Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 10

» Hyperspectral Image Spectral-Spatial Feature Extraction via Tensor Principal Component Analysis
Abstract:
We consider the tensor-based spectral-spatial feature extraction problem for hyperspectral image classification. First, a tensor framework based on circular convolution is proposed. Based on this framework, we extend the traditional principal component analysis (PCA) to its tensorial version tensor PCA (TPCA), which is applied to the spectral-spatial features of hyperspectral image data. The experiments show that the classification accuracy obtained using TPCA features is significantly higher than the accuracies obtained by its rivals.
Autors: Yuemei Ren;Liang Liao;Stephen John Maybank;Yanning Zhang;Xin Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1431 - 1435
Publisher: IEEE
 
» Hysteresis Switching Control of the Ćuk Converter Operating in Discontinuous Conduction Modes
Abstract:
In this brief, the behaviors of the Ćuk converter operating in discontinuous conduction modes (DCMs) under a hysteresis controlled switching are studied. The hysteresis switching is defined in terms of values of a common quadratic Lyapunov function and Lyapunov stability conditions are established for all possible switchings, which represent a DCM of operation. A set of simulation results are provided to illustrate the converter’s behaviors when the hysteresis switching control results in discontinuous modes of operation.
Autors: Aleksandra Lekić;Dušan M. Stipanović;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1077 - 1081
Publisher: IEEE
 
» I Hear, Therefore I Know Where I Am: Compensating for GNSS Limitations with Cellular Signals
Abstract:
Global navigation satellite systems (GNSSs) have been the prevalent positioning, navigation, and timing technology over the past few decades. However, GNSS signals suffer from four main limitations.
Autors: Zaher Zak M. Kassas;Joe Khalife;Kimia Shamaei;Joshua Morales;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 111 - 124
Publisher: IEEE
 
» I tymshare do you? [Past Forward]
Abstract:
“There is no cloud,” goes the quip. “It’s just someone else’s computer.” It’s funny because it’s true: With cloud computing, your data and apps reside in a remote data center, which you share with many users even if it feels like it’s all just for you. Remarkably, a very similar mode of computing was also popular from the 1960s into the 1980s, when it was called time-sharing. At one point, the pioneering firm Tymshare boasted the world’s largest commercial computer network. Rivaling even the ARPANET, it gave customers the illusion of having a powerful machine at their disposal, even if it was really someone else’s.
Autors: David C. Brock;
Appeared in: IEEE Spectrum
Publication date: Sep 2017, volume: 54, issue:9, pages: 60 - 60
Publisher: IEEE
 
» I/O Stack Optimization for Efficient and Scalable Access in FCoE-Based SAN Storage
Abstract:
Due to the high complexity in software hierarchy and the shared queue & lock mechanism for synchronized access, existing I/O stack for accessing the FCoE based SAN storage becomes a performance bottleneck, thus leading to a high I/O overhead and limited scalability in multi-core servers. In order to address this performance bottleneck, we propose a synergetic and efficient solution that consists of three optimization strategies for accessing the FCoE based SAN storage: (1) We use private per-CPU structures and disabling kernel preemption method to process I/Os, which significantly improves the performance of parallel I/O in multi-core servers; (2) We directly map the requests from the block-layer to the FCoE frames, which efficiently translates I/O requests into network messages; (3) We adopt a low latency I/O completion scheme, which substantially reduces the I/O completion latency. We have implemented a prototype (called FastFCoE, a protocol stack for accessing the FCoE based SAN storage). Experimental results demonstrate that FastFCoE achieves efficient and scalable I/O throughput, obtaining 1132.1K/836K IOPS (6.6/5.4 times as much as original Linux Open-FCoE stack) for read/write requests.
Autors: Yunxiang Wu;Fang Wang;Yu Hua;Dan Feng;Yuchong Hu;Wei Tong;Jingning Liu;Dan He;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2514 - 2526
Publisher: IEEE
 
» IAS Annual Meeting: Colocation with ECCE [President's Message]
Abstract:
Presents the President’s message for this issue of the publication.
Autors: Tomy Sebastian;
Appeared in: IEEE Industry Applications Magazine
Publication date: Sep 2017, volume: 23, issue:5, pages: 4 - 13
Publisher: IEEE
 
» ICRA 2017 in Singapore [Society News]
Abstract:
Autors: Malika Meghjani;Albert Causo;I-Ming Chen;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 173 - 175
Publisher: IEEE
 
» Identifiability for Blind Source Separation of Multiple Finite Alphabet Linear Mixtures
Abstract:
We give under weak assumptions a complete combinatorial characterization of identifiability for linear mixtures of finite alphabet sources, with unknown mixing weights and unknown source signals, but known alphabet. This is based on a detailed treatment of the case of a single linear mixture. Notably, our identifiability analysis applies also to the case of unknown number of sources. We provide sufficient and necessary conditions for identifiability and give a simple sufficient criterion together with an explicit construction to determine the weights and the source signals for deterministic data by taking advantage of the hierarchical structure within the possible mixture values. We show that the probability of identifiability is related to the distribution of a hitting time and converges exponentially fast to one when the underlying sources come from a discrete Markov process. Finally, we explore our theoretical results in a simulation study. This paper extends and clarifies the scope of scenarios for which blind source separation becomes meaningful.
Autors: Merle Behr;Axel Munk;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5506 - 5517
Publisher: IEEE
 
» Identification and Experimental Validation of an Induction Motor Thermal Model for Improved Drivetrain Design
Abstract:
The ability of an electric powertrain to perform according to mechanical specifications is equally important as assessing its thermal protection limits, which are affected by its electrical and thermal properties. Although rated parameters (such as power, torque, etc.) are easily accessible in catalogs of equipment producers, more specific properties like mass/length of copper winding, heat dissipation factor, etc., are not available to customers. Therefore, an effective selection of drivetrain components is limited due to the lack of sufficient data and the need to consult critical design decisions with suppliers. To overcome this limitation, we propose a method to estimate the temperature rise of motor drives based on popular loadability curves, which are provided in catalogs. A simple first-order thermal model is applied to represent heating/cooling phenomenon of motor drives. The parameters’ identification process is formulated as a nonlinear optimization problem and solved using commercial software products. Within the proposed approach, it becomes possible to include the effect of reduced torque availability at low speeds in self-ventilated motors during design of electric actuation systems. Contrary to using a discrete set of permissible overload conditions from the catalogs, the current methodology allows for evaluating a temperature rise of a motor drive for any overload magnitude, duty cycle, and ambient temperature. This greatly improves flexibility of the design process and facilitates communication in a supplier–customer dialog. The discussed method is verified against reference overload recommendations, yielding the same thermal protection levels, and validated using the experimental results, producing identical motor temperature rise profiles as the ones measured on the laboratory test bench.
Autors: Witold Pawlus;Jan Thomas Birkeland;Huynh Van Khang;Michael R. Hansen;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2017, volume: 53, issue:5, pages: 4288 - 4297
Publisher: IEEE
 
» Identification and Sign-Ambiguity-Free Calculations of Reciprocal Characteristic Parameters in Microwave Applications
Abstract:
Various microwave circuit characterizations and measurements, such as extracting forward and backward propagation factors in thru-reflect-line calibration and choosing the correct reflection coefficient in the transmission/reflection method for material characterization, involve the calculation of complex reciprocal characteristic parameters. The calculation procedure is generally obstructed by assignment between the real physical parameters and the calculated values and sign choice of square roots. This letter shows that the complex reciprocal characteristic parameters can be explicitly differentiated by the relative magnitudes of their moduli, and the problems of parameter identification and sign choice can be eliminated by proper rearrangement of the operands in the square root function and the aid of complex hyperbolic functions. Therefore, the calculation formula for each of the reciprocal roots is fixed without undetermined signs and conforms to the passive or active conventions.
Autors: Kuen-Fwu Fuh;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2017, volume: 27, issue:9, pages: 773 - 775
Publisher: IEEE
 
» Identification of partial discharges in power transformers: An approach driven by practical experience
Abstract:
High voltage power transformers are the most challenging equipment for asset managers in that their failures are often due to thermal, electrical, ambient, and mechanical stresses that interact in a synergic way. An accurate failure mode analysis is often prevented by the compound nature of the insulation (partly solid, partly liquid, self-regenerative, and highly flammable) and by the high probability that failures involve explosions. Insulation failure is, by far, the costlier event with an average cost of about $150,000 (1999) per outage [1]. Therefore, it is worthwhile to understand better the symptoms that indicate an imminent failure.
Autors: S. Ganeshan;J. Murugesan;A. Cavallini;F. Negri;B. Valecillos;U. Piovan;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Sep 2017, volume: 33, issue:5, pages: 23 - 31
Publisher: IEEE
 
» IEEE Administrative Meeting and Technical Talk in Abu Dhabi [Around the Globe]
Abstract:
Presents information on the IEEE Administrative Meeting and Technical Talk in Abu Dhabi.
Autors: Nazih Khaddaj Mallat;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2017, volume: 18, issue:6, pages: 136 - 137
Publisher: IEEE
 
» IEEE Standards Association P7007 ? Call for Participation [Standards]
Abstract:
Autors: Edson Prestes;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 176 - 176
Publisher: IEEE
 
» IEEE Technical Talk at Al Ain University [Around the Globe]
Abstract:
On 1 June 2016, the College of Engineering at Al Ain University of Science and Technology (AAU), in conjunction with the Joint Chapter of the UAE IEEE Microwave Theory and Techniques Society and IEEE Instrumentation and Measurement Society along with the IEEE AAU student branch, organized a technical talk, "The Engineering of the Human Joint: Advances in Orthopedics Research and Computer Navigation" presented by Dr. Farid Amirouche of the University of Illinois at Chicago, United States.
Autors: Nazih Khaddaj Mallat;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2017, volume: 18, issue:6, pages: 139 - 139
Publisher: IEEE
 
» Image Restoration: From Sparse and Low-Rank Priors to Deep Priors [Lecture Notes]
Abstract:
The use of digital imaging devices, ranging from professional digital cinema cameras to consumer grade smartphone cameras, has become ubiquitous. The acquired image is a degraded observation of the unknown latent image, while the degradation comes from various factors such as noise corruption, camera shake, object motion, resolution limit, hazing, rain streaks, or a combination of them. Image restoration (IR), as a fundamental problem in image processing and low-level vision, aims to reconstruct the latent high-quality image from its degraded observation. Image degradation is, in general, irreversible, and IR is a typical ill-posed inverse problem. Due to the large space of natural image contents, prior information on image structures is crucial to regularize the solution space and produce a good estimation of the latent image. Image prior modeling and learning then are key issues in IR research. This lecture note describes the development of image prior modeling and learning techniques, including sparse representation models, low-rank models, and deep learning models.
Autors: Lei Zhang;Wangmeng Zuo;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 172 - 179
Publisher: IEEE
 
» Imagined Hand Clenching Force and Speed Modulate Brain Activity and Are Classified by NIRS Combined With EEG
Abstract:
Simultaneous acquisition of brain activity signals from the sensorimotor area using NIRS combined with EEG, imagined hand clenching force and speed modulation of brain activity, as well as 6-class classification of these imagined motor parameters by NIRS-EEG were explored. Near infrared probes were aligned with C3 and C4, and EEG electrodes were placed midway between the NIRS probes. NIRS and EEG signals were acquired from six healthy subjects during six imagined hand clenching force and speed tasks involving the right hand. The results showed that NIRS combined with EEG is effective for simultaneously measuring brain activity of the sensorimotor area. The study also showed that in the duration of (0, 10) s for imagined force and speed of hand clenching, HbO first exhibited a negative variation trend, which was followed by a negative peak. After the negative peak, it exhibited a positive variation trend with a positive peak about 6–8 s after termination of imagined movement. During (−2, 1) s, the EEG may have indicated neural processing during the preparation, execution, and monitoring of a given imagined force and speed of hand clenching. The instantaneous phase, frequency, and amplitude feature of the EEG were calculated by Hilbert transform; HbO and the difference between HbO and Hb concentrations were extracted. The features of NIRS and EEG were combined to classify three levels of imagined force [at 20/50/80% MVGF (maximum voluntary grip force)] and speed (at 0.5/1/2 Hz) of hand clenching by SVM. The average classification accuracy of the NIRS-EEG fusion feature was 0.74 ± 0.02. These results may provide increased control commands of force and speed for a brain-controlled robot based on NIRS-EEG.
Autors: Yunfa Fu;Xin Xiong;Changhao Jiang;Baolei Xu;Yongcheng Li;Hongyi Li;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2017, volume: 25, issue:9, pages: 1641 - 1652
Publisher: IEEE
 
» Imitation Learning for Dynamic VFI Control in Large-Scale Manycore Systems
Abstract:
Manycore chips are widely employed in high-performance computing and large-scale data analysis. However, the design of high-performance manycore chips is dominated by power and thermal constraints. In this respect, voltage–frequency island (VFI) is a promising design paradigm to create scalable energy-efficient platforms. By dynamically tailoring the voltage and frequency of each island, we can further improve the energy savings within given performance constraints. Inspired by the recent success of imitation learning (IL) in many application domains and its significant advantages over reinforcement learning (RL), we propose the first architecture-independent IL-based methodology for dynamic VFI (DVFI) control in manycore systems. Due to its popularity in the EDA community, we consider an RL-based DVFI control methodology as a strong baseline. Our experimental results demonstrate that IL is able to obtain higher quality policies than RL (on average, 5% less energy with the same level of performance) with significantly less computation time and hardware area overheads (3.1X and 8.8X, respectively).
Autors: Ryan Gary Kim;Wonje Choi;Zhuo Chen;Janardhan Rao Doppa;Partha Pratim Pande;Diana Marculescu;Radu Marculescu;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2017, volume: 25, issue:9, pages: 2458 - 2471
Publisher: IEEE
 
