple antenna wire-tap channel in the presence of a multi-antenna cooperative jammer is studied. In particular, the secure degrees of freedom (s.d.o.f.) of this channel is established, with antennas at the transmitter, antennas at the legitimate receiver, and antennas at the eavesdropper, for all possible values of the number of antennas, , at the cooperative jammer. In establishing the result, several different ranges of need to be considered separately. The lower and upper bounds for these ranges of are derived, and are shown to be tight. The achievability techniques developed rely on a variety of signaling, beamforming, and alignment techniques, which vary according to the (relative) number of antennas at each terminal and whether the s.d.o.f. is integer valued. Specifically, it is shown that, whenever the s.d.o.f. is integer valued, Gaussian signaling for both transmission and cooperative jamming, linear precoding at the transmitter and the cooperative jammer, and linear processing at the legitimate receiver, are sufficient for achieving the s.d.o.f. of the channel. By contrast, when the s.d.o.f. is not an integer, the achievable schemes need to rely on structured signaling at the transmitter and the cooperative jammer, and joint signal space and signal scale alignment. The converse is established by combining an upper bound, which allows for full cooperation between the transmitter and the cooperative jammer, with another upper bound which exploits the secrecy and - eliability constraints.
Autors: Mohamed Nafea;Aylin Yener;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7420 - 7441
Publisher: IEEE
 
» Security Constrained Multi-Stage Transmission Expansion Planning Considering a Continuously Variable Series Reactor
Abstract:
This paper introduces a continuously variable series reactor (CVSR) to the transmission expansion planning (TEP) problem. The CVSR is a flexible ac transmission system (FACTS)-like device, which has the capability of controlling the overall impedance of the transmission line. However, the cost of the CVSR is about one-tenth of a similar rated FACTS device, which potentially allows large numbers of devices to be installed. The multi-stage TEP with the CVSR considering the security constraints is formulated as a mixed-integer linear programming model. The nonlinear part of the power flow introduced by the variable reactance is linearized by a reformulation technique. To reduce the computational burden for a practical large-scale system, a decomposition approach is proposed. The detailed simulation results on the IEEE 24-bus and a more practical Polish 2383-bus system demonstrate the effectiveness of the approach. Moreover, the appropriately allocated CVSRs add flexibility to the TEP problem and allow reduced planning costs. Although the proposed decomposition approach cannot guarantee global optimality, a high-level picture of how the network can be planned reliably and economically considering CVSR is achieved.
Autors: Xiaohu Zhang;Kevin Tomsovic;Aleksandar Dimitrovski;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4442 - 4450
Publisher: IEEE
 
» Security Semantics Modeling with Progressive Distillation
Abstract:
The prevalence of Android platform has attracted adversaries to craft malicious payloads for illegal profit. Such malicious artifacts are frequently reused and embedded in benign, paid apps to lure victims that the apps have been cracked for free. To discover these fraudulent apps, administrators of app markets desire an automated scanning process to maintain the health of app ecosystem. However, conventional approaches cannot be efficiently applied due to the lack of a scalable, effective approach to malware characteristics aggregation. On the other hand, the vast number of apps significantly increases the analysis complexity. In this paper, we propose Petridish which generates discriminative models against the repacked malicious apps. These representative models of malicious semantics can be progressively distilled with malign and benign samples. These models can further detect repacked malicious apps. Our experiment shows that, after two retraining rounds, Petridish achieved an average of 28 percent progressive detection improvement from 63 to 91.2 percent for the large families, exceeding 38 test samples in size. With noise reduction, it accomplished 88 percent detection rate and 1.7 percent false alarm rate. The characteristics aggregation approach will become critical in the age of app explosion.
Autors: Zong-Xian Shen;Chia-Wei Hsu;Shiuhpyng Winston Shieh;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3196 - 3208
Publisher: IEEE
 
» Segmental Prediction for Video Coding
Abstract:
The emerging standards for screen content coding (SCC) and 3D video coding known as High Efficiency Video Coding (HEVC)-SCC and 3D-HEVC, respectively, have been developed as extensions of HEVC. Compared with camera-captured video, screen content video and depth maps usually contain significantly fewer colors or sample intensities and much sharper edges in a frame. In this paper, a new coding method named segmental prediction is proposed to code screen content and depth maps more efficiently. First, samples in a prediction block are classified into several segments according to the sample intensities. Second, a particular predictor is calculated for each segment. Then an offset for a segment is derived at the encoder side and signaled to the decoder side. Finally, a single sample value is assigned to each segment in the reconstructed block. The experimental results show that the proposed approach can achieve a 2.2% average Bjontegaard Distortion-rate (BD-rate) saving under the HEVC-SCC common test conditions (CTCs) for sequences of the category YUV, text and graphics with motion, 1080p, with the all intra configuration. It can also achieve a 0.6% average BD-rate saving for synthesized views under the 3D-HEVC CTCs with the random access configuration.
Autors: Kai Zhang;Jicheng An;Han Huang;Jian-Liang Lin;Yu-Wen Huang;Shaw-Min Lei;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2425 - 2436
Publisher: IEEE
 
» Segmentation of Skeleton and Organs in Whole-Body CT Images via Iterative Trilateration
Abstract:
Whole body oncological screening using CT images requires a good anatomical localisation of organs and the skeleton. While a number of algorithms for multi-organ localisation have been presented, developing algorithms for a dense anatomical annotation of the whole skeleton, however, has not been addressed until now. Only methods for specialised applications, e.g., in spine imaging, have been previously described. In this work, we propose an approach for localising and annotating different parts of the human skeleton in CT images. We introduce novel anatomical trilateration features and employ them within iterative scale-adaptive random forests in a hierarchical fashion to annotate the whole skeleton. The anatomical trilateration features provide high-level long-range context information that complements the classical local context-based features used in most image segmentation approaches. They rely on anatomical landmarks derived from the previous element of the cascade to express positions relative to reference points. Following a hierarchical approach, large anatomical structures are segmented first, before identifying substructures. We develop this method for bone annotation but also illustrate its performance, although not specifically optimised for it, for multi-organ annotation. Our method achieves average dice scores of 77.4 to 85.6 for bone annotation on three different data sets. It can also segment different organs with sufficient performance for oncological applications, e.g., for PET/CT analysis, and its computation time allows for its use in clinical practice.
Autors: Marie Bieth;Loic Peter;Stephan G. Nekolla;Matthias Eiber;Georg Langs;Markus Schwaiger;Bjoern Menze;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2276 - 2286
Publisher: IEEE
 
» Seismic Random Noise Attenuation Using Synchrosqueezed Wavelet Transform and Low-Rank Signal Matrix Approximation
Abstract:
Random noise elimination acts as an important role in the seismic signal processing. Generally, noise in seismic data can be divided into two categories of coherent and incoherent or random noise. Suppression of wide-band noise which is characterized by random oscillation in seismic data over time is one of the challenging issues in the seismic data processing. This paper describes a new noise suppression algorithm for seismic data denoising. The seismic data, trace-by-trace are transformed into sparse subspace using the synchrosqueezed wavelet transform, then the obtained sparse time-frequency representation is decomposed into semilow-rank and sparse components using the Optshrink algorithm. Finally, the denoised seismic trace can be recovered by back-transforming the semilow-rank component to the time domain using inverse synchrosqueezed wavelet transform. The proposed method is assessed using a single synthetic seismic trace and a synthetic seismic section with two crossover linear and curve events with two discontinuities that are buried in the random noise. We have also evaluated the method using a prestack real seismic data set from an oil field in the southwest of Iran. A comparison is performed between the proposed method and the semisoft GoDec algorithm, classical f-x singular spectrum analysis, and prediction Wiener filter. The results visually and quantitatively confirmed the superiority of the proposed method in contrast to the other well-established noise reduction methods.
Autors: Rasoul Anvari;Mohammad Amir Nazari Siahsar;Saman Gholtashi;Amin Roshandel Kahoo;Mokhtar Mohammadi;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6574 - 6581
Publisher: IEEE
 
» Selecting Power-Efficient Signal Features for a Low-Power Fall Detector
Abstract:
Falls are a serious threat to the health of older people. A wearable fall detector can automatically detect the occurrence of a fall and alert a caregiver or an emergency response service so they may deliver immediate assistance, improving the chances of recovering from fall-related injuries. One constraint of such a wearable technology is its limited battery life. Thus, minimization of power consumption is an important design concern, all the while maintaining satisfactory accuracy of the fall detection algorithms implemented on the wearable device. This paper proposes an approach for selecting power-efficient signal features such that the minimum desirable fall detection accuracy is assured. Using data collected in simulated falls, simulated activities of daily living, and real free-living trials, all using young volunteers, the proposed approach selects four features from a set of ten commonly used features, providing a power saving of 75.3%, while limiting the error rate of a binary classification decision tree fall detection algorithm to 7.1%.
Autors: Changhong Wang;Stephen J. Redmond;Wei Lu;Michael C. Stevens;Stephen R. Lord;Nigel H. Lovell;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2729 - 2736
Publisher: IEEE
 
» Self-Energy Concept for the Numerical Solution of the Liouville-von Neumann Equation
Abstract:
A new numerical approach is presented for the determination of the statistical density matrix as a solution of the Liouville-von Neumann equation in center-mass coordinates. The numerical discretization is performed by utilizing a finite volume method, which leads to a discretized drift and diffusion operator. The solution is based on the eigenvector basis of the discretized diffusion operator with its corresponding eigenvalues and on the introduction of the self-energy concept. More specifically, the self-energy concept is essential to describe open-boundary problems adequately. Furthermore, this approach allows the definition of inflow and outflow conditions. The method presented is investigated with regard to the conventional Wigner transport equation and the quantum transmitting boundary method, when investigating coherent effects.
Autors: Khuram Shahzad Khalid;Lukas Schulz;Dirk Schulz;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1053 - 1061
Publisher: IEEE
 
» Self-Limited CBRAM With Threshold Selector for 1S1R Crossbar Array Applications
Abstract:
In this letter, we demonstrate a self-limited conductive-bridging random access memory (CBRAM) that removes the necessity for external current compliance in a one selector–one resistor (1S1R) architecture. The standard Ge2Sb2Te5 (GST) is used as a CBRAM switching layer. In addition, Te-rich GST is also considered. Their performance is then compared. Both samples exhibit self-limited on-current characteristics, and the on-currents of the standard GST and Te-rich GST are ~300 and , respectively. The observed self-limited characteristics are caused by the Te in the GST layer because in the presence of Te, Cu tends to form a more stable CuTe phase that restrict Cu filament growth. Furthermore, to confirm the feasibility of crossbar array applications, the 1S1R device is evaluated using a Ag/TiO2-based threshold selector device reported in our previous work. Hence, we confirm leakage current reduction, a uniform resistance distribution, and stable retention characteristics in the 1S1R configuration with no external current compliance.
Autors: Jeonghwan Song;Jiyong Woo;Seokjae Lim;Solomon Amsalu Chekol;Hyunsang Hwang;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1532 - 1535
Publisher: IEEE
 
» Self-Regulated Reconfigurable Voltage/Current-Mode Inductive Power Management
Abstract:
A reconfigurable power management structure for inductive power delivery has been proposed by adaptively employing either resonant voltage or current mode (VM or CM) to improve the inductive power transmission performance against coils’ coupling distance (d), orientation (), and load impedance (RL) variations. At the presence of these variations, unlike conventional VM and CM power managements with poor voltage- and power-conversion efficiencies (VCE and PCE), respectively, the proposed voltage/current-mode inductive power management (VCIPM) chip can achieve high VCE by automatically switching to CM when the receiver (Rx) coil voltage (VR) is smaller than the required load voltage (VL), and achieve high PCE by operating in VM when VR > VL. In addition, since VM and CM are only suitable for small and large RL within the range of hundreds of ohms and above, respectively, the VCIPM chip can extend the RL range. The VCIPM chip also eliminates the need for two off-chip capacitors by performing rectification, regulation, and over-voltage protection (OVP) in one step with one off-chip capacitor. In VM, intentional reverse current is employed for both voltage regulation and OVP, while the Rx coil switching frequency (fsw) is adjusted for voltage regulation in CM. The theory behind the proposed VCIPM structure has been presented and validated by simulations and measurements. A VCIPM prototype chip was fabricated in a 0.35- 2P4M standard CMOS process occupying 0.52-mm2 active area. In measurements, the VCIPM chip, operating at 1 MHz, achieved - high VCE of 4.1 V/V for RL of 100 by operating in CM with fsw = 166.6 kHz, and extended d and from 6 to 13.5 cm (125%) and 30° to 75° (150%), respectively, compared to its VM counterpart by adaptively switching from VM to CM.
Autors: Hesam Sadeghi Gougheri;Mehdi Kiani;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Nov 2017, volume: 52, issue:11, pages: 3056 - 3070
Publisher: IEEE
 
» Self-Seeded RSOA Fiber Cavity Laser and the Role of Rayleigh Backscattering—An Analytical Model
Abstract:
Reflective semiconductor optical amplifiers (RSOAs) in a fiber cavity are attractive self-seeding optical sources for wavelength division multiplexed (WDM) access networks. This paper presents an analytical model of this fiber cavity laser (FCL). The model accounts for the Rayleigh backscattering (RB) of the fiber cavity as a primary mechanism of optical feedback inside the FCL. Moreover, it also includes the reflectivity of the remote node mirror. The purpose of the model is to analytically estimate the threshold RSOA gain required for the FCL to lase, by taking into account the fiber cavity length, the related attenuation and the RB. The model is suitable to experimentally characterize the Rayleigh backscattering coefficient, once the threshold gain of RSOA-FCL is measured.
Autors: Dejan M. Gvozdić;Angelina R. Totović;Jasna V. Crnjanski;Marko M. Krstić;Simon A. Gebrewold;Juerg Leuthold;Milan L. Mašanović;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4845 - 4850
Publisher: IEEE
 
