Electrical and Electronics Engineering publications abstract of: 05-2017 sorted by title, page: 7

» Embedded-Silicon-Strip-to-Hybrid-Plasmonic Waveguide Polarization Mode Converter
Abstract:
A novel polarization mode converter bridging a conventional embedded silicon strip waveguide and a metal-capped hybrid plasmonic waveguide is proposed. Innovative design principles based on gradient ascent of the TM polarization fraction in conjunction with the modal index contour for practical initial designs are developed and numerically verified. The mode conversion efficiency (MCE), insertion loss (IL), and the polarization conversion efficiency (PCE) at nm are 87.58%, 0.5899 dB, and 99.84%, respectively. The respective 1-dB optical bandwidths for the MCE and IL are about 133 and 140 nm, while the PCE is > 98% over a 102-nm spectral range. The low-index silica spacer is found to impose the most stringent fabrication requirement.
Autors: Yin-Jung Chang;Ren-Wei Feng;
Appeared in: IEEE Photonics Technology Letters
Publication date: May 2017, volume: 29, issue:9, pages: 759 - 762
Publisher: IEEE
 
» Embedding Spatio-Temporal Information into Maps by Route-Zooming
Abstract:
Analysis and exploration of spatio-temporal data such as traffic flow and vehicle trajectories have become important in urban planning and management. In this paper, we present a novel visualization technique called route-zooming that can embed spatio-temporal information into a map seamlessly for occlusion-free visualization of both spatial and temporal data. The proposed technique can broaden a selected route in a map by deforming the overall road network. We formulate the problem of route-zooming as a nonlinear least squares optimization problem by defining an energy function that ensures the route is broadened successfully on demand while the distortion caused to the road network is minimized. The spatio-temporal information can then be embedded into the route to reveal both spatial and temporal patterns without occluding the spatial context information. The route-zooming technique is applied in two instantiations including an interactive metro map for city tourism and illustrative maps to highlight information on the broadened roads to prove its applicability. We demonstrate the usability of our spatio-temporal visualization approach with case studies on real traffic flow data. We also study various design choices in our method, including the encoding of the time direction and choices of temporal display, and conduct a comprehensive user study to validate our embedded visualization design.
Autors: Guodao Sun;Ronghua Liang;Huamin Qu;Yingcai Wu;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: May 2017, volume: 23, issue:5, pages: 1506 - 1519
Publisher: IEEE
 
» Emerging 3-D Imaging and Display Technologies
Abstract:
We have become an information-centric society vastly dependent on the collection, communication, and presentation of information. At any given moment, it is likely that we are in the vicinity of some form of a display as displays play a prominent role in a variety of devices and applications. Three-dimensional imaging and display technologies are important components for presentation and visualization of information and for creating real-world-like environments in communication. There are broad applications of 3-D imaging and display technologies in computers, communication, mobile devices, TV, video, entertainment, robotics, metrology, security and defense, healthcare, and medicine.
Autors: Bahram Javidi;A. Murat Tekalp;
Appeared in: Proceedings of the IEEE
Publication date: May 2017, volume: 105, issue:5, pages: 786 - 788
Publisher: IEEE
 
» Emerging Embedded and Cyber Physical System Security Challenges and Innovations
Abstract:
Autors: Kim-Kwang Raymond Choo;Mehran Mozaffari Kermani;Reza Azarderakhsh;Manimaran Govindarasu;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: May 2017, volume: 14, issue:3, pages: 235 - 236
Publisher: IEEE
 
» Empirical Analysis of the Use of the VISIR Remote Lab in Teaching Analog Electronics
Abstract:
Remote laboratories give students the opportunity of experimenting in STEM by using the Internet to control and measure an experimental setting. Remote laboratories are increasingly used in the classroom to complement, or substitute for, hands-on laboratories, so it is important to know its learning value. While many authors approach this question through qualitative analyses, this paper reports a replicated quantitative study that evaluates the teaching performance of one of these resources, the virtual instrument systems in reality (VISIR) remote laboratory. VISIR, described here, is the most popular remote laboratory for basic analog electronics. This paper hypothesizes that use of a remote laboratory has a positive effect on students’ learning process. This report analyzes the effect of the use of VISIR in five different groups of students from two different academic years (2013–2014 and 2014–2015), with three teachers and at two educational levels. The empirical experience focuses on Ohm’s Law. The results obtained are reported using a pretest and post-test design. The tests were carefully designed and analyzed, and their reliability and validity were assessed. The analysis of knowledge test question results shows that the post-test scores are higher that the pretest. The difference is significant according to Wilcoxon test (), and produces a Cohen effect size of 1.0. The VISIR remote laboratory’s positive effect on students’ learning processes indicates that remote laboratories can produce a positive effect in students’ learning if an appropriate activity is used.
Autors: Javier Garcia-Zubia;Jordi Cuadros;Susana Romero;Unai Hernandez-Jayo;Pablo Orduña;Mariluz Guenaga;Lucinio Gonzalez-Sabate;Ingvar Gustavsson;
Appeared in: IEEE Transactions on Education
Publication date: May 2017, volume: 60, issue:2, pages: 149 - 156
Publisher: IEEE
 
» Empirical Determination of the Effect of Lifter Wear in Mill Power for Dry Grinding
Abstract:
Grinding stage has one of the highest production costs in mining operations due to the intensive use of energy needed for the comminution process. Hence, any improvement in the energy use of this process will have an important impact on production costs. Paper presents the results of an extensive testing program to determine the effect of lifter wear on the power demanded by the grinding mill. Selected power–speed curves covering up to 110% of critical speed are reported. Using these results, a lifter wear factor is proposed to include this effect on the power demand expressions of grinding mills. Results show that for dry grinding, as the lifters wear, the power needed for a specific operating condition increases. Using these results, mill operators will have an important piece of information to set the best operating point for an efficient ore comminution and efficient energy consumption. It will also help to define the appropriate date for a liner change.
Autors: Richard A. Cartes Varas;M. Aníbal Valenzuela;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2621 - 2627
Publisher: IEEE
 
» Enabling Backoff for SCM Wake-Up Radio: Protocol and Modeling
Abstract:
In sub-carrier modulation (SCM) wake-up radio (WuR) enabled wireless sensor networks, a node can initiate data transmission at any instant of time. In this letter, we propose to activate a backoff procedure before sending wake-up calls (WuCs) in order to avoid potential collisions among WuCs. Consequently, no backoff is needed for the main radio after a WuC is received. A discrete-time Markov chain model is developed to evaluate the performance. Numerical results on network throughput, energy efficiency, average delay, and collision probability reveal the benefits of enabling backoff for SCM-WuRs, especially under heavy traffic loads or saturated traffic conditions.
Autors: Debasish Ghose;Frank Y. Li;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1031 - 1034
Publisher: IEEE
 
» Enabling Focus Cues in Head-Mounted Displays
Abstract:
Developing head-mounted displays (HMDs) that offer uncompromised optical pathways to both digital and physical worlds without encumbrance and discomfort confronts many grand challenges, both from technological perspectives and human factors. Among the many challenges, minimizing visual discomfort is one of the key obstacles. One of the key contributing factors to visual discomfort is the lack of the ability to render proper focus cues in HMDs to stimulate natural eye accommodation responses, which leads to the wellknown problem of vergence–accommodation conflict. This paper provides a comprehensive summary of various technical approaches toward enabling focus cues in HMDs for both virtual reality (VR) and augmented reality (AR) applications.
Autors: Hong Hua;
Appeared in: Proceedings of the IEEE
Publication date: May 2017, volume: 105, issue:5, pages: 805 - 824
Publisher: IEEE
 
» Enabling Mobile and Wireless Technologies for Smart Cities: Part 3
Abstract:
The articles in this special section focuses on the deployment of mobile and wireless technologies and services in smart cities.
Autors: Ejaz Ahmed;Muhammad Imran;Mohsen Guizani;Ammar Rayes;Jaime Lloret;Guangjie Han;Wael Guibene;
Appeared in: IEEE Communications Magazine
Publication date: May 2017, volume: 55, issue:5, pages: 24 - 25
Publisher: IEEE
 
» Enabling the Extraction of Climate-Scale Temporal Salinity Variations from Aquarius: An Instrument Based Long-Term Radiometer Drift Correction
Abstract:
All channels of the Aquarius radiometer were observed to have calibration instability consisting of a drift in the antenna temperature during the first couple of months of the mission and pseudo-periodic oscillations of the antenna temperature over the mission life. For the version 4 Aquarius processing, both of these anomalies were corrected by removing a time variable bias in the Aquarius measurements relative to a seven-day global average from a salinity model. In order to accurately track long-term variation of salinity on climate scales it is necessary to decouple Aquarius radiometric calibration from ocean salinity models. In this paper, a new technique is used to investigate the nature of anomalies using nonocean vicarious external sources such as Antarctic ice or Amazonian rain forests. Two completely different solutions are developed to correct the pseudo-periodic oscillations as well as the drift of the Aquarius radiometers, decoupling the Aquarius measurements from salinity model.
Autors: Sidharth Misra;Shannon T. Brown;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: May 2017, volume: 55, issue:5, pages: 2913 - 2923
Publisher: IEEE
 
» Energizing 5G: Near- and Far-Field Wireless Energy and Data Trantransfer as an Enabling Technology for the 5G IoT
Abstract:
We are surrounded in our daily lives by a multitude of small, relatively inexpensive computing devices, many equipped with communication and sensing features. From these has evolved the concept of "pervasive intelligence" [1], [2], a basis from we can envision our future world as an Internet of Things/Internet of Everything (IoT/IoE), in terms of both a consumer IoT/IoE (interconnected devices within an individual's environment) and the Industrial IoT (interconnectedness to improve business-to-business services, mainly through machineto-machine interactions) [3].
Autors: Alessandra Costanzo;Diego Masotti;
Appeared in: IEEE Microwave Magazine
Publication date: May 2017, volume: 18, issue:3, pages: 125 - 136
Publisher: IEEE
 
» Energy and Spectral Efficiency of Cellular Networks With Discontinuous Transmission
Abstract:
Cell discontinuous transmission (DTX) has been proposed as a solution to reduce the energy consumption of cellular networks. This paper investigates the impact of network traffic load on the spectral and energy efficiency of cellular networks with DTX. The signal-to-interference-plus-noise ratio (SINR) distribution as a function of traffic load is derived first. Then, the sufficient condition for ignoring thermal noise and simplifying the SINR distribution is investigated. Based on the simplified SINR distribution, the network spectral and energy efficiency as functions of network traffic load are derived. It is shown that the network spectral efficiency increases monotonically in traffic load, while the optimal network energy efficiency depends on the ratio of the sleep-mode power consumption to the active-mode power consumption of base stations. If the ratio is larger than a certain threshold, the network energy efficiency increases monotonically with network traffic load and is maximized when the network is fully loaded. Otherwise, the network energy efficiency first increases and then decreases in network traffic load. The optimal load can be identified with a binary search algorithm. The power ratio threshold depends solely on the path loss exponent , e.g., 56% for . All these analytic results are further validated by the numerical simulations.
Autors: Peiliang Chang;Guowang Miao;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2017, volume: 16, issue:5, pages: 2991 - 3002
Publisher: IEEE
 
» Energy and Spectral Efficiency Tradeoff for Massive MIMO Systems With Transmit Antenna Selection
Abstract:
This correspondence investigates the fundamental tradeoff between the spectral efficiency (SE) and energy efficiency (EE) for massive multiple-input multiple-output (MIMO) systems with linear precoding and transmit antenna selection, where both the circuit power consumption and the large-scale fading are considered. The EE and SE are optimized with respect to the number of transmit antennas and transmit power, and consequently, we formulate the EE–SE tradeoff as a mixed-integer-continuous-variable multiobjective optimization (MOO) problem. Using the derived EE–SE relations, the properties of the Pareto front for the EE–SE tradeoff are analyzed. To solve the complicated MOO problem, we develop two algorithms: the weighted-sum particle swarm optimization (WS-PSO) algorithm and the normal-boundary-intersection particle swarm optimization (NBI-PSO) algorithm. Simulation results show that the two algorithms can achieve the Pareto optimal EE-SE tradeoff, and NBI-PSO provides more evenly distributed solutions than WS-PSO.
Autors: Zujun Liu;Weimin Du;Dechun Sun;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 4453 - 4457
Publisher: IEEE
 
» Energy Based Limit Cycle Control of Elastically Actuated Robots
Abstract:
A new control law for elastic joint robots that allows to regulate an energy function of the system to a desired value is presented in this technical note. Being able to either remove energy from the system or inject into it, oscillations can be both damped out and induced. The proposed nonlinear dynamic state feedback controller forces the system to evolve on a submanifold of the configuration space. The reduced dynamics of the system and of the controller itself are similar to a single elastic joint, for which an asymptotically stable limit cycle is obtained regulating an energy function to a positive desired value. When the desired value of the energy function is chosen to be zero, then the asymptotically stable limit cycle reduces to an asymptotically stable equilibrium point. In this case the oscillations are damped out and the desired task-space configuration is reached. The design of the controller extensively uses the concept of conditional stability, so that the limit cycle can be designed for a lower dimensional dynamical system, although it will result to be a limit cycle for the whole system.
Autors: Gianluca Garofalo;Christian Ott;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2490 - 2497
Publisher: IEEE
 