» Impact of Using a Robot Patient for Nursing Skill Training in Patient Transfer
Abstract:
In the past few decades, simulation training has been used to help nurses improve their patient-transfer skills. However, the effectiveness of such training remains limited because it lacks effective ways of simulating patients’ actions realistically. It is difficult for nurses to use the skills learned from simulation training to transfer an actual patient. Therefore, we developed a robot patient that could simulate the behavior of patients’ limbs for patient-transfer training. This study examined the performance of the robot used in training and evaluated its training effectiveness. Four nursing teachers individually transferred the robot patient and then scored the robot patient's ability to simulate patients’ actions and its suitability for skill training. An experiment using pre-post control group design was carried out to examine the robot patient's training effectiveness compared with the human simulated patient. The participants were 20 nursing students and one nursing teacher who was responsible for scoring the students’ skills in the pre-test and post-test. All of the students were assigned to train with either the proposed robot patient or a healthy person simulating the patient. The results show that all four nursing teachers regarded the robot patient's actions as realistic. In addition, all four teachers agreed that the robot patient was suitable for skill training. The results also show that the proposed robot patient is more challenging than the current method, which employs a healthy person to simulate the patient. Significant skill improvement (p < 0.01) was observed in the experimental group when transferring the robot patient.
Autors: Zhifeng Huang;Chingszu Lin;Masako Kanai-Pak;Jukai Maeda;Yasuko Kitajima;Mitsuhiro Nakamura;Noriaki Kuwahara;Taiki Ogata;Jun Ota;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Sep 2017, volume: 10, issue:3, pages: 355 - 366
Publisher: IEEE
 
» Impedance Modeling of Three-Phase Voltage Source Converters in DQ, Sequence, and Phasor Domains
Abstract:
This paper presents a modular approach for the impedance modeling of three-phase voltage source converters (VSC) by representing the VSC dynamics using three-by-three transfer matrix in the dq, sequence, and phasor domains. The transfer matrix form simplifies the modeling process by separately modeling the ac and dc side dynamics, and describing the VSC dynamics independent of the ac and dc side networks. It also explicitly captures coupling among the dominant frequency components of the ac and dc side voltages and currents in the off-diagonal elements. Modeling of the VSC ac and dc side impedances, including the effects of the network on the other side of the VSC, is presented using the transfer matrix models. Transfer matrix based impedance modeling in the three domains and several stability analysis case studies are presented for a VSC-based HVDC station in an offshore wind farm. It is shown that the coupling between the ac and dc networks, and between the positive and negative sequence components of the three-phase quantities, play an important role in the low-frequency stability of the VSC. Impedance models and stability analysis predictions are validated using the wind farm simulations.
Autors: Shahil Shah;Leila Parsa;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1139 - 1150
Publisher: IEEE
 
» Implementation of LLMF Control Algorithm for Three-Phase Grid-Tied SPV-DSTATCOM System
Abstract:
This paper proposes a three-phase single-stage grid integrated solar photovoltaic distributed static compensator (SPV-DSTATCOM) system using a leaky least mean fourth (LLMF) control algorithm. The prime contributions of this paper include: 1) the SPV generating system, which fulfills the active power requirement of connected loads and supplies the excess power to the grid; 2) the voltage-source converter (VSC) acts as a dc–ac inverter and DSTATCOM, which provides reactive power compensation, harmonics filtering, load balancing, power factor correction, zero voltage regulation, and mitigates several other power quality issues; 3) even when the SPV power is unavailable, the VSC operates as a DSTATCOM, which enhances the utilization factor of devices; and 4) the LLMF-based control approach for fundamental component extraction from load currents for good harmonics compensation as well as to keep the overall system stable and to achieve rapid response at changing conditions. The proposed system is modeled and simulated using MATLAB/Simulink as well as its performance is verified experimentally on a developed prototype.
Autors: Rahul Kumar Agarwal;Ikhlaq Hussain;Bhim Singh;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7414 - 7424
Publisher: IEEE
 
» Improve Control to Output Dynamic Response and Extend Modulation Index Range With Hybrid Selective Harmonic Current Mitigation-PWM and Phase-Shift PWM for Four-Quadrant Cascaded H-Bridge Converters
Abstract:
The selective harmonic current mitigation pulsewidth modulation (SHCM-PWM) technique can be used in cascaded multilevel converters to extend the harmonic reduction spectrum, reduce the coupling inductance and increase the efficiency. The offline SHCM-PWM technique has small number of switching transitions as its switching angles can only change once in a fundamental cycle and relatively long time delays because it uses FFT. As a result, its dynamic response has a lot to desire. As it will be proven in this paper, in four-quadrant power converters, to have a good transient dynamic response, both active and reactive power must be controlled at least two times in a fundamental cycle. In this paper, a hybrid modulation technique is introduced. The proposed technique uses SHCM-PWM under steady state and phase-shift PWM (PSPWM) under transient. In addition, in order to extend the modulation index range and ensure that SHCM-PWM can process four-quadrant active and reactive power, the constraints of the switching angles for the SHCM-PWM are modified. Simulations and experiments are conducted on a seven-level cascaded H-bridge converter to verify the proposed technique.
Autors: Amirhossein Moeini;Hui Zhao;Shuo Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 6854 - 6863
Publisher: IEEE
 
» Improved 3-D Analytical Model for Axial-Flux Eddy-Current Couplings With Curvature Effects
Abstract:
An improved 3-D analytical model for axial-flux permanent-magnet eddy-current couplings is presented in this paper. As the problem is solved in a 3-D cylindrical coordinate system, the proposed model directly takes into account the radial edge effects and the curvature effects on the torque prediction without the need of any correction factor. It is shown that, the new analytical model is very accurate, even for the geometries where the curvature effects are very pronounced. Another advantage of the proposed model is the great reduction of computation time compared to 3-D finite-elements simulations and an easier adaptation for parametric studies and optimization.
Autors: Thierry Lubin;Abderrezak Rezzoug;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 9
Publisher: IEEE
 
» Improved Carry-in Workload Estimation for Global Multiprocessor Scheduling
Abstract:
As an important and fundamental tool for analyzing the schedulability of a real-time task set on the multiprocessor platform, response time analysis (RTA) has been researched for several years on both Global Fixed Priority (G-FP) and Global Earliest Deadline First (G-EDF) scheduling. This paper proposes a new analysis that improves over current state-of-the-art RTA methods for both G-FP and G-EDF scheduling, by reducing their pessimism. The key observation is that when estimating the carry-in workload, all the existing RTA techniques depend on the worst case scenario in which the carry-in job should execute as late as possible and just finishes execution before its worst case response time (WCRT). But the carry-in workload calculated under this assumption may be over-estimated, and thus the accuracy of the response time analysis may be impacted. To address this problem, we first propose a new method to estimate the carry-in workload more precisely. The proposed method does not depend on any specific scheduling algorithm and can be used for both G-FP and G-EDF scheduling. We then propose a general RTA algorithm that can improve most existing RTA tests by incorporating our carry-in estimation method. To further improve the execution efficiency, we also introduce an optimization technique for our RTA tests. Experiments with randomly generated task sets are conducted and the results show that, compared with the state-of-the-art technologies, the proposed tests exhibit considerable performance improvements, up to 9 and 7.8 percent under G-FP and G-EDF scheduling respectively, in terms of schedulability test precision.
Autors: Quan Zhou;Guohui Li;Jianjun Li;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2527 - 2538
Publisher: IEEE
 
» Improved Contrast-Enhanced Power Doppler Using a Coherence-Based Estimator
Abstract:
While plane-wave imaging can improve the performance of power Doppler by enabling much longer ensembles than systems using focused beams, the long-ensemble averaging of the zero-lag autocorrelation R(0) estimates does not directly decrease the mean noise level, but only decreases its variance. Spatial variation of the noise due to the time-gain compensation and the received beamforming aperture ultimately limits sensitivity. In this paper, we demonstrate that the performance of power Doppler imaging can be improved by leveraging the higher lags of the autocorrelation [e.g., R(1), R(2),…] instead of the signal power (R(0)). As noise is completely uncorrelated from pulse-to-pulse while the flow signal remains correlated significantly longer, weak signals just above the noise floor can be made visible through the reduction of the noise floor. Finally, as coherence decreases proportionally with respect to velocity, we demonstrate how signal coherence can be targeted to separate flows of different velocities. For instance, we show how long-time-range coherence of microbubble contrast-enhanced flow specifically isolates slow capillary perfusion (as opposed to conduit flow).
Autors: Charles Tremblay-Darveau;Avinoam Bar-Zion;Ross Williams;Paul S. Sheeran;Laurent Milot;Thanasis Loupas;Dan Adam;Matthew Bruce;Peter N. Burns;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2017, volume: 36, issue:9, pages: 1901 - 1911
Publisher: IEEE
 
» Improved Dynamic Dependability Assessment Through Integration With Prognostics
Abstract:
The use of average data for dependability assessments results in an outdated system-level dependability estimation, which can lead to incorrect design decisions. With increasing availability of online data, there is room to improve traditional dependability assessment techniques. Namely, prognostics is an emerging field, which provides asset-specific failure information that can be reused to improve the system-level failure estimation. This paper presents a framework for prognostics-updated dynamic dependability assessment. The dynamic behavior comes from runtime updated information, asset interdependencies, and time-dependent system behavior. A case study from the power generation industry is analyzed, and results confirm the validity of the approach for improved near real-time unavailability estimations.
Autors: Jose Ignacio Aizpurua;Victoria M. Catterson;Yiannis Papadopoulos;Ferdinando Chiacchio;Gabriele Manno;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 893 - 913
Publisher: IEEE
 
» Improved Handover Through Dual Connectivity in 5G mmWave Mobile Networks
Abstract:
The millimeter wave (mmWave) bands offer the possibility of orders of magnitude greater throughput for fifth-generation (5G) cellular systems. However, since mmWave signals are highly susceptible to blockage, channel quality on any one mmWave link can be extremely intermittent. This paper implements a novel dual connectivity protocol that enables mobile user equipment devices to maintain physical layer connections to 4G and 5G cells simultaneously. A novel uplink control signaling system combined with a local coordinator enables rapid path switching in the event of failures on any one link. This paper provides the first comprehensive end-to-end evaluation of handover mechanisms in mmWave cellular systems. The simulation framework includes detailed measurement-based channel models to realistically capture spatial dynamics of blocking events, as well as the full details of Medium Access Control, Radio Link Control, and transport protocols. Compared with conventional handover mechanisms, this paper reveals significant benefits of the proposed method under several metrics.
Autors: Michele Polese;Marco Giordani;Marco Mezzavilla;Sundeep Rangan;Michele Zorzi;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 2069 - 2084
Publisher: IEEE
 
» Improved Model of Synchronous Generators Internal Faults Based on Circuit-Coupled FEM
Abstract:
A precise simulation of the internal faults of synchronous generators is crucial for the design of the main protection scheme; therefore, an accurate model is necessary. In this paper, based on the circuit-coupled finite element method (CCFEM), an improved model of a synchronous generator with internal faults is proposed, wherein the localized model of each stator coil is built as per its actual structure. Using this model, the internal fault occurring inside the coil can be accurately simulated, better approximating the location of the actual fault point; thus, the fault currents can be calculated more accurately. The accuracy of the improved model is verified by a dynamic simulation experiment. Moreover, the electromagnetic magnitudes, such as the air gap flux density, fault currents, field current, and all the damper currents are investigated in detail, under fault conditions, thereby revealing the fault characteristics more clearly and providing a basis for designing protection schemes.
Autors: Baojun Ge;Shiyong Xiao;Zhihui Liu;Dajun Tao;Xiaobo Sun;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 876 - 884
Publisher: IEEE
 
» Improved Perturbation Vector Generation Method for Accurate SRAM Yield Estimation
Abstract:
Accurate yield estimation under parametric variation is one of the most integral parts for robust and nonwasted circuit design. In particular, due to the significant impact of disparity on the high-replication circuit, precise yield estimation is essential in SRAM design. In this paper, we propose an enhanced perturbation vector generation method to improve the accuracy of the yield estimation of the conventional direct SRAM yield computation method, which are access disturb margin (ADM) and write margin (WRM) first, by splitting the concave yield metric space, the estimation error caused by linear approximation can be significantly reduced with minor increase in simulation runtime. In addition, to compensate the inaccuracy of the conventional perturbation vector, a calibration method to reflect the multi-dc condition in SRAM assist operations is also proposed. Numerical results show that 37% improved estimation accuracy and 29% reduced estimation error can be achieved compared to the conventional ADM/WRM in the wide voltage range.
Autors: Woong Choi;Jongsun Park;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Sep 2017, volume: 36, issue:9, pages: 1511 - 1521
Publisher: IEEE
 