» Semantic Development and Integration of Standards for Adoption and Interoperability
Abstract:
Semantic applications can help commercial applications perform quickly and reliably by improving ecosystem interoperability. Converting and integrating current standards specifications to OWL models could support the adoption of semantic models, as well as machine-processable standards compliance and data interoperability.
Autors: Jack Hodges;Kimberly García;Steven Ray;
Appeared in: Computer
Publication date: Nov 2017, volume: 50, issue:11, pages: 26 - 36
Publisher: IEEE
 
» Semisupervised PolSAR Image Classification Based on Improved Cotraining
Abstract:
In order to obtain good classification performance of polarimetric synthetic aperture radar (PolSAR) images, many labeled samples are needed for training. However, it is difficult, expensive, and time-consuming to obtain labeled samples in practice. On the other hand, unlabeled samples are substantially cheaper and more plentiful than labeled ones. In addressing this issue, semisupervised learning techniques are proposed. In this paper, a novel semisupervised algorithm based on an improved cotraining process is proposed for PolSAR image classification. First, we propose an indirect analysis strategy to analyze the nature of sufficiency and independence between two different views for cotraining. Then, an improved cotraining process with a new sample selection strategy is presented, which can effectively take advantage of unlabeled samples to improve the performance of classification, particularly when labeled samples are limited. Finally, a new postprocess method based on a similarity principle and a superpixel algorithm is developed to improve the consistency of the classification. Experimental results on three real PolSAR images show that our proposed method is an effective classification method, and is superior to other traditional methods.
Autors: Wenqiang Hua;Shuang Wang;Hongying Liu;Kun Liu;Yanhe Guo;Licheng Jiao;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4971 - 4986
Publisher: IEEE
 
» Sensing Dynamic Forces by Fe–Ga in Compression
Abstract:
This paper concerns the sensing of dynamic force/stress by means of a measuring system based on the use of an Fe–Ga sample (Galfenol) coupled to a magnetic circuit. The study is focused on the measurement of the effective magnetic field, detected at the rod specimen surface, and its variation under time-dependent applied sinusoidal stress , oscillating at frequencies between 5 and 20 Hz at different values of applied bias field (2.5 kA/m kA/m). For the considered frequency and range, the measured tends to linearly depend on , in contrast with the corresponding induction variation behavior (), where hysteresis effects appear. With in the range of ±15 MPa, we obtain 0.06 MPa resolution in the determination of the alternating stress , a result pointing to the effectiveness and sensitivity of this Galfenol-based method for detection and measurement of time-dependent stresses.
Autors: Mauro Zucca;Pasquale Mei;Enzo Ferrara;Fausto Fiorillo;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Sequential Necessary and Sufficient Conditions for Capacity Achieving Distributions of Channels With Memory and Feedback
Abstract:
We derive sequential necessary and sufficient conditions for any channel input conditional distribution to maximize the finite-time horizon directed information defined by , where , for channel distributions and , where and are the channel input and output random processes, and is a finite non-negative integer. We apply the necessary and sufficient conditions to application examples of time-varying channels with memory to derive recursive closed form expressions of the optimal distributions, which maximize the finite-time horizon directed information. Furthermore, we derive the feedback capacity from the asymptotic properties of the optimal distributions by investigating the limit without any ´ a p- iori assumptions, such as stationarity, ergodicity, or irreducibility of the channel distribution. The framework based on sequential necessary and sufficient conditions can be easily applied to a variety of channels with memory, beyond the ones considered in this paper.
Autors: Photios A. Stavrou;Charalambos D. Charalambous;Christos K. Kourtellaris;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7095 - 7115
Publisher: IEEE
 
» Shaped Beam Synthesis Based on Superposition Principle and Taylor Method
Abstract:
A technique for the synthesis of shaped beam radiation patterns is proposed. The new synthesis method is based on superposition principle and Taylor method. The method may control the sidelobe level of the shaped beam. The approach includes four steps: 1) get the distribution of pencil beam array with low sidelobe by Taylor method; 2) let the beams scan as a phased array to the specific angles according to the requirement of the shaped beam, The sum pattern is close to the shaping beam; 3) determine the value of angles and weights; and 4) count the distribution of the shaped beam array according to the new array factor function. Numerical results are provided to assess the capabilities of the proposed design method. The method develops an effective approach for the synthesis of shaped beams via uniform linear arrays. Both the ripple and sidelobe level of shaped beam may be controlled by the new synthesis method.
Autors: J.-Y. Li;Y.-X. Qi;S.-G. Zhou;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6157 - 6160
Publisher: IEEE
 
» Short- and Long-Term Learning of Feedforward Control of a Myoelectric Prosthesis with Sensory Feedback by Amputees
Abstract:
Human motor control relies on a combination of feedback and feedforward strategies. The aim of this study was to longitudinally investigate artificial somatosensory feedback and feedforward control in the context of grasping with myoelectric prosthesis. Nine amputee subjects performed routine grasping trials, with the aim to produce four levels of force during four blocks of 60 trials across five days. The electrotactile force feedback was provided in the second and third block using multipad electrode and spatial coding. The first baseline and last validation block (open-loop control) evaluated the effects of long- (across sessions) and short-term (within session) learning, respectively. The outcome measures were the absolute error between the generated and target force, and the number of force saturations. The results demonstrated that the electrotactile feedback improved the performance both within and across sessions. In the validation block, the performance did not significantly decrease and the quality of open-loop control (baseline) improved across days, converging to the performance characterizing closed-loop control. This paper provides important insights into the feedback and feedforward processes in prosthesis control, contributing to the better understanding of the role and design of feedback in prosthetic systems.
Autors: Matija Štrbac;Milica Isaković;Minja Belić;Igor Popović;Igor Simanić;Dario Farina;Thierry Keller;Strahinja Došen;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2133 - 2145
Publisher: IEEE
 
» Signal Dependent Transform Based on SVD for HEVC Intracoding
Abstract:
Transform is used to compact the energy of the blocks into a small number of coefficients and is widely used in recent image/video coding standards. In the latest video coding standard high efficiency video coding (HEVC), a combination of discrete cosine transform (DCT) and discrete sine transform (DST) is adopted to transform the residuals from intra prediction. Since the DCT and DST are the fixed transforms that are derived from the Gauss-Markov model, some of residual blocks may not be compacted well by the DCT/DST. In this paper, we propose a signal dependent transform based on singular value decomposition (SVD) for HEVC intracoding. The proposed transform (SDT-SVD) is derived by performing SVD on the synthetic block and applied to the residual block considering the structural similarity between them. Furthermore, we extend SDT-SVD to template matching prediction (TMP) to further improve the intracoding performance. Experimental results show that the proposed transform on angular intra prediction (AIP) outperforms the latest HEVC reference software with a bit rate reduction of 1.0% on average and it can be up to 2.1%. When the proposed transform is extended to TMP-based intracoding, the overall bit rate reduction is 2.7% on average and can be up to 5.8%.
Autors: Tao Zhang;Haoming Chen;Ming-Ting Sun;Debin Zhao;Wen Gao;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2404 - 2414
Publisher: IEEE
 
» Signal Processing Is More than Its Beloved Name [President's Message]
Abstract:
Autors: Rabab Ward;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 5 - 7
Publisher: IEEE
 
» Signals and Signal Processing: The Invisibles and the Everlastings [From the Editor]
Abstract:
Autors: Min Wu;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 4 - 7
Publisher: IEEE
 
» Simple Ears Inspire Frequency Agility in an Engineered Acoustic Sensor System
Abstract:
Standard microphones and ultrasonic devices are generally designed with a static and flat frequency response in order to address multiple acoustic applications. However, they may not be flexible or adaptable enough to deal with some requirements. For instance, when operated in noisy environments such devices may be vulnerable to wideband background noise which will require further signal processing techniques to remove it, generally relying on digital processor units. In this paper, we consider if microphones and ultrasonic devices could be designed to be sensitive only at selected frequencies of interest, whilst also providing flexibility in order to adapt to the different signals of interest and to deal with environmental demands. This research exploits the concept where the “transducer becomes part of the signal processing chain” by exploring feedback processes between mechanical and electrical mechanisms that together can enhance peripheral sound processing. This capability is present within a biological acoustic system, namely in the ears of certain moths. That was used as the model of inspiration for a smart acoustic sensor system which provides dynamic adaptation of its frequency response with amplitude and time dependence according to the input signal of interest.
Autors: José Guerreiro;Joseph C. Jackson;James F. C. Windmill;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7298 - 7305
Publisher: IEEE
 
» Simple High-Performance Metal-Plating Procedure for Stereolithographically 3-D-Printed Waveguide Components
Abstract:
This letter presents a simple and cheap metal-plating procedure for plastic 3-D printed microwave components. The devices are built using a Stereolithographic printer and then metalized by a two-step process consisting in a silver-painted substrate followed by copper electrodeposition. The method achieves good adhesion of the metal to the plastic body and high conductivity. Resonators and -band filters have been fabricated and tested, showing excellent performance in terms of dimensional accuracy and low loss, with quality factors better than 6500. The technique can be usefully employed for fast and cheap prototyping of microwave components at least up to the -band.
Autors: Marco Dionigi;Cristiano Tomassoni;Giuseppe Venanzoni;Roberto Sorrentino;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 953 - 955
Publisher: IEEE
 
» SimRank on Uncertain Graphs
Abstract:
SimRank is a similarity measure between vertices in a graph. Recently, many algorithms have been proposed to efficiently evaluate SimRank similarities. However, the existing algorithms either overlook uncertainty in graph structures or depends on an unreasonable assumption. In this paper, we study SimRank on uncertain graphs. Following the random-walk-based formulation of SimRank on deterministic graphs and the possible world model of uncertain graphs, we first define random walks on uncertain graphs and show that our definition of random walks satisfies Markov’s property. We formulate our SimRank measure based on random walks on uncertain graphs. We discover a critical difference between random walks on uncertain graphs and random walks on deterministic graphs, which makes all existing SimRank computation algorithms on deterministic graphs inapplicable to uncertain graphs. For SimRank computation, we consider computing both single-pair SimRank and single-source top- SimRank. We propose three algorithms, namely the sampling algorithm with high efficiency, the two-phase algorithm with comparable efficiency and higher accuracy, and a speeding-up algorithm with much higher efficiency. Meanwhile, we present an optimized algorithm for efficient computing the single-source top- SimRank. The experimental results verify the effectiveness of our SimRank measure and the efficiency of the proposed SimRank computation algorithms.
Autors: Rong Zhu;Zhaonian Zou;Jianzhong Li;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Nov 2017, volume: 29, issue:11, pages: 2522 - 2536
Publisher: IEEE
 
» Simulating the Canopy Reflectance of Different Eucalypt Genotypes With the DART 3-D Model
Abstract:
Finding suitable models of canopy reflectance in forward simulation mode is a prerequisite for their use in inverse mode to characterize canopy variables of interest, such as leaf area index (LAI) or chlorophyll content. In this study, the accuracy of the three-dimensional reflectance model DART (Discrete Anisotropic Radiative Transfer) was assessed for canopies of different genotypes of Eucalyptus, having distinct biophysical and biochemical characteristics, to improve the knowledge on how these characteristics are influencing the reflectance signal as measured by passive orbital sensors. The first step was to test the model suitability to simulate reflectance images in the visible and near infrared. We parameterized DART model using extensive measurements from Eucalyptus plantations including 16 contrasted genotypes. Forest inventories were conducted and leaf, bark, and forest floor optical properties were measured. Simulation accuracy was evaluated by comparing the mean top of canopy (TOC) bidirectional reflectance of DART with TOC reflectance extracted from a Pleiades very high resolution satellite image. Results showed a good performance of DART with mean reflectance absolute error lower than 2%. Intergenotype reflectance variability was correctly simulated, but the model did not succeed at catching the slight spatial variation for a given genotype, excepted when large gaps appeared due to tree mortality. The second step consisted of sensitivity analysis to explore which biochemical or biophysical characteristics influenced more the canopy reflectance between genotypes. Perspectives for using DART model in inversion mode in these ecosystems were discussed.
Autors: Julianne de Castro Oliveira;Jean-Baptiste Féret;Flávio Jorge Ponzoni;Yann Nouvellon;Jean-Philippe Gastellu-Etchegorry;Otávio Camargo Campoe;José Luiz Stape;Luiz Carlos Estraviz Rodriguez;Guerric le Maire;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4844 - 4852
Publisher: IEEE
 
» Simulating the Effects of Skin Thickness and Fingerprints to Highlight Problems With Non-Invasive RF Blood Glucose Sensing From Fingertips
Abstract:
The non-invasive measurement of blood glucose is a popular research topic where RF/microwave sensing of glucose is one of the promising methods in this area. From the many available measurement sites in the human body, fingertips appear to be a good choice due to a good amount of fresh blood supply and homogeneity in terms of biological layers present. The non-invasive RF measurement of blood glucose relies on the detection of the change in the permittivity of the blood using a resonator as a sensor. However, the change in the permittivity of blood due to the variation in glucose content has a limited range resulting in a very small shift in the sensor’s frequency response. Any inconsistency between measurements may hinder the measurement results. These inconsistencies mostly arise from the varied thickness of the biological layers and variation of fingerprints that are unique to every human. Therefore, the effects of biological layers and fingerprints in fingertips were studied in detail and are reported in this paper.
Autors: Volkan Turgul;Izzet Kale;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7553 - 7560
Publisher: IEEE
 