» Energy Beamforming for Wireless Power Transfer in MISO Heterogeneous Network With Power Beacon
Abstract:
This letter considers an energy harvesting heterogeneous network (EHHN) in which a power beacon (PB) for radio-frequency-energy transfer coexists with a base station for information transfer. In this network, a tradeoff exists between harvested energy and information rate, because the energy transfer of the PB causes the interference to the information transfer. To determine the optimal energy-transfer strategy under this tradeoff, we propose an energy beamforming scheme that maximizes the weighted sum of the harvested energy and the information rate in multiple-input single-output EHHN. Because the weighted-sum-maximization problem is nonconvex, we partition it into a difference of convex functions problem and a convex-maximization problem, and then solve them using efficient convex-based algorithms. In simulation, the proposed beamforming scheme is shown to achieve a near-optimal rate-energy region for the considered problem.
Autors: Jong-Hyeok Park;Yo-Seb Jeon;Soohee Han;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1163 - 1166
Publisher: IEEE
 
» Energy Efficiency Challenges of 5G Small Cell Networks
Abstract:
The deployment of a large number of small cells poses new challenges to energy efficiency, which has often been ignored in 5G cellular networks. While massive MIMO will reduce the transmission power at the expense of higher computational cost, the question remains as to which (computation or transmission power) is more important in the energy efficiency of 5G small cell networks. Thus, the main objective in this article is to investigate the computation power based on the Landauer principle. Simulation results reveal that more than 50 percent of the energy is consumed by the computation power at 5G small cell BSs. Moreover, the computation power of a 5G small cell BS can approach 800 W when massive MIMO (e.g., 128 antennas) is deployed to transmit high volume traffic. This clearly indicates that computation power optimization can play a major role in the energy efficiency of small cell networks.
Autors: Xiaohu Ge;Jing Yang;Hamid Gharavi;Yang Sun;
Appeared in: IEEE Communications Magazine
Publication date: May 2017, volume: 55, issue:5, pages: 184 - 191
Publisher: IEEE
 
» Energy Efficiency for Clustered Heterogeneous Multicores
Abstract:
Heterogeneous multicore systems clustered in multiple Voltage Frequency Islands (VFIs) are the next-generation solution for power and energy efficient computing systems. Due to the heterogeneity, the power consumption and execution time of a task changes not only with Dynamic Voltage and Frequency Scaling (DVFS), but also according to the task-to-island assignment, presenting major challenges for power management and energy minimization techniques. This paper focuses on energy minimization of periodic real-time tasks (or performance-constrained tasks) on such systems, in which the cores in an island are homogeneous and share the same voltage and frequency, but different islands have different types and numbers of cores and can be executed at other voltages and frequencies. We present an efficient algorithm to minimize the total energy consumption while satisfying the timing constraints of all tasks. Our technique consists of the coordinated selection of the voltage and frequency levels for each island, together with a task partitioning strategy that considers the energy consumption of the task executing on different islands and at different frequencies, as well as the impact of the frequency and the underlying core architecture to the resulting execution time. Every task is then mapped to the most energy efficient island for the selected voltage and frequency levels, and to a core inside the island such that the workloads of the cores in a VFI are balanced. We experimentally evaluate our technique and compare it to state-of-the-art solutions, resulting in average in 25 percent less energy consumption (and up to 87 percent for some cases), while guaranteeing that all tasks meet their deadlines.
Autors: Santiago Pagani;Anuj Pathania;Muhammad Shafique;Jian-Jia Chen;Jörg Henkel;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2017, volume: 28, issue:5, pages: 1315 - 1330
Publisher: IEEE
 
» Energy Efficiency Optimization in 3-D Small Cell Networks-Based Sleep Strategy
Abstract:
In this letter, we focus on energy efficiency in small cell networks where a large number of small cells are spatial deployed in dense urban area. We optimize the energy efficiency by sleep mechanism under average connection ratio (ACR) and average user rate constrains. First, we derive the average rate in 3-D small cell networks by Matern Hardcore point process. Then, based on monotonicity analysis, the optimal small cell sleep probability is calculated to satisfy both ACR and average rate constrains. In addition, we also formulate an optimal maximum connection number of small cell that minimizes the energy consumption subject to the joint constraint of ACR and average rate. Numerical results show that with the sleep strategy, the small cell networks energy consumption can be reduce about 21% of the total. Our optimal sleep probability and maximum connection number can be effectively applied to design small cell sleep strategy for 3-D small cell networks.
Autors: Ziyu Pan;Qi Zhu;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1131 - 1134
Publisher: IEEE
 
» Energy Harvesting Communication Using Finite-Capacity Batteries With Internal Resistance
Abstract:
Modern systems will increasingly rely on energy harvested from their environment. Such systems utilize batteries to smooth out the random fluctuations in harvested energy. These fluctuations induce highly variable battery charge and discharge rates, which affect the efficiencies of practical batteries that typically have non-zero internal resistance. In this paper, we study an energy harvesting communication system using a finite battery with non-zero internal resistance. We adopt a dual-path architecture, in which harvested energy can be directly used, or stored and then used. In a frame, both time and power can be split between energy storage and data transmission. For a single frame, we derive an analytical expression for the rate optimal time and power splitting ratios between harvesting energy and transmitting data. We then optimize the time and power splitting ratios for a group of frames, assuming non-causal knowledge of harvested power and fading channel gains, by giving an approximate solution. When only the statistics of the energy arrivals and channel gains are known, we derive a dynamic programming-based policy and propose three sub-optimal policies, which are shown to perform competitively. In summary, this paper suggests that battery internal resistance significantly impacts the design and performance of energy harvesting communication systems and must be considered.
Autors: Rajshekhar Vishweshwar Bhat;Mehul Motani;Teng Joon Lim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2017, volume: 16, issue:5, pages: 2822 - 2834
Publisher: IEEE
 
» Energy-Aware Dynamic Selection of Overlay and Underlay Spectrum Sharing for Cognitive Small Cells
Abstract:
Small cell (SC) base stations with cognitive capabilities are seen as an efficient way to cope with interference between the SC base stations and macrocell base stations (MBSs). Cognitive SCs may access the spectrum by means of overlay or underlay mode. An efficiency of the overlay mode fully depends on the activity of macrocell users (MUEs), since insufficient resources remain for small cell users (SUEs). Contrarily, the main weakness of the underlay mode is that it can result in low transmission efficiency due to restricted transmission power. Apart from the transmission efficiency of both modes, an energy consumption of the SCs should not be disregarded. Thus, we propose a centralized scheme selecting the spectrum sharing mode in the downlink, according to both the SUEs’ throughput and the energy consumption of the SCs. The objective is to maximize the overall performance of the SCs, while their energy consumption is taken into account. Then, we also propose a distributed algorithm in order to decrease complexity and signaling overhead of the centralized scheme. The results show that the proposed dynamic selection significantly outperforms all competitive schemes in terms of the SUEs’ throughput, while the throughput of MUEs is intact, and only negligible signaling overhead is generated in the case of the proposed distributed algorithm. Moreover, the proposed algorithm is able to notably decrease the energy consumption of the SCs.
Autors: Pavel Mach;Zdenek Becvar;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 4120 - 4132
Publisher: IEEE
 
» Energy-Efficient Management of Cognitive Radio Terminals With Quality-Based Activation
Abstract:
In cooperative cognitive radio systems (CRSs), where battery-powered cognitive radio terminals (CTs) frequently sense and report primary user’s (PU’s) existence to exploit a spectrum hole, energy efficiency (EE) is a challenging design issue. To improve EE in CRSs, letting only some of the CTs be active in sensing and reporting [called a quality-based activation (QBA)] is proposed in this letter. With QBA, CTs that have good channel quality in a data channel (DCH) as well as a reporting channel (RCH) are allowed to sense and report. A possible drawback of such conditional activation is that it could limit the participation of CTs in a scheduling procedure, and hence, may result in losing certain system throughput. Throughput and EE of CRSs with the proposed QBA are investigated and it is shown, with numerical examples, that QBA does not decrease the throughput and provides significant improvement in EE.
Autors: Junaid Imtiaz;Dongwoo Kim;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1171 - 1174
Publisher: IEEE
 
» Engineering Outreach: Yesterday, Today, and Tomorrow [SP Education]
Abstract:
This article discusses the current landscape of outreach efforts in the United States to engage K-12 students in engineering. It then provides an overview of two programs run by the College of Engineering and Applied Sciences, and the Institute for Science, Technology, Engineering, and Mathematics Education at Stony Brook University (SBU) to promote student participation and interest in engineering. These efforts are aligned with the recently released Next Generation Science Standards (NGSS), which emphasize incorporating engineering design principles in K-12 science education. We describe two models, one in the form of an on-campus summer camp and the other as a series of after-school activities with both on-and off-campus offerings. These experiences are rarely available in K-12 schools and have the added benefit of exposing students to engineering faculty and researchers. The programs are focused on electrical and computer engineering with emphasis on signal and information processing and analysis and have hosted more than 200 students for the past six years.
Autors: Monica F. Bugallo;Angela M. Kelly;
Appeared in: IEEE Signal Processing Magazine
Publication date: May 2017, volume: 34, issue:3, pages: 69 - 100
Publisher: IEEE
 
» Enhanced Cellular Coverage and Throughput Using Rateless Codes
Abstract:
Rateless codes have been shown to provide robust error correction over a wide range of binary and noisy channels. Using a stochastic geometry model, this paper studies the performance of rateless codes in the cellular downlink and compares it with the performance of fixed-rate codes. For the case of Rayleigh fading, an accurate approximation is proposed for the distribution of the packet transmission time of -bit information packets using rateless codes. The two types of channel coding schemes are compared by evaluating the typical user and per-user success probability and the rate. Based on both the analytical results and simulations, the paper shows that rateless coding provides a significant throughput gain relative to fixed-rate coding. Moreover, the benefit is not restricted to the typical user but applies to all users in the cellular network.
Autors: Amogh Rajanna;Martin Haenggi;
Appeared in: IEEE Transactions on Communications
Publication date: May 2017, volume: 65, issue:5, pages: 1899 - 1912
Publisher: IEEE
 
» Enhanced Performance of Thiophene-Rich Heteroacene, Dibenzothiopheno [6,5-b:6’,5’-f] Thieno[3,2-b]Thiophene Thin-Film Transistor With MoOx Hole Injection Layers
Abstract:
In this letter, we demonstrated a high performance organic thin-film transistor using thermally evaporated amorphous phase MoOx as a hole injection layer between metal electrodes and organic semiconductor. The fabricated organic thin-film transistors showed the field-effect mobility of 7 cm/Vs in linear and saturation regimes and an ON/OFF current ratio of . The MoOx hole injection layers significantly reduced the injection barrier from metal electrode, resulting in the improvement of ohmic contact properties of a synthesized thiophene-rich heteroacene, dibenzothiopheno [6,5-b:6’,5’-f] thieno [3,2-b] thiophene p-type organic semiconductor, as compared with those with single metals. Furthermore, high performance organic thin-film transistors can be successfully realized with Al electrode, which is not suitable for p-type organic semiconductors due to its low work function by introducing a 75-nm-thick MoOx hole injection layer.
Autors: Youngjun Yun;Ajeong Choi;Suk Gyu Hahm;Jong Won Chung;Yong Uk Lee;Ji Young Jung;Joo-Young Kim;Jeong-Il Park;Sangyoon Lee;Jaewon Jang;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 649 - 652
Publisher: IEEE
 
» Enhanced Self-Sensing Capability of Permanent-Magnet Synchronous Machines: A Novel Saliency Modulation Rotor End Approach
Abstract:
This paper investigates a novel rotor configuration of a permanent-magnet synchronous machine (PMSM) in which a saliency modulation rotor end is added to the machine rotor to improve the self-sensing capability. The saliency-based self-sensing control method is widely adopted for position estimation at stand-still and low speed range. However, the performance is heavily affected by saturation effects for conventional PMSMs, because the machine saliency variates with increased fundamental stator flux under loaded operation. The proposed scheme provides an additional space anisotropic to the rotor. Saliency modulation of the rotor end is electrically asynchronous with the machine fundamental reference frame. Hence the tracked machine saliency provided by the rotor end is no longer affected by saturation effects. In addition, for medium and high speed ranges, the rotor end saliency can be modulated with the fundamental voltage and the rotor position can be tracked without superposed injection. A genetic algorithm optimization environment joined with finite element analysis allows obtaining optimized rotor end geometry for better position signal quality. The expected self-sensing performance is validated by experimental results.
Autors: Tianhao Wang;He Zhang;Qiang Gao;Zhuang Xu;Jing Li;Chris Gerada;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3548 - 3556
Publisher: IEEE
 