» Improved Sorting Architecture for ${K}$ -Best MIMO Detection
Abstract:
This brief presents an improved sorting architecture for -best multiple-input multiple-output (MIMO) detection. In the proposed architecture, two properties of the -best MIMO detection are exploited for simplifications: the order among siblings from the same parent node can be easily identified; the order among the -best nodes is dispensable. Besides, the generalized mergesort-based architecture for the -best sorting is presented so that the proposed sorter can be constructed for any power-of-two and modulation scheme. Compared to the conventional ones, the proposed architecture lowers not only the hardware complexity but also the latency significantly.
Autors: Byeong Yong Kong;In-Cheol Park;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1042 - 1046
Publisher: IEEE
 
» Improved Statistical Fault Detection Technique and Application to Biological Phenomena Modeled by S-Systems
Abstract:
In our previous work, we have demonstrated the effectiveness of the linear multiscale principal component analysis (PCA)-based moving window (MW)-generalized likelihood ratio test (GLRT) technique over the classical PCA and multiscale principal component analysis (MSPCA)-based GLRT methods. The developed fault detection algorithm provided optimal properties by maximizing the detection probability for a particular false alarm rate (FAR) with different values of windows, and however, most real systems are nonlinear, which make the linear PCA method not able to tackle the issue of non-linearity to a great extent. Thus, in this paper, first, we apply a nonlinear PCA to obtain an accurate principal component of a set of data and handle a wide range of nonlinearities using the kernel principal component analysis (KPCA) model. The KPCA is among the most popular nonlinear statistical methods. Second, we extend the MW-GLRT technique to one that utilizes exponential weights to residuals in the moving window (instead of equal weightage) as it might be able to further improve fault detection performance by reducing the FAR using exponentially weighed moving average (EWMA). The developed detection method, which is called EWMA-GLRT, provides improved properties, such as smaller missed detection and FARs and smaller average run length. The idea behind the developed EWMA-GLRT is to compute a new GLRT statistic that integrates current and previous data information in a decreasing exponential fashion giving more weight to the more recent data. This provides a more accurate estimation of the GLRT statistic and provides a stronger memory that will enable better decision making with respect to fault detection. Therefore, in this paper, a KPCA-based EWMA-GLRT method is developed and utilized in practice to improve fault detection in biological phenomena modeled by S-systems and to enhance monitoring process mean. The idea behind a KPCA-based EWMA-GLRT fault detection algorithm is to com- ine the advantages brought forward by the proposed EWMA-GLRT fault detection chart with the KPCA model. Thus, it is used to enhance fault detection of the Cad System in E. coli model through monitoring some of the key variables involved in this model such as enzymes, transport proteins, regulatory proteins, lysine, and cadaverine. The results demonstrate the effectiveness of the proposed KPCA-based EWMA-GLRT method over , GLRT, EWMA, Shewhart, and moving window-GLRT methods. The detection performance is assessed and evaluated in terms of FAR, missed detection rates, and average run length (ARL1) values.
Autors: Majdi Mansouri;Mohamed N. Nounou;Hazem N. Nounou;
Appeared in: IEEE Transactions on NanoBioscience
Publication date: Sep 2017, volume: 16, issue:6, pages: 504 - 512
Publisher: IEEE
 
» Improved Synthetic Basis Functions Method for Nonperiodic Scaling Structures With Arbitrary Spatial Attitudes
Abstract:
Synthetic basis functions method (SBFM) is an improved approach of method of moment which utilizes fewer high-order synthetic functions to replace Rao-Wilton-Glisson functions to discretize surface currents and make inner products. Thus, this approach can drastically decrease the number of unknowns and lower the requirements of PC’s memory. Especially for periodic structures, computational efficiency will be improved sharply since synthetic functions defined on different subblocks can be set identical and the process of constructing synthetic functions needs to be calculated only once. However, for nonperiodic structures, this advantage no longer exists due to the diversities of synthetic functions defined on different subblocks. In that case, synthetic functions need to be calculated block by block. Targeted at this problem, an improved SBFM is proposed for nonperiodic scaling structures whose subblocks only share identical/similar contour features, but spatial attitudes, spatial positions, and geometrical sizes can be arbitrary. Based on theoretical analysis, the improved SBFM employs a special triangulating method for each subblock which makes synthetic functions defined on them reusable. In this way, synthetic functions need to be calculated only once too for nonperiodic scaling structures. Compared to traditional SBFM, this approach decreases the elapsed time of constructing synthetic functions and memory cost of synthetic functions’ expansion coefficients to ( is the number of subblocks) and is of great help in the analysis of large scale targets such as complex nonperiodic arrays. Finally, accuracy of this approach is validated by both simulating and measured results.
Autors: Yanlin Xu;Hu Yang;Junqi Lu;Weikang Yu;Wenlu Yin;Da Peng;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4728 - 4741
Publisher: IEEE
 
» Improved Synthetic Power Grid Modeling With Correlated Bus Type Assignments
Abstract:
This paper presents our study results on the correlated assignment of generation, load, or connection buses in a given grid topology and the development of an optimized search algorithm to improve the proposed synthetic grid model, called RT-nestedSmallWorld. A numerical measure, called “bus type entropy”, was proposed in an initial study on this subject to characterize the correlation of bus type assignments in realistic grids. In this paper, its definition has been redefined and improved with the help of some newly obtained data of realistic grids so that the scaling property of a real-world grid's entropy value versus the network size can be effectively captured with a curve-fitting approach. With the help of the derived scaling function, we will be able to determine an appropriate target entropy value that a correlated bus type assignment should assume in a specific N-bus grid network. Therefore, our previously proposed synthetic power grid modeling has been enhanced with a direct search procedure for the best bus type assignments in a specific N-bus grid topology, saving the mandatory, but most of the time unattainable, requirement of a set of realistic grid data with a comparable network size for identifying the search target. Finally, the performance of the proposed approach is examined based on some available grid data including the IEEE test cases, the NYISO-2935, the ERCOT-5633, and the WECC-16994 systems.
Autors: Seyyed Hamid Elyas;Zhifang Wang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3391 - 3402
Publisher: IEEE
 
» Improved Tangent Space-Based Distance Metric for Lithographic Hotspot Classification
Abstract:
A distance metric of patterns is crucial to hotspot cluster analysis and classification. In this paper, we propose an improved tangent space (ITS)-based distance metric for hotspot cluster analysis and classification. The proposed distance metric is an important extension of the well-developed tangent space method in computer vision. It can handle patterns containing multiple polygons, while the traditional tangent space method can only deal with patterns with a single polygon. It inherits most of the advantages of the traditional tangent space method, e.g., it is easy to compute and is tolerant with small variations or shifts of the shapes. The ITS-based distance metric is a more reliable and accurate metric for hotspot cluster analysis and classification. We also propose a hierarchical density-based clustering method for hotspot clustering. It is more suitable for arbitrary shaped clusters.
Autors: Fan Yang;Subarna Sinha;Charles C. Chiang;Xuan Zeng;Dian Zhou;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Sep 2017, volume: 36, issue:9, pages: 1545 - 1556
Publisher: IEEE
 
» Improvement of AMSR2 Soil Moisture Products Over South Korea
Abstract:
Soil moisture (SM) is a critical parameter for interpreting the status of land surfaces and vegetation because it has an important role in the exchange of water and heat energy between the land surface and atmosphere. SM can be retrieved with satellite microwave sensors, which offer several advantages in that they are cost-effective, give rapid results, and provide data for inaccessible or isolated areas. In addition, these sensors cover large areas and perform periodic multi-channel observations. The advanced microwave scanning radiometer-2 (AMSR2), a successor of Advanced Microwave Scanning Radiometer for the Earth Observing System, provides regular global SM data products, which the Korea Meteorological Administration uses to calculate daily mean and seven-day moving window SM do not agree well with ground measurements in South Korea, and must be corrected for reliable drought monitoring. In this study, we used Global Land Data Assimilation System SM data to calibrate AMSR2 SM. In addition, we applied and combined two methods to correct AMSR2 SM: 1) linear regression with input variables, including insolation, daily precipitation, and the normalized difference vegetation index and 2) the cumulative distribution function (CDF) matching method. The results of the combined linear regression and CDF matching method were in better agreement with the in situ data than those of either method alone. Correcting AMSR2 SM by using the combined method improved the correlation coefficient (R) from 0.19 to 0.59 and the root-mean-square error from 0.23 to 0.09.
Autors: Chang Suk Lee;Jun Dong Park;Jinho Shin;Jae-Dong Jang;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Sep 2017, volume: 10, issue:9, pages: 3839 - 3849
Publisher: IEEE
 
» Improvement of Back-EMF Self-Sensing For Induction Machines When Using Deadbeat-Direct Torque and Flux Control
Abstract:
Back-electromotive force (back-EMF) self-sensing is commonly used in induction machine (IM) drive systems for its maintenance cost and safety considerations. In recent years, compared with standard indirect field oriented control, deadbeat-direct torque and flux control (DB-DTFC) has been shown to be a highly effective method for IM control with a fixed switching frequency. It has advantages such as fast torque dynamics with one step dynamic response for torque and flux with no current regulator. This paper evaluates the synergy between back-EMF self-sensing technology and DB-DTFC for IM drive systems. In this paper, an observer-based closed-loop back-EMF tracking self-sensing control in an IM DB-DTFC drive system is presented. It includes a back-EMF state filter, back-EMF tracking observer, and cascaded motion observer. Back-EMF harmonic decoupling is explored to improve the low-speed performance. The band-pass filter method (BPF) for back-EMF self-sensing is also presented. Finally, the closed loop system dynamic stiffness at very low speeds, with and without the BPF method, is experimentally evaluated.
Autors: Kang Wang;Robert D. Lorenz;Noor Aamir Baloch;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2017, volume: 53, issue:5, pages: 4569 - 4578
Publisher: IEEE
 
» Improvement of Pyramidal Tract Side Effect Prediction Using a Data-Driven Method in Subthalamic Stimulation
Abstract:
Objective: subthalamic nucleus deep brain stimulation (STN DBS) is limited by the occurrence of a pyramidal tract side effect (PTSE) induced by electrical activation of the pyramidal tract. Predictive models are needed to assist the surgeon during the electrode trajectory preplanning. The objective of the study was to compare two methods of PTSE prediction based on clinical assessment of PTSE induced by STN DBS in patients with Parkinson's disease. Methods: two clinicians assessed PTSE postoperatively in 20 patients implanted for at least three months in the STN. The resulting dataset of electroclinical tests was used to evaluate two methods of PTSE prediction. The first method was based on the volume of tissue activated (VTA) modeling and the second one was a data-driven-based method named Pyramidal tract side effect Model based on Artificial Neural network (PyMAN) developed in our laboratory. This method was based on the nonlinear correlation between the PTSE current threshold and the 3-D electrode coordinates. PTSE prediction from both methods was compared using Mann–Whitney U test. Results: 1696 electroclinical tests were used to design and compare the two methods. Sensitivity, specificity, positive- and negative-predictive values were significantly higher with the PyMAN method than with the VTA-based method (P < 0.05). Conclusion: the PyMAN method was more effective than the VTA-based method to predict PTSE. Significance: this data-driven tool could help the neurosurgeon in predicting adverse side effects induced by DBS during the electrode trajectory preplanning.
Autors: Clement Baumgarten;Yulong Zhao;Paul Sauleau;Cecile Malrain;Pierre Jannin;Claire Haegelen;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2134 - 2141
Publisher: IEEE
 
» Improvement of the Frequency Characteristics of Graphene Field-Effect Transistors on SiC Substrate
Abstract:
Analog applications attract increasing interest for graphene field-effect transistors (GFETs). GFET with a cutoff frequency of up to 427 GHz has been reported; however, the device suffered from the large parasitic parameters and poor drain current saturation, which made their maximum oscillation frequency lower than the cutoff frequency. In this letter, quasi-free-standing bilayer graphene transistors with a gate length of 60 nm and ultra-thin gate dielectric are fabricated by an improved, self-aligned, process. Good gate coupling is achieved, and parasitic parameters are suppressed to a significant extent. The as-measured extrinsic cutoff frequency reaches 70 GHz and the maximum oscillation frequency reaches 120 GHz, which are the highest extrinsic frequencies reported for graphene transistors to date. Our results show the application potential of graphene RF devices in future high-speed electronic systems.
Autors: C. Yu;Z. Z. He;X. B. Song;Q. B. Liu;T. T. Han;S. B. Dun;J. J. Wang;C. J. Zhou;J. C. Guo;Y. J. Lv;Z. H. Feng;S. J. Cai;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1339 - 1342
Publisher: IEEE
 
» Improvement of Torque Capability of Permanent-Magnet Motor by Using Hybrid Rotor Configuration
Abstract:
This paper proposes a novel hybrid rotor permanent-magnet (HRPM) motor to improve torque capability, including average torque and torque ripple. The key of the proposed motor is that it can utilize high PM torque of surface-inserted PM (SPM) rotor module and high reluctance torque of interior PM (IPM) rotor module at the same time. Meanwhile, the shifting angle of SPMs and open angle of air barriers are introduced to improve the average torque and reduce the torque ripple, respectively. The two variables are employed to create circumferential asymmetry of the rotor for generating an angular difference of the electromagnetic torque between adjacent N-pole and S-pole, thus minimizing torque ripple. In order to evaluate the proposed motor, an IPM motor and a SPM motor with the same dimension and volume of PM are used as benchmarks. Through theoretical analysis and experimental test, it is verified that the proposed HRPM motor can offer higher torque density and lower torque ripple simultaneously.
Autors: Guohai Liu;Gaohong Xu;Wenxiang Zhao;Xinxin Du;Qian Chen;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 953 - 962
Publisher: IEEE
 