» Simulation and Analysis of Three-Dimensional Electromagnetism, Heat Transfer, and Gas Flow for Flow-Levitation System
Abstract:
Magnetic levitation systems are influenced by an intense demand to gain greater feature sizes of metal nanoparticles and to increase the production efficiency for the flow-levitation (FL) method. This paper presents a systematic stability and temperature analysis of the process during the induction heating based on ANSYS. The comprehensive model was a liquid aluminum droplet levitated electromagnetically in an axisymmetric magnetic field induced by different sets of coaxial circular coils. First, we developed an optimized coil with a double helix structure to compare the force applied to the sample, electric field distribution, and temperature distribution in the eddy current field with an initial coil structure. The optimized coil has a more stable and efficient induction heating process for the FL method. We also utilized the optimized coil geometry to predict the maximum parameters of the electromagnetic induction system used to fabricate Al nanoparticles. The results from this approach shows that the turns = 2 + 3, D = 24 mm, I = ∼350 A, d = 1∼2 mm, with an equilibrium coefficient k of 0.30, are the maximum and optimal settings in the frequency of 400 kHz induction heating process.
Autors: Xiaoyang Zheng;Jiangshan Luo;Kai Li;Yong Yi;Kai Du;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1106 - 1114
Publisher: IEEE
 
» Simulation of LSPR Sensor Based on Exposed-Core Grapefruit Fiber With a Silver Nanoshell
Abstract:
A localized surface plasmon resonance (LSPR) sensor based on exposed-core grapefruit fiber (EC-GF) with a silver nanoshell (SNS) is presented. The SNS, composed of a dielectric core coated with a thin silver layer, is placed at the exposed section of the EC-GF as the sensing channel to avoid the metal coating, and then deposited with the analyte to avert the liquid filling. Two orthogonal polarized resonance peaks (x-polarized and y-polarized) can be observed due to the birefringence and each polarization exhibits multipolar plasmon resonances, which can realize the cross reference. Due to the good features of the SNS, the position of the LSPR band can be tuned in a broad range, from 2100 to 4020 nm, making the proposed sensor of great importance for biosensing. An extremely high sensitivity 7903.03 nm/RIU is obtained in the sensing range of 1.33-1.42, almost twice as high as the same type works. The influence of the SNS structure on the sensor's performance is also investigated numerically.
Autors: Xianchao Yang;Ying Lu;Baolin Liu;Jianquan Yao;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4728 - 4733
Publisher: IEEE
 
» Simulation-Based Interpretation and Alignment of High-Resolution Optical and SAR Images
Abstract:
The successful alignment of optical and synthetic aperture radar (SAR) satellite data requires that we account for the effects of sensor-specific geometric distortion, which is a consequence of the different imaging concepts of the sensors. This paper introduces SimGeoI, a simulation framework for the object-related interpretation of optical and SAR images, as a solution to this problem. Using metainformation from the images and a digital surface model as input, the processor follows the steps of scene definition, ray tracing, image generation, geocoding, interpretation layer generation, and image part extraction. Thereby, for the first time, object-related sections of optical and SAR images are automatically identified and extracted in world coordinates under consideration of three-dimensional object shapes. A case study for urban scenes in Munich and London, based on WorldView-2 images and high-resolution TerraSAR-X data, confirms the potential of SimGeoI in the context of a perspective-independent and object-focused analysis of high-resolution satellite data.
Autors: Stefan Auer;Isabel Hornig;Michael Schmitt;Peter Reinartz;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4779 - 4793
Publisher: IEEE
 
» Simultaneous Angular Rate Estimates Extracted From a Single Axisymmetric Resonator
Abstract:
An axisymmetric planar microelectromechanical (MEM) resonator resonator is configured, such that the elliptical pair of modes near 13.5kHz, and the pair of modes near 23.8kHz, are both degenerate, i.e., the frequency difference within a given pair of modes is close to the resonance bandwidth. This configuration enables not only the exploitation of the standard elliptical pair of modes for angular rate sensing but also permits the operation of the pair of modes as a high-sensitivity Coriolis vibratory gyro. The performance for each pair of modes separately acting as a vibratory gyro is quantified, however, the control architecture also facilitates the simultaneous operation of both pairs of modes. In this scenario, two measurements of angular rate are extracted from a single resonator and although the short-term rate noise associated with the pair is an order of magnitude larger than the rate extracted from the pair, the long-term drift in the rate offsets are correlated. Thus, a filter architecture for fusing the rate measurements is proposed and it is shown how the derived rate estimate possesses superior offset stability but also retains the low short-term noise associated with the rate measurement from the pair.
Autors: Howard Ge;Robert M’Closkey;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7460 - 7469
Publisher: IEEE
 
» Simultaneous Evaluation of Conductive/Near-Field Noise Suppression in Co-Zr-Nb Film Using Magnetic Circuit
Abstract:
This paper discusses the integrated evaluation of the conductive and near-field noise suppression using magnetic circuit network. The proposed magnetic circuit evaluated the ferromagnetic resonance (FMR) loss and near-field intensity simultaneously and agreed with the measured value. The validity of the evaluation is successfully clarified. It is clarified that the near-field shielding effectiveness is maximized at the intrinsic FMR frequency, because the reluctance of the magnetic film is minimized. It is also clarified that the conductive noise suppression is maximized and the near-field shielding effectiveness is simultaneously minimized at the shifted FMR frequency by the demagnetizing field, because the magnetic circuit resonates. These results demonstrate that the proposed magnetic network model is of great usefulness for developing the integrated design method of the magnetic film-type noise suppressor.
Autors: Sho Muroga;Yasushi Endo;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Simultaneous Optimization of Airspace Congestion and Flight Delay in Air Traffic Network Flow Management
Abstract:
Air traffic flow management (ATFM) aims to facilitate the utilization of airspace and airport resources and is critical in air transportation systems. During the past decades, several challenging problems have arisen from this domain and attracted intensive studies. This paper addresses the problem of alleviating the airspace congestion and reducing the flight delays in ATFM simultaneously. We formulate this problem as a multi-objective air traffic network flow optimization (MATNFO) problem. In this MATNFO model, comprehensive ATFM actions, for instance, ground-holding, airborne-holding, rerouting, and speed control, are considered. Meanwhile, a systematic approach, namely route and time-slot assignment (RTA) algorithm, is developed to solve the MATNFO problem. The idea of divide-and-conquer is embedded in the algorithm by sequentially applying both route searching module and time refinement module. Furthermore, for the sake of efficiency, a pre-selection operator is proposed as one heuristic strategy to identify promising solutions and reduce the search space by defining a sector equilibrium metric. Experiments on real data of the Chinese airspace show that the RTA algorithm outperforms an existing competitor and three related multi-objective evolutionary algorithms. In addition, RTA is competent for high-quality real-time air traffic network flow assignment.
Autors: Kai-Quan Cai;Jun Zhang;Ming-Ming Xiao;Ke Tang;Wen-Bo Du;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3072 - 3082
Publisher: IEEE
 
» Simultaneous Ultrasonic Measurement of Thickness and Speed of Sound in Elastic Plates Using Coded Excitation Signals
Abstract:
Layer thickness and the speed of sound are important parameters for nondestructive testing applications. If one of the parameters is known, the other one can be determined by simple time-of-flight (TOF) measurement of ultrasound. However, often these parameters are both unknown. In this contribution, we examine and adapt ultrasonic imaging techniques using coded excitation signals to simultaneously measure the thickness and the speed of sound of homogeneous elastic plates of unknown material. Good axial resolution is required to measure thin samples. We present a new approach for transmission signal conditioning to improve axial resolution. This conditioning consists of enhancing spectral components that are damped by the transducer prior to transmit. Due to the long duration of coded excitation signals, pulse compression techniques are required for TOF measurements. Common pulse compression filters are discussed, and appropriate filtering of the compression waveform is designed to keep the sidelobe level (SLL) acceptably low. An experimental assessment of the presented measurement techniques reveals that the signal conditioning substantially increases the axial resolution. However, a tapered Wiener filter should be used for the best tradeoff between SLL and axial resolution. We used the proposed method to measure different plates of steel, aluminum, and polymethylmethacrylate of various thicknesses, and the results show very good agreement with the reference values, which we obtained with a micrometer screw and by standard TOF measurement, respectively. The relative error for the plate thickness is smaller than 2.2% and that for the speed of sound is smaller than 3%. It is remarkable that plate thickness could be measured down to 60% of the wavelength.
Autors: Daniel A. Kiefer;Michael Fink;Stefan J. Rupitsch;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1744 - 1757
Publisher: IEEE
 
» Single Sample Fictitious Play
Abstract:
This paper is concerned with distributed learning and optimization in large-scale settings. The well-known fictitious play (FP) algorithm has been shown to achieve Nash equilibrium learning in certain classes of multiagent games. However, FP can be computationally difficult to implement when the number of players is large. Sampled FP (SFP) is a variant of FP that mitigates the computational difficulties arising in FP by using a Monte Carlo (i.e., sampling based) approach. Despite its computational advantages, a shortcoming of SFP is that the number of samples that must be drawn at each iteration grows without bound as the algorithm progresses. In this paper, we propose single sample FP (SSFP)—A variant of SFP in which only one sample needs to be drawn in each round of the algorithm. Convergence of SSFP to the set of Nash equilibria is proven. Simulation results show the performance of SSFP is comparable to that of SFP, despite drawing far fewer samples.
Autors: Brian Swenson;Soummya Kar;João Xavier;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6026 - 6031
Publisher: IEEE
 
» Single-Camera-Based Method for Step Length Symmetry Measurement in Unconstrained Elderly Home Monitoring
Abstract:
Objective: single-camera-based gait monitoring is unobtrusive, inexpensive, and easy-to-use to monitor daily gait of seniors in their homes. However, most studies require subjects to walk perpendicularly to camera's optical axis or along some specified routes, which limits its application in elderly home monitoring. To build unconstrained monitoring environments, we propose a method to measure step length symmetry ratio (a useful gait parameter representing gait symmetry without significant relationship with age) from unconstrained straight walking using a single camera, without strict restrictions on walking directions or routes. Methods: according to projective geometry theory, we first develop a calculation formula of step length ratio for the case of unconstrained straight-line walking. Then, to adapt to general cases, we propose to modify noncollinear footprints, and accordingly provide general procedure for step length ratio extraction from unconstrained straight walking. Results: Our method achieves a mean absolute percentage error (MAPE) of 1.9547% for 15 subjects’ normal and abnormal side-view gaits, and also obtains satisfactory MAPEs for non-side-view gaits (2.4026% for 45°-view gaits and 3.9721% for 30°-view gaits). The performance is much better than a well-established monocular gait measurement system suitable only for side-view gaits with a MAPE of 3.5538%. Conclusion: Independently of walking directions, our method can accurately estimate step length ratios from unconstrained straight walking. Significance: This demonstrates our method is applicable for elders’ daily gait monitoring to provide valuable information for elderly health care, such as abnormal gait recognition, fall risk assessment, etc.
Autors: Xi Cai;Guang Han;Xin Song;Jinkuan Wang;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2618 - 2627
Publisher: IEEE
 
» Single-Layered Circularly Polarized Substrate-Integrated Waveguide Horn Antenna Array
Abstract:
In this communication, a circularly polarized (CP) substrate-integrated waveguide horn antenna is proposed and studied. The CP horn antenna is implemented on a single-layer substrate with a thickness of at the center frequency (1.524 mm) for 24 GHz system applications. It comprises of an integrated phase controlling and power dividing structure, two waveguide antennas, and an antipodal linearly tapered slot antenna. With such a phase controlling and power dividing structure fully integrated inside the horn antenna, two orthogonal electric fields of the equal amplitude with 90° phase difference are achieved at the aperture plane of the horn antenna, thus, yielding an even effective circular polarization in a compact single-layered geometry. The measured results of the prototyped horn antenna exhibit a 5% bandwidth (23.7–24.9 GHz) with an axial ratio below 3 dB and a VSWR below 2. The gain of the antenna is around 8.5 dBi.
Autors: Yifan Yin;Behnam Zarghooni;Ke Wu;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6161 - 6166
Publisher: IEEE
 
» Single-Source Multiple-Coil Homogeneous Induction Heating
Abstract:
This paper proposes and implements an approach to achieve homogeneous heating in a single-source multiple-coil induction heating system. In a traditional induction heating system, one of the key disadvantages is the inhomogeneous heating effect. In particular, the heating power concentrates on a small ring area of the pan, while the outer part receives much lower power. The proposed induction heating system consists of two concentric coils with its compensated capacitors connecting in series, respectively. Currents in the two coils are controlled by newly employing the magnetic resonant coupling mechanism so that the heating power distribution in the inner and outer parts of the pan can be adjusted accordingly. Therefore, the proposed induction heating can achieve homogeneity and simplicity simultaneously by optimizing the operating frequency of only one inverter. Both the simulation and experimental results are given to validate the feasibility of the proposed homogeneous induction heating.
Autors: Wei Han;K. T. Chau;Zhen Zhang;Chaoqiang Jiang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Single-Turn Magnet With an Additional Balanced Winding and Flux Concentrators
Abstract:
The balanced winding displaced in the cavity, the magnet provides the possibility for obtaining the stronger magnet field without enhancing mechanical stresses in the conductors. The model of such a system is the single-turn magnet with an additional triple-thread spiral winding. The equilibrium condition with respect to the radial force takes place at definite values of the axial current and pitch of the turns. In order to decrease the transverse field provoking the azimuthal force, the correction system in the form of cylindrical conductors with slits has been used. The discharging of the end part of the additional winding from the axial force is achieved using the flat concentrators of the flux.
Autors: German Abramovich Shneerson;Kirill Alexandrovich Danilin;Alexey Pavlovich Nenashev;Anatoly Alexeevich Parfentiev;Artem Anatolievich Pozdeev;Dmitry Alexandrovich Dyogtev;Dmitry Petrov;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 3038 - 3041
Publisher: IEEE
 
» SiRF 2018 [RWW]
Abstract:
Presents information on the SiRF 2018 conference.
Autors: Dietmar Kissinger;
Appeared in: IEEE Microwave Magazine
Publication date: Nov 2017, volume: 18, issue:7, pages: 23 - 104
Publisher: IEEE
 