» Enhancing Flatbed Printer Accuracy and Throughput: Optimal Rational Feedforward Controller Tuning Via Iterative Learning Control
Abstract:
Advanced control methods potentially enable performance improvements in printing systems for minor additional costs. The aim of this paper is to develop a control framework that is capable of delivering throughput and accuracy enhancements for an industrial flatbed inkjet printer. The proposed method involves iterative learning control with a rational feedforward parameterization to enable varying position references which are required for printing. Experimental results highlight the efficacy of the proposed method in a comparison with related pre-existing learning control approaches.
Autors: Joost Bolder;Jurgen van Zundert;Sjirk Koekebakker;Tom Oomen;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 4207 - 4216
Publisher: IEEE
 
» Enhancing Network Parameter Error Detection and Correction via Multiple Measurement Scans
Abstract:
Although the normalized Lagrange multiplier (NLM) method has been shown to be very effective for network parameter error identification, errors in parameters corresponding to insensitive NLMs still remain difficult to detect and correct. This paper proposes an enhanced method for detecting and correcting network parameter errors based on multiple measurement scans. The method is developed by first deriving the relationship between parameter errors and the associated Langrage multipliers in state estimation. This is then used to clarify the reason behind the sensitivity issue of NLMs and the improvements made by performing multiple scans. An approach for estimating the necessary number of scans for satisfying various detection requirements is also proposed. Moreover, a local parameter error correction procedure based on multiple scans is presented, with detailed discussion of the local network selection and the number of required measurement scans. Simulation results in a very large utility system in North America illustrate the effectiveness of the analysis and methods proposed in this paper.
Autors: Yuzhang Lin;Ali Abur;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2417 - 2425
Publisher: IEEE
 
» Enhancing Power Transformer Differential Protection to Improve Security and Dependability
Abstract:
Current differential principle is a well-known principle used for protection of transformers, motors, generators, buses, and any other type of power equipment with input and output current measurements. Further, the principle is used in developing percent differential protection, which can be programmed to the desired sensitivity for detecting in-zone faults and security during external faults. This protection dependability is usually achieved by modeling a differential-restraining characteristic with two regions, operating and nonoperating, and tracking the real differential restraint ratio during faults. Some external faults with high dc offset and high X/R system time constant would easily saturate the installed current transformers (CTs), which in return would cause high differential/restraint ratio above the preset characteristic into the operating region. In such cases, the differential protection would operate and cause unwanted transformer trip. This paper focuses on some enhancements applied to the differential principle of the main differential protection; it also defines guidance on how to setup the protection for better sensitivity and security. The paper is supported by fault cases, showing the improved security and dependability during internal/external faults with and without CT saturation.
Autors: Lubomir Sevov;Umar Khan;Zhiying Zhang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2642 - 2649
Publisher: IEEE
 
» Enhancing the Gaming Experience Using 3D Spatial User Interface Technologies
Abstract:
Three-dimensional (3D) spatial user interface technologies have the potential to make games more immersive and engaging and thus provide a better user experience. Although technologies such as stereoscopic 3D display, head tracking, and gesture-based control are available for games, it is still unclear how their use affects gameplay and if there are any user performance benefits. The authors have conducted several experiments on these technologies in game environments to understand how they affect gameplay and how we can use them to optimize the gameplay experience.
Autors: Arun Kulshreshth;Kevin Pfeil;Joseph J. LaViola;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2017, volume: 38, issue:3, pages: 16 - 23
Publisher: IEEE
 
» Entanglement-Assisted Capacities of Compound Quantum Channels
Abstract:
We study universal quantum codes for entanglement-assisted quantum communication over compound quantum channels. In this setting, sender and receiver do not know the specific channel that will be used for communication, but only know the set that the channel is selected from. We investigate different variations of the problem: uninformed users, informed receiver, informed sender, and feedback assistance. We derive single-letter formulas for all corresponding channel capacities. Our proofs are based on one-shot decoupling bounds and properties of smooth entropies.
Autors: Mario Berta;Hrant Gharibyan;Michael Walter;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2017, volume: 63, issue:5, pages: 3306 - 3321
Publisher: IEEE
 
» Epileptic Focus Localization Using Discrete Wavelet Transform Based on Interictal Intracranial EEG
Abstract:
Over the past decade, with the development of machine learning, discrete wavelet transform (DWT) has been widely used in computer-aided epileptic electroencephalography (EEG) signal analysis as a powerful time-frequency tool. But some important problems have not yet been benefitted from DWT, including epileptic focus localization, a key task in epilepsy diagnosis and treatment. Additionally, the parameters and settings for DWT are chosen empirically or arbitrarily in previous work. In this work, we propose a framework to use DWT and support vector machine (SVM) for epileptic focus localization problem based on EEG. To provide a guideline in selecting the best settings for DWT, we decompose the EEG segments in seven commonly used wavelet families to their maximum theoretical levels. The wavelet and its level of decomposition providing the highest accuracy in each wavelet family are then used in a grid search for obtaining the optimal frequency bands and wavelet coefficient features. Our approach achieves promising performance on two widely-recognized intrancranial EEG datasets that are also seizure-free, with an accuracy of 83.07% on the Bern-Barcelona dataset and an accuracy of 88.00% on the UBonn dataset. Compared with existing DWT-based approaches in epileptic EEG analysis, the proposed approach leads to more accurate and robust results. A guideline for DWT parameter setting is provided at the end of the paper.
Autors: Duo Chen;Suiren Wan;Forrest Sheng Bao;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: May 2017, volume: 25, issue:5, pages: 413 - 425
Publisher: IEEE
 
» Equipment Utilization Enhancement in Photolithography Area Through a Dynamic System Control Using Multi-Fidelity Simulation Optimization With Big Data Technique
Abstract:
Photolithographic (Photo) plays a key role in semiconductor manufacturing because of its importance to advanced process shrinking. Even with a small improvement in its operational efficiency, the cost competitiveness in production can be enhanced as a result of the huge amount of share capital cost. However, it is difficult to stabilize the throughput rhythm of Fabs, while keeping a high equipment utilization for Photo. In the light of Industry 4.0 and big data, a huge potential of maintaining a desired system performance by (near) real-time dynamic system control is highly anticipated. But it also poses challenges to intelligently handling mass data acquisition and allocating computing resources. This research aims to maximize the equipment utilization in Photo by an efficient multi-model simulation optimization approach with big data techniques in the era of Industry 4.0. dynamic Photo configurator and abnormality detector are the two critical units in our proposed system framework; the former can make a quick decision to optimize the system configuration while receiving the adjustment request from the latter. The results from an empirical study show the practical viability of proposed approach that the capacity loss in Photo has been effectively improved.
Autors: Liam Y. Hsieh;Edward Huang;Chun-Hung Chen;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: May 2017, volume: 30, issue:2, pages: 166 - 175
Publisher: IEEE
 
» Ergodic Spectral Efficiency in MIMO Cellular Networks
Abstract:
This paper shows how the application of stochastic geometry to the analysis of wireless networks is greatly facilitated by: () a clear separation of time scales; (ii) the abstraction of small-scale effects via ergodicity; and (iii) an interference model that reflects the receiver’s lack of knowledge of how each individual interference term is faded. These procedures render the analysis both more manageable and more precise, as well as more amenable to the incorporation of subsequent features. In particular, the paper presents analytical characterizations of the ergodic spectral efficiency of cellular networks with single-user multiple-input multiple-output and sectorization. These characterizations, in the form of easy-to-evaluate expressions, encompass the coverage, the distribution of spectral efficiency over the network locations, and the average thereof.
Autors: Geordie George;Ratheesh K. Mungara;Angel Lozano;Martin Haenggi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2017, volume: 16, issue:5, pages: 2835 - 2849
Publisher: IEEE
 
» Erratum to “An Online UPS System That Eliminates the Inrush Current Phenomenon While Feeding Multiple Load Transformers”
Abstract:
Autors: Syed Sabir Hussain Bukhari;Thomas A. Lipo;Byung-Il Kwon;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2650 - 2650
Publisher: IEEE
 
» Error-Resilient Integrated Clock Gate for Clock-Tree Power Optimization on a Wide Voltage IOT Processor
Abstract:
Energy-efficiency optimization occupies an important position in the Internet of Things application. The error-resilience technique has begun to emerge and brought the performance and energy benefits as a new vision for alternative computing, because it eliminates the overconstrained margin in current processor design flow and protects the system from process, supply voltage, temperature, and aging variations through an error-resilient mechanism rather than expensive guardbands. However, as a traditional clock-tree power optimization technique, the clock gating mechanism cannot work in such a system when it faces the timing violation problem. In this paper, we propose an error-resilient integrated clock gate (ERICG) and its automatic integration methodology in error detection and correction (EDAC) system design flow. ERICG can provide the ability of in situ timing EDAC with only four additional transistors compared with a conventional integrated clock gate. The SPICE simulation shows that it is a metastable-hardened cell and can work well in the wide voltage operation (0.5~ 1.1 V) including the near-threshold region. We implement it in a commercial C-SKY CK802 processor based on an SMIC 40-nm technology. The result shows that it improves the energy efficiency by 68% compared with the non-EDAC design and lowers the total power by 28.72% over the conventional EDAC design at 0.6 V.
Autors: Tao-Tao Zhu;Jian-Yi Meng;Xiao-Yan Xiang;Xiao-Lang Yan;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2017, volume: 25, issue:5, pages: 1681 - 1693
Publisher: IEEE
 
» Error-Resilient Video Encoding Using Parallel Independent Signature Processing
Abstract:
Soft errors resulting from encoding video sequences on unreliable hardware can create significant artifacts in decoded video sequences, contributing to extreme video quality degradation. Modern systems are required to operate under increasingly challenging constraints, including smaller feature sizes and lower operating voltage, increasing the likelihood of soft errors in the video encoding hardware. These conditions are of particular concern for energy-limited battery-operated systems since they may be required to operate in nonideal environments and/or continue operating with a practically depleted energy source. The proposed parallel independent signature processing design performs error detection and mitigation in video encoding hardware, enabling a graceful degradation of quality when encoding by using unreliable hardware. The effects of soft errors are minimized by preventing the error propagation normally associated with errors in encoded video sequences. This allows for the recovery of quality when errors are present in the video encoding system. Conventional video encoding techniques are designed to handle worst case error rates by increasing gate sizes and/or increasing the operating voltage of the system. Such designs have error-rate limits, and when these limits are reached, the systems tend to fail catastrophically, resulting in an unrecoverable signal. The proposed design allows for single upset events to translate into single transient artifacts in a decoded video sequence.
Autors: Joshua W. Wells;Abhijit Chatterjee;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: May 2017, volume: 27, issue:5, pages: 1077 - 1090
Publisher: IEEE
 
» ESD Robust Fully Salicided 5-V Integrated Power MOSFET in Submicron CMOS
Abstract:
A novel high electrostatic discharge (ESD), robust fully salicided 5-V integrated CMOS power MOSFET design is developed and demonstrated without the use of conventional salicide blocking ballast resistor. This scheme builds the ballast resistors on the top of the source and drain, without any increase in silicon footprint unlike prior methods, while maintaining standard transistor parametric performance.
Autors: Jian-Hsing Lee;Natarajan Mahadeva Iyer;Manjunatha Prabhu;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 623 - 625
Publisher: IEEE
 
» Estimate of Ocean Wind Vectors Inside Tropical Cyclones From Polarimetric Radiometer
Abstract:
Microwave polarimetry provides a distinctive opportunity to retrieve wind speed (WS) and wind direction (WD) inside tropical cyclones (TCs) due to the high atmospheric transmissivity through clouds and under rain conditions. A WS retrieval algorithm for WS above 20 m/s in TCs using brightness temperature at 6.8- and 10.7-GHz has been developed and a new set of parameters has been optimized from WindSat TB and the HWind analysis matches. This algorithm is estimated to have an encouraging degree of accuracy for retrieving WS in TCs. For WS above 20 m/s, the mean (std) of the differences between retrieved WS and HWind analysis for 17 TCs from 2003 to 2009 is 0.2 m/s (3.1 m/s). WD signals in the third (T3) and fourth Stokes (T4) parameters at 10.7-, 18.7- and 37-GHz for ocean surfaces in TCs under rain are presented. T3 observations from the WindSat 10.7-, 18.7-, and 37-GHz channels are collocated with the ocean-surface winds from the HWind analysis. The collocated data are binned as a function of WS and WD. The 10.7 GHz T3 data show clear 4-K peak-to-peak directional signals at 30–40 m/s WS after correction for the atmospheric attenuation. The data are fitted by harmonics of the relative azimuth angles between the HWind analysis and radiometer look directions. The new coefficients of WD harmonics are used to retrieve WD in TCs under rain using WindSat T3 and T4 channels. The rms difference between retrieved WD and HWind WD is 24.2.
Autors: Xiaobin Yin;Zhenzhan Wang;Qingtao Song;Yingzhu Huang;Ruanyu Zhang;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2017, volume: 10, issue:5, pages: 1701 - 1714
Publisher: IEEE
 