» Improvements of Interfacial and Electrical Properties for Ge MOS Capacitor by Using TaYON Interfacial Passivation Layer and Fluorine Incorporation
Abstract:
Ge metal–oxide–semiconductor capacitor with HfTiON/TaYON stacked gate dielectric treated by fluorine plasma is fabricated, and its interfacial and electrical properties are compared with its counterparts without the TaYON interfacial passivation layer or the fluorine-plasma treatment. Experimental results show that the sample exhibits excellent performances: low interface-state density ( cmeV, small flatband voltage (0.34 V), good capacitance–voltage behavior, small frequency dispersion, and low gate leakage current ( A/cm2 at V). These should be attributed to the suppressed growth of unstable Ge oxides on the Ge surface during gate dielectric annealing by the TaYON interlayer and fluorine incorporation, thus greatly reducing the defective states at/near the TaYON/Ge interface and improving the electrical properties of the device.
Autors: Yong Huang;Jing-Ping Xu;Lu Liu;Zhi-Xiang Cheng;Pui-To Lai;Wing-Man Tang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3528 - 3533
Publisher: IEEE
 
» Improving Execution Concurrency of Large-Scale Matrix Multiplication on Distributed Data-Parallel Platforms
Abstract:
Matrix multiplication is a dominant but very time-consuming operation in many big data analytic applications. Thus its performance optimization is an important and fundamental research issue. The performance of large-scale matrix multiplication on distributed data-parallel platforms is determined by both computation and IO costs. For existing matrix multiplication execution strategies, when the execution concurrency scales up above a threshold, their execution performance deteriorates quickly because the increase of the IO cost outweighs the decrease of the computation cost. This paper presents a novel parallel execution strategy CRMM (Concurrent Replication-based Matrix Multiplication) along with a parallel algorithm, Marlin, for large-scale matrix multiplication on data-parallel platforms. The CRMM strategy exploits higher execution concurrency for sub-block matrix multiplication with the same IO cost. To further improve the performance of Marlin, we also propose a number of novel system-level optimizations, including increasing the concurrency of local data exchange by calling native library in batch, reducing the overhead of block matrix transformation, and reducing disk heavy shuffle operations by exploiting the semantics of matrix computation. We have implemented Marlin as a library along with a set of related matrix operations on Spark and also contributed Marlin to the open-source community. For large-sized matrix multiplication, Marlin outperforms existing systems including Spark MLlib, SystemML and SciDB, with about , and speedup on average, respectively. The evaluation upon a real-world DNN workload also indicates that Marlin outperforms above systems by about , and speedup, respectively.
Autors: Rong Gu;Yun Tang;Chen Tian;Hucheng Zhou;Guanru Li;Xudong Zheng;Yihua Huang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2539 - 2552
Publisher: IEEE
 
» Improving Large-Scale Image Retrieval Through Robust Aggregation of Local Descriptors
Abstract:
Visual search and image retrieval underpin numerous applications, however the task is still challenging predominantly due to the variability of object appearance and ever increasing size of the databases, often exceeding billions of images. Prior art methods rely on aggregation of local scale-invariant descriptors, such as SIFT, via mechanisms including Bag of Visual Words (BoW), Vector of Locally Aggregated Descriptors (VLAD) and Fisher Vectors (FV). However, their performance is still short of what is required. This paper presents a novel method for deriving a compact and distinctive representation of image content called Robust Visual Descriptor with Whitening (RVD-W). It significantly advances the state of the art and delivers world-class performance. In our approach local descriptors are rank-assigned to multiple clusters. Residual vectors are then computed in each cluster, normalized using a direction-preserving normalization function and aggregated based on the neighborhood rank. Importantly, the residual vectors are de-correlated and whitened in each cluster before aggregation, leading to a balanced energy distribution in each dimension and significantly improved performance. We also propose a new post-PCA normalization approach which improves separability between the matching and non-matching global descriptors. This new normalization benefits not only our RVD-W descriptor but also improves existing approaches based on FV and VLAD aggregation. Furthermore, we show that the aggregation framework developed using hand-crafted SIFT features also performs exceptionally well with Convolutional Neural Network (CNN) based features. The RVD-W pipeline outperforms state-of-the-art global descriptors on both the Holidays and Oxford datasets. On the large scale datasets, Holidays1M and Oxford1M, SIFT-based RVD-W representation obtains a mAP of 45.1 and 35.1 percent, while CNN-based RVD-W achieve a mAP of 63.5 and 44.8 percent, all yielding superior performance to the - tate-of-the-art.
Autors: Syed Sameed Husain;Miroslaw Bober;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Sep 2017, volume: 39, issue:9, pages: 1783 - 1796
Publisher: IEEE
 
» Improving MOSFETs’ TID Tolerance Through Diamond Layout Style
Abstract:
This letter describes an experimental comparative study of the total ionizing dose (TID) effects due to Co-60 gamma irradiation between hexagonal (Diamond) and conventional rectangular gates metal-oxide semiconductor field-effect transistors (MOSFETs), regarding the same bias conditions during irradiation. The transistors were manufactured by using the 350 nm commercial bulk complementary metal-oxide semiconductor (CMOS) integrated-circuits (ICs) technology. The innovative hexagonal gate layout proposal can reduce the parameter deviations of TID effects in MOSFETs in, approximately, 30%, 400%, and 100% in terms of the threshold voltage, leakage drain current, and subthreshold slope, respectively, regarding the standard MOSFET counterparts. Therefore, the Diamond MOSFET can be considered as a low-cost alternative device to be used in space CMOS ICs applications.
Autors: L. E. Seixas;O. L. Gonçalez;R. Souza;S. Finco;R. G. Vaz;G. A. da Silva;S. P. Gimenez;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Sep 2017, volume: 17, issue:3, pages: 593 - 595
Publisher: IEEE
 
» Improving SAR Automatic Target Recognition Models With Transfer Learning From Simulated Data
Abstract:
Data-driven classification algorithms have proved to do well for automatic target recognition (ATR) in synthetic aperture radar (SAR) data. Collecting data sets suitable for these algorithms is a challenge in itself as it is difficult and expensive. Due to the lack of labeled data sets with real SAR images of sufficient size, simulated data play a big role in SAR ATR development, but the transferability of knowledge learned on simulated data to real data remains to be studied further. In this letter, we show the first study of Transfer Learning between a simulated data set and a set of real SAR images. The simulated data set is obtained by adding a simulated object radar reflectivity to a terrain model of individual point scatters, prior to focusing. Our results show that a Convolutional Neural Network (Convnet) pretrained on simulated data has a great advantage over a Convnet trained only on real data, especially when real data are sparse. The advantages of pretraining the models on simulated data show both in terms of faster convergence during the training phase and on the end accuracy when benchmarked on the Moving and Stationary Target Acquisition and Recognition data set. These results encourage SAR ATR development to continue the improvement of simulated data sets of greater size and complex scenarios in order to build robust algorithms for real life SAR ATR applications.
Autors: David Malmgren-Hansen;Anders Kusk;Jørgen Dall;Allan Aasbjerg Nielsen;Rasmus Engholm;Henning Skriver;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1484 - 1488
Publisher: IEEE
 
» Improving System Efficiency for the More Electric Aircraft: A Look at dc\/dc Converters for the Avionic Onboard dc Microgrid
Abstract:
The More Electric Aircraft (MEA) initiative aims to increase the penetration of electrical systems in aircraft to decrease weight and further develop overall efficiency and reliability [1]. Newer aircraft, such as the Boeing 787 and the Airbus A380, have more electrical power installed compared with older models, and this trend is not expected to change any time soon. Although most aircraft feature some amount of electrical power, this is often limited to the electronics (i.e., flight or entertainment systems) or auxiliary systems (i.e., lighting or anti-icing). The core systems of the actuation still rely on hydraulic power.
Autors: Giampaolo Buticchi;Levy Costa;Marco Liserre;
Appeared in: IEEE Industrial Electronics Magazine
Publication date: Sep 2017, volume: 11, issue:3, pages: 26 - 36
Publisher: IEEE
 
» Improving the Electrical Performance of a Quantum Well FET With a Shell Doping Profile by Heterojunction Optimization
Abstract:
This paper investigates the impacts of typical semiconductor material properties—electron affinity, bandgap, and dielectric constant, on the electrical performance of a p-type core–shell heterojunction nanowire FET by numerical simulations. At the heterojunction, a valence band offset of 200 meV forms a sufficient energy barrier confining the holes in the quantum well, resulting in the optimal OFF-state current. A higher dielectric constant of the shell region is found to be able to decrease the leakage current of the device. The optimum conditions from the parameter analysis are demonstrated by a realistic and achievable material combination of Si/SiGe for the core–shell configuration. This paper provides physical insights into the materialwise impacts for designing the proposed transistor showing the reduced OFF-current and a better subthreshold swing for low-power applications.
Autors: Malkundi Puttaveerappa Vijay Kumar;Chia-Ying Hu;Amey Mahadev Walke;Kuo-Hsing Kao;Tien-Sheng Chao;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3563 - 3568
Publisher: IEEE
 
» Incentive-Aware Time-Sensitive Data Collection in Mobile Opportunistic Crowdsensing
Abstract:
Data collection is a crucial operation in mobile opportunistic crowdsensing. The design of data collection is challenging due to the fact that smart devices have limited resources to conduct complex computation and sensing tasks in mobile opportunistic networks. In this paper, we propose a time-sensitive incentive-aware mechanism for mobile opportunistic crowdsensing data collection, in which each sensing data has an attached time-sensitive value that decays over time. We focus on the cooperative data collection problem in mobile opportunistic crowdsensing, where data collectors cooperate with mobile users to send data back to requesters. However, due to the selfishness of mobile users, we use an incentive mechanism to stimulate the mobile users to participate in the data collection. The objective is to maximize data collectors’ and mobile relay users’ rewards. We formulate the interaction among data carrier and mobile relay users as a two-user cooperative game, we apply the asymmetric Nash bargain solution to obtain the optimal cooperation decision and transfer payment. Extensive simulation results based on the real-world traces are provided to validate the superiority of our proposed schemes.
Autors: Yufeng Zhan;Yuanqing Xia;Yang Liu;Fan Li;Yu Wang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 7849 - 7861
Publisher: IEEE
 
» Incomplete-Leaf Multilevel Fast Multipole Algorithm for Multiscale Penetrable Objects Formulated With Volume Integral Equations
Abstract:
Recently introduced incomplete-leaf (IL) tree structures for multilevel fast multipole algorithm (referred to as IL-MLFMA) is proposed for the analysis of multiscale inhomogeneous penetrable objects, in which there are multiple orders of magnitude differences among the mesh sizes. Considering a maximum Schaubert–Wilton–Glisson function population threshold per box, only overcrowded boxes are recursively divided into proper smaller boxes, leading to IL tree structures consisting of variable box sizes. Such an approach: 1) significantly reduces the CPU time for near-field calculations regarding overcrowded boxes, resulting a superior efficiency in comparison with the conventional MLFMA where fixed-size boxes are used and 2) effectively reduces the computational error of the conventional MLFMA for multiscale problems, where the protrusion of the basis/testing functions from their respective boxes dramatically impairs the validity of the addition theorem. Moreover, because IL-MLFMA is able to use deep levels safely and without compromising the accuracy, the memory consumption is significantly reduced compared with that of the conventional MLFMA. Several examples are provided to assess the accuracy and the efficiency of IL-MLFMA for multiscale penetrable objects.
Autors: Manouchehr Takrimi;Özgür Ergül;Vakur B. Ertürk;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4914 - 4918
Publisher: IEEE
 
» Individual Secrecy for the Broadcast Channel
Abstract:
This paper studies the problem of secure communications over broadcast channels under the individual secrecy constraints. That is, the transmitter wants to send two independent messages to two legitimate receivers in the presence of an eavesdropper, while keeping the eavesdropper ignorant of each message (i.e., the information leakage rate from each message to the eavesdropper is made vanishing). Building upon Carleial–Hellman’s secrecy coding, Wyner’s secrecy coding, and the framework of Marton’s coding together with techniques, such as rate splitting and indirect decoding, an achievable individual secrecy rate region is established with the characterization of capacity regions for some special cases. In particular, the individual secrecy capacity region for the linear deterministic model is fully characterized, and for the Gaussian model, a constant gap (i.e., 0.5 b within the individual secrecy capacity region) result is obtained. To illustrate the impact of different secrecy constraints on the corresponding capacity regions, comparisons are made with those satisfying joint secrecy and without secrecy constraints. Overall, when compared with the joint secrecy constraint, the results allow for trading off secrecy level and throughput in the system.
Autors: Yanling Chen;O. Ozan Koyluoglu;Aydin Sezgin;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5981 - 5999
Publisher: IEEE
 