» Site Preference and Hyperfine Structure in Doped Z-Type Hexaferrite Ba1.5Sr1.5Co2(Fe1–xAlx)24O41 Investigated by Mössbauer Spectroscopy
Abstract:
The Ba1.5Sr1.5Co2(Fe1–xAlx)24O41 (x = 0, 0.01, 0.03, and 0.05) polycrystalline samples were synthesized by the polymerizable complex method. Based on the Rietveld refinement, the crystal structures of samples were found to be single phased and determined to be rhombohedral with space group of P63/mmc. The hysteresis curves of these samples were measured under 20 kOe at 295 K, showing that they were not saturated with increasing Al ion contents because spin structure was modified due to the reduction of magnetic anisotropy. With increasing Al ions contents, the value of M20kOe decreases due to the preferential occupation of non-magnetic Al ions in the up-spin site, while Hc increases. The Mössbauer spectra of the samples were obtained at 295 K, and analyzed as six distinguishable sextets (4f, 4f, 12k, 4f, 12k, and 2d) below due to the superposition of ten sextets of Fe sites corresponding to the Z-type hexagonal ferrite. The occupation number of up-spin site decreases with increasing Al ions. This suggests that the Al ions preferentially occupy the tetrahedral sublattices, leading to decrease in .
Autors: Jung Tae Lim;Chul Sung Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Sizing Optimization of the Synchronous Generator and the Measurement Uncertainty Analysis
Abstract:
This paper discusses the design process of a generator to utilize waste diesel engines in the automotive industry, and presents the results of the design, analysis, and test evaluation of a 78 kW permanent magnet synchronous generator. In the initial design process using the finite-element analysis and space harmonic analysis, the number of poles and slots was determined. Then, the generator characteristics were investigated by the torque per rotor unit volume method and the , -axis equivalent circuit. Last, the optimal size of the generator was determined. This process makes it possible to design in consideration of efficiency, inductance, material cost, and temperature characteristics. A prototype of the model was created and tested with uncertainty analysis, and a comparison between the experimental results and the results of the optimization was conducted to validate the analytic approach.
Autors: Youn-Hwan Kim;Hae-Joong Kim;Sang-Yong Jung;Jae-Won Moon;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 8
Publisher: IEEE
 
» Sketch-Based Articulated 3D Shape Retrieval
Abstract:
Sketch-based queries are a suitable and superior alternative to traditional text- and example-based queries for 3D shape retrieval. The authors developed an articulated 3D shape retrieval method that uses easy-to-obtain 2D sketches. In contrast to existing sketch-based retrieval systems that lower the 3D database models to 2D, their algorithm implicitly lifts the 2D query to 2.5D by inferring depth information from possibly self-intersecting sketches using a good continuation rule. It does not require 3D example models to initiate queries, but results show that it achieves accuracy comparable to a state-of-the-art example-based 3D shape retrieval method.
Autors: Yusuf Sahillioğlu;Metin Sezgin;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 88 - 101
Publisher: IEEE
 
» Slack Inspection Method of High-Tension Bolt Using Electromagnetic Field Without Influence of Lift-Off Between Bolt Head and Inspection Sensor
Abstract:
In the automobile industry, the simple inspection method of detecting the slack of the high-tension bolt in the engine section is desired. Since the permeability of the compression direction inside the steel is decreased when the steel material is compressed, the permeability of the compressed domain in the bolt is decreased when the fastened force of the bolt is increased. Therefore, the evaluation of the slack of the bolt is possible by detecting the difference of the magnetic characteristics near the compressed position in the bolt. However, the detection signal is also influenced by the change of distance (lift-off) between the bolt and an electromagnetic sensor. In this paper, the inspection method for measuring the slack of the bolt taking account of the lift-off is proposed using the 3-D edge-based hexahedral nonlinear finite element method and the experimental verification.
Autors: Yuji Gotoh;Nozomi Shigematsu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Small Curvature Sensor Based on Butterfly-Shaped Mach–Zehnder Interferometer
Abstract:
A novel and small curvature sensor based on the butterfly-shaped Mach–Zehnder interferometer is proposed and experimentally demonstrated. The sensing element is a tapered hollow-core fiber sandwiched between two single-mode fibers. The fusion-collapsed region around the first fusion interface excites the high-order modes, and the butterfly-shaped structure couples the high-order modes back into the core and interferes with the fundamental mode in the second fusion-collapsed interface. Simulation of the butterfly-shaped structure is carried out by the beam propagation method to determine an optimized size of sensing element. The experimental results show that the light intensity variation of the interference spectrum is almost linearly proportional to the change of curvature, and the curvature sensitivity and resolution of the proposed sensor can be up to −10.9041 dB/m−1 and 0.000917 m−1, respectively, in the range from 0.387 to 1.285 m−1. The proposed curvature sensor is compact in size, high sensitive, and inexpensive. The excellent electromagnetic interference resistance and fabrication simplicity make the device an attractive candidate for curvature measurement in harsh environments.
Autors: Yong Zhao;Mao-qing Chen;Feng Xia;Lu Cai;Xue-Gang Li;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4644 - 4649
Publisher: IEEE
 
» Small-Signal Model for 2D-Material Based FETs Targeting Radio-Frequency Applications: The Importance of Considering Nonreciprocal Capacitances
Abstract:
A small-signal equivalent circuit of 2D-material based FETs is presented. Charge conservation and nonreciprocal capacitances have been assumed, so the model can be used to make reliable predictions at both device and circuit levels. In this context, explicit and exact analytical expressions of the main radio-frequency figures of merit of these devices are given. Moreover, a direct parameter extraction methodology is provided based on S-parameter measurements. In addition to the intrinsic capacitances, transconductance and output conductance, our approach allows extracting the series combination of drain–source metal contact and access resistances. Accounting for these extrinsic resistances is of upmost importance when dealing with low dimensional FETs.
Autors: Francisco Pasadas;Wei Wei;Emiliano Pallecchi;Henri Happy;David Jiménez;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4715 - 4723
Publisher: IEEE
 
» Smart Grid Simulations and Their Supporting Implementation Methods
Abstract:
In this tutorial we present the state-of-the-art as well as new methods for simulating various planning, operation, stability, reliability, and economic models of electric power systems. The discussion is driven by both first-principle models and empirical models. First-principle models result from the fundamental physics and engineering principles that govern the behavior of various components of a grid. Empirical models, on the other hand, are models that result from statistics and data analysis. We overview a wide spectrum of applications starting from planning models with a time-scale of simulation in years to real-time models where the time-scale can be in the order of milliseconds. We present a list of simulation software popularly used by the power engineering research community across the world. The increasingly important roles of power electronics, communication and computing, model aggregation, hybrid simulation, faster-than-real-time simulation, and co-simulation in emulating the daily operation of a grid are enumerated. The importance of research testbeds for testing, verification and validation of complex grid models at various temporal and spatial scales is also highlighted. The overall goal is to provide a vision on how simulations and their supporting implementation methods can help us in understanding the evolving behavior of tomorrow’s power networks as a truly intelligent cyber-physical system.
Autors: Aranya Chakrabortty;Anjan Bose;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2220 - 2243
Publisher: IEEE
 
» Smartphone-Based Gait Recognition: From Authentication to Imitation
Abstract:
This work evaluates the security strength of a smartphone-based gait recognition system against zero-effort and live minimal-effort impersonation attacks under realistic scenarios. For this purpose, we developed an Android application, which uses a smartphone-based accelerometer to capture gait data continuously in the background, but only when an individual walks. Later, it analyzes the recorded gait data and establishes the identity of an individual. At first, we tested the performance of this system against zero-effort attacks by using a dataset of 35 participants. Later, live impersonation attacks were performed by five professional actors who are specialized in mimicking body movements and body language. These attackers were paired with their physiologically close victims, and they were given live audio and visual feedback about their latest impersonation attempt during the whole experiment. No false positives under impersonation attacks, indicate that mimicry does not improve chances of attackers being accepted by our gait authentication system. In 29 percent of total impersonation attempts, when attackers walked like their chosen victim, they lost regularity between their steps which makes impersonation even harder for attackers.
Autors: Muhammad Muaaz;René Mayrhofer;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3209 - 3221
Publisher: IEEE
 
» Snowpack Density Retrieval Using Fully Polarimetric TerraSAR-X Data in the Himalayas
Abstract:
This paper focuses on the development of a novel algorithm for deriving snowpack density over the snow-covered region of the Himalayas. The analysis utilizes fully polarimetric TerraSAR-X synthetic aperture radar data sets, field observations, and other ancillary information for the retrieval of snowpack density. The algorithm involves the development of a new generalized hybrid decomposition model. The generalized volume scattering parameter from the decomposition model is inverted for snow density estimation. A few field data measurements’ campaigns were carried out, within near-real time of satellite passing over the area, to collect various parameters such as temperature, water content, and the density of the snowpack at varying depths. These field observations are further used for validation of the results obtained from the inversion algorithm. It is also found that the model-estimated snowpack density is highly congruent with the field-measured snowpack density. The mean absolute error of snowpack density, root-mean-square error, and index of agreement are found to be 9.9 kg/, 10 kg/, and 0.96, respectively, which are well within the acceptable range.
Autors: Gulab Singh;Ashutosh Verma;Sanjeev Kumar; Snehmani;Ashwagosha Ganju;Yoshio Yamaguchi;Anil V. Kulkarni;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6320 - 6329
Publisher: IEEE
 
» Social-Aware Rate Based Content Sharing Mode Selection for D2D Content Sharing Scenarios
Abstract:
Device-to-device (D2D) content sharing has become a promising solution to support the growing popularity of multimedia contents for local services. Considering the randomness of content location, the limited storage and transmission capability of devices, and the coexistence of altruistic and selfish user behaviors, how to optimally match the demanders to the providers of contents and how to stimulate an efficient cooperation are of importance for achieving the full benefits of D2D content sharing. Especially when the base-station-to-device (B2D), D2D, and novel multi-D2D sharing modes coexist, the issue of content sharing mode selection plays the predominant role in such matching. In this paper, we introduce a notion of social-aware rate, which combines the social selfishness from the social knowledge with the link rate to ensure the physical link quality and the effective cooperation together. Then, the social-aware rate-based content sharing mode selection problem is modeled as a maximum weighted mixed matching problem, which can be computationally reduced to a submodular welfare problem subject to a matroid constraint. Subsequently, we develop a best-effort distributed algorithm framework, which displays alternatives of various computation complexities and approximation ratios to satisfy the diverse practical needs.
Autors: Dan Wu;Liang Zhou;Yueming Cai;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2571 - 2582
Publisher: IEEE
 
» Soft Magnetic Properties of Thin Nanocrystalline Particles Due to the Interplay of Random and Coherent Anisotropies
Abstract:
We investigated coercive fields of 200 nm nm nm rectangular nanocrystalline thin films as a function of grain size using finite-element simulations. To this end, we created granular finite-element models with grain sizes ranging from 5 to 60 nm, and performed micromagnetic hysteresis calculations along the -axis (easy direction) as well as along the -axis (hard direction). We then used an extended random anisotropy model to interpret the results and to illustrate the interplay of random anisotropy and shape-induced anisotropy, which is coherent on a much larger scale, in thin films.
Autors: Anton Bachleitner-Hofmann;Bernhard Bergmair;Thomas Schrefl;Armin Satz;Dieter Suess;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Soft Prosthetic Forefinger Tactile Sensing via a String of Intact Single Mode Optical Fiber
Abstract:
We report a prosthetic forefinger with distributed tactile sensing capability based on an embedded single mode fiber (SMF) sensor. We developed a human-size prosthetic forefinger by using soft silicon rubber via a fast wax-casting procedure. A strand of SMF was directly embedded along the palmar side of the prosthetic forefinger. For the first time to our knowledge, an SMF sensor is embedded in a soft silicon rubber-made prosthetic forefinger for distributed tactile sensing that eases the fabrication processes and affords judicious way in large-area, high-resolution applications. Our tactile sensor is interrogated with a distributed Rayleigh backscattering-based optical frequency domain reflectometry system. A series of experiments were conducted to verify the proposed tactile sensor. The reported soft silicon rubber-made prosthetic forefinger with built-in fiber optic sensors opens up promising possibilities for the development of sensing abilities and feedback strategies in artificial intelligence.
Autors: Yang Du;Qingbo Yang;Jie Huang;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7455 - 7459
Publisher: IEEE
 
» Software Toolbox for Low-Frequency Conductivity and Current Density Imaging Using MRI
Abstract:
Objective: Low-frequency conductivity and current density imaging using MRI includes magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DT-MREIT), conductivity tensor imaging (CTI), and magnetic resonance current density imaging (MRCDI). MRCDI and MREIT provide current density and isotropic conductivity images, respectively, using current-injection phase MRI techniques. DT-MREIT produces anisotropic conductivity tensor images by incorporating diffusion weighted MRI into MREIT. These current-injection techniques are finding clinical applications in diagnostic imaging and also in transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), and electroporation where treatment currents can function as imaging currents. To avoid adverse effects of nerve and muscle stimulations due to injected currents, conductivity tensor imaging (CTI) utilizes B1 mapping and multi-b diffusion weighted MRI to produce low-frequency anisotropic conductivity tensor images without injecting current. This paper describes numerical implementations of several key mathematical functions for conductivity and current density image reconstructions in MRCDI, MREIT, DT-MREIT, and CTI. Methods: To facilitate experimental studies of clinical applications, we developed a software toolbox for these low-frequency conductivity and current density imaging methods. This MR-based conductivity imaging (MRCI) toolbox includes 11 toolbox functions which can be used in the MATLAB environment. Results: The MRCI toolbox is available at http://iirc.khu.ac.kr/software.html . Its functions were tested by using several experimental datasets, which are provided together with the toolbox. Conclusion: Users of the toolbox can focus on experimental designs and interpretations of reconstructed images instead of developing their own image reconstruction softwares. We expect more toolbox functions to be added from future research outcomes.
Autors: Saurav Z. K. Sajib;Nitish Katoch;Hyung Joong Kim;Oh In Kwon;Eung Je Woo;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2505 - 2514
Publisher: IEEE
 