» Estimating Random Errors of Scatterometer, Altimeter, and Model Wind Speed Data
Abstract:
Scatterometer and altimeter wind data are very important for data assimilation and verification of numerical weather prediction models. Standard deviation of absolute random errors can be estimated using the triple collocation technique. However, error correlations between various wind sources (e.g., due to data assimilation) complicate the error estimation. A method is used to alleviate the impact of error correlations between the scatterometer and the model that assimilates such data. Using twenty-two datasets of triplet composed of Jason-2 altimeter, Metop-A/B scatterometers (ASCAT-A/B, respectively), and ECMWF model analysis and forecasts (1 altimeter × 2 scatterometers × 11 model analysis and forecasts = 22 datasets) covering a period of two years from August 2013 to July 2015, the correlation coefficient between the errors of scatterometers and the model analysis was found to be about 0.33 for those datasets. This correlation reduces with forecast lead time until it almost vanishes at day seven. Altimeter and scatterometer errors are not correlated. The standard deviation of wind speed random errors of Jason-2, ASCAT-A/B, and the IFS analysis are estimated as 0.7, 0.8, and 0.9 m/s, respectively. As expected, there was no difference between ASCAT-A and ASCAT-B results.
Autors: Saleh Abdalla;Giovanna De Chiara;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2017, volume: 10, issue:5, pages: 2406 - 2414
Publisher: IEEE
 
» Estimating Sag and Wind-Induced Motion of Overhead Power Lines With Current and Magnetic-Flux Density Measurements
Abstract:
Overhead high-voltage transmission lines (HVTLs) extend over diverse geographic regions under uneven weather conditions, where sag and wind-induced conductor motion poses serious issues for uninterrupted power distribution by HVTLs. Sag reduces the ground clearance of the line, whereas conductor motion may result in phase to phase short circuit, and damage to support structure. A real-time estimate of these factors is deemed important to develop requisite prevention measures. In this paper, we present a novel method to cater for sag and motion estimation in real-world scenarios. Our method can detect a change in sag and conductor motion, whether it is symmetrical or unsymmetrical to one or more conductors. We require uniaxial magnetic-field (MF) sensors mounted at support tower, equal to conductors, and synchronized with current-transformer (CT) data at substation. The sensors provide noncontact MF measurements, which are time stamped and transmitted to the substation. The data are then simultaneously processed along with electric current readings from the CT. For processing, we developed a unified algorithm that first distinguishes variation in sag from motion in conductor. Then, it estimates the corresponding sag or motion in any of the conductors. The method is verified first by numerical simulations, and then with a scaled setup in laboratory. Different test cases were identified by the algorithm. Error remains % for unsymmetrical sag estimation. In addition, trajectory of a conductor in motion is retrieved. Where the root mean square error between actual and retrieved conductor amplitude was only 0.0833 for the observation window of 200 ms.
Autors: Arsalan Habib Khawaja;Qi Huang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2017, volume: 66, issue:5, pages: 897 - 909
Publisher: IEEE
 
» Estimating Soil Salinity Under Various Moisture Conditions: An Experimental Study
Abstract:
Soil salinization is one of the most common land desertification processes that can be found worldwide. It is a certainly severe environment hazard and threatens the stability of ecosystems. As a rapid and inexpensive tool, remote sensing technology combining with the measurements of soil spectra has been widely concerned on identifying and mapping salt effect on lands. However, as effects of the soil moisture often immerge the effects of salt to soil reflectance spectra, soil moisture became a major factor to restrict soil salinity monitoring from soil reflectance. High soil moisture content will lead to failure on soil salinity estimation from soil reflectance data. In this paper, a semianalytical model using an exponent function was developed to estimate soil salt content (SSC) under different moisture levels based on a control laboratory experiment. And the root-mean-square error and mean relative error were 0.799 g/kg and 31.294%, respectively, when the model was applied to estimate SSCs by wet soil reflectance. To sum up, considering both effects of soil moisture and soil salt on soil reflectance, the semianalytical model reduced SSC estimated error. The approach presented in this paper provides a new way of estimating soil salinity from soil spectra under various soil moisture conditions, and it will be a potential application for large-scale SSC mapping.
Autors: Xiguang Yang;Ying Yu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: May 2017, volume: 55, issue:5, pages: 2525 - 2533
Publisher: IEEE
 
» Estimating the Accuracy Level Among Individual Detections in Clustered Microcalcifications
Abstract:
Computerized detection of clustered microcalcifications (MCs) in mammograms often suffers from the occurrence of false positives (FPs), which can vary greatly from case to case. We investigate how to apply statistical estimation to determine the number of FPs that are present in a detected MC lesion. First, we describe the number of true positives (TPs) by a Poisson–binomial probability distribution, wherein a logistic regression model is trained to determine the probability for an individual detected MC to be a TP based on its detector output. Afterward, we model the spatial occurrence of FPs in a lesion area by a spatial point process (SPP), of which the distribution parameters are estimated from the detections in the lesion and its surrounding region. Furthermore, to improve the estimation accuracy, we incorporate the Poisson–binomial distribution of the number of TPs into the SPP model using maximum a posteriori estimation. In the experiments, we demonstrated the proposed approach on the detection results from a set of 188 full-field digital mammography (FFDM) images (95 cases) by three existing MC detectors. The results showed that there was a strong consistency between the estimated and the actual number of TPs (or FPs) for these detectors. When the fraction of FPs in detection was varied from 20% to 50%, both the mean and median values of the estimation error were within 11% of the total number of detected MCs in a lesion. In particular, when the number of FPs increased to as high as 11.38 in a cluster on average, the error was 2.51 in the estimated number of FPs. In addition, lesions estimated to be more accurate in detection were shown to have better classification accuracy (for being malignant or benign) than those estimated to be less accurate.
Autors: María V. Sainz de Cea;Robert M. Nishikawa;Yongyi Yang;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: May 2017, volume: 36, issue:5, pages: 1162 - 1171
Publisher: IEEE
 
» Estimation and Attitude Control in CONASAT's Nominal Operation Mode: An Approach for SDRE Filter and PID Control
Abstract:
CubeSat attracted interest of international community with numerous studies being developed in some universities, schools or even space enthusiastic. Miniaturization of components and use of conventional electronics reduced costs with space projects, that previously restricted access to space to only a few nations at costs of several million dollars. So, governments and space agencies, especially in developing nations, has begun to invest in small satellite projects, because now they can have space missions at low cost. Thus, the National Institute for Space Research (INPE), in Brazil, has planning some CubeSat missions as an academic tool to spread the space technology across the country to universities and researches. One of the missions in development is the Nanosatellite Constellation for Environmental Data Collection (CONASAT). This project intends to launch at least two small satellites to replace the SCD1 and SCD2 satellites of the Brazilian's environmental data collection system. The main objective of this paper is to propose state estimation technique, known as State-Dependent Riccati Equation (SDRE), together with a PID controller based on attitude error given by the Euler angle and axis for nominal mode attitude control of CONASAT. Simulations were performed using an open computational tool for attitude and orbit simulation.
Autors: Brehme Dnapoli Reis de Mesquita;Helio Koiti Kuga;Valdemir Carrara;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 835 - 842
Publisher: IEEE
 
» Estimation of Current and Sag in Overhead Power Transmission Lines With Optimized Magnetic Field Sensor Array Placement
Abstract:
Power distribution mechanism in smart grid necessitates the development of an easy-to-install and contactless sensing system to monitor the operational state of overhead high-voltage transmission lines. Here, we propose a robust phase current and sag estimation method at support structures. Novelty in our work is the use of dual-axis magnetic field (MF) sensors equal to the number of phase conductors. This is realized by installing an array of sensors optimally placed in the same vertical plane as of conductors on the tower. The optimal position of sensor array was found while minimizing the condition number of governing linear system close to unity. For any circuit configuration, our method processes the sensed MF vector projections through a linear system, which is based on the Biot–Savart law. It considers the practical factors, such as sag, span length, and sensor-to-conductor distance. An algorithm is then designed to estimate the electric current and sag by iterative comparison between the measured and calculated MF. The method is first tested by numerical simulations for a typical one-circuit configuration, which involves three scenarios of symmetrical and unsymmetrical sag in conductors. The algorithm converges to a maximum error of % within 300 iterations. We then experimentally verify our scheme on a scaled laboratory setup. Retrieved current and sag values were verified with the readings from ammeter and vernier caliper, respectively. The results prove the viability of our approach within % deviation for current and % for sag in all conductors.
Autors: Arsalan Habib Khawaja;Qi Huang;Jian Li;Zhenyuan Zhang;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2017, volume: 53, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Estimation of Sparse Massive MIMO-OFDM Channels With Approximately Common Support
Abstract:
In this letter, we reveal that in the massive multiple-input multiple-output system with large bandwidth, sub-channels of orthogonal frequency division multiplexing share approximately sparse common support due to the frequency difference of subcarriers. We use the approximate message passing with nearest neighbor sparsity pattern learning (AMP-NNSPL) algorithm to adaptively learn the underlying structure for improving the accuracy of channel estimation, where the learning strategy is newly derived by solving an optimization problem. In addition, the performance of the AMP-NNSPL is well predicted by the state evolution. Simulation results demonstrate the superiority of the algorithm in systems with large bandwidth.
Autors: Xincong Lin;Sheng Wu;Linling Kuang;Zuyao Ni;Xiangming Meng;Chunxiao Jiang;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1179 - 1182
Publisher: IEEE
 
» Estimation of the Lens Distortion Model by Minimizing a Line Reprojection Error
Abstract:
Most techniques for camera calibration that use planar calibration patterns require the computation of a lens distortion model and a homography. Both are simultaneously refined using a bundle adjustment that minimizes the reprojection error of a collection of points when projected from the scene onto the camera sensor. These points are usually the corners of the rectangles of a calibration pattern. However, if the lens shows a significant distortion, the location and matching of the corners can be difficult and inaccurate. To cope with this problem, instead of point correspondences, we propose to use line correspondences to compute the reprojection error. We have designed a fully automatic algorithm to estimate the lens distortion model and the homography by computing line correspondences and minimizing the line reprojection error. In the experimental setup, we focus on the analysis of the quality of the obtained lens distortion model. We present some experiments that show that the proposed method outperforms the results obtained by standard methods to compute lens distortion models based on line rectification.
Autors: Daniel Santana-Cedrés;Luis Gomez;Miguel Alemán-Flores;Agustín Salgado;Julio Esclarín;Luis Mazorra;Luis Alvarez;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:9, pages: 2848 - 2855
Publisher: IEEE
 
» Evaluating and Extending the Ocean Wind Climate Data Record
Abstract:
Satellite microwave sensors, both active scatterometers and passive radiometers, have been systematically measuring near-surface ocean winds for nearly 40 years, establishing an important legacy in studying and monitoring weather and climate variability. As an aid to such activities, the various wind datasets are being intercalibrated and merged into consistent climate data records (CDRs). The ocean wind CDRs (OW-CDRs) are evaluated by comparisons with ocean buoys and intercomparisons among the different satellite sensors and among the different data providers. Extending the OW-CDR into the future requires exploiting all available datasets, such as OSCAT-2 scheduled to launch in July 2016. Three planned methods of calibrating the OSCAT-2 σo measurements include 1) direct Ku-band σo intercalibration to QuikSCAT and RapidScat; 2) multisensor wind speed intercalibration; and 3) calibration to stable rainforest targets. Unfortunately, RapidScat failed in August 2016 and cannot be used to directly calibrate OSCAT-2. A particular future continuity concern is the absence of scheduled new or continuation radiometer missions capable of measuring wind speed. Specialized model assimilations provide 30-year long high temporal/spatial resolution wind vector grids that composite the satellite wind information from OW-CDRs of multiple satellites viewing the Earth at different local times.
Autors: Frank J. Wentz;Lucrezia Ricciardulli;Ernesto Rodriguez;Bryan W. Stiles;Mark A. Bourassa;David G. Long;Ross N. Hoffman;Ad Stoffelen;Anton Verhoef;Larry W. O'Neill;J. Tomas Farrar;Douglas Vandemark;Alexander G. Fore;Svetla M. Hristova-Veleva;F.
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2017, volume: 10, issue:5, pages: 2165 - 2185
Publisher: IEEE
 
» Evaluating Gaussian and Rayleigh-Based Mathematical Models for T and P-waves in ECG
Abstract:
This paper presents a comparative study of modelling and segmentation of P and T waves in electrocardiograms, using three different mathematical models: Gaussian function, a composition of two Gaussian functions and Rayleigh probability density function (Rayleigh pdf). In order to evaluate the adaptability and the matching degree between each model and each characteristic wave, we compute the normalized root mean square (RMS) error, as well as the evolution of the fitting parameters related to each kernel throughout ECG records from the well-known QT database. Concerning the delineation of P and T-waves, we apply Wavelet Transform for estimating T-wave and P-wave peak locations and combine each developed model with an approach based on the computation of Trapezium's area to locate the end point of each T-wave and the beginning and end point of each P-wave. The composition of two Gaussian functions has produced the most accurate results concerning wave modelling, providing average values of normalized RMS errors equal to 9,15% and 18,70%, respectively for T-wave and P-wave. Rayleigh pdf provided the most stable fitting parameters. For T-wave end location, the most accurate results were computed when using the kernel composition of two Gaussian functions, for which the average time error was 4,49 ± 14,32 ms. For P-wave begin and P-wave end locations, the most accurate results were computed when using kernel Rayleigh pdf, for which the average time errors were, respectively, -4,23 ± 14,84 ms and 2,26 ± 13,14 ms.
Autors: Joao Paulo do Vale Madeiro;Elves Mauro Boa Esperanca dos Santos;Paulo Cesar Cortez;John Hebert da Silva Felix;Fernando Soares Schlindwein;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 843 - 853
Publisher: IEEE
 