» Indoor Airborne Ultrasonic Wireless Communication Using OFDM Methods
Abstract:
Concerns still exist over the safety of prolonged exposure to radio frequency (RF) wireless transmissions and there are also potential data security issues due to remote signal interception techniques such as Bluesniping. Airborne ultrasound may be used as an alternative to RF for indoor wireless communication systems for securely transmitting data over short ranges, as signals are difficult to intercept from outside the room. Two types of air-coupled capacitive ultrasonic transducer were used in the implementation of an indoor airborne wireless communication system. One was a commercially available SensComp series 600 ultrasonic transducer with a nominal frequency of 50 kHz, and the other was a prototype transducer with a high- dielectric layer operating at higher frequencies from 200 to 400 kHz. Binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and quadrature amplitude modulation (QAM)-based orthogonal frequency division multiplexing modulation methods were successfully implemented using multiple orthogonal subchannels. The modulated ultrasonic signal packets were synchronized using a wireless link, and a least-squares channel estimation algorithm was used to compensate the phase and amplitude distortion introduced by the air channel. By sending and receiving the ultrasonic signals using the SensComp transducers, the achieved maximum system data rate was up to 180 kb/s using 16-QAM with ultrasonic channels from 55 to 99 kHz, over a line-of-sight transmission distance of 6 m with no detectable errors. The transmission range could be extended to 9 and 11 m using QPSK and BPSK modulation schemes, respectively. The achieved data rates for the QPSK and BPSK schemes were 90 and 45 kb/s using the same bandwidth. For the high- ultrasonic transducers, a maximum data rate up to 800 kb/s with no measura- le errors was achieved up to a range of 0.7 m. The attainable transmission ranges were increased to 1.1 and 1.2 m with data rates of 400 and 200 kb/s using QPSK and BPSK, respectively.
Autors: Wentao Jiang;William M. D. Wright;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1345 - 1353
Publisher: IEEE
 
» Inertia Emulation in AC/DC Interconnected Power Systems Using Derivative Technique Considering Frequency Measurement Effects
Abstract:
Virtual inertia is known as an inevitable part of the modern power systems with high penetration of renewable energy. Recent trend of research is oriented in different methods of emulating the inertia to increase the sustainability of the system. In the case of dynamic performance of power systems especially in Automatic Generation Control (AGC) issue, there are concerns considering the matter of virtual inertia. This paper proposes an approach for analyzing the dynamic effects of virtual inertia in two-area AC/DC interconnected AGC power systems. Derivative control technique is used for higher level control application of inertia emulation. This method of inertia emulation is developed for two-area AGC system, which is connected by parallel AC/DC transmission systems. Based on the proposed technique, the dynamic effect of inertia emulated by storage devices for frequency and active power control are evaluated. The effects of frequency measurement delay and phase-locked loop effect are also considered by introducing a second-order function. Simulations performed by MATLAB software demonstrate how virtual inertia emulation can effectively improve the performance of the power system. A detailed eigenvalue analysis is also performed to support the positive effects of the proposed method.
Autors: Elyas Rakhshani;Pedro Rodriguez;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3338 - 3351
Publisher: IEEE
 
» Inference for Multicomponent Systems With Dependent Failures
Abstract:
Multicomponent systems may experience failures with correlations amongst failure times of groups of components, and some subsets of components may experience common cause, simultaneous failures. We present a novel, general approach to model construction and inference in multicomponent systems incorporating these correlations in an approach that is tractable even in very large systems. In our formulation, the system is viewed as being made up of independent overlapping subsystems (IOS). In these systems, components are grouped together into overlapping subsystems, and further into nonoverlapping subunits. Each subsystem has an independent failure process, and each component's failure time is the time of the earliest failure in all of the subunits of which it is a part. We apply this method to observations of an IOS model based on a multicomponent system accumulating damage due to a series of shocks, and with no repair/rectification actions. The model associates individual shock processes with each subsystem, and includes the Marshall–Olkin multivariate exponential model as a special case. We present approaches to simulation and to the estimation of the parameters of the model, given component failure data for various system configurations (series, parallel, and other arrangements).
Autors: Richard Arnold;Stefanka Chukova;Yu Hayakawa;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 616 - 629
Publisher: IEEE
 
» Influence of Anatomical Detail and Tissue Conductivity Variations in Simulations of Multi-Contact Nerve Cuff Recordings
Abstract:
Accurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters. To construct the model, in vivo recordings were obtained in a rat sciatic nerve using an 8-channel nerve cuff electrode, after which the nerve was imaged using magnetic resonance imaging (MRI). The FE model was constructed based on the MRI data, and included progressive branching of the fascicles. Neural pathways were defined in the model for the tibial, peroneal and sural fascicles. The locations of these pathways were selected so as to maximize the correlations between the simulated and in vivo recordings. The sensitivity analysis showed that varying the conductivities of neural tissues had little influence on the ability of the model to reproduce the recording patterns obtained experimentally. On the other hand, the increased anatomical detail did substantially alter the recording patterns observed, demonstrating that incorporating fascicular branching is an important consideration in models of nerve cuff recordings. The model used in this study constitutes an improved simulation tool and can be used in the design of neural interfaces.
Autors: Purbasha Garai;Ryan G. L. Koh;Martin Schuettler;Thomas Stieglitz;José Zariffa;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2017, volume: 25, issue:9, pages: 1653 - 1662
Publisher: IEEE
 
» Influence of Axial Magnetic Field on Cathode Plasma Jets in High-Current Vaccum Arc
Abstract:
The cathode plasma jets in vacuum arc and the effect of magnetic field on them have been studied for several years and these studies are helpful to understand the arc characteristics and improve the controlling effect of magnetic field on arc plasma. In this paper, the experiments of the cup-shaped axial magnetic field (AMF) contacts were conducted in which a Helmholtz coil was introduced to generate different external imposed AMFs. It was found that the appearance of arc plasma was changed by variation of the external imposed AMF. If the composite AMF in arc column increased gradually, the obvious individual cathode plasma jets were detected, the arc constriction decreased, and the arc stability increased. Meanwhile, the inclination of cathode plasma jets was observed and the inclination direction was found to be consistent with the magnetic field vector direction which is closely related to the composite AMF. By variation of the external imposed AMF and its direction, the inclination direction of cathode plasma jets also changed. The criterion to detect obvious cathode jets in arc column is obtained that at the contact peripheral where R> 80.5% R0 (R0 is the contact radius), the AMF strength is no less than 4.5 mT/kA. It was also found that if the composite AMF in interelectrode gap points to different directions at a certain moment, it may lead to the transfer of arc column from the center to the edge of the interelectrode region and the arc instability until when the composite AMF in the interelectrode gap points to the same direction. It can be concluded that the appearance of individual cathode plasma jets can be manipulated by the variation of AMF, which is helpful to study the interaction between arc plasma and electrodes, especially the anode, and improve the interruption performance at higher current.
Autors: Dingge Yang;Shenli Jia;Weidong Qi;Jingfeng Wu;Sen Wang;Yanhua Han;Bin Ding;Heng Zhang;Wenhui Li;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2596 - 2603
Publisher: IEEE
 
» Influence of Drain Doping Engineering on the Ambipolar Conduction and High-Frequency Performance of TFETs
Abstract:
In this paper, the effect of a proposed drain doping engineering on the ambipolar conduction and high-frequency performance of tunneling FETs (TFETs) is investigated using 2-D TCAD simulations. The proposed TFET structure is based on using a high-doped region above a low-doped region of the drain side. It is demonstrated that when splitting the drain into two regions, one with high doping above the other of low doping, the tunneling width at the channel–drain interface increases. This increase in the tunneling width causes an appreciable reduction of ambipolar current in the TFET. Moreover, high-frequency figures of merit regarding the transconductance (), source-to-gate and drain-to-gate capacitances, and unit-gain cutoff frequency () are analyzed. It is found that the combination of drain doping regions could enhance the high-frequency performance. Additionally, the proposed technique does not deteriorate the ON-current levels.
Autors: Ahmed Shaker;Mona El Sabbagh;Mohammed M. El-Banna;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3541 - 3547
Publisher: IEEE
 
» Influence of Microscopic Electric Field Enhancement on Microparticle Impact Phenomena Based on Fractal Modeling
Abstract:
The objective of this paper is to study the influence of microscopic electric field enhancement caused by microprotrusions on microparticle impact phenomena based on fractal modeling. In this paper, microprotrusions with a radius of and heights 0, 1, 2, 5, and are considered, according to the height–width ratios 0, 0.2, 0.4, 1, and 2, respectively. The microparticles and contacts are assumed to be made of copper. The radius of the microparticle is assumed to be and the applied voltage is 60 kV. First, microprotrusions with different height–width ratios are modeled based on fractal theory. Then, the microscopic electric field distortions caused by microprotrusions on the contact surface are simulated based on fractal models of microprotrusions. The impact velocities of microparticles under different cases are calculated based on basic microparticle theories. Finally, the microparticle impact phenomena are simulated using the smoothed particle hydrodynamics method under the microscopic electric field caused by microprotrusions on the contact surface. The results show that the microscopic electric field enhancement caused by microprotrusions will have a significant influence on impact velocities, the characteristics of secondary particles, and the craters produced on the target contact surface. The results of this paper may provide some useful information to further understand the vacuum breakdown initiated by microparticles.
Autors: Yingyao Zhang;Xinye Xu;Lijun Jin;Zhenlian An;Yingsan Geng;Jianhua Wang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2588 - 2595
Publisher: IEEE
 
» Influence of the Manufacturing Process of a Claw-Pole Alternator on Its Stator Shape and Acoustic Noise
Abstract:
This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.
Autors: Antoine Tan-Kim;Nicolas Hagen;Vincent Lanfranchi;Stéphane Clénet;Thierry Coorevits;Jean-Claude Mipo;Jérôme Legranger;Frédéric Palleschi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2017, volume: 53, issue:5, pages: 4389 - 4395
Publisher: IEEE
 
» Infrastructure Circuits for Lifetime Improvement of Ultra-Low Power IoT Devices
Abstract:
An ultra-low power (ULP), energy-harvesting system-on-chip, that can operate in various application scenarios, is needed for enabling the trillions of Internet-of-Things (IoT) devices. However, energy from the ambient sources is little and system power consumption is high. Circuits and system development require an optimal use of available energy. In this paper, we present circuits that can improve the energy utilization in an IoT device by providing improvements at critical points of the flow of harvested energy. A boost converter circuit, that can harvest energy from 10-mV input voltage and a few nanowatt of input power, makes more harvested energy available for the IoT device. A single-inductor-multiple-output buck-boost converter provides high-efficiency and low-voltage power management solution to put most of the harvested energy for system use. A real time clock and ULP bandgap reference circuit significantly reduce the standby power consumption. The proposed ULP circuits are developed in 130-nm CMOS technology. The combined effects of these circuits and the system design technique can improve the life-time of an example IoT device by over four times in higher power consumption mode and over 70 times in ULP mode.
Autors: Nasim Shafiee;Shikhar Tewari;Benton Calhoun;Aatmesh Shrivastava;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2598 - 2610
Publisher: IEEE
 
» Input Voltage Mapping Optimized for Resistive Memory-Based Deep Neural Network Hardware
Abstract:
Artificial neural network (ANN) computations based on graphics processing units (GPUs) consume high power. Resistive random-access memory (RRAM) has been gaining attention as a promising technology for implementing power-efficient ANNs, replacing GPU. However, nonlinear – characteristics of RRAM devices have been limiting its use for ANN implementation. In this letter, we propose a method and a circuit to address issues due to the nonlinear – characteristics. We demonstrate the feasibility of the method by simulating its application to multiple neural networks, from multi-layer perceptron to deep convolutional neural network based on a typical RRAM model. Results from classifying datasets including ImageNet show that the proposed method produces much higher accuracy than the naive linear mapping for a wide range of nonlinearity.
Autors: Taesu Kim;Hyungjun Kim;Jinseok Kim;Jae-Joon Kim;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1228 - 1231
Publisher: IEEE
 
» Input-Parallel Output-Series DC-DC Boost Converter With a Wide Input Voltage Range, For Fuel Cell Vehicles
Abstract:
An input-parallel, output-series dc–dc Boost converter with a wide input voltage range is proposed in this paper. An interleaved structure is adopted in the input side of this converter to reduce input current ripple. Two capacitors are connected in series on the output side to achieve a high voltage gain. The operating principles and steady-state characteristics of the converter are presented and analyzed in this paper. A 400 V/1.6 kW prototype has been created which demonstrates that a wide range of voltage gain can be achieved by this converter and it is shown that the maximum efficiency of the converter is 96.62% and minimum efficiency is 94.14%. The experimental results validate the feasibility of the proposed topology and its suitability for fuel cell vehicles.
Autors: Ping Wang;Lei Zhou;Yun Zhang;Jing Li;Mark Sumner;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2017, volume: 66, issue:9, pages: 7771 - 7781
Publisher: IEEE
 
» Insights Into the Operation of Hyper-FET-Based Circuits
Abstract:
Devices combining transistors and phase transition materials are being investigated to obtain steep switching and a boost in the ratio and, thus, to solve power and energy limitations of CMOS technologies. This paper analyzes the operation of circuits built with these devices. In particular, we use a recently projected device called hyper-FET to simulate different circuits, and to analyze the impact of the degraded dc output voltage levels of hyper-FET logic gates on their circuit operation. Experiments have been carried out to evaluate power of these circuits and to compare with counterpart circuits using FinFETs. The estimated power advantages from device level analysis are also compared with the results of circuit level measurements. We show that these estimations can reduce, cancel, or even lead to power penalties in low switching and/or low-frequency circuits. We also discuss relationships with some device level parameters showing that circuit level considerations should be taken into account for device design.
Autors: María J. Avedillo;Juan Núñez;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3912 - 3918
Publisher: IEEE
 