» Solar Photovoltaic and Thermal Energy Systems: Current Technology and Future Trends
Abstract:
Solar systems have become very competitive solutions for residential, commercial, and industrial applications for both standalone and grid connected operations. This paper presents an overview of the current status and future perspectives of solar energy (mainly photovoltaic) technology and the required conversion systems. The focus in the paper is put on the current technology, installations challenges, and future expectations. Various aspects related to the global solar market, the photovoltaic (PV) modules cost and technology, and the power electronics converter systems are addressed. Research trends and recommendations for each of the PV system sectors are also discussed.
Autors: Mariusz Malinowski;Jose I. Leon;Haitham Abu-Rub;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2132 - 2146
Publisher: IEEE
 
» Solving the 5G Mobile Antenna Puzzle: Assessing Future Directions for the 5G Mobile Antenna Paradigm Shift
Abstract:
Advances in antenna technologies for cellular hand-held devices have been synchronous with the evolution of mobile phones over nearly 40 years. Having gone through four major wireless evolutions [1], [2], starting with the analog-based first generation to the current fourth-generation (4G) mobile broadband, technologies from manufacturers and their wireless network capacities today are advancing at unprecedented rates to meet our unrelenting service demands. These ever-growing demands, driven by exponential growth in wireless data usage around the globe [3], have gone hand in hand with major technological milestones achieved by the antenna design community. For instance, realizing the theory regarding the physical limitation of antennas [4]-[6] was paramount to the elimination of external antennas for mobile phones in the 1990s. This achievement triggered a variety of revolutionary mobile phone designs and the creation of new wireless services, establishing the current cycle of cellular advances and advances in mobile antenna technologies.
Autors: Wonbin Hong;
Appeared in: IEEE Microwave Magazine
Publication date: Nov 2017, volume: 18, issue:7, pages: 86 - 102
Publisher: IEEE
 
» SonoNet: Real-Time Detection and Localisation of Fetal Standard Scan Planes in Freehand Ultrasound
Abstract:
Identifying and interpreting fetal standard scan planes during 2-D ultrasound mid-pregnancy examinations are highly complex tasks, which require years of training. Apart from guiding the probe to the correct location, it can be equally difficult for a non-expert to identify relevant structures within the image. Automatic image processing can provide tools to help experienced as well as inexperienced operators with these tasks. In this paper, we propose a novel method based on convolutional neural networks, which can automatically detect 13 fetal standard views in freehand 2-D ultrasound data as well as provide a localization of the fetal structures via a bounding box. An important contribution is that the network learns to localize the target anatomy using weak supervision based on image-level labels only. The network architecture is designed to operate in real-time while providing optimal output for the localization task. We present results for real-time annotation, retrospective frame retrieval from saved videos, and localization on a very large and challenging dataset consisting of images and video recordings of full clinical anomaly screenings. We found that the proposed method achieved an average F1-score of 0.798 in a realistic classification experiment modeling real-time detection, and obtained a 90.09% accuracy for retrospective frame retrieval. Moreover, an accuracy of 77.8% was achieved on the localization task.
Autors: Christian F. Baumgartner;Konstantinos Kamnitsas;Jacqueline Matthew;Tara P. Fletcher;Sandra Smith;Lisa M. Koch;Bernhard Kainz;Daniel Rueckert;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2204 - 2215
Publisher: IEEE
 
» Spaceborne Observations of the Diurnal Variation of Shortwave Aerosol Direct Radiative Effect at Top of Atmosphere Over the Dust-Dominated Arabian Sea and the Atlantic Ocean
Abstract:
The ScaRaB payload onboard the low-inclination Megha-Tropiques (MT) satellite has been making observations of radiative fluxes at the top of the atmosphere (TOA) for different local times (LTs) of the day over the tropics since October 2011. This provides a unique opportunity to investigate the diurnal variation of the regional instantaneous aerosol direct radiative effect efficiency (IADREE) at TOA, which is otherwise not possible using the available long-term satellite observations carried out using similar sensors onboard polar sun-synchronous satellites. In this paper, the diurnal variations of the IADREE over the Arabian Sea and the Atlantic Ocean during June–September, when both these regions are engulfed by large-scale mineral dust plumes transported from the adjoining deserts, are investigated using collocated multiyear (2012–2014) observations of the MT-ScaRaB measured shortwave fluxes and MODIS-derived aerosol optical depth. The estimates of the IADREE made using the MT-ScaRaB data at 13:30 LT are found to be in agreement with those derived from the Cloud and the Earth’s Radiant Energy System data at this LT, at which the latter observations are carried out. The IADREE derived from the MT-ScaRaB shows diurnal peak value of −53 ± 10 Wm and −40 ± 3 Wm at solar zenith angle of ~40° over the Arabian Sea and the Atlantic Ocean, respectively. Diurnal mean aerosol direct radiative effect efficiency at TOA during June–September is −22 ± 4.5 Wm over the Arabian Sea and −18 ± 3.6 Wm over the Atlantic Ocean.
Autors: Manoj Kumar Mishra;Ashok Kumar Gupta;K. Rajeev;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6610 - 6616
Publisher: IEEE
 
» SPACF: A Secure Privacy-Preserving Authentication Scheme for VANET With Cuckoo Filter
Abstract:
Vehicular ad-hoc networks (VANETs) have been emerging based on the state-of-art technologies in wireless and network communications. The message authentications between vehicles and roadside units are essential for the security of VANETs. Messages should be signed and verified before they could be trusted. The real identity of vehicles should not be revealed, but which is only traceable by authorized parties. Existing solutions either rely heavily on a tamper-proof hardware device or cannot satisfy the security requirement. Communication overhead as another issue has also not been well addressed in previously reported studies. To address these issues, in this paper, we propose the SPACF scheme that is based on software without relying on any special hardware. We use the Cuckoo filter and the binary search methods to achieve higher success rate than the previous schemes in the batch verification phase. In order to guarantee that it can satisfy message authentication requirement, existential unforgeability of underlying signature against adaptively chosen-message attack is proved under the elliptic curve discrete logarithm problem in the random oracle model. The evaluation results show that our proposed scheme is more efficient than the previous schemes since it is pairing free and does not use map-to-point hash functions, and it satisfies security and privacy requirements of vehicular ad hoc networks.
Autors: Jie Cui;Jing Zhang;Hong Zhong;Yan Xu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10283 - 10295
Publisher: IEEE
 
» Sparse Array Quiescent Beamformer Design Combining Adaptive and Deterministic Constraints
Abstract:
In this paper, we examine sparse array quiescent beamforming for multiple sources in interference-free environment. To maximize the output signal-to-noise ratio (SNR), the beamformer design comprises two intertwined stages, the determination of beamforming weights and the reconfiguration of array structure. The SNR maximization may produce high sidelobe levels, making the receiver vulnerable to interferences. We consider the problem of achieving maximum SNR beamforming subject to specified quiescent pattern constraints and, as such, combine both adaptive and deterministic approaches for sparse array configurations. We employ two convex relaxation methods and an iterative linear fractional programming algorithm to solve the nonconvex antenna selection problem for sparse array beamformers. Simulation examples demonstrate that the array configuration plays a vital role in determining the beamforming performance in interference-free scenarios.
Autors: Xiangrong Wang;Moeness Amin;Xianghua Wang;Xianbin Cao;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5808 - 5818
Publisher: IEEE
 
» Sparse Bayesian Learning-Based Seismic Denoise by Using Physical Wavelet as Basis Functions
Abstract:
Attenuating random noise is a fundamental yet necessary step for subsequent seismic image processing and interpretation. We introduce a sparse Bayesian learning (SBL)-based seismic denoise method by using the physical wavelet as the basis function. The physical wavelet estimated from seismic and well logging data can appropriately describe the characteristics of the seismic data. Thus, it is an appropriate choice of basis function. Moreover, the tradeoff regularization parameter for determining denoise quality can be adaptively estimated according to the updated data misfit and sparseness degree during the iterative process of the SBL algorithm. The motivation behind the denoise method using sparse representations is that seismic signals can be sparsely represented by using several physical wavelets, whereas noise cannot. Both synthetic and real seismic data examples are adopted to demonstrate the effectiveness of the method.
Autors: Li Deng;Sanyi Yuan;Shangxu Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1993 - 1997
Publisher: IEEE
 
» Sparse Bayesian Learning-Based Time-Variant Deconvolution
Abstract:
In seismic exploration, the wavelet-filtering effect and -filtering (amplitude attenuation and velocity dispersion) effect blur the reflection image of subsurface layers. Therefore, both wavelet- and -filtering effects should be reduced to retrieve a high-quality subsurface image, which is significant for fine reservoir interpretation. We derive a nonlinear time-variant convolution model to sparsely represent nonstationary seismograms in time domain involving these two effects and present a time-variant deconvolution (TVD) method based on sparse Bayesian learning (SBL) to solve the model to obtain a high-quality reflectivity image. The SBL-based TVD essentially obtains an optimum posterior mean of the reflectivity image, which is regarded as the inverted reflectivity result, by iteratively solving a Bayesian maximum posterior and a type-II maximum likelihood. Because a hierarchical Gaussian prior for reflectivity controlled by model-dependent hyper-parameters is adopted to approximately represent the fact that reflectivity is sparse, SBL-based TVD can retrieve a sparse reflectivity image through the principled sequential addition and deletion of -dependent time-variant wavelets. In general, strong reflectors are acquired relatively earlier, whereas weak reflectors and deep reflectors are imaged later. The method has the capacity to avoid false artifacts represented by sequential positive or negative reflectivity spikes with short two-way travel time, which typically occur within stationary deconvolution outcomes. Synthetic, laboratorial, and field data examples are used to demonstrate the effectiveness of the method and illustrate its advantages over SBL-based stationary deconvolution and TVD using an -norm or an -norm regularization. The results show that SBL-based TVD is a potentially effective, stable, and high-quality imaging tool.
Autors: Sanyi Yuan;Shangxu Wang;Ming Ma;Yongzhen Ji;Li Deng;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6182 - 6194
Publisher: IEEE
 
» Sparse Distributed Multitemporal Hyperspectral Unmixing
Abstract:
Blind hyperspectral unmixing jointly estimates spectral signatures and abundances in hyperspectral ima-ges (HSIs). Hyperspectral unmixing is a powerful tool for analyzing hyperspectral data. However, the usual huge size of HSIs may raise difficulties for classical unmixing algorithms, namely, due to limitations of the hardware used. Therefore, some researchers have considered distributed algorithms. In this paper, we develop a distributed hyperspectral unmixing algorithm that uses the alternating direction method of multipliers and sparse regularization. The hyperspectral unmixing problem is split into a number of smaller subproblems that are individually solved, and then the solutions are combined. A key feature of the proposed algorithm is that each subproblem does not need to have access to the whole HSI. The algorithm may also be applied to multitemporal HSIs with due adaptations accounting for variability that often appears in multitemporal images. The effectiveness of the proposed algorithm is evaluated using both simulated data and real HSIs.
Autors: Jakob Sigurdsson;Magnus O. Ulfarsson;Johannes R. Sveinsson;José M. Bioucas-Dias;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6069 - 6084
Publisher: IEEE
 
» Spatial Downscaling of SMAP Soil Moisture Using MODIS Land Surface Temperature and NDVI During SMAPVEX15
Abstract:
The Soil Moisture Active Passive (SMAP) mission provides a global surface soil moisture (SM) product at 36-km resolution from its L-band radiometer. While the coarse resolution is satisfactory to many applications, there are also a lot of applications which would benefit from a higher resolution SM product. The SMAP radiometer-based SM product was downscaled to 1 km using Moderate Resolution Imaging Spectroradiometer (MODIS) data and validated against airborne data from the Passive Active L-band System instrument. The downscaling approach uses MODIS land surface temperature and normalized difference vegetation index to construct soil evaporative efficiency, which is used to downscale the SMAP SM. The algorithm was applied to one SMAP pixel during the SMAP Validation Experiment 2015 (SMAPVEX15) in a semiarid study area for validation of the approach. SMAPVEX15 offers a unique data set for testing SM downscaling algorithms. The results indicated reasonable skill (root-mean-square difference of 0.053 m3/m3 for 1-km resolution and 0.037 m3/m3 for 3-km resolution) in resolving high-resolution SM features within the coarse-scale pixel. The success benefits from the fact that the surface temperature in this region is controlled by soil evaporation, the topographical variation within the chosen pixel area is relatively moderate, and the vegetation density is relatively low over most parts of the pixel. The analysis showed that the combination of the SMAP and MODIS data under these conditions can result in a high-resolution SM product with an accuracy suitable for many applications.
Autors: Andreas Colliander;Joshua B. Fisher;Gregory Halverson;Olivier Merlin;Sidharth Misra;Rajat Bindlish;Thomas J. Jackson;Simon Yueh;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2107 - 2111
Publisher: IEEE
 
» Spatial Group Sparsity Regularized Nonnegative Matrix Factorization for Hyperspectral Unmixing
Abstract:
In recent years, blind source separation (BSS) has received much attention in the hyperspectral unmixing field due to the fact that it allows the simultaneous estimation of both endmembers and fractional abundances. Although great performances can be obtained by the BSS-based unmixing methods, the decomposition results are still unstable and sensitive to noise. Motivated by the first law of geography, some recent studies have revealed that spatial information can lead to an improvement in the decomposition stability. In this paper, the group-structured prior information of hyperspectral images is incorporated into the nonnegative matrix factorization optimization, where the data are organized into spatial groups. Pixels within a local spatial group are expected to share the same sparse structure in the low-rank matrix (abundance). To fully exploit the group structure, image segmentation is introduced to generate the spatial groups. Instead of a predefined group with a regular shape (e.g., a cross or a square window), the spatial groups are adaptively represented by superpixels. Moreover, the spatial group structure and sparsity of the abundance are integrated as a modified mixed-norm regularization to exploit the shared sparse pattern, and to avoid the loss of spatial details within a spatial group. The experimental results obtained with both simulated and real hyperspectral data confirm the high efficiency and precision of the proposed algorithm.
Autors: Xinyu Wang;Yanfei Zhong;Liangpei Zhang;Yanyan Xu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6287 - 6304
Publisher: IEEE
 