» Evaluating Generating Unit Unavailability Using Bayesian Power Priors
Abstract:
Generating unit unavailability assessment is an important task in the power system generation expansion planning aimed at managing an acceptable degree of security of supply. In the case of the newly installed or planned units, the sample size of the data for unavailability assessment is limited and inadequate to provide the desired accuracy in the unavailability estimation. A new concept based on the Bayesian power prior approach has been developed to utilize the data from similar generating units. The original contribution of the present work is a model that incorporates the data of unavailability from other generating units into the statistical analysis of unavailability of the analysed generating unit to improve the accuracy of the estimation. The empirical results show that for unavailability estimation, the power prior Bayesian approach exhibits better than the classical statistical approach in both the standard error of estimate and confidence interval as the measures of accuracy.
Autors: Ivan Lorencin;Miloš Pantoš;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2315 - 2323
Publisher: IEEE
 
» Evaluation of 4-D Reaction Integrals in the Method of Moments: Coplanar Element Case
Abstract:
Recently, the benefits of simultaneously treating source and testing integrals in the numerical evaluation of 4-D reaction integrals have been reported. The reported schemes usually first transform the reaction integral to parametric coordinates, and some combination of radial, angular, and/or line segment integrals is then used to treat coincident, edge-adjacent, or vertex-adjacent triangular source and test element pairs. However, advantages of the reported approaches are tempered by their lack of generality and severely degraded performance on poorly shaped elements, the latter caused primarily by the parametric transformations’ severe distortion of the kernel’s circularly concentric level contours. Here, for coplanar element pairs and kernels with 1/ singularities, we apply the surface divergence theorem twice to obtain a novel formula for 4-D reaction integrals, generalizing earlier schemes while retaining their benefits and without distorting the original configuration space. Numerical results illustrate the method’s efficiency, which is improved by employing appropriate transformations to further smooth the resulting integrands and hence accelerate their convergence. The reaction integral formula can be extended to noncoplanar elements.
Autors: Donald R. Wilton;Francesca Vipiana;William A. Johnson;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2479 - 2493
Publisher: IEEE
 
» Evaluation of Load Frequency Control Performance Based on Standard Deviational Ellipses
Abstract:
This paper discusses new criterion for the evaluation of load frequency control (LFC) performance. The proposed LFC performance evaluation is based on a standard deviational ellipse that characterizes a bivariate relationship between the frequency deviation and the area's interchange power variation. The standard deviational ellipse is evaluated using Tyler's maximum-likelihood estimator, which is distribution-free within the family of elliptical distributions. In addition, a target standard deviational ellipse is proposed, using predefined values for a target frequency bound and the area's frequency bias. The presented approach is based on the accordance of the estimated ellipse with the target ellipse, resulting in several grades for the LFC performance. A comparison of the proposed criterion is made with other LFC performance criteria known from the literature. Extensive measurements were applied, and the obtained results show the correctness of the proposed approach.
Autors: Boštjan Polajžer;Robert Brezovnik;Jožef Ritonja;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2296 - 2304
Publisher: IEEE
 
» Evaluation of Potential and Impedance Integrals in Analysis of Axially Symmetric Metallic Structures to Prescribed Accuracy Up To Machine Precision
Abstract:
This paper presents a novel method for evaluating potential and impedance integrals appearing in the method of moment analysis of arbitrary axially symmetric metallic structures based on exact wire kernel and higher order bases. Due to new variable transforms proposed for singularity cancellation and smoothing the integrands, high accuracy up to machine precision is achieved using relatively small number of integration points. Simple formulas are determined for predicting a number of integration points needed for prescribed accuracy. Benefits of high-precision evaluation of impedance integrals are illustrated on a number of numerical examples.
Autors: Aleksandra J. Krneta;Branko M. Kolundzija;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2526 - 2539
Publisher: IEEE
 
» Evaluation of the Range Accuracy and the Radiometric Calibration of Multiple Terrestrial Laser Scanning Instruments for Data Interoperability
Abstract:
Terrestrial laser scanning (TLS) data provide 3-D measurements of vegetation structure and have the potential to support the calibration and validation of satellite and airborne sensors. The increasing range of different commercial and scientific TLS instruments holds challenges for data and instrument interoperability. Using data from various TLS sources will be critical to upscale study areas or compare data. In this paper, we provide a general framework to compare the interoperability of TLS instruments. We compare three TLS instruments that are the same make and model, the RIEGL VZ-400. We compare the range accuracy and evaluate the manufacturer's radiometric calibration for the uncalibrated return intensities. Our results show that the range accuracy between instruments is comparable and within the manufacturer's specifications. This means that the spatial XYZ data of different instruments can be combined into a single data set. Our findings demonstrate that radiometric calibration is instrument specific and needs to be carried out for each instrument individually before including reflectance information in TLS analysis. We show that the residuals between the calibrated reflectance panels and the apparent reflectance measured by the instrument are greatest for highest reflectance panels (residuals ranging from 0.058 to 0.312).
Autors: Kim Calders;Mathias I. Disney;John Armston;Andrew Burt;Benjamin Brede;Niall Origo;Jasmine Muir;Joanne Nightingale;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: May 2017, volume: 55, issue:5, pages: 2716 - 2724
Publisher: IEEE
 
» Evaluation Scheme for EMI of Train Body Voltage Fluctuation on the BCU Speed Sensor Measurement
Abstract:
The voltage fluctuation between the train body (TB) and the train’s wheel axis (TB voltage fluctuation for short), might cause electromagnetic interference (EMI) on brake control unit (BCU) speed sensor in some high-speed trains (HSTs), which may cause faulty measurement of train speed and incorrect operation of train door. Using a relevant event that occurred in China railways high-speed 380CL-type train as case study, this paper presents an evaluation scheme for the EMI influence of TB voltage fluctuation on the speed measurement of BCU speed sensor. First, the EMI channels are researched, and a model representing the relation between TB voltage and voltage signal reflecting measured speed is deduced. Second, an evaluation scheme for speed measurement influenced by EMI is designed on this basis, where TB voltage and voltage signal reflecting measured speed are taken as the input and the output of model, respectively. The evaluation aimed at EMI is realized by judging the correctness of model output. Later, a real-life experiment is performed in the Chinese Nanjing station to verify the validity and feasibility of evaluation scheme. Last, some application studies are made to evaluate the presented scheme under multiple specific conditions, such as different TB contact conditions or different train speeds. The comparison results illustrate that the scheme can not only provide an opportunity to judge the correctness of speed measurement under the premise of collecting TB voltages, but also provide references in taking timely measures to prevent faulty speed measurement such as weakening TB voltage fluctuations.
Autors: Ke Huang;Zhigang Liu;Feng Zhu;Zongsheng Zheng;Ye Cheng;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2017, volume: 66, issue:5, pages: 1046 - 1057
Publisher: IEEE
 
» Event-Triggered Optimal Control for Partially Unknown Constrained-Input Systems via Adaptive Dynamic Programming
Abstract:
Event-triggered control has been an effective tool in dealing with problems with finite communication and computation resources. In this paper, we design an event-triggered control for nonlinear constrained-input continuous-time systems based on the optimal policy. Constraints on controls are handled using a bounded function. To learn the optimal solution with partially unknown dynamics, an online adaptive dynamic programming algorithm is proposed. The identifier network, the critic network, and the actor network are employed to approximate the unknown drift dynamics, the optimal value, and the optimal policy, respectively. The identifier is tuned based on online data, which further trains the critic and actor at triggering instants. A concurrent learning technique repeatedly uses past data to train the critic. Stability of the closed-loop system, and convergence of neural networks to the optimal solutions are proved by Lyapunov analysis. In the end, the algorithm is applied to the overhead crane system to observe the performance. The event-triggered optimal controller with constraints stabilizes the system and consumes much less sampling times.
Autors: Yuanheng Zhu;Dongbin Zhao;Haibo He;Junhong Ji;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 4101 - 4109
Publisher: IEEE
 
» Evidential Fusion Based Technique for Detecting Landslide Barrier Lakes From Cloud-Covered Remote Sensing Images
Abstract:
Landslide barrier lakes usually form quickly after disasters and require very timely remote sensing images to monitor the land-cover change. However, cloud-free images are not always available in emergency situations. This paper provides a method to fuse multitemporal cloud-covered images for change detection, based on the evidential fusion framework. First, the frame of discernment is defined by postclassification comparison results. Second, a way of measuring the basic belief assignment (BBA) is introduced based on the confusion matrixes. Next, a simple BBA redistribution process is proposed to deal with cloud coverage problems. Then, the complementary and redundant information from the input images can be fused following the evidence combination and decision making rules in the evidential fusion framework. Finally, the land-cover change map can be derived. Thanks to the Dempster–Shafer evidence theory, the proposed method can complete the change detection process—including data fusion and cloud removal—in an integrated manner. The proposed method is applied to detect the landslide barrier lake in a real case study, using a series of cloud-covered images from the GF-1 satellite. Result comparisons show that the proposed method is more effective than some basic fusion strategies that perform change detection and cloud removal in separate steps. Then, some approaches to improve the proposed method are discussed: introducing new evidence combination rule, improving the classification accuracy, and adding new evidences. All the results indicate the potential of evidential fusion for change detection from cloud-covered images.
Autors: Xi Chen;Jing Li;Yunfei Zhang;Weiguo Jiang;Liangliang Tao;Wei Shen;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2017, volume: 10, issue:5, pages: 1742 - 1757
Publisher: IEEE
 
» Evolutionary Nonnegative Matrix Factorization Algorithms for Community Detection in Dynamic Networks
Abstract:
Discovering evolving communities in dynamic networks is essential to important applications such as analysis for dynamic web content and disease progression. Evolutionary clustering uses the temporal smoothness framework that simultaneously maximizes the clustering accuracy at the current time step and minimizes the clustering drift between two successive time steps. In this paper, we propose two evolutionary nonnegative matrix factorization (ENMF) frameworks for detecting dynamic communities. To address the theoretical relationship among evolutionary clustering algorithms, we first prove the equivalence relationship between ENMF and optimization of evolutionary modularity density. Then, we extend the theory by proving the equivalence between evolutionary spectral clustering and ENMF, which serves as the theoretical foundation for hybrid algorithms. Based on the equivalence, we propose a semi-supervised ENMF (sE-NMF) by incorporating a priori information into ENMF. Unlike the traditional semi-supervised algorithms, a priori information is integrated into the objective function of the algorithm. The main advantage of the proposed algorithm is to escape the local optimal solution without increasing time complexity. The experimental results over a number of artificial and real world dynamic networks illustrate that the proposed method is not only more accurate but also more robust than the state-of-the-art approaches.
Autors: Xiaoke Ma;Di Dong;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2017, volume: 29, issue:5, pages: 1045 - 1058
Publisher: IEEE
 
» Evolutive Strategy to Inducing Chaos in a Gene Regulatory Network
Abstract:
In the present paper we propose an Evolutionary Strategy of Multiobjective Optimization like an alternative method to induce chaotic dynamics in a genetic regulatory network, called V-System, which was created by joining two systems of equations: one oscillating and one with a hysteresis dynamics. The genetic regulatory network is represented by four differential equations with seventeen parameters, which variables show the proteins concentrations. The multiobjective fitness function is built like a linear combination, involving a numerical approximation to Lyapunov exponents in the system, which is only dependent of the parameters fixed values. The optimization problem optimum represents the set of parameters values where the system is more chaotic. We present the numerical results of the evolutionary strategy and we show the convergence of the individuals in the population to the critical points in one of the subsystems in the V-System.
Autors: Hector Guardado Muro;Eunice Esther Ponce de Leon Senti;Aurora Torres Soto;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 916 - 921
Publisher: IEEE
 
» Exact and Approximate Capacitance and Force Expressions for the Electrostatic Interaction Between Two Equal-Sized Charged Conducting Spheres
Abstract:
We analyze the electrostatic interaction between two equal-sized charged conducting spheres. We obtain exact closed-form expressions for the capacitance coefficients and the electrostatic force in terms of the special q -digamma function. Additionally, we provide simpler-to-use approximate expressions for the capacitance coefficients and the force between the spheres, and then compare the approximations with the exact results.
Autors: Shubho Banerjee;Mason Levy;McKenna Davis;Blake Wilkerson;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2455 - 2460
Publisher: IEEE
 