» Insights Into the Power-Off and Power-On Transient Performance of Power-Rail ESD Clamp Circuits
Abstract:
The power-off and power-on transient performance of power-rail electrostatic discharge (ESD) clamp circuits is investigated in this paper. In order to serve this purpose, the transient performance of a timed shutoff power-rail ESD clamp circuit in a 65-nm CMOS process is characterized by a three-terminal test method. Based on the characterization results, several insights are summarized: it is found that the bigFET response time of the investigated circuit is dependent on the pulse peak voltage. Besides, the resistor–capacitor network is verified to be a slew-rate detector instead of a rise-time detector. Moreover, the different bigFET response mechanisms under various power-on disturbances are clarified. In addition, the validity of these insights for other designs is also discussed in this paper.
Autors: Guangyi Lu;Yuan Wang;Yize Wang;Xing Zhang;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Sep 2017, volume: 17, issue:3, pages: 577 - 584
Publisher: IEEE
 
» Integrated Evaluation of Reliability and Stability of Power Systems
Abstract:
This paper investigates the impacts of transient instability on power system reliability. Traditionally, composite system reliability evaluation has been performed based on steady-state estimation of load curtailments; system dynamics have often been ignored, mostly due to computational complexity. In this paper, three probabilistic transient stability indices are proposed to assess system robustness against dynamic contingencies and to account for system instability in computing reliability indices. A direct method is utilized for transient stability assessment based on computing the energy margin of the system under fault events (energy margins measure the ability of a system to withstand contingencies). Energy margins along with the probability of occurrences of the events are used to update the probabilistic transient stability indices. The dependencies of reliability and stability indices on the fault clearing time are also evaluated. This method is applied on the reduced Western Electricity Coordinating Council and the New England 39 bus test systems. The results indicate the importance of considering the effect of stability in reliability evaluation.
Autors: Mohammed Benidris;Joydeep Mitra;Chanan Singh;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 4131 - 4139
Publisher: IEEE
 
» Integrated Reciprocal Conversion With Selective Direct Operation for Energy Harvesting Systems
Abstract:
Energy harvesting IoT systems aim for energy neutrality, i.e., harvesting at least as much energy as is needed. This, however, is complicated by variations in environmental energy and application demands. Conventional systems use separate power converters to interface between the harvester and the storage, and then to the CPU system. Reciprocal power conversion has recently been proposed to perform both roles, eliminating redundancy and minimizing losses. This paper proposes to enhance this topology with “selective direct operation,” which completely bypasses the converter when appropriate. The integrated system, with 82% bidirectional conversion efficiency, was validated in 65-nm CMOS with only the harvester, battery, and decoupling capacitors being off-chip. Optimized for operation with cm2 photo-voltaic cell and a 32-b sub-threshold processor, the scheme enables up to 16% otherwise wasted energy to be utilized to provide >30% additional compute cycles under realistic indoor lighting conditions. Measured results show 84% peak conversion efficiency and energy neutral execution of benchmark sensor software (ULPBench) with cold-start capability.
Autors: Anand Savanth;Alex S. Weddell;James Myers;David Flynn;Bashir M. Al-Hashimi;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2370 - 2379
Publisher: IEEE
 
» Integrated Transmission and Distribution System Power Flow and Dynamic Simulation Using Mixed Three-Sequence/Three-Phase Modeling
Abstract:
The interactions between distribution and transmission systems have increased significantly in recent years. However, in traditional power system simulation tools, transmission and distribution systems are separately modeled and analyzed. Hence, it is difficult to analyze the impacts of distribution systems on transmission systems and their interactions in detail. To facilitate the analysis of integrated transmission and distribution (T&D) systems, a novel modeling framework is proposed in this paper, where the transmission system is modeled as one subsystem in three-sequence detail, while each distribution system connected to it is represented as a subsystem and modeled in three-phase detail. With this modeling approach, unbalanced conditions at the boundary between T&D systems and within the transmission system can be represented. The integrated T&D power flow is solved by iteratively solving a three-sequence power flow for the transmission system and a three-phase power flow for each distribution system. Furthermore, a new dynamic simulation algorithm for integrated T&D system is proposed. The main challenge in developing this integrated T&D dynamic simulation is associated with different network representations in the transmission and distribution systems. With a partitioned solution approach adopted for dynamic simulation, the multi-area Thévenin equivalent approach is utilized in the network solution step to address this challenge. The proposed algorithms have been tested against an all electromagnetic transient simulation.
Autors: Qiuhua Huang;Vijay Vittal;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3704 - 3714
Publisher: IEEE
 
» Integrating Ego, Homophily, and Structural Factors to Measure User Influence in Online Community
Abstract:
Research problem: In the current information age, people are increasingly accustomed to sharing their special interests online and are influenced by the relationships developed from that sharing. The purpose of this study was to better measure peer influence in these online communities. Research questions: 1. How can peer influence in online communities be measured in a way that comprehensively incorporates peer-based characteristics, the homophily effect, and the structural position of a user in the network? 2. Is the method proposed in this study superior to other existing methods? Literature review: Previous literature on measuring online user influence can be classified into two streams: 1. Those that focus on the intrinsic characteristics of social media players to measure peer influence; 2. Those that address social network structure. Relevant computing algorithms include Topic-Based PageRank, Quality-Structure index, and so on. Although the first stream considers afocal peer's intrinsic characteristics, it overlooks the interpeer attraction in terms of similarity and discrepant knowledge among peers. The second stream mostly stresses the structures of social networks to measure network-wide peer influence but underestimates the effect of interpeer attraction that may leverage every diffusion step of peer influence through the network. To fill this research gap, this study proposes a new method of measuring network user influence that incorporates peers' intrinsic factors, interpeer influence factors as homophily effect, and network structure. Homophily refers to the degree to which pairs of individuals who interact are similar with respect to certain attributes. Methodology: From the communication sender-receiver perspective, we developed a computable method that incorporates peer-based characteristics, the homophily effect, and the structural position of a user in the network to measure the social network user influence. Two empirical studies - ere subsequently conducted in a social network service-based online community and an online professional logistics community to verify the effectiveness of the proposed method. Results and conclusions: The empirical results show that our proposed method provides higher prediction accuracy of user influence rank in an online community than the other existing methods. These findings lay a foundation for future theoretical exploration and provide a useful tool for targeting influential users in online communities such as blogs, bulletin board systems, and forums.
Autors: Chenghong Zhang;Tian Lu;Shoucong Chen;Cheng Zhang;
Appeared in: IEEE Transactions on Professional Communication
Publication date: Sep 2017, volume: 60, issue:3, pages: 292 - 305
Publisher: IEEE
 
» Integrating Poly-Silicon and InGaZnO Thin-Film Transistors for CMOS Inverters
Abstract:
The applications of a-InGaZnO thin-film transistors (TFTs) to logic circuits have been limited owing to the intrinsic n-channel operation. In this paper, we demonstrated a hybrid inverter constructed by p-channel low-temperature poly-silicon (LTPS) TFTs and n-channel amorphous-indium–gallium–zinc–oxide (a-IGZO) TFTs. Hydrogenated LTPS TFTs and a-IGZO TFTs have been successfully fabricated on the same panel, followed by a rapid thermal annealing treatment to remove the hydrogens in the a-IGZO TFTs. The resulted hybrid inverter exhibits large noise margin closed to and a high voltage gain as 68.3. Due to the complementary configurations in the static state, the inverter shows small current and thus consumes low power in hundreds of picowatts. As all the fabrication processes are compatible with conventional techniques, the reported results may open new opportunities in circuit design and applications for oxide TFTs.
Autors: ChangDong Chen;Bo-Ru Yang;Chuan Liu;Xing-Yu Zhou;Yuan-Jun Hsu;Yuan-Chun Wu;Jang-Soon lm;Po-Yen Lu;Man Wong;Hoi-Sing Kwok;Han-Ping D. Shieh;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3668 - 3671
Publisher: IEEE
 
» Integrating Two Stages as a Common-Mode Transformerless Photovoltaic Converter
Abstract:
A single-phase common-mode transformerless grid-connected photovoltaic (PV) converter, which is based on the integration of two stages, is proposed in this paper. Transformer elimination in grid-connected PV systems has many advantages. It not only reduces cost, size, and weight but also increases the complete system efficiency. Since there is no galvanic isolation between grid and PV array, a leakage current may appear due to the PV parasitic capacitance to the ground, if this is not taken into account in the converter design. This paper presents a dc/dc boost converter integrated with a full-bridge inverter. The integration of these two stages reduces the ground leakage current. The neutral line of the grid is directly connected to the negative terminal of the PV array, eliminating any possibility of leakage current in this terminal. The principle of operation of the transformerless converter is analyzed, and a 200-W topology is experimentally tested.
Autors: Nimrod Vázquez;Jeziel Vázquez;Joaquín Váquero;Claudia Hernández;Esli Vázquez;René Osorio;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7498 - 7507
Publisher: IEEE
 
» Integration of DC Microgrids as Virtual Synchronous Machines Into the AC Grid
Abstract:
A smart and autonomous integration concept for dc microgrids into the legacy ac grid is proposed based on the virtual synchronous machine (VSM) concept. It utilizes a dc–ac converter as a universal VSM-based interface (VSMBI) between the ac grid and various distributed energy resources (DER) connected on the dc side. The control strategy of it includes: 1) a frequency regulation improved from previous VSM works, which is suitable for the microgrid integration; 2) an improved dual droop control between the ac frequency and the dc side energy storages; 3) a power system stabilizer to enhance the system stability. Under this concept, the VSMBI integrates the DERs, loads and energy storages in the dc microgrid into a VSM. The VSMBI and the dc microgrid together will respond to short-term and long-term requirements of the grid frequency regulation, and achieve autonomous power management for the ac grid and the dc microgrid. It is therefore an important step forward in supporting high DER penetration. The concept, its design and small-signal analysis are presented in this paper. Its effectiveness and functions are verified by simulation and experimental results.
Autors: Dong Chen;Yizhe Xu;Alex Q. Huang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7455 - 7466
Publisher: IEEE
 
» Integration of Six-Phase EV Drivetrains Into Battery Charging Process With Direct Grid Connection
Abstract:
The paper proposes two novel topologies for integrated battery charging of electric vehicles. The integration is functional and manifests through re-utilization of existing propulsion drivetrain components, primarily a six-phase inverter and a six-phase machine, to serve as components of a fast (three-phase) charging system. An important feature of the proposed charging systems is that they are with direct grid connection, thus nonisolated from the mains. Torque is not produced in machines during the charging process. The paper provides a comprehensive evaluation of the novel systems, together with an existing topology. Various aspects of the considered chargers are detailed and elaborated, including current balancing, interleaving modulation strategy, and influence of rotor field pulsation on control and overall performance. A control strategy is proposed and the theory and control scheme are verified by experiments.
Autors: Ivan Subotic;Nandor Bodo;Emil Levi;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1012 - 1022
Publisher: IEEE
 
» Intercalibration of AMSR2 NASA Team 2 Algorithm Sea Ice Concentrations With AMSR-E Slow Rotation Data
Abstract:
Sea ice estimates from AMSR2 are intercalibrated with AMSR-E fields through a two-step process. First, slow rotation 2 r/min AMSR-E data is used to derive regression equations from colocated pairs of AMSR2 and AMSR-E brightness temperatures (Tbs). The regression equations are used to modify AMSR2 Tbs into AMSR-E equivalent Tbs that are then input into the NASA Team 2 (NT2) sea ice concentration algorithm used for the AMSR-E standard products. The regressed Tbs result in changes in sea ice concentration of a few percent compared to using the original un-regressed AMSR2 Tbs. Next, sea ice estimates from the F17 SSMIS sensor are used as a bridge to compare AMSR-E total sea ice extent estimates in 2010 with AMSR2 total sea ice extent estimates in 2013. Based on this comparison, a further adjustment is made to a weather filter threshold used in the NT2 algorithm to minimize the total extent bias between AMSR2 and AMSR-E using a double-differencing approach. The adjustments reduced apparent bias with AMSR-E from ∼200 000 km2 for the original unmodified AMSR2 Tbs to –700 and 4700 km2 for the Arctic and Antarctic, respectively. These differences are within the range of previous passive microwave sea ice intercalibrations. The adjusted AMSR2 sea ice fields provide a nearly 15-year time series of sea ice change; depending on the lifetime of AMSR2 and possible follow-on sensors, AMSR2 has the potential to be part of a multidecadal record of sea ice change.
Autors: Walter N. Meier;Alvro Ivanoff;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Sep 2017, volume: 10, issue:9, pages: 3923 - 3933
Publisher: IEEE
 