» Spatial Power Combiner With Low-Impedance Inputs and Increased Isolation
Abstract:
A 2.5-, 8-way, 1–6 GHz spatial power combiner with increased isolation is presented. Insertion losses are better than 1.8 dB on the 1–6 GHz, except on a few peaks. Isolation is better than −10 dB for 45° inputs pairs and better than −15 dB for other pairs. This power combiner provides wide bandwidth, high isolation, and low input impedance at the same time.
Autors: Hadrien Theveneau;Christophe Gaquière;Romain Lenglet;Matthieu Werquin;Jean-Christophe Joly;Stèphane Tortel;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 956 - 958
Publisher: IEEE
 
» Spatial-Aware Hierarchical Collaborative Deep Learning for POI Recommendation
Abstract:
Point-of-interest (POI) recommendation has become an important way to help people discover attractive and interesting places, especially when they travel out of town. However, the extreme sparsity of user-POI matrix and cold-start issues severely hinder the performance of collaborative filtering-based methods. Moreover, user preferences may vary dramatically with respect to the geographical regions due to different urban compositions and cultures. To address these challenges, we stand on recent advances in deep learning and propose a Spatial-Aware Hierarchical Collaborative Deep Learning model (SH-CDL). The model jointly performs deep representation learning for POIs from heterogeneous features and hierarchically additive representation learning for spatial-aware personal preferences. To combat data sparsity in spatial-aware user preference modeling, both the collective preferences of the public in a given target region and the personal preferences of the user in adjacent regions are exploited in the form of social regularization and spatial smoothing. To deal with the multimodal heterogeneous features of the POIs, we introduce a late feature fusion strategy into our SH-CDL model. The extensive experimental analysis shows that our proposed model outperforms the state-of-the-art recommendation models, especially in out-of-town and cold-start recommendation scenarios.
Autors: Hongzhi Yin;Weiqing Wang;Hao Wang;Ling Chen;Xiaofang Zhou;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Nov 2017, volume: 29, issue:11, pages: 2537 - 2551
Publisher: IEEE
 
» Spatially Adaptive Sparse Representation for Target Detection in Hyperspectral Images
Abstract:
As sparse representation gradually obtains better and better results in the analysis of hyperspectral imagery and sparsity-based algorithms are becoming more and more popular, especially in target detection. However, these methods mostly assume an absolute equal contribution by all neighboring pixels while detecting the central pixel. There is no doubt that this approach is unsuitable for pixels located in heterogeneous areas. In this letter, to address this problem, spatially adaptive sparse representation for target detection in hyperspectral images (HSIs) is proposed. Neighboring spatial information is utilized by considering the different contributions of the distinct neighborhood pixels. The different weights are determined according to the similarity between the neighboring pixels and the central test pixel. The proposed algorithm was tested on two HSIs and demonstrated outstanding detection performance when compared with other commonly used detectors.
Autors: Yiming Zhang;Bo Du;Yuxiang Zhang;Liangpei Zhang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1923 - 1927
Publisher: IEEE
 
» Spatially Consistent Street-by-Street Path Loss Model for 28-GHz Channels in Micro Cell Urban Environments
Abstract:
This paper considers a fundamental issue of path loss (PL) modeling in urban micro cell (UMi) environments, namely the spatial consistency of the model as the mobile station moves along a trajectory through street canyons. This paper is motivated by the observed non-stationarity of the PL. We show that the traditional model of power law PL plus log-normally distributed variations can provide misleading results that can have serious implications for system simulations. Rather, the PL parameters have to be modeled as random variables that change from street to street and also as a function of the street orientation. Variations of the PL, taken over the ensemble of the whole cell (or multiple cells), thus consist of the compound effect of these PL parameter variations together with the traditional shadowing variations along the trajectory of movement. Ray-tracing results demonstrate that ignoring this effect can lead to a severe overestimation of the local standard deviation in a given area. Then, a spatially consistent stochastic street-by-street PL model is established, and a parameterization for 28-GHz UMi cells is given. The model correctly describes the PL as a function of the street orientation as well as the large variance observed for all the PL model parameters.
Autors: Aki Karttunen;Andreas F. Molisch;Sooyoung Hur;Jeongho Park;Charlie Jianzhong Zhang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7538 - 7550
Publisher: IEEE
 
» Spatio-Temporal Analysis of Passenger Travel Patterns in Massive Smart Card Data
Abstract:
Metro systems have become one of the most important public transit services in cities. It is important to understand individual metro passengers’ spatio-temporal travel patterns. More specifically, for a specific passenger: what are the temporal patterns? what are the spatial patterns? is there any relationship between the temporal and spatial patterns? are the passenger’s travel patterns normal or special? Answering all these questions can help to improve metro services, such as evacuation policy making and marketing. Given a set of massive smart card data over a long period, how to effectively and systematically identify and understand the travel patterns of individual passengers in terms of space and time is a very challenging task. This paper proposes an effective data-mining procedure to better understand the travel patterns of individual metro passengers in Shenzhen, a modern and big city in China. First, we investigate the travel patterns in individual level and devise the method to retrieve them based on raw smart card transaction data, then use statistical-based and unsupervised clustering-based methods, to understand the hidden regularities and anomalies of the travel patterns. From a statistical-based point of view, we look into the passenger travel distribution patterns and find out the abnormal passengers based on the empirical knowledge. From unsupervised clustering point of view, we classify passengers in terms of the similarity of their travel patterns. To interpret the group behaviors, we also employ the bus transaction data. Moreover, the abnormal passengers are detected based on the clustering results. At last, we provide case studies and findings to demonstrate the effectiveness of the proposed scheme.
Autors: Juanjuan Zhao;Qiang Qu;Fan Zhang;Chengzhong Xu;Siyuan Liu;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3135 - 3146
Publisher: IEEE
 
» Special Photonic Crystal Modal Interferometer for Highly Sensitive Biosensing
Abstract:
We present an all-fiber Mach–Zehnder modal interferometer based on a special photonic crystal fiber taper and its performance as a transducer for biological sensing. The sensor showed refractive index sensitivity around 722.3 nm/RIU for measurements between 1.30864 and 1.32014 RIU We investigated the interferometer as a transducer for an immunosensor system after immobilization of an antigen over the activated taper waist, where it detected the interaction between antigen and antibody achieving a record detection limit of 125 pg/ml of antibody concentration. This extra low detection limit allows the modal interferometer to be used in biosensing applications, such as disease diagnosis, or in the food industry.
Autors: Juan Esteban Betancur-Ochoa;Vladimir P. Minkovich;Yeison Javier Montagut-Ferizzola;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4747 - 4751
Publisher: IEEE
 
» Special Section on the 2017 International Conference on Compound Semiconductor Manufacturing Technology (CS-MANTECH)
Abstract:
As guest editors for the special section on the 2017 International Conference on Compound Semiconductor Manufacturing Technology (CS-MANTECH), we are pleased to present IEEE Transactions on Semiconductor Manufacturing readers with a selection of papers based on work presented at this year’s conference. The CS-MANTECH conference provides a technical forum for presenting advances in compound semiconductor devices and associated manufacturing technologies. The high performance of devices based on compound semiconductors has long made them the material of choice in RF, microwave, and millimeter-wave systems. While advances continue to be made in these traditional applications, compound semiconductors are increasingly finding their way into power systems via SiC and GaN device technologies, and are also increasingly integrated with silicon-based technologies to provide enhanced system-level performance and functionality. In addition, narrow-gap III-Vs are being explored as alternative-channel materials for aggressively-scaled logic.
Autors: Celicia Della-Morrow;Drew Hanser;Patrick Fay;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 448 - 449
Publisher: IEEE
 
» Spectra Measurements Using Piezoelectric Diaphragms to Detect Burn in Grinding Process
Abstract:
Researchers have evaluated a great number of monitoring techniques in order to control the surface condition of ground parts. Piezoelectric diaphragms of lead zirconate titanate are used in many fields, but these sensors are not common in the monitoring of the machining processes. This paper proposes a method for monitoring the workpiece surface condition (normal grinding and burn) by using a piezoelectric diaphragm and feature extraction techniques. A comparison is made with a conventional acoustic emission sensor, which is a traditional sensor in the monitoring of the machining processes. Grinding tests were performed in a surface-grinding machine with Society of Automotive Engineers (SAE) 1045 steel and cubic boron nitride (CBN) grinding wheel, where the signals were collected at 2 MHz. The workpieces were thoroughly analyzed through visual inspection, surface roughness and hardness measurements, and metallographic analyses. Study on the frequency content of both signals was carried out in order to select bands closely related to the workpiece surface condition. Digital filters were applied to the raw signals and features were extracted and analyzed. The root mean square values filtered in the selected bands for both sensors presented a better fitting to the linear regression, which is highly desirable for setting a threshold to detect burn and implementing into a monitoring system. Also, the basic damage index results show an excellent behavior for grinding burn monitoring for both sensors. The method was verified by using a different grinding wheel, which clearly shows its effectiveness and demonstrates the potential use of the low-cost piezoelectric diaphragm for grinding burn monitoring.
Autors: Danilo M. S. Ribeiro;Paulo R. Aguiar;Luiz F. G. Fabiano;Doriana M. D’Addona;Fabricio Guimarães Baptista;Eduardo C. Bianchi;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 3052 - 3063
Publisher: IEEE
 
» Spectral Efficiency Analysis for Downlink NOMA Aided Spatial Modulation With Finite Alphabet Inputs
Abstract:
As the conventional spatial modulation (SM) system lacks an efficient downlink multiple access scheme, this paper proposes a novel downlink nonorthogonal multiple access aided multiple-input multiple-output SM system with finite alphabet inputs. Mutual information (MI) is used to characterize the system's achievable spectral efficiency (SE). Because the MI lacks a closed-form formulation, in this paper we propose a computational-efficient lower bound to provide an approximation to the simulated MI. Besides, preprocessing is also designed at the receiver to mitigate the detrimental effect of channel correlation, which leads to striking a higher SE performance. Simulation results not only confirm the accuracy of our SE analysis, but also substantiate the superior SE performance achieved by the proposed preprocessing.
Autors: Xuesi Wang;Jintao Wang;Longzhuang He;Jian Song;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10562 - 10566
Publisher: IEEE
 
» Spectral-Element Method With Divergence-Free Constraint for 2.5-D Marine CSEM Hydrocarbon Exploration
Abstract:
Rapid simulations of large-scale low-frequency subsurface electromagnetic measurements are still a challenge because of the low-frequency breakdown phenomenon that makes the system matrix extremely poor-conditioned. Hence, significant attention has been paid to accelerate the numerical algorithms for Maxwell’s equations in both integral and partial differential forms. In this letter, we develop a novel 2.5-D method to overcome the low-frequency breakdown problem by using the mixed spectral element method with the divergence-free constraint and apply it to solve the marine-controlled-source electromagnetic systems. By imposing the divergence-free constraint, the proposed method considers the law of conservation of charges, unlike the conventional governing equation for these problems. Therefore, at low frequencies, the Gauss law guarantees the stability of the solution, and we can obtain a well-conditioned system matrix even as the frequency approaches zero. Several numerical experiments show that the proposed method is well suited for solving low-frequency electromagnetic problems.
Autors: Yuanguo Zhou;Mingwei Zhuang;Linlin Shi;Guoxiong Cai;Na Liu;Qing Huo Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1973 - 1977
Publisher: IEEE
 
» Spectrally Efficient Channel Estimation for Asynchronous Amplify-and-Forward Two-Way Relay Networks
Abstract:
In this paper, we consider the problem of channel estimation for asynchronous amplify-and-forward (AF) two-way relay networks. We propose a novel semi-blind channel estimation algorithm for this problem based on the expectation-maximization (EM) framework. The proposed EM algorithm has low complexity, and only a small number of EM iterations are needed to achieve convergence. The semi-blind Cramer-Rao bound (CRB) for channel estimation in asynchronous AF two-way relay networks is also obtained. Using simulations, we show that the proposed EM algorithm significantly outperforms pilot-based estimation by using only a limited number of received data samples in addition to the pilot samples. Furthermore, the achieved mean-squared error performance almost overlaps with the obtained CRB. Finally, a semi-blind generalized likelihood ratio testing (GLRT) method is proposed to tackle sequence arriving order (SAO) detection at the terminals and is shown to yield a higher probability of detection than the pilot-based GLRT for SAO detection.
Autors: Saeed Abdallah;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7333 - 7347
Publisher: IEEE
 
» Spelling With a Small Mobile Brain-Computer Interface in a Moving Wheelchair
Abstract:
Research into brain-computer interfaces (BCIs), which spell words using brain signals, has revealed that a desktop version of such a speller, the edges paradigm, offers several advantages: This edges paradigm outperforms the benchmark row-column paradigm in terms of accuracy, bitrate, and user experience. It has remained unknown whether these advantages prevailed with a new version of the edges paradigm designed for a mobile device. This paper investigated and evaluated in a rolling wheelchair a mobile BCI, which implemented the edges paradigm on small displays with which visual crowding tends to occur. How the mobile edge paradigm outperforms the mobile row-column paradigm has implications for understanding how principles of visual neurocognition affect BCI speller use in a mobile context. This investigation revealed that all the advantages of the edges paradigm over the row-column paradigm prevailed in this setting. However, the reduction in adjacent errors for the edges paradigm was unprecedentedly limited to horizontal adjacent errors. The interpretation offered is that dimensional constraints of visual interface design on a smartphone thus affected the neurocognitive processes of crowding.
Autors: Qasem T. Obeidat;Tom A. Campbell;Jun Kong;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2169 - 2179
Publisher: IEEE
 