» Exact Moderate Deviation Asymptotics in Streaming Data Transmission
Abstract:
In this paper, a streaming transmission setup is considered, where an encoder observes a new message in the beginning of each block and a decoder sequentially decodes each message after a delay of blocks. In this streaming setup, the fundamental interplay between the coding rate, the error probability, and the blocklength in the moderate deviations regime is studied. For output symmetric channels, the moderate deviations constant is shown to improve over the block coding or non-streaming setup by exactly a factor of for a certain range of moderate deviations scalings. For the converse proof, a more powerful decoder, to which some extra information is fedforward is assumed. The error probability is bounded first for an auxiliary channel and this result is translated back to the original channel by using a newly developed change-of-measure lemma, where the speed of decay of the remainder term in the exponent is carefully characterized. For the achievability proof, a known coding technique that involves a joint encoding and decoding of fresh and past messages is applied with some manipulations in the error analysis.
Autors: Si-Hyeon Lee;Vincent Y. F. Tan;Ashish Khisti;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2017, volume: 63, issue:5, pages: 2726 - 2736
Publisher: IEEE
 
» Experience With a Multidisciplinary, Team-Taught Smart Grid Cyber Infrastructure Course
Abstract:
Electric power systems are going through a major upgrade with the integration of advanced technologies to enable the smarter electric grid (SEG). The SEG will use information and communications technology to have enhanced controllability and will become more interactive. This ongoing change also necessitates educating professionals and future generation of engineers to manage evolving complexity of the electric grid. This paper presents experiences in the design and teaching of a unique multidisciplinary team-taught course on smart grid cyber infrastructure to provide a new generation of engineers with a solid foundation of smart grid concepts and their associated challenges. This paper identifies the course topics covered, learning objectives, and assessment activities for the class as well as lessons learned based on course evaluations obtained from multiple offerings. All of the course material is available in public domain and can be easily adopted at another educational institution.
Autors: Anurag K. Srivastava;Adam L. Hahn;Olusola O. Adesope;Carl H. Hauser;David E. Bakken;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2267 - 2275
Publisher: IEEE
 
» Experimental Characterization of the Thermal Time Constants of GaN HEMTs Via Micro-Raman Thermometry
Abstract:
Gallium nitride (GaN) high-electron mobility transistors (HEMTs) are a key technology for realizing next generation high-power RF amplifiers and high-efficiency power converters. However, elevated channel temperatures due to self-heating often severely limit their power handling capability. Although the steady-state thermal behavior of GaN HEMTs has been studied extensively, significantly fewer studies have considered their transient thermal response. In this paper, we report a methodology for measuring the transient temperature rise and thermal time constant spectrum of GaN HEMTs via time-resolved micro-Raman thermometry with a temporal resolution of 30 ns. We measured a broad spectrum of time constants from ns to ms that contribute to the temperature rise of an ungated GaN-on-SiC HEMT due to aggressive, multidimensional heat spreading in the die and die-attach. Our findings confirm previous theoretical analysis showing that one or two thermal time constants cannot adequately describe the transient temperature rise and that the temperature reaches steady-state at , where and are the thickness and thermal diffusivity of the substrate. This paper provides a practical methodology for validating transient thermal models of GaN HEMTs and for obtaining experimental values of the thermal resistances and capacitances for compact electrothermal modeling.
Autors: Kevin R. Bagnall;Omair I. Saadat;Sameer Joglekar;Tomás Palacios;Evelyn N. Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2121 - 2128
Publisher: IEEE
 
» Experimental Realization of Thermal Stability Enhancement of Nickel Germanide Alloy by Using TiN Metal Capping
Abstract:
In this paper, we demonstrated the enhancement of thermal stability of nickel germanide (NiGe) alloy up to 600 °C by using titanium nitride (TiN) metal capping. A high ratio of was achieved by capping TiN metal on Ni for NiGe alloy formation at 600 °C. Detailed analyses were performed for realizing the mechanism for TiN capping on NiGe/Ge, including vertical element diffusion profile observation through depth-profiling X-ray photoelectron spectroscopy (XPS), element diffusion distribution by energy-dispersive X-ray spectroscopy mapping, and direct junction leakage current path detection by conductive atomic force microscopy. The experimental results indicated that TiN capping can reduce the risk of agglomeration and form a graded NiGe/Ge Schottky junction that is beneficial for suppressing the degradation of junction leakage. Subsequently, we compared the electrical performance of TiN/NiGe/n-Ge at various N/Ti ratios of TiNs. Based on the depth-profiling XPS results and electrical performance, TiN with an N/Ti ratio of approximately 1:1 can resist the Ni and Ge diffusion, which facilitates the suppression of the agglomeration process. However, the TiN capping layers with an N/Ti ratio of less than approximately 1:1 (Ti-rich) were not favorable for resisting Ni and Ge diffusion.
Autors: Chen-Han Chou;Yi-He Tsai;Chung-Chun Hsu;Yu-Hau Jau;Yu-Hsien Lin;Wen-Kuan Yeh;Chao-Hsin Chien;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2314 - 2320
Publisher: IEEE
 
» Experimental Study of Electrically Compact Retrodirective Monopole Antenna Arrays
Abstract:
Auto-pointing and angular super-resolution properties of the radiation patterns generated by an electrically compact retrodirective monopole antenna array are demonstrated experimentally for the first time. The operation of electrically compact (element spacings less than one-fifth of the radiation wavelength) retrodirective antenna arrays that were theoretically considered in our previous work is confirmed by measurement. Particularly, it is shown that the direction-of-arrival information carried by an incident electromagnetic wave can be encoded into the evanescent near field of an electrically small resonant antenna array with a spatial rate higher than the spatial oscillation rate of the incident field in free space. This observation is supported by the near-field measurements, demonstrating that the magnitude of the scattered (evanescent) field in the array environment can exceed the magnitude of the incident field in free space by at least 6 dB. Retrodirective array antenna matching and the feasibility of a frequency-division full-duplex communication link based on the proposed antenna arrays are also discussed.
Autors: Oleksandr Malyuskin;Vincent F. Fusco;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2339 - 2347
Publisher: IEEE
 
» Experimental Study on Deflection Behavior of Vacuum Arcs Under the Influence of External Transverse Magnetic Field
Abstract:
In real power system, when the three-phase short-circuit fault occurs, the vacuum arc in one phase will be influenced by the transverse magnetic field generated by neighbor phases and bus bars. This kind of effect is the main cause of the unstable arc and deflected erosion of contact plates, which leads to the failure of vacuum circuit breakers interruption. The objective of this paper is to get more insight into the influence of external transverse magnetic field (ETMF) on vacuum arc’s behavior. The experiments were conducted in a demountable vacuum chamber with pressure about Pa. The cup-type axial magnetic field contacts were used, whose material was pure copper and the diameter is 35 mm. The uniform ETMF in the arc region was generated by two parallel bulk permanent magnets. The experiments were conducted under different ETMFs (0, 15, and 25 mT) and current levels (1-, 2.5-, and 4-kA rms) with different gap distances (6, 8.5, and 11 mm). The videos of arc column were recorded by a high-speed charge-coupled device camera. Under the action of ETMF, the vacuum arc got deflected. Due to the retrograde motion of cathode spots and Ampere force acting on arc column, the deflection behaviors during three typical periods (that is, initial, peak value, and close-to-current-zero period) were different. Moreover, the deflection level of vacuum arc at current peak value moment was greatly impacted by ETMF and gap distance. Larger the ETMF and gap distance were, higher the deflection level at current peak value moment was. The simulation results of arc deflection based on magnetic-hydrodynamic model were in agreement with experimental results in trends.
Autors: Shenli Jia;Zhonghao Qian;Lijun Wang;Wein Xin Shi;Jie Deng;Xiao Zhang;Zongqian Shi;
Appeared in: IEEE Transactions on Plasma Science
Publication date: May 2017, volume: 45, issue:5, pages: 868 - 874
Publisher: IEEE
 
» Experimental Study on Flexible ZnO Based Nanogenerator Using Schottky Contact for Energy Harvesting Applications
Abstract:
This paper presents the synthesis and implementation of a metal-insulator-semiconductor-type energy harvester. The proposed harvester generates power from ambient vibration. The flexible nanogenerator (NG) is developed from well- aligned ZnO nanorods (NRs) on kapton substrate with ITO sputtered bottom contact using the low-temperature hydrothermal method. PMMA insulation region is coated over NRs with silver (Ag) as top electrode to reduce the external screening effect thereby improving the output signal strength. The crystalline and morphological properties of the NRs are studied using X-ray diffraction, field emission scanning electron microscopy analysis, Fourier transform infrared spectroscopy, and photoluminescence.The current–voltage characteristics of the ZnO NRs exhibited a clear rectifying behavior, attributed to the formation of a Schottky contact between ZnO and Ag contact with an insulation of PMMA layer. An experimental study to evaluate the device performance is carried out using tip excitation method. The synthesized NG generates open-circuit voltage of 400 mV, circuit current across optimum load of 10 kΩ is 30 μA, and giving a maximum power density of 9 μ Wcm–2 at a force of 0.5 N at 12 Hz. Furthermore, the impedance analysis is performed for estimating the relationship between screening effects and RC time constant (T RC).
Autors: Kirubaveni Savarimuthu;Govindaraj Rajamanickam;Radha Shankararajan;Ramasamy Perumal;Arokiyadoss Rayarfrancis;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: May 2017, volume: 16, issue:3, pages: 469 - 476
Publisher: IEEE
 
» Experimental Validation of a Fast Forward Model for Guided Wave Tomography of Pipe Elbows
Abstract:
Ultrasonic guided wave tomography (GWT) methods for the detection of corrosion and erosion damage in straight pipe sections are now well advanced. However, successful application of GWT to pipe bends has not yet been demonstrated due to the computational burden associated with the complex forward model required to simulate guided wave propagation through the bend. In a previous paper [Brath et al., IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 61, pp. 815–829, 2014], we have shown that the speed of the forward model can be increased by replacing the 3-D pipe bend with a 2-D rectangular domain in which guided wave propagation is formulated based on an artificially inhomogeneous and elliptically anisotropic (INELAN) acoustic model. This paper provides further experimental validation of the INLEAN model by studying the traveltime shifts caused by the introduction of shallow defects on the elbow of a pipe bend. Comparison between experiments and simulations confirms that a defect can be modeled as a phase velocity perturbation to the INLEAN velocity field with accuracy that is within the experimental error of the measurements. In addition, it is found that the sensitivity of traveltime measurements to the presence of damage decreases as the damage position moves from the interior side of the bend (intrados) to the exterior one (extrados). This effect is due to the nonuniform ray coverage obtainable when transmitting the guided wave signals with one ring array of sources on one side of the elbow and receiving with a second array on the other side.
Autors: Alex J. Brath;Francesco Simonetti;Peter B. Nagy;Geir Instanes;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: May 2017, volume: 64, issue:5, pages: 859 - 871
Publisher: IEEE
 
» Experimental Verification of an Electrical Drive Fed by a Modular Multilevel TSBC Converter When the Motor Frequency Gets Closer or Equal to the Supply Frequency
Abstract:
This paper provides an experimental discussion on an adjustable-speed electrical drive fed by a modular multilevel triple-star bridge-cell (TSBC) converter. The TSBC converter is suitable for medium-voltage high-power motor drives with regenerative braking. However, it suffers from capacitor-voltage fluctuation that becomes more serious as the motor frequency gets closer or equal to the supply frequency. This paper presents a practical solution of it with an acceptable increase in all the nine cluster currents. The solution is characterized by a motor-magnetizing-current controller that makes a significant contribution to theoretically eliminating the low-frequency component contained in each capacitor voltage. Experimental waveforms, which are obtained from a three-phase downscaled model rated at 400 V and 15 kW, verify exhibit satisfactory start-up performance from a standstill to the rated motor frequency that is equal to the supply frequency.
Autors: Wataru Kawamura;Yuto Chiba;Makoto Hagiwara;Hirofumi Akagi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2297 - 2306
Publisher: IEEE
 
» Explaining Explanation, Part 1: Theoretical Foundations
Abstract:
This is the first in a series of essays that addresses the manifest programmatic interest in developing intelligent systems that help people make good decisions in messy, complex, and uncertain circumstances by exploring several questions: What is an explanation? How do people explain things? How might intelligent systems explain their workings? How might intelligent systems help humans be better understanders as well as better explainers? This article addresses the theoretical foundations.
Autors: Robert R. Hoffman;Gary Klein;
Appeared in: IEEE Intelligent Systems
Publication date: May 2017, volume: 32, issue:3, pages: 68 - 73
Publisher: IEEE
 
» Exploiting Non-Orthogonal Multiple Access in Cooperative Relay Sharing
Abstract:
We propose and investigate a dual-hop cooperative relaying scheme using non-orthogonal multiple access (NOMA) (termed NOMA-RS), where two sources communicate with their corresponding destinations in parallel over the same frequency band via a common relay. In this scheme, after receiving symbols transmitted in parallel by both sources with different allocated powers, the relay forwards a super-position coded composite signal using NOMA to the destinations. One of the main benefits of NOMA-RS is that multiple (two) sources can share the same relay, unlike the previous works. Through the simulations and mathematical analysis, we demonstrate the effectiveness of the proposed protocol in terms of ergodic sum capacity by considering perfect and imperfect successive interference cancellation.
Autors: Md. Fazlul Kader;Muhammad Basit Shahab;Soo Young Shin;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1159 - 1162
Publisher: IEEE
 