» Intercarrier Interference-Aware Pilot-Aided Channel Estimation in OFDM Systems
Abstract:
Linear pilot-aided channel estimation in orthogonal-frequency division multiplexing systems is carried out optimally via 2D Wiener filters. The standard approach employed in conventional receivers is based on cascaded Wiener filtering. In doing so, suboptimal performance is tolerated for the sake of lower complexity. By means of the 2D+1D filtering scheme proposed in this paper, the performance of cascaded filtering is enhanced while maintaining the low complexity of the approach. A theoretical analysis of different cascaded Wiener filtering approaches is provided, and the approaches are compared. Furthermore, the effect of Doppler-induced intercarrier interference (ICI) is taken into account for the calculation of the mean-squared error (MSE) of the different channel estimation schemes. Additionally, practical real-time adaptive versions of these schemes are demonstrated. Results from full link-level simulations with respect to the digital video broadcasting standard for satellite services to handheld devices are presented. The proposed 2D+1D filtering scheme shows enhanced MSE and bit error rate performance than both conventional scheme and more advanced ICI cancellation schemes, since it provides more accurate channel estimates in high Doppler spread conditions.
Autors: Mohammed Almoneer;Christian Rohde;Khaled Hassan;Wolfgang H. Gerstacker;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2017, volume: 63, issue:3, pages: 449 - 462
Publisher: IEEE
 
» Interface Electronics for Tactile Sensors Based on Piezoelectric Polymers
Abstract:
In this paper, we propose a novel design approach for the interface electronics of piezoelectric polymer tactile sensing systems. An interface electronics prototype based on commercial off-the-shelf (COTS) components having the same operating principle as the proposed approach has been fabricated. The system has been validated by using an experimental setup, where electrical and electromechanical characterization are carried out. The interface electronics measures charge of about 0.15 pC for applied forces as low as 12.5 mN at the working frequency of 27 Hz. The experimental average sensitivity of the system is 0.6 pC/kPa in the frequency range from 10 to 250 Hz. Long term goal is to miniaturize the interface electronics for the development of embedded tactile systems in prosthetic and robotic applications.
Autors: Luigi Pinna;Ali Ibrahim;Maurizio Valle;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 5937 - 5947
Publisher: IEEE
 
» Interfacial Tuning for Detection of Cortisol in Sweat Using ZnO Thin Films on Flexible Substrates
Abstract:
We have demonstrated the detection of stress hormone cortisol from sweat using a flexible biosensing platform. Sweat-based detection faces many challenges such as stability of electrodes, sensitivity, and specificity. The surface states of zinc oxide (ZnO) can be leveraged for immobilizing various linker molecules for ultraspecific detection of biomolecules. In this study, we have used thiol-based linker molecule for binding to zinc terminations. We tested DSP from 5 to 100 mmol concentration in order to understand the effect of varying molarity on the electron transport properties of ZnO thin films. We performed electrochemical impedance spectroscopy measurements and Mott–Schottky analysis after incubation of the dispensed DSP linker on ZnO thin films. The optimized concentration of DSP was further incorporated in the immunoassay for detection of cortisol from 1 to 200 ng/mL spiked in sweat.
Autors: Rujuta D. Munje;Sriram Muthukumar;Shalini Prasad;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Sep 2017, volume: 16, issue:5, pages: 832 - 836
Publisher: IEEE
 
» Interference in IM/DD optical wireless communication networks
Abstract:
The emerging field of optical wireless communications (OWC) offers exceptional promise as a technology for next-generation wireless networks. High data rate capabilities and ultra-dense access point deployment will allow OWC to supplement traditional RF technologies and remove congestion from the crowded RF spectrum. When implementing OWC via intensity modulation with direct detection (IM/DD), peak optical power emission constrains the instantaneous optical power. Average optical power is also constrained by eye safety regulations and illumination requirements of infrared and visible light communication (VLC) systems, respectively. These constraints differ from the conventional electrical power constraint of RF and wireline systems. Accordingly, performance metrics such as signal-to-noise ratio (SNR) and signal-to-interference-plus-noise ratio (SINR) have been redefined in relation to the optical channel constraints in order to provide fair comparison across OWC implementations. In densely deployed networks, interference has a significant effect on system performance. Two key properties simplify the analysis of RF networks: 1) the relationship between electrical power and interference variance is modulation agnostic and 2) many interferers are typically assumed. The former allows SINR to be defined in terms of the channel constraint and the latter allows the aggregate disturbance from interference-plus-noise to be modeled as an additive Gaussian random component. In OWC networks, the optical power constraints relate to interference variance in a modulation specific manner, and the highly directional optical channel creates instances where a small set of interferers dominate the aggregate disturbance. In this work, we first derive bounds on the variance of OWC interference under the constraints of an OWC channel. We then evaluate the accuracy of assuming that interference follows a Gaussian distribution. Finally, we show results of a study in a testbed environment w- th 15 VLC-enabled LED luminaires in order to empirically evaluate OWC interference characteristics.
Autors: Michael Rahaim;Thomas D. C. Little;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Sep 2017, volume: 9, issue:9, pages: D51 - D63
Publisher: IEEE
 
» Interferences in Match Kernels
Abstract:
We consider the design of an image representation that embeds and aggregates a set of local descriptors into a single vector. Popular representations of this kind include the bag-of-visual-words, the Fisher vector and the VLAD. When two such image representations are compared with the dot-product, the image-to-image similarity can be interpreted as a match kernel. In match kernels, one has to deal with interference, i.e., with the fact that even if two descriptors are unrelated, their matching score may contribute to the overall similarity. We formalise this problem and propose two related solutions, both aimed at equalising the individual contributions of the local descriptors in the final representation. These methods modify the aggregation stage by including a set of per-descriptor weights. They differ by the objective function that is optimised to compute those weights. The first is a “democratisation” strategy that aims at equalising the relative importance of each descriptor in the set comparison metric. The second one involves equalising the match of a single descriptor to the aggregated vector. These concurrent methods give a substantial performance boost over the state of the art in image search with short or mid-size vectors, as demonstrated by our experiments on standard public image retrieval benchmarks.
Autors: Naila Murray;Hervé Jégou;Florent Perronnin;Andrew Zisserman;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Sep 2017, volume: 39, issue:9, pages: 1797 - 1810
Publisher: IEEE
 
» Interlaminar Magnetic Flux Assessment of a Transformer Core Measured by an Extra-Thin Printed Foil Detector
Abstract:
Transformer cores represent complex 3-D magnetization systems with balancing off-plane fluxes, normal to magnetization plane. Therefore, for optimizations of core performance, not only the information about the local induction distributions in the plane, but also perpendicular to it is highly essential. The conventional sensors for detections of off-plane inductions () are either of very high thicknesses, causing significant air gaps between laminations, or require extremely laborious preparations and are not reusable. In this paper, we developed an extra-thin (), reusable foil detector with handles for easy and precise insertion and positioning in the interior of a laminated core. The detector was assembled by a low-cost 3-D printer, equipped with a micro-dispersing system for printing of conductive ink, controlled by in-house developed software. The manufactured foil sensor, due to its high mechanical stability, enables detections of off-plane flux at many different locations within an entire core. The detector was effectively tested in a three-phase model transformer core, stacked from three packages of different width. The results prove the important role of sensor thickness for precise detection of off-plane induction. Peak induction increases in a strong non-linear way with increasing nominal magnetization . Maxima of arise close to border regions of packages. ceases for $B_{\mathrm{ NOM}}< 1.5$ T, favoring low level of audible noise.
Autors: Georgi Shilyashki;Helmut Pfützner;Christian Huber;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6
Publisher: IEEE
 
» Intrinsic Contact Sensing for Touch Interface With Movable Structure
Abstract:
Intrinsic contact sensing is a method of using force sensors for separate tactile sensing without sensors arranged on the outer shell. Although the method is effective in some applications, the method has been limited to a fixed geometric shape. This study therefore proposes a method for movable structures. The contact position is estimated without geometric shape information by utilizing force/torque change over time. Additionally, this paper has proposed a method of eliminating the gravity term, which is a problem when using a structure-variable end effector as an interface. Calibration to decrease the calculation error was also introduced. Experimental evaluation using a wagon with drawers as the structure-variable object was done to verify the effectiveness of the proposed method.
Autors: Toshiaki Tsuji;Tatsuki Seki;Sho Sakaino;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7342 - 7349
Publisher: IEEE
 
» Intrinsic speed limit of negative capacitance transistors
Abstract:
The emergence of negative capacitance as a way to limit power dissipation in CMOS logic transistors has raised the question of response delay of ferroelectric negative capacitance. Latency requirements for digital logic require a response time on the order of 10 ps or less. In this letter, we establish a coherent theoretical framework to analyze the delay between the clock edge at the gate and the response of the semiconductor channel in a ferroelectric negative capacitance transistor. The standard Landau–Khalatnikov equation approximates the slow, diffusive limit of the classical equation of motion. Therefore, using it to predict the response speed is unphysical. After extracting the damping and kinetic inductance from THz spectroscopy data, we simulate the full classical equation of motion and analyze the delay. We find that for doped hafnium oxides, the intrinsic delay is around 270 fs, far less than what is required for digital logic.
Autors: Korok Chatterjee;Alexander John Rosner;Sayeef Salahuddin;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1328 - 1330
Publisher: IEEE
 
» Intrinsically Switchable Frequency Reconfigurable Barium Strontium Titanate Resonators and Filters
Abstract:
Multimode transceivers for the next generation of wireless devices require new and innovative frequency-agile microwave circuit designs to reduce their complexity, size, and cost. Intrinsically switchable frequency reconfigurable thin-film bulk acoustic resonators (FBARs) and filters that utilize these resonators are presented here for the very first time. Barium strontium titanate (BST) is a ferroelectric material that exhibits electric-field-induced piezoelectricity, which allows for the design of voltage controlled bulk acoustic wave devices. In this paper, a frequency reconfigurable resonator consisting of two series connected BST-based FBARs and a reconfigurable dual-band filter consisting of two 1.5 stage ladder-type bandpass filters are discussed. Their small size, simple design, and zero static power consumption make multifunctional ferroelectric thin-film devices attractive for use in adaptive and reconfigurable radios.
Autors: Victor Lee;Seungku Lee;Seyit Ahmet Sis;Amir Mortazawi;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3221 - 3229
Publisher: IEEE
 
» Introducing a Novel Parallel Hole Collimator: The Theoretical and Monte Carlo Investigations
Abstract:
To assess function of various organs as well as recognize malignancy in its initial stages, single photon emission computed tomography system is employed in which the collimators can obtain the qualified images toward better diagnostic on the lesions and metabolic performance. Although new designs and optimized methods as well as the analytical models have been proposed to improve tradeoff between resolution and sensitivity in the collimators, but opposing behavior of them still remains as one of the major problems associated with the parallel hole collimators (PCs). In this paper, a new design, namely, extended parallel hole collimator (EPC) in which trapezoidal denticles are added upon the collimator septa at the detector side, has been proposed to improve performance of the PCs. Two PCs as PC35 and PC41 with hole sizes of 1.5 mm and hole lengths of 35 and 41 mm, respectively, are considered for comparison and investigation of the EPC performance. Theory and Monte Carlo simulations have been carried out to evaluate some of its related parameters such as sensitivity, resolution, and contrast. To reconstruct the tomographic images of Jaszczak phantom, the maximum-likelihood expectation maximization algorithm is chosen. The results have been indicated that the EPC has increased the amount of sensitivity as 10.2% compared to the PCs at the same resolution, and decreased the penetrating ratio as well as produced the tomographic images with lower noise coefficient (NC%), and improved contrast to noise ratio. Finally, it is found that the EPC may obtain the qualified images.
Autors: Vahid Moslemi;Mansour Ashoor;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Sep 2017, volume: 64, issue:9, pages: 2578 - 2587
Publisher: IEEE
 
» Introduction to the feature issue on IEEE ICC 2016 ONS Symposium and OWC Workshop
Abstract:
This Feature Issue is based on extended revised versions of top-ranked papers presented at the Optical Networks and Systems Symposium and the Optical Wireless Communications Workshop that were held at the IEEE International Conference on Communications (ICC 2016). The papers appearing in this Feature Issue cover a wide range of topics, including visible light communications, passive optical networks, and 5G optical transport networks.
Autors: Walter Cerroni;Zabih Ghassemlooy;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Sep 2017, volume: 9, issue:9, pages: ICC1 - ICC2
Publisher: IEEE
 
» Introduction to the IEEE Journal on Selected Topics in Signal Processing and IEEE Transactions on Signal and Information Processing Over Networks Joint Special Issue on Graph Signal Processing
Abstract:
The papers in this special issue are intended to address some of the main research challenges in Graph Signal Processing by presenting a collection of the latest advances in the domain. These papers examine key representation, learning and processing aspects for signals living on graphs and networks, as well as new methods and applications in graph signal processing. Numerous applications rely on the processing of high dimensional data that reside on irregular or otherwise unordered structures that are naturally modeled as networks. The need for new tools to process such data has led to the emergence of the field of graph signal processing, which merges algebraic and spectral graph theoretic concepts with computational harmonic analysis to process signals on structures such as graphs. This important new paradigm in signal processing research, coupled with its numerous applications in very different domains, has fueled the rapid development of an inter-disciplinary research community that has been working on theoretical aspects of graph signal processing and applications to diverse problems such as big data analysis, coding and compression of 3D point clouds, biological data processing, and brain network analysis.
Autors: Pascal Frossard;Pier Luigi Dragotti;Antonio Ortega;Michael G. Rabbat;Alejandro Ribeiro;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Sep 2017, volume: 11, issue:6, pages: 771 - 773
Publisher: IEEE
 