» Spin Diffusion Length in Ferromagnet/Superconductor Bilayers
Abstract:
We report a systematic study on the bilayers of ferromagnetic Sm1–xSrxMnO3 (SSMO) and superconducting YBa2Cu3O7 (YBCO). The bilayer structure is composed of one SSMO layer of 10-nm thickness and one layer of YBCO of various thicknesses. The measurements of X-ray diffraction/reflectivity, resistivity, and magnetization were carried out for determining the crystalline properties and the superconducting temperatures of bilayers. A significant suppression of superconducting temperature is observed in all bilayers, indicating that the spin-polarized quasi-particles of SSMO are efficiently injected into the YBCO layer. The experimental results will be discussed in term of the spin diffusion length of polarized quasi-particles with a model of inverse proximity.
Autors: S. L. Cheng;T. H. Chuang;J. G. Lin;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Spin-Current Manipulation of Photo-Induced Magnetization Dynamics in Heavy Metal/Ferromagnet Double Layer-Based Nanostructures
Abstract:
Spin currents offer a way to control static and dynamic magnetic properties, and therefore, they are crucial for the next-generation magnetoresistive random access memory devices or spin-torque oscillators. Manipulating the dynamics is especially interesting within the context of photo-magnonics. In typical 3d transition metal ferromagnets, such as CoFeB, the lifetime of light-induced magnetization dynamics is restricted to about 1 ns, which, e.g., strongly limits the opportunities to exploit the wave nature in a magnonic crystal filtering device. Here, we investigate the potential of spin currents to increase the spin-wave lifetime in a functional bilayer system, consisting of a heavy metal [8 nm of -Tantalum (Platinum)] and 5 nm CoFeB. Due to the spin Hall effect, the heavy metal layer generates a transverse spin current when a lateral charge current passes through the strip. Using time-resolved all-optical pump-probe spectroscopy, we investigate how this spin current affects the magnetization dynamics in the adjacent CoFeB layer. We observed a linear spin-current manipulation of the effective Gilbert damping parameter for the Kittel mode from which we were able to determine the system’s spin Hall angles. Furthermore, we measured a strong influence of the spin current on a high-frequency mode. We interpret this mode as an exchange dominated higher order spin-wave resonance. Thus, we infer a strong dependence of the exchange constant on the spin current.
Autors: Steffen Wittrock;Dennis Meyer;Markus Müller;Henning Ulrichs;Jakob Walowski;Maria Mansurova;Ulrike Martens;Markus Münzenberg;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Spin-Transfer-Driven Dynamics of Magnetic Vortices and Antivortices in Dots With Crystalline Cubic Anisotropy
Abstract:
We study the magnetization dynamics of a vortex- or antivortex-containing nanodot driven by an out-of-plane polarized electric current within micromagnetic simulations. The dot is an ultra-thin structure created using a material with strong crystalline cubic anisotropy. It is in-plane ordered with an effective fourfold anisotropy. In the case of the antivortex, we consider astroid-shaped dots, while in the case of the vortex, the circular dots and the astroid-shaped ones. Unlike in the soft-magnetic dots, the vortex (antivortex) textures in thin layers with sufficiently strong fourfold anisotropy consist of four closure domains independent of the dot shape. The magnetization in the domain walls (DWs) deviates from the dot plane under the action of the out-of-plane polarized electric current normal to the dot, which drives the DW propagation—a rotation of the texture around the vortex (antivortex) center. The DW velocity is dependent on the distance from the vortex (antivortex) core; thus, the DWs deform under the current creating a fourfold spiral shape. For sufficiently hard cubic magnets, we find a regime of the oscillatory dynamics of the dot [a cyclic switching between the spiral state and the closure-domain vortex (antivortex) state]. For softer magnets, we consider a spin-transfer-driven fast magnetization reversal of the vortex state mediated by the creation of the spiral state.
Autors: Andrzej Janutka;Przemysław Gawroński;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Spin-Valve Junction With Transfer-Free MoS2 Spacer Prepared by Sputtering
Abstract:
The prospects of spintronic devices based on 2-D materials originate from their outstanding spin-related properties. Fabrication of such devices typically involves transfer processes that yield inferior interfaces due to trapped contaminants or cavities at 2-D material/electrode interfaces. Here, we report a transfer-free fabrication process of MoS2 films by RF magnetron sputtering, and demonstrate its application in the La0.7Sr0.3MnO3/MoS2/Ni0.8Fe0.2 spin-valve structure. The Raman spectroscopy shows and vibration modes of MoS2, suggesting the growth of crystalline MoS2 layers. A giant magnetoresistance ratio of 0.8% at 20 K was observed. The results suggest a scalable route for fabricating MoS2-based electronic and spintronic devices with a transfer-free process for obtaining reliable contacts.
Autors: W. C. Wong;S. M. Ng;H. F. Wong;C. L. Mak;C. W. Leung;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Spin-Wave Switching in the Side-Coupled Magnonic Stripes
Abstract:
This study of the spin waves coupling in the magnonic coupler, formed by the laterally coupled magnonic stripes, is performed by the means of finite-element and micromagnetic simulations. The efficiency of the spin-wave coupling is improved by the geometry design and choice of the appropriate magnetization direction inside each magnonic stripe. The proposed side-coupled magnetic stripes enable the improvement of performance of the advanced integrated magnonic devices and offer a range of further opportunities in planar magnonics.
Autors: Alexandr V. Sadovnikov;Sergey A. Odintsov;Evgeniy N. Beginin;Svetlana E. Sheshukova;Yurii P. Sharaevskii;Sergey A. Nikitov;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Splitting of Ferromagnetic Resonance Spectra in Periodically Modulated 1-D Magnonic Crystal
Abstract:
In this paper, we present a systematic study of a series of 1-D magnonic crystals defined as periodic arrays of grooves in a Permalloy thin film. Thin films of Ni80Fe20 with dimensions by and thickness 40 nm were prepared on the top of signal line of coplanar waveguides by a combination of photolithography, e-beam lithography and lift-off processing. Starting from thin films, stripe-type periodic structures (grooves) with a depth of 4 nm were created in a controlled manner by focused ion beam. By changing the dimensions of the distance between the grooves, it was possible to systematically tune single, double, triple, and quadruple ferromagnetic resonance (FMR) absorption modes. Broadband FMR experiments were carried out to collect the frequency and field-dependent FMR spectra. The experimental results are corroborated with micromagnetic simulations.
Autors: Shankar Khanal;Pemba Sherpa;Leonard Spinu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Splitting of Spin Waves in Strain Reconfigurable Magnonic Stripe
Abstract:
We report on the study of the spin wave (SW) propagation in the magnonic waveguide which consists of an irregular magnetic thin film and a piezoelectric layer. We demonstrate that the use of a finite-width piezoelectric layer on the top of a magnetic waveguide leads to controllable SW splitting. By means of numerical simulation, we demonstrate the functionality of the proposed structure. We show that the switching of SW power is possible due to electric field variation and thus the proposed structure can act as a frequency-selective multichannel SW splitter and multiplexer.
Autors: Alexander V. Sadovnikov;Andrey A. Grachev;Evgeniy N. Beginin;Svetlana E. Sheshukova;Yurii P. Sharaevsky;Alexey A. Serdobintsev;Dmitry M. Mitin;Sergey A. Nikitov;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» SRTM DEM-Aided Mapping Satellite-1 Image Geopositioning Without Ground Control Points
Abstract:
A Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM)-aided geopositioning method is proposed to solve the problem of geopositioning without ground control points for Mapping Satellite-1 imagery. The method comprises coarse and accurate correction stages, and it compensates errors gradually. DEM extraction and DEM matching are important steps in both the stages, the objectives of which are to compensate the relative and absolute errors in an image, respectively. The SRTM DEM is integrated into all the processes to take full advantage of its consistent and high accuracy. Experimental results showed that this method could greatly improve geometry accuracy and obtain stable and highly accurate geopositioning for Mapping Satellite-1 images, regardless of the land area proportion (LAP) or the production mode. The planimetric and vertical accuracies were better than 8.1 and 5.2 m, respectively, which could satisfy the accuracy requirements of mapping at 1:50 000 scale. The computational efficiency depends on the LAP and target DEM resolution.
Autors: Xiaowei Chen;Baoming Zhang;Minyi Cen;Haitao Guo;Tonggang Zhang;Chuan Zhao;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2137 - 2141
Publisher: IEEE
 
» Stability Analysis of Polynomially Dependent Systems by Eigenvalue Perturbation
Abstract:
In this technical note we present a stability analysis approach for polynomially-dependent one-parameter systems. The approach, which appears to be conceptually appealing and computationally efficient and is referred to as an eigenvalue perturbation approach, seeks to characterize the analytical and asymptotic properties of eigenvalues of matrix-valued functions or operators. The essential problem dwells on the asymptotic behavior of the critical eigenvalues on the imaginary axis, that is, on how the imaginary eigenvalues may vary with respect to the varying parameter. This behavior determines whether the imaginary eigenvalues cross from one half plane into another, and hence plays a critical role in determining the stability of such systems. Our results reveal that the eigenvalue asymptotic behavior can be characterized by solving a simple generalized eigenvalue problem, leading to numerically efficient stability conditions.
Autors: Jie Chen;Peilin Fu;César-Fernando Méndez-Barrios;Silviu-Iulian Niculescu;Hongwei Zhang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5915 - 5922
Publisher: IEEE
 
» Stability of Excitation of Traveling Waves in Gyrotrons With Low-Relativistic Electron Beams
Abstract:
A number of application require compact low-power gyrotrons with relatively low operating currents. In order to provide the start of such gyrotrons, one should use long-length operating cavities with high diffraction Q-factors, and, therefore, with significant losses of the radiated wave power due to Ohmic heating of the cavity wall. In this paper, we demonstrate that in low-voltage gyrotrons there is a possibility for stable operation at higher order axial modes possessing relatively low diffraction Q-factors. An enhanced efficiency of the beam-wave interaction is provided due to the excitation of such modes in the traveling-wave-tube regime.
Autors: Yuriy K. Kalynov;Ivan V. Osharin;Andrey V. Savilov;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4693 - 4699
Publisher: IEEE
 
» Stability Properties of Coupled Impedance Passive LTI Systems
Abstract:
We study the stability of the feedback interconnection of two impedance passive linear time-invariant systems, of which one is finite dimensional. The closed-loop system is well known to be impedance passive, but no stability properties follow from this alone. We are interested in two main issues: 1) the strong stability of the operator semigroup associated with the closed-loop system, 2) the input–output stability (meaning transfer function in ) of the closed-loop system. Our results are illustrated with the system obtained from the nonuniform SCOLE (NASA Spacecraft Control Laboratory Experiment) model representing a vertical beam clamped at the bottom, with a rigid body having a large mass on top, connected with a trolley mounted on top of the rigid body, via a spring and a damper. Such an arrangement, called a tuned mass damper (TMD), is used to stabilize tall buildings. We show that the SCOLE-TMD system is strongly stable on the energy state space and that the system is input–output stable from the horizontal force input to the horizontal velocity output.
Autors: Xiaowei Zhao;George Weiss;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5769 - 5779
Publisher: IEEE
 
» Stack Structure Dependence of Magnetic Properties of PtMn/[Co/Ni] Films for Spin-Orbit Torque Switching Device
Abstract:
We investigate the stack structure dependence of magnetic properties on thin films that consist of an antiferromagnetic PtMn and a ferromagnetic Co/Ni multilayer for field-free spin-orbit torque-induced magnetization switching devices. Magnetic parameters, such as the spontaneous magnetization, effective and interfacial magnetic anisotropies, and exchange bias field are quantified as a function of stack structure. Engineering of the stack allows the improvement of current-induced magnetization switching characteristics compared with a previous work, which is confirmed using patterned Hall cross devices.
Autors: William A. Borders;Shunsuke Fukami;Hideo Ohno;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Stack-Size Sensitive On-Chip Memory Backup for Self-Powered Nonvolatile Processors
Abstract:
Wearable devices gain increasing popularity since they can collect important information for healthcare and well-being purposes. Compared with battery, energy harvesting is a better power source for these wearable devices due to many advantages. However, harvested energy is naturally unstable and program execution will be interrupted frequently. Nonvolatile processors demonstrate promising advantages to back up volatile state before the system energy is depleted. However, it also introduces non-negligible energy and area overhead. In this paper, we aim to reduce the amount of data that need to be backed up during a power failure. Based on the observation that stack size varies along program execution, we propose to analyze the application program and identify efficient backup positions, by which the stack content to back up can be significantly reduced. The evaluation results show an average of 45.7% reduction on nonvolatile stack size for stack backup, with 0.58% storage overhead. In the mean time, with the proposed schemes, the energy utilization and program forward progress can be greatly improved compared with instant backup.
Autors: Mengying Zhao;Chenchen Fu;Zewei Li;Qingan Li;Mimi Xie;Yongpan Liu;Jingtong Hu;Zhiping Jia;Chun Jason Xue;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1804 - 1816
Publisher: IEEE
 