» Exploiting Overlapped Bands for Efficient Broadcast in Multichannel Wireless Networks
Abstract:
In wireless networks, broadcasting is a fundamental communication primitive for network management and information sharing. However, in multichannel networks, broadcast efficiency is very poor as devices are distributed across various channels. Thus, a sender tries all channels to broadcast a single message, causing large overhead. In this paper, we propose a novel, drastically different scheme for efficient broadcast in multichannel networks. Our scheme leverages an overlapped band of adjacent channels, which is the frequency range that partially overlapped channels share within their channel boundaries. Specifically, a sender advertises a rendezvous channel through the overlapped band of adjacent channels; message sharing is done on the rendezvous channel. Our scheme employs signaling via overlapped band (SOB), which defines a new signal processing mechanism for communication via the overlapped band. SOB is integrated with the following Multiple Access Control (MAC) layer mechanisms: 1) Reserve idle spectrum fragment to reduce waiting time, 2) multisender agreement on rendezvous channel to support multisender broadcasts, and 3) reinforce switch notification to reduce the residing time at a wrong channel. Our scheme can also be integrated with two remarkably simple but efficient mechanisms for improving the packet delivery ratio and reducing delay in a multiple contention domain. We implemented our scheme on the SORA software radio platform. Experimental results validated communication through the overlapped band. Intensive simulation studies showed that our scheme dramatically outperformed a previous approach.
Autors: Jae-Han Lim;Katsuhiro Naito;Ji-Hoon Yun;Mario Gerla;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 4355 - 4370
Publisher: IEEE
 
» Exploring Data Validity in Transportation Systems for Smart Cities
Abstract:
Efficient urban transportation systems are widely accepted as essential infrastructure for smart cities, and they can highly increase a city�s vitality and convenience for residents. The three core pillars of smart cities can be considered to be data mining technology, IoT, and mobile wireless networks. Enormous data from IoT is stimulating our cities to become smarter than ever before. In transportation systems, data-driven management can dramatically enhance the operating efficiency by providing a clear and insightful image of passengers� transportation behavior. In this article, we focus on the data validity problem in a cellular network based transportation data collection system from two aspects: internal time discrepancy and data loss. First, the essence of time discrepancy was analyzed for both automated fare collection (AFC) and automated vehicular location (AVL) systems, and it was found that time discrepancies can be identified and rectified by analyzing passenger origin inference success rate using different time shift values and evolutionary algorithms. Second, the algorithmic framework to handle location data loss and time discrepancy was provided. Third, the spatial distribution characteristics of location data loss events were analyzed, and we discovered that they have a strong and positive relationship with both high passenger volume and shadowing effects in urbanized areas, which can cause severe biases on passenger traffic analysis. Our research has proposed some data-driven methodologies to increase data validity and provided some insights into the influence of IoT level data loss on public transportation systems for smart cities.
Autors: Yongxin Liu;Xiaoxiong Weng;Jiafu Wan;Xuejun Yue;Houbing Song;Athanasios V. Vasilakos;
Appeared in: IEEE Communications Magazine
Publication date: May 2017, volume: 55, issue:5, pages: 26 - 33
Publisher: IEEE
 
» Exploring Interpersonal Influence by Tracking User Dynamic Interactions
Abstract:
As one of the most popular social media platforms today, Twitter provides people with an effective way to communicate and interact with each other. Through these interactions, influence among users gradually emerges and changes people's opinions. Although previous work has studied interpersonal influence as the probability of activating others during information diffusion, they ignore an important fact that information diffusion is the result of influence, while dynamic interactions among users produce influence. In this article, the authors propose a novel temporal influence model to learn users' opinion behaviors regarding a specific topic by exploring how influence emerges during communications. The experiments show that their model performs better than other influence models with different influence assumptions when predicting users' future opinions, especially for the users with high opinion diversity.
Autors: Chengyao Chen;Wenjie Li;Dehong Gao;Yuexian Hou;
Appeared in: IEEE Intelligent Systems
Publication date: May 2017, volume: 32, issue:3, pages: 28 - 35
Publisher: IEEE
 
» Exploring Tag Distribution in Multi-Reader RFID Systems
Abstract:
Radio Frequency Identification (RFID) brings a revolutionary change in a range of applications by automatically monitoring and tracking products. With the proliferation of RFID-enabled applications, multiple readers are needed for ensuring the full coverage of numerous RFID tags. In this paper, we focus on the tag distribution problem in multi-reader RFID systems. The problem is to fast identify the tag set beneath each reader, which is a fundamental premise of efficient product inventory and management. Only with such tag set information can we localize specific tags in a reader and expedite the tag query information collection. As an RFID system usually contains a large number of tags and multiple readers, the traditional solution to identify tags by individual readers is highly time inefficient. We propose an Inference-Based protocol (IB) that identifies the tag distribution based on information inference rules and the aggregated physical signals to improve operational efficiency. In our protocol, three kinds of inference rules based on internal information reported by a single reader, external information shared by multiple readers, and history information retained by the system are fully exploited to infer tag distribution. With these rules, all readers can cooperatively work together and quickly obtain the tag distribution in the system. We also build a prototype RFID system using the USRP-based reader and WISP programmable tags, and then implement the IB protocol. The experimental results and extended simulations show that IB outperforms the state-of-the-art protocols.
Autors: Feng Zhu;Bin Xiao;Jia Liu;Bin Wang;Qingfeng Pan;Li-Jun Chen;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: May 2017, volume: 16, issue:5, pages: 1300 - 1314
Publisher: IEEE
 
» Extended Efficiency Range, Equal-Cell Doherty Amplifier Design Using Explicit Circuit Model
Abstract:
This letter presents the design of a symmetrical Doherty power amplifier (DPA) with extended high-efficiency range by using a new and explicit circuit model. Theoretical analysis reveals that by the adjustment of the electrical length of transmission line sections in the proposed circuit model, new DPA variants with simple circuitry and enhanced output back-off (OBO) are obtained. For experimental verification, a 42-dBm, 2-GHz DPA with OBO of 9.5 dB was designed and fabricated using identical GaN HEMT devices. Under continuous-wave stimulation, measurement results indicate good Doherty behavior can be obtained with 9.5-dB back-off efficiency of 51%–61% and saturation efficiency of 68%–72% over 1.85–2.1 GHz. Moreover, with single carrier WCDMA signal (centered at 2.1 GHz) and peak-to-average power ratio of 9.6 dB, the proposed design is found to deliver an average drain efficiency of 58% and adjacent channel leakage power of −47 dBc at an output power level of 32.5 dBm.
Autors: Xiao-Hu Fang;Hao-Yu Liu;Kwok-Keung M. Cheng;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: May 2017, volume: 27, issue:5, pages: 497 - 499
Publisher: IEEE
 
» Extrafoveal Video Extension for an Immersive Viewing Experience
Abstract:
Between the recent popularity of virtual reality (VR) and the development of 3D, immersion has become an integral part of entertainment concepts. Head-mounted Display (HMD) devices are often used to afford users a feeling of immersion in the environment. Another technique is to project additional material surrounding the viewer, as is achieved using cave systems. As a continuation of this technique, it could be interesting to extend surrounding projection to current television or cinema screens. The idea would be to entirely fill the viewer's field of vision, thus providing them with a more complete feeling of being in the scene and part of the story. The appropriate content can be captured using large field of view (FoV) technology, using a rig of cameras for 110 to 360 capture, or created using computer-generated images. The FoV is, however, rather limited in its use for existing (legacy) content, achieving between 36 to 90 degrees () field, depending on the distance from the screen. This paper seeks to improve this FoV limitation by proposing computer vision techniques to extend such legacy content to the peripheral (extrafoveal) vision without changing the original creative intent or damaging the viewer's experience. A new methodology is also proposed for performing user tests in order to evaluate the quality of the experience and confirm that the sense of immersion has been increased. This paper thus presents: i) an algorithm to spatially extend- the video based on human vision characteristics, ii) its subjective results compared to state-of-the-art techniques, iii) the protocol required to evaluate the quality of the experience (QoE), and iv) the results of the user tests.
Autors: Laura Turban;Fabrice Urban;Philippe Guillotel;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: May 2017, volume: 23, issue:5, pages: 1520 - 1533
Publisher: IEEE
 
» FabSquare: Fabricating Photopolymer Objects by Mold 3D Printing and UV Curing
Abstract:
The FabSquare system is a personal fabrication method that lets users fabricate objects by molding photopolymers inside a 3D printed mold. The molds are printed with UV-transparent materials that allow for UV curing--the polymerization and solidification of the fluid content. The molds can be repeatedly reused to fabricate identical objects or create new objects with identical geometry, but different components. Because the necessary equipment is easily obtainable and affordable, the FabSquare approach is suitable for ordinary users in nonspecialized labs, allowing them to rapidly fabricate a range of objects. https://extras.computer.org/extra/mcg2017030034s1.mp4https://extras.computer.org/extra/mcg2017030034s2.pdf
Autors: Vahid Babaei;Javier Ramos;Yongquan Lu;Guillermo Webster;Wojciech Matusik;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2017, volume: 38, issue:3, pages: 34 - 42
Publisher: IEEE
 
» Family of Enhanced ZCS Single-Stage Single-Phase Isolated AC–DC Converter for High-Power High-Voltage DC Supply
Abstract:
AC–DC power supply is essential equipment which builds the connection between the ac grid and the dc loads. In order to achieve high-power density and high efficiency, a family of enhanced zero-current-switched (ZCS) single-stage single-phase isolated ac–dc converters is proposed for high-power high-voltage dc application. Only one resonant capacitor is required for the proposed converters to realize ZCS operation. On the other hand, the over voltage problem which exists in former developed ZCS ac–dc topologies is eliminated. Thus, lower voltage rating IGBTs can be applied. Higher efficiency is realized. At the same time, these converters inherit the feature such as one-stage power conversion, low conduction loss, good total harmonics distortion performance, etc. A 3 kW prototype is built to verify the proposed converters. A comparison is made to show the efficiency improvement clearly.
Autors: Chushan Li;Dewei Xu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3629 - 3639
Publisher: IEEE
 
» Fast and Accurate Computation of the Multilook Interferometric Phase Probability Density Function
Abstract:
This letter reports a method to compute the multilook interferometric phase probability density function (pdf) used in interferometric synthetic aperture radar (InSAR). The method is fast and accurate for at least 10 000 looks and the full range of interferometric correlations. This is accomplished by computing the products of large and small numbers in the underlying hypergeometric series logarithmically and by deriving a single-term recursion relation to accelerate the computation. This letter extends the usable range of inputs to the multilook interferometric phase pdf for radar systems with a large number of looks and the entire practical range of interferometric correlation.
Autors: Mark S. Haynes;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: May 2017, volume: 14, issue:5, pages: 769 - 772
Publisher: IEEE
 
» Fast and Efficient Analysis of Radome-Enclosed Antennas in Receiving Mode by an Iterative-Based Hybrid Integral Equation/Modified Surface Integration Method
Abstract:
An iterative-based hybrid method, which combines the volume-surface integral equation (VSIE) and the modified surface integration (MSI) method, is presented to analyze the radome-enclosed antennas in receiving mode. Compared with the previously published hybrid approaches, this method improves computational accuracy by including the effects of shaded wall of the radome and the mutual interactions between antennas and radome during the numerical solution of the VSIE in an iterative manner. By embedding different parts of the antenna-radome structure (ARS) into three distinct oct-trees, the multilevel fast multipole algorithm (MLFMA) is used to accelerate both the VSIE solution and the surface/volume integrations in the MSI stage. The new method obtains more accurate results than its original version within less CPU time, and keeps good accuracy with much less memory usage and computational time when compared with the MLFMA-accelerated full-wave VSIE solution for the entire ARS.
Autors: Binbin Wang;Mang He;Jinbo Liu;Chuanfang Zhang;Houjun Sun;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2436 - 2445
Publisher: IEEE
 
» Fast Grid Security Assessment With N − k Contingencies
Abstract:
The challenge of grid security assessment with contingencies lies in a huge amount of transmission security constraints and even for the modest values of N and k, the computational complexity would be very high. A new method for fast grid security assessment is presented in this paper for DC grid. The key idea is to construct a small number of representative constraints to equivalently “represent” the huge number of original security constraints. It is proved that applying the representative constraints is sufficient to assess grid security as the original security constraints do. An important feature of the new method is that the representative constraints need to be constructed only once offline. They are only related to the parameters of transmission network and do not change with power injections. Numerical testing is performed for IEEE-RTS 24-bus system, IEEE 118-bus system, and the Polish 2383-bus system. The number of representative constraints to be assessed is only 1.1%, 0.32%, and 0.27% of that of the original constraints, respectively, and the computational time of security assessment is greatly reduced.
Autors: Yafei Yang;Xiaohong Guan;Qiaozhu Zhai;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2193 - 2203
Publisher: IEEE
 