» Introduction to the Special Issue: 2016 IEEE International Ultrasonics Symposium
Abstract:
The 2016 IEEE International Ultrasonics Symposium was held in Tours, France, from September 18–21, 2016. Tours is in the heart of the French Chateau country and the Vinci Convention Center, a short walk from the Loire, provided an expansive venue for this conference. Sponsored by the IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society, this symposium brings together technologists from academia, government labs, and industry to openly share their progress through posters, presentations, exhibits, short courses, and informal gatherings. The symposium strives for truly global representation and active involvement of students, early-career, and established practitioners.
Autors: L. Scott Smith;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1274 - 1275
Publisher: IEEE
 
» Introduction to the Special Section on the 2016 IEEE BCTM and IEEE CSICS
Abstract:
This Special Section of the IEEE Journal of Solid-State Circuits presents the most interesting papers on integrated circuits from the 2016 IEEE Bipolar and BiCMOS Circuits and Technology Meeting (BCTM) and the 2016 IEEE Compound Semiconductor Integrated Circuits Symposium (CSICS) which cover the latest research on silicon-germanium and III-V integrated circuits and their use in state-of-the-art communication, radar, and imaging systems.
Autors: Bodhisatwa Sadhu;Sorin P. Voinigescu;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2017, volume: 52, issue:9, pages: 2224 - 2225
Publisher: IEEE
 
» Inverse Feedback Shapers for Coupled Multibody Systems
Abstract:
The concept of inverse feedback shapers is fully developed in this report for the case of multibody systems with strongly coupled dynamics. The presented results constitute a nontrivial extension of the previous papers by the authors on input shaping focusing on effectively decoupled controlled and flexible parts. As the main technical result, the target mode for the inverse shaper design is identified based on an input–output transformation of the multibody system into the controlled subsystem, the attached residual oscillatory dynamics, and an internal feedback loop representing the dynamical coupling. A state feedback controller, applied for the selected generalized coordinate, is considered throughout this paper.
Autors: Martin Hromčík;Tomáš Vyhlídal;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4804 - 4810
Publisher: IEEE
 
» Inverse Power Factor Droop Control for Decentralized Power Sharing in Series-Connected-Microconverters-Based Islanding Microgrids
Abstract:
Series-connected microconverters have been used to integrate distributed energy resources into grid mains through a single-stage power conversion. When this string converter is switched to islanding operation mode, it is preferred to share the local load demand by series microconverter modules in a decentralized manner. Due to the characteristics of series connection, the well-understood P–f droop and Q–E droop control for parallel distributed generation units in a conventional islanding microgrid is not applicable in this case. To solve this problem, the feasibility of using a simple power factor-frequency inverse droop control for series-connected islanding microconverters is discussed in this paper. The proposed method can achieve simultaneous real and reactive power sharing without the assistance of any communications between series microconverters. Furthermore, the accuracy of power sharing is not affected by the variations of microgrid feeder parameters or the disturbance of the point of common coupling (PCC) nonlinear loads. Simulated and experimental results are provided to verify the correctness of the proposed method.
Autors: Jinwei He;Yunwei Li;Beihua Liang;Chengshan Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7444 - 7454
Publisher: IEEE
 
» Investigating Applications in Health Care [Book\Software Reviews]
Abstract:
This book explains the multiple directions in which RF/microwave technologies are heading toward healthcare and biosensing applications, the achievements that have been made so far, and the challenges for researchers to solve in the near future. It consists of seven chapters by 15 authors, many of whom are active on the IEEE Microwave Theory and Techniques Society (MTT-S) Technical Coordinating Committee MTT-10, Biological Effects and Medical Applications. Apart from the first two chapters (which are tutorials on microwave technology and the dielectric properties of tissue), the book consists of five chapters that review different applications of RF/microwave energy to health care and biosensing. This book provides essential theories and solutions for the transmitter and receiver hardware block. The solutions offered are very practical for a circuit system designer. Whether the particular applications of RF/microwaves discussed in this volume will ever pass muster and enter the realm of evidence-based medicine remains to be seen. In their focus on the nuts and bolts of engineering, the authors of this otherwise meritorious volume are telling only a small part of the story about developing medical technology.
Autors: Kenneth R. Foster;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2017, volume: 18, issue:6, pages: 126 - 127
Publisher: IEEE
 
» Investigation of a Fault-Tolerant Three-Level T-Type Inverter System
Abstract:
In recent years, a three-level T-type inverter has attracted considerable attention due to its advantages, such as simple structure and higher efficiency. However, the reliability of a three-level T-type inverter is particularly important as increased power switches are used. Therefore, a fault-tolerant three-level T-type inverter is proposed in this paper. Fault diagnosis and fault-tolerant control strategies for power switches both in half-bridge and neutral-point bridge are investigated. Under fault-tolerant operation, redundant fourth-leg is used to balance neutral-point voltage and the low-frequency voltage oscillation is eliminated completely. The fault ride-through capability and high-quality output waveforms can be obtained. The effectiveness of the proposed inverter topology and control methods is validated by the simulation and experimental results.
Autors: Shuai Xu;Jianzhong Zhang;Jun Hang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2017, volume: 53, issue:5, pages: 4613 - 4623
Publisher: IEEE
 
» Investigation of an Electromagnetic Wearable Resonance Kinetic Energy Harvester With Ferrofluid
Abstract:
Human motion energy harvester can offer clean and continuous power, and therefore plays an important role in powering mobile devices, which suffer from short standby time because of the limited capability of the battery. In this paper, we investigate an electromagnetic resonance wearable kinetic energy harvester, which is comprised of an oscillator and a carbon fiber tube with two coils wound on its surface. The oscillator is comprised of a columnar PM connected to the two end covers with two elastic strings. The designed resonant frequency is 8–10 Hz, which is higher than the major frequency range of human motion (2–4 Hz), but it can absorb high frequency energy of impulse, such as footfall. Thus, the harvester can wear on legs to absorb the kinetic energy of footfall by resonance. The ferrofluid is adopted to decrease friction, which is one of the main challenges for improving efficiency of this type of energy harvester. The ferrofluid prevents the PM from touching the wall of the tube resulting in significant friction reduction. The FEM simulation results indicate that the ferrofluid can keep the vibrator (a permanent magnet) contactless even subjecting to ten times gravity acceleration. The maximum average output power of 9.5 mW is obtained with a total weight of 80.5 g when running at a speed of 10 km/h. A energy harvest circuit is carried out and an average power of 0.28 s can be stored.
Autors: Shuai Wu;P. C. K. Luk;Chunfang Li;Xiangyu Zhao;Zongxia Jiao;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6
Publisher: IEEE
 
» Investigation of Anomalous Hysteresis in MOS Devices With ZrO2 Gate Dielectrics
Abstract:
Abnormal capacitance-voltage (CV) behavior is observed in metal-oxide semiconductor devices with zirconium oxide-gate dielectrics using a pulse CV technique. The relative positions of forward and reverse CV traces measured by the pulse technique are opposite those by conventional CV measurement. This unusual phenomenon is inconsistent with charge trapping and de-trapping, but may be mainly attributable to the interface dipoles at the high-/SiOx interface. This anomaly is sensitive to growth temperature as well as the post-deposition annealing process. Lower deposition temperature leads to more interface dipoles. However, after annealing in either nitrogen or forming gas ambient, the relative positions of forward and reverse CV curves measured by the pulse technique are consistent with those obtained by conventional CV measurement.
Autors: Qifeng Lu;Yanfei Qi;Ce Zhou Zhao;Chenguang Liu;Chun Zhao;Stephen Taylor;Paul R. Chalker;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Sep 2017, volume: 17, issue:3, pages: 526 - 530
Publisher: IEEE
 
» Investigation of Effects of Asymmetries on the Performance of Permanent Magnet Synchronous Machines
Abstract:
Asymmetries in permanent magnet synchronous machines (PMSM) can result from manufacturing tolerances or optimization techniques that deliberately introduce them on rotor, stator, or both. This paper analyzes the impact of such unbalance on the air gap pressure, that is radial and tangential to the direction of motion, by means of Maxwell Stress Tensor; also, their consequences on torque pulsations and unbalanced magnetic pulling. Neglecting the manufacturing variations in the analysis of high power density PMSMs underestimates the resultant torque ripple. Additionally, new vibration modes occur due to unbalanced radial pressure. On the other hand, a geometry optimized to minimize torque ripple through controlled asymmetry is investigated, the approach compensates harmonics in torque effectively, but such compensation does not have the same effect on radial forces. Finite element analysis and experimentation are used to support the analysis and it is found that an asymmetric PMSM with low torque ripple will not necessarily produce lower vibrations and noise.
Autors: Alejandro J. Piña Ortega;Longya Xu;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1002 - 1011
Publisher: IEEE
 
» Investigation of the Radio-Frequency Discharge in a High Current Negative Hydrogen Ion Source With a Global Enhanced Vibrational Kinetic Model
Abstract:
A numerical investigation of the radio-frequency hydrogen discharge in the high current negative hydrogen ion source (HCNHIS) is presented using a global enhanced vibrational kinetic model (GEVKM). The HCNHIS consists of a high-pressure (2–65 torr) radio-frequency discharge chamber where the main production of high-lying vibrational states of the hydrogen molecules occurs. The hydrogen plasma flow in the discharge chamber is reduced by a series of bypass tubes and enters through a nozzle into a low-pressure (1–15 mtorr) negative hydrogen ion production chamber where H are generated mainly by the dissociative attachment of low-energy electrons to rovibrationally excited hydrogen molecules. The GEVKM is applied to the HCNHIS discharge and involves volume-averaged equations for 21 hydrogen species (atoms, ions, and molecules in excited states) and electrons. The GEVKM is supplemented with outlet boundary conditions for the nozzle and bypass tubes of the HCNHIS and accounts for compressibility, viscous, and rarefaction effects. GEVKM simulations of the RF discharge are performed with inlet flow rates of 5–1000 sccm and absorbed powers of 200–1000 W using the HCNHIS-2 design which is configured with an extractor grid attached to a short negative ion production region. These simulations investigate the effects of the absorbed power and the inlet flow rate on the chemical composition, electron and heavy particles temperature, wall temperature, the maximum extractable H current in the discharge chamber, as well as optimum operational parameters of HCNHIS-2. GEVKM simulations of the HCNHIS-2 discharge are used to obtain estimates of the H current and compared with Faraday cup measurements taken at the extraction grid.
Autors: Sergey N. Averkin;Nikolaos A. Gatsonis;Lynn Olson;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2460 - 2471
Publisher: IEEE
 
» Investigation on Economic and Reliable Operation of Meshed MTDC/AC Grid as Impacted by Offshore Wind Farms
Abstract:
The influence of complementarity balancing connected grid and control of offshore wind power generation on the economic and reliable operation of hybrid multiterminal HVDC (MTDC) and AC power system is investigated in the paper. The variances of distribution curve of both transmission loss of AC/DC system and voltage of critical nodes assessed by cumulant-based method are used to demonstrate how the different complementarity conditions, generation balancing strategies, MTDC grid topologies, and control schemes affect power system operation. In this paper, a study case of 16-generator 68-bus power system connected with three offshore wind farms is presented. The variance indices of transmission loss and voltage magnitude are calculated and then compared under different complementarity levels, active power balancing strategies, HVDC transmission systems, and controls, respectively. The analysis reveals that higher complementarity and multi-machine balancing strategy can effectively reduce system operational cost and enhance operational reliability. Compared to the point-to-point topology, the control pattern and parameter setting of multi-terminal topology are two key factors to determine its impact on system operation.
Autors: S. Q. Bu;W. Du;H. F. Wang;Y. Liu;X. Liu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3901 - 3911
Publisher: IEEE
 
» Investigation on Low Voltage Operation of Electrovibration Display
Abstract:
This paper presents three methods of input voltage signals that allow low voltage operation of an electrovibration display while preserving the perceptual feel and strength of electrovibration stimuli. The first method uses the amplitude modulation of a high-frequency carrier-signal. The second method uses a dc-offset, and the third method uses a combination of the two methods. The performance of the three methods was evaluated by a physical experiment that measured and analyzed static (dc-component) and dynamic (vibratory component) friction forces and two subsequent psychophysical studies. The physical experiment showed that only the dc -offset method enabled a statistically significant increase in the static friction force between the fingertip and the surface of the electrovibration display. The static friction increase was closely related to the root mean square of input voltage level. In contrast, all of the three methods increased the dynamic friction force significantly, which was deemed to be related to the high frequency effect validated in the previous literature. The first psychophysical study showed that the three proposed methods can significantly reduce the peak-to-peak (p-p) amplitude of an input voltage signal while generating perceptually equally strong electrovibrations to that produced by the conventional method. Using lower p-p voltage has the merits of a simpler electrical circuit and less electromagnetic noise, saving the overall system cost. Further, the perceived intensity of electrovibration was more correlated to the dynamic friction force than the static friction force. The second psychophysical study was a discrimination experiment, and it demonstrated that all the three proposed methods and the conventional method can provide perceptually similar stimuli despite their different signal forms and voltage amplitudes. Our experimental investigation allowed us to conclude that the d- -offset method is the best way to lower the driving voltage of an electrovibration display while providing perceptually equivalent electrovibrations.
Autors: Jeonggoo Kang;Heewon Kim;Seungmoon Choi;Ki-Duk Kim;Jeha Ryu;
Appeared in: IEEE Transactions on Haptics
Publication date: Sep 2017, volume: 10, issue:3, pages: 371 - 381
Publisher: IEEE
 

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