» Staggered SAR: Performance Analysis and Experiments With Real Data
Abstract:
Synthetic aperture radar (SAR) remote sensing allows high-resolution imaging independent of weather conditions and sunlight illumination and is therefore very attractive for the systematic observation of dynamic processes on the earth’s surface. Conventional SAR systems are, however, limited in that a wide swath can only be imaged at the expense of a degraded azimuth resolution. This limitation can be overcome by using systems with multiple receive subapertures displaced in along-track, but a very long antenna is required to map a wide swath. If a relatively short antenna with a single aperture in along-track is available, it is still possible to map a wide area: multiple subswaths can simultaneously be imaged using digital beamforming in elevation, but “blind ranges” are present between adjacent swaths, as the radar cannot receive while it is transmitting. Staggered SAR overcomes the problem of blind ranges by continuously varying the pulse repetition interval (PRI). A proper selection of the PRIs, together with moderate oversampling in azimuth, allows an accurate interpolation of the nonuniformly sampled raw data into a uniform grid, so that resampled data can then be focused with a conventional SAR processor. This approach thereby allows high-resolution imaging of a wide continuous swath without the need for a long antenna with multiple subapertures. In this paper, the performance of staggered SAR is thoroughly discussed and novel methods for the evaluation of the range and azimuth ambiguity-to-signal ratios in staggered SAR are proposed. An L-band design example based on a reflector antenna with multiple feeds shows that outstanding ambiguity performance is obtained, provided that data are moderately oversampled in azimuth. As an additional benefit, the energy of range and azimuth ambiguities is spread over large areas: ambiguities therefore appear in the image as a noise-like disturbance rather than loca- ized artifacts. The impact of staggered SAR operation on image quality is furthermore assessed with experiments using real data. As the first step, highly oversampled F-SAR airborne data have been used to generate equivalent staggered SAR data sets and to evaluate the performance for different oversampling factors and interpolation methods. Then, the radar instrument of the German satellite TerraSAR-X has been commanded to acquire data over the lake Constance in staggered SAR mode. Measurements on these data show very good agreement with predictions from simulations. Staggered SAR is currently being considered as the baseline acquisition mode for Tandem-L, a proposal for a polarimetric and interferometric spaceborne SAR mission to monitor dynamic processes on the earth’s surface with unprecedented accuracy and resolution.
Autors: Michelangelo Villano;Gerhard Krieger;Marc Jäger;Alberto Moreira;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6617 - 6638
Publisher: IEEE
 
» State and Unknown Input Observers for Nonlinear Systems With Bounded Exogenous Inputs
Abstract:
A systematic design methodology for state observers for a large class of nonlinear systems with bounded exogenous inputs (disturbance inputs and sensor noise) is proposed. The nonlinearities under consideration are characterized by an incremental quadratic constraint parameterized by a set of multiplier matrices. Linear matrix inequalities are developed to construct observer gains, which ensure that a performance output based on the state estimation error satisfies a prescribed degree of accuracy. Furthermore, conditions guaranteeing estimation of the unknown inputs to arbitrary degrees of accuracy are provided. The proposed scheme is illustrated with a numerical example, which does not satisfy the so-called “matching conditions.”
Autors: Ankush Chakrabarty;Martin J. Corless;Gregery T. Buzzard;Stanisław H. Żak;Ann E. Rundell;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5497 - 5510
Publisher: IEEE
 
» Static and Dynamic Magnetic Properties of Sputtered Fe–Ga Thin Films
Abstract:
We present the measurements of the static and dynamic properties of polycrystalline iron–gallium films, ranging from 20 to 80 nm and sputtered from an Fe0.8Ga0.2 target. Using a broadband ferromagnetic resonance setup in a wide frequency range, perpendicular standing spin-wave resonances were observed with the external static magnetic field applied in-plane. The field corresponding to the strongest resonance peak at each frequency is used to determine the effective magnetization, the -factor, and the Gilbert damping. Furthermore, the dependence of spin-wave mode on field-position is observed for several frequencies. The analysis of broadband dynamic properties allows determination of the exchange stiffness pJ/m and Gilbert damping for 40 and 80 nm thick films. These values are approximately consistent with values seen in epitaxially grown films, indicating the potential for the industrial fabrication of magnetostrictive FeGa films for microwave applications.
Autors: Daniel B. Gopman;Vimal Sampath;Hasnain Ahmad;Supriyo Bandyopadhyay;Jayasimha Atulasimha;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Statistical Anomaly Detection in Human Dynamics Monitoring Using a Hierarchical Dirichlet Process Hidden Markov Model
Abstract:
Understanding of human dynamics has drawn attention to various areas. The wide spread of positioning technologies, such as GPS facilitates location information to be obtained with high spatio-temporal resolution as well as at low costs. By collecting individual location information in real time, monitoring of human dynamics has recently become possible and is expected to the area of dynamic traffic control. In this monitoring, detecting anomalous states of human dynamics become important. This research aims to define an anomaly detection problem of the human dynamics monitoring with time-series gridded population data and develop an anomaly detection method for this problem. According to the result of a review we have conducted, we discussed the characteristics of the anomaly detection in human dynamics monitoring and categorized our problem to a semi-supervised anomaly detection problem that detects contextual anomalies behind time-series data. We developed an anomaly detection method based on a sticky hierarchical Dirichlet process hidden Markov model, which is able to estimate the number of latent states according to the input data. Results of the experiment with synthetic data showed that our proposed method has good fundamental performance with respect to the detection rate. Through the experiments with real gridded population data, anomalies were detected when and where an actual social event had occurred.
Autors: Takashi Fuse;Keita Kamiya;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3083 - 3092
Publisher: IEEE
 
» Stator Shape Design Method for Improving Power Density in PM Motor
Abstract:
In this paper, we propose a stator shape design method for improving power density in a small permanent magnet motor. In order to calculate iron loss correctly, we analyze a motor by using 2-D finite element method (FEM) in which an E&S model is introduced. Moreover, external circuit equations are solved coupled with equations in electromagnetic field by FEM to calculate copper loss correctly. It is possible to calculate power density correctly by evaluating loss and weight of a motor correctly whether stator shape is changed. As a result, we show that our analysis technique is useful as a shape design method of a motor’s stator for improving power density.
Autors: Naoya Soda;Masato Enokizono;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» STC: A Simple to Complex Framework for Weakly-Supervised Semantic Segmentation
Abstract:
Recently, significant improvement has been made on semantic object segmentation due to the development of deep convolutional neural networks (DCNNs). Training such a DCNN usually relies on a large number of images with pixel-level segmentation masks, and annotating these images is very costly in terms of both finance and human effort. In this paper, we propose a simple to complex (STC) framework in which only image-level annotations are utilized to learn DCNNs for semantic segmentation. Specifically, we first train an initial segmentation network called Initial-DCNN with the saliency maps of simple images (i.e., those with a single category of major object(s) and clean background). These saliency maps can be automatically obtained by existing bottom-up salient object detection techniques, where no supervision information is needed. Then, a better network called Enhanced-DCNN is learned with supervision from the predicted segmentation masks of simple images based on the Initial-DCNN as well as the image-level annotations. Finally, more pixel-level segmentation masks of complex images (two or more categories of objects with cluttered background), which are inferred by using Enhanced-DCNN and image-level annotations, are utilized as the supervision information to learn the Powerful-DCNN for semantic segmentation. Our method utilizes 40K simple images from Flickr.com and 10K complex images from PASCAL VOC for step-wisely boosting the segmentation network. Extensive experimental results on PASCAL VOC 2012 segmentation benchmark well demonstrate the superiority of the proposed STC framework compared with other state-of-the-arts.
Autors: Yunchao Wei;Xiaodan Liang;Yunpeng Chen;Xiaohui Shen;Ming-Ming Cheng;Jiashi Feng;Yao Zhao;Shuicheng Yan;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2314 - 2320
Publisher: IEEE
 
» Stereo Image Retrieval Using Height and Planar Visual Word Pairs
Abstract:
The wide availability of high-resolution satellite stereo images has created a surging demand for effective stereo image retrieval methods. Recently, few retrieval methods have been designed specifically for stereo images having unique characteristics (e.g., viewing number and viewing angles), and often have insufficient retrieval accuracy. A new content-based stereo image retrieval method is achieved with height and planar visual word pairs, which are generated from the stereo extracted digital surface models and orthoimages. Experimental results of the International Society for Photogrammetry and Remote Sensing stereo benchmark test data set show that our method outperforms the state-of-the-art methods in terms of accuracy and stability. Our method achieves a high retrieval precision of 0.9, and has a high efficiency. Our method is stable for two stereo pairs, covering the same scene from different sensors, which usually have a small ranking difference in the returned ranking list. Our method is helpful to quickly and accurately locate desired stereo images from large quantities of multisensor stereo images.
Autors: Feifei Peng;Jing Luo;Gaoqiang Wang;Kunlun Qi;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2082 - 2086
Publisher: IEEE
 
» Stochastic Phase Synchronization of Perpendicularly Magnetized Spin-Torque Oscillators With the Second-Order Uniaxial Anisotropy
Abstract:
Stochastic phase synchronization is investigated for spin-torque oscillators (STOs) with perpendicularly magnetized free layer with the first- and second-order magnetic anisotropy. We numerically calculated the magnetization dynamics for the pair of STOs receiving a dc current with Gaussian noise through common current source, and found that the STOs with the second-order magnetic anisotropy synchronized more effectively than that without the second-order magnetic anisotropy. We analyzed the response of the oscillation phase to a perturbative current, i.e., phase resetting curve, and also found that the STO with the second-order uniaxial anisotropy performs better with stochastic phase synchronization.
Autors: Hiroko Arai;Hiroshi Imamura;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Strain Effects on the Interaction Between NO2 and the Mo-Edge of the MoS2 Zigzag Nanoribbon
Abstract:
Density functional theory based theoretical studies on the interaction of NO2 molecule with the Mo-edge of MoS2 zigzag nanoribbon have been presented in this paper. Effects from uniaxial tensile strain on the structure and physical properties of the nanoribbon and the adsorption process are discussed in detail. Without strain, NO2 dissociates and adsorbs onto the Mo-edge, with an adsorption energy of –0.91 eV, and the nanoribbon is metallic. With strain and without the presence of NO2, the nanoribbon remains metallic. However, with the presence and interaction from NO2, the nanoribbon under strain shows a band gap opening. Meanwhile, there is an increase in the magnitude of the adsorption energy, indicating more stable adsorbed structures with strain.
Autors: Xiaowei Wang;Junxia Shi;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 982 - 990
Publisher: IEEE
 
» Strain-Mediated Magnetization Reversal Through Spin-Transfer Torque
Abstract:
Recent experiments have shown the ability to introduce an anisotropy energy to the energy landscape of a thin-film nanomagnet through the use of mechanical strain. Assuming this strain-induced anisotropy is large enough, the low-energy state of the nanomagnet is altered and can be used to initialize the magnetization along a given axis. Utilizing this effect, we propose a more energy efficient method of nanomagnet reversal through spin-transfer torque (STT). This is accomplished by first initializing the magnetization to a high-energy state and then applying a short current pulse to nudge the magnetization in the appropriate energy basin. Using extensive numerical simulations, we qualitatively analyze this type of reversal and find the optimal parameters for reliable functionality while in the presence of thermal noise. We demonstrate that despite negating the initial portion of nominal STT reversal, where the STT must fight against the damping torque of the initial energy-basin, the magnitude of spin current required for our proposed strain-mediated reversal is equivalent to the nominal case. However, the strain-meditated reversal is beneficial by minimizing the spin-current pulsewidth necessary for reliable operation allowing for large energy savings. Assuming the strain-anisotropy is significantly larger than the nanomagnet’s internal free-axis anisotropy, strain-mediated reversals offer a energy reduction over nominal STT reversals.
Autors: Nickvash Kani;John T. Heron;Azad Naeemi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 8
Publisher: IEEE
 
» Strained Germanium Gate-All-Around pMOS Device Demonstration Using Selective Wire Release Etch Prior to Replacement Metal Gate Deposition
Abstract:
Strained Ge p-channel gate-all-around (GAA) devices with Si-passivation are demonstrated on high-density 45-nm active pitch starting from 300-mm SiGe strain relaxed buffer wafers. While single horizontal Ge nanowire (NW) devices are demonstrated, the process flow described in this paper can be adjusted to make vertically stacked horizontal Ge NWs to increase the drive per footprint. The demonstrated short-channel devices have round Ge NWs with 9-nm diameter and are the Ge GAA devices with the smallest channel and gate dimensions ( nm) published to date. Electrostatics and off-state leakage are maintained down to the shortest gate lengths studied, showing drain-induced barrier lowering of 30 mV/V and sub-20 nA/ at V and nm. The short-channel device subthreshold slope SS and performance can be further improved by use of high-pressure annealing in hydrogen, yielding the best SSLIN and SSSAT of 71 and 76 mV/dec reported so far for any -nm Ge pMOS channel device.
Autors: L. Witters;H. Arimura;F. Sebaai;A. Hikavyy;A. P. Milenin;R. Loo;A. De Keersgieter;G. Eneman;T. Schram;K. Wostyn;K. Devriendt;A. Schulze;R. Lieten;S. Bilodeau;E. Cooper;P. Storck;E. Chiu;C. Vrancken;P. Favia;E. Vancoille;J. Mitard;R. Langer;A. Opdebee
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4587 - 4593
Publisher: IEEE
 
» Strategies to Empower Existing Automated Material Handling Systems to Rising Requirements
Abstract:
Due to reasons like higher flexibility demands, smaller lot sizes in production, and tool upgrades leading to higher throughputs, existing automated material handling systems are facing ever rising requirements. At the same time, the potential to upgrade transport system hardware is limited due to technical reasons as well as its interconnected nature. This paper, therefore, focuses on new possibilities regarding the integration of already existing but not yet used information into automated material handling system (AMHS) control, and presents three different approaches for improvement: 1) improving empty vehicle management strategies by incorporating near-future transports demands; 2) balancing track utilization by adjusting path selection processes; and 3) interaction between AMHS and scheduling/dispatching, in order to consider potential bottle-necks. Each of these approaches improves AMHS performance; in combination they have the potential to empower the system to handle future demands with little or no hardware manipulations.
Autors: Robert Schmaler;Christian Hammel;Thorsten Schmidt;Matthias Schoeps;Joerg Luebke;Ralf Hupfer;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 440 - 447
Publisher: IEEE
 

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