» Fast Packet Classification Based on Hybrid Cutting
Abstract:
Most existing packet classification algorithms adopt only one cutting strategy. However, the proposed algorithm adopts a hybrid one that combines equi-sized cuttings with pivot-based cuttings, so it can significantly increase cutting efficiency. Therefore, it can have distinct features, such as smaller table size, larger supportable rule set, and higher classification performance compared with the existing competitors.
Autors: Jae-Hyeong Wee;Wooguil Pak;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1011 - 1014
Publisher: IEEE
 
» Fault-Tolerant Converter With a Modular Structure for HVDC Power Transmitting Applications
Abstract:
For the high-voltage direct-current (HVDC) power transmission system of offshore wind power, dc/dc converters are the potential solution to collect the power generated by off-shore wind farms to HVDC terminals. The converters operate with high-voltage gain, high efficiency, and fault tolerance over a wide range of operating conditions. In this paper, an isolated ultrahigh step-up dc/dc converter with a scalable modular structure is proposed for HVDC offshore wind power collection. A flyback-forward converter is employed as the power cell to form the expandable electrically isolated modular dc/dc converter. The duty ratio and phase-shift angle control are also developed for the proposed converter. Fault-tolerant characteristics of the converter are illustrated through the redundancy operation and fault-ride-through tests. Redundancy operation is designed to maintain high operation efficiency of the converters and fault-ride-through operation improves the converter reliability under harsh operating conditions. Analytical studies are carried out, and a 750-W prototype with three modular cells is built and experimentally tested to verify the performance of the proposed modular dc/dc converter.
Autors: Yihua Hu;Guipeng Chen;Yang Liu;Lin Jiang;Peng Li;Stephen J. Finney;Wenping Cao;Huifeng Chen;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 2245 - 2256
Publisher: IEEE
 
» FBG Thermal Sensing Features for Hot Spot Monitoring in Random Wound Electric Machine Coils
Abstract:
This paper investigates the key design and operational features of embedded fiber Bragg grating (FBG) sensing for thermal hot spot monitoring in random wound coils, such as used in low voltage electrical machines. To this end thermal experiments are performed on test wound coils embedded with FBG sensors to examine the vital application features of embedded sensor design, such as the sensor packaging material choice, in-situ calibration, sensitivity to vibration, and thermal response time. Measurement error rates are examined and quantified in representative practical tests. The reported results enable a much improved understanding of the performance implications of embedded FBG sensor design features and the attainable in-situ hot spot thermal monitoring performance in random wound coils.
Autors: Anees Mohammed;Siniša Djurović;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:10, pages: 3058 - 3067
Publisher: IEEE
 
» FBMC System: An Insight Into Doubly Dispersive Channel Impact
Abstract:
It has been claimed that filter bank multicarrier (FBMC) systems suffer from negligible performance loss caused by moderate dispersive channels in the absence of guard time protection between symbols. However, a theoretical and systematic explanation/analysis for the statement is missing in the literature to date. In this paper, based on one-tap minimum mean square error (MMSE) and zero-forcing (ZF) channel equalizations, the impact of doubly dispersive channel on the performance of FBMC systems is analyzed in terms of mean square error of received symbols. Based on this analytical framework, we prove that the circular convolution property between symbols and the corresponding channel coefficients in the frequency domain holds loosely with a set of inaccuracies. To facilitate analysis, we first model the FBMC system in a vector/matrix form and derive the estimated symbols as a sum of desired signal, noise, intersymbol interference (ISI), intercarrier interference (ICI), interblock interference (IBI), and estimation bias in the MMSE equalizer. Those terms are derived one-by-one and expressed as a function of channel parameters. The numerical results reveal that under harsh channel conditions, e.g., with large Doppler spread or channel delay spread, the FBMC system performance may be severely deteriorated and error floor will occur.
Autors: Lei Zhang;Pei Xiao;Adnan Zafar;Atta ul Quddus;Rahim Tafazolli;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 3942 - 3956
Publisher: IEEE
 
» Feasibility Study of Using Electrically Conductive Concrete for Electromagnetic Shielding Applications as a Substitute for Carbon-Laced Polyurethane Absorbers in Anechoic Chambers
Abstract:
This paper investigates conductive concrete in electromagnetic shielding applications as a viable alternative to carbon-laced polyurethane, which is used as an absorber material in anechoic chambers. To greatly increase concrete’s electromagnetic shielding performance, carbon black, graphite powder, and steel fibers are introduced to its composition. Samples of conductive concrete have been prepared and its shielding effectiveness is evaluated. The test method is based on using power spectrum analysis to characterize the degree of shielding due to the different mechanisms of reflection and absorption. The tested samples are in the shape of anechoic chambers pyramidal cones, to provide gradual impedance gradient. Slabs with flat surface are also built and tested in order to compare the results. Measured data are then compared with published figures for commercial chamber performances. The range of frequency tested is from 1 to 5.5 GHz. The pyramidal conductive concrete samples yield an excellent shielding effectiveness of approximately 65 dB as opposed to the carbon-laced polyurethane performance of 50 dB.
Autors: Tuqa Khalid;Lutfi Albasha;Nasser Qaddoumi;Sherif Yehia;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2428 - 2435
Publisher: IEEE
 
» Feature Constrained Multi-Task Learning Models for Spatiotemporal Event Forecasting
Abstract:
Spatial event forecasting from social media is potentially extremely useful but suffers from critical challenges, such as the dynamic patterns of features (keywords) and geographic heterogeneity (e.g., spatial correlations, imbalanced samples, and different populations in different locations). Most existing approaches (e.g., LASSO regression, dynamic query expansion, and burst detection) address some, but not all, of these challenges. Here, we propose a novel multi-task learning framework that aims to concurrently address all the challenges involved. Specifically, given a collection of locations (e.g., cities), forecasting models are built for all the locations simultaneously by extracting and utilizing appropriate shared information that effectively increases the sample size for each location, thus improving the forecasting performance. The new model combines both static features derived from a predefined vocabulary by domain experts and dynamic features generated from dynamic query expansion in a multi-task feature learning framework. Different strategies to balance homogeneity and diversity between static and dynamic terms are also investigated. And, efficient algorithms based on Iterative Group Hard Thresholding are developed to achieve efficient and effective model training and prediction. Extensive experimental evaluations on Twitter data from civil unrest and influenza outbreak datasets demonstrate the effectiveness and efficiency of our proposed approach.
Autors: Liang Zhao;Qian Sun;Jieping Ye;Feng Chen;Chang-Tien Lu;Naren Ramakrishnan;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2017, volume: 29, issue:5, pages: 1059 - 1072
Publisher: IEEE
 
» Field Demonstration of a Real-Time 100-Gb/s PON Based on 10G-Class Optical Devices
Abstract:
We have demonstrated the first field trial of a real-time 100-Gb/s passive optical network with downstream/upstream data rates of 25/10-Gb/s/λ based on 10G-class optical devices supporting 0–40 km differential reach. We employ a single delay-interferometer (DI) to realize chirp management as well as frequency equalization to combat the chromatic dispersion during the fiber transmission and equalize the frequency response of the bandwidth-limited system. Owing to the periodical characteristic, DI can successfully manage the four downstream wavelengths simultaneously. As for the upstream transmission, a fiber Bragg grating is employed to compensate the dispersion of the four upstream channels. In addition, an optical amplification deployed at the optical line termination (OLT) is used to amplify the downstream optical power and pre-amplify the upstream signal for supporting more users. All the active and passive components except for transceivers are packaged into a single module in the OLT. The system stability is verified within 67-h real-time bit error rate measurement. We obtained a power budget of 33 dB with 0–40 km reach of standard single mode fiber based on non-return-to-zero on-off-keying modulation format for both downstream and upstream.
Autors: Honglin Ji;Lilin Yi;Zhengxuan Li;Lei Xue;Xiang Li;Qi Yang;Suyi Wang;Ying Yang;Shaohua Yu;Weisheng Hu;
Appeared in: Journal of Lightwave Technology
Publication date: May 2017, volume: 35, issue:10, pages: 1914 - 1921
Publisher: IEEE
 
» Field Measurement and Analysis of Long-Reach and High-Splitting-Ratio 10G-EPON With Optical Amplifier in Central Office
Abstract:
It is important to economize the infrastructure of the access network and enhance its profitability because it represents the greatest part of network infrastructure cost. As 10G-EPON can be cost-effectively shared among various access services, it is one of the strong candidates to reduce the infrastructure cost of the next-generation access network. To further enhance cost effectiveness, it is useful to improve the acceptable link budget of access systems by using optical amplifiers (OAs), which can increase the splitting ratios and extend the reachable distance of the system. In this paper, we demonstrate an :1 redundant 10G-EPON system with dual-rate central-office-set-type semiconductor optical amplifier (CO-SOA). Our 10G-EPON system reduces OPEX and CAPEX due to its extended reachable distance and elimination of intermediate offices while keeping its system reliability with the :1 protection system. Moreover, we also develop a method for estimating the total reachable distance of 10G-EPON systems with OAs in order to quantitatively evaluate the effect of extending reachable distance on various combinations of splitting ratio based on the results of actual demonstrations. Analyses of field measurement results clarify that the proposed system has sufficient design flexibility so as to satisfy the subscriber distribution requirements as regards the factors of splitting ratio and reachable distance. The results indicate that the :1 optical subscriber unit protection with CO-SOAs is a promising approach to practical 10G-EPON systems that are cost effective and reliable.
Autors: Takuya Tsutsumi;Yoshihito Sakai;Toshihito Fujiwara;Hiroshi Ou;Yasutaka Kimura;Takeshi Sakamoto;Ken-Ichi Suzuki;Manabu Kubota;Akihiro Otaka;
Appeared in: Journal of Lightwave Technology
Publication date: May 2017, volume: 35, issue:10, pages: 1775 - 1784
Publisher: IEEE
 
» Field Simulation Approach for Computing the Commutation Angle Error of EC Motors
Abstract:
Electronically commutated motors produce a mechanical torque by switching the currents in their stator winding system according to the instantaneous rotor position during rotation. The rotor position is determined by Hall sensors capturing the magnetic field of the rotor's permanent magnets. In operation, the Hall sensors are exposed not only to the rotor field, but also to the field of stator windings. This inevitably leads to a certain commutation angle error (CA error) and a reduced motor performance. This paper presents a general 3-D magnetic field simulation approach for computing the CA error and for finding an optimal position of the Hall sensors. The obtained numerical results and their verification by measurements are presented in detail.
Autors: Christian Koster;Jens Schulze;Thomas Schmidiger;Raniero Pittini;Jasmin Smajic;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2017, volume: 53, issue:3, pages: 1942 - 1947
Publisher: IEEE
 
» Fin-Array Tunneling Trigger With Tunable Hysteresis on (001) Silicon Substrate
Abstract:
We report the fabrication and characterization of a GaAs fin-array tunneling trigger monolithically integrated on an exact (001) silicon substrate. A Schmitt-trigger-like behavior was observed under double sweep condition by connecting the tunnel diode with an on-chip load resistor. The tunneling trigger circuit was studied using load line analysis. Critical parameters of the circuit were extracted. We found that the circuit hysteresis can be tuned by tailoring of the diode dimensions and load resistor values.
Autors: Yu Han;Qiang Li;Kei May Lau;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 556 - 559
Publisher: IEEE
 
» Finding Needles in a Haystack: Missing Tag Detection in Large RFID Systems
Abstract:
Radio frequency identification technology has been widely used in missing tag detection to reduce and avoid inventory shrinkage. In this application, promptly finding out the missing event is of paramount importance. However, the existing missing tag detection protocols cannot efficiently handle the presence of a large number of unexpected tags whose IDs are not known to the reader, which shackles the time efficiency. To deal with the problem of detecting missing tags in the presence of unexpected tags, this paper introduces a two-phase Bloom filter-based missing tag detection (BMTD) protocol. The proposed BMTD exploits Bloom filter in sequence to first deactivate the unexpected tags and then test the membership of the expected tags, thus dampening the interference from the unexpected tags and considerably reducing the detection time. Moreover, the theoretical analysis of the protocol parameters is performed to minimize the detection time of the proposed BMTD and achieve the required reliability simultaneously. In addition, we derive a critical threshold on the unexpected tag size for the execution of first phase in BMTD. Extensive experiments are then conducted to evaluate the performance of the proposed BMTD. The results demonstrate that the proposed BMTD significantly outperforms the state-of-the-art solutions.
Autors: Jihong Yu;Lin Chen;Rongrong Zhang;Kehao Wang;
Appeared in: IEEE Transactions on Communications
Publication date: May 2017, volume: 65, issue:5, pages: 2036 - 2047
Publisher: IEEE
 
» Finite Element Small-Signal Simulation of Electromagnetic Devices Considering Eddy Currents in the Laminations
Abstract:
This paper presents the validation of a small-signal finite-element simulation strategy comparing different simulation approaches. At first, a full 3-D non-linear model in the time domain is presented. Then, the small-signal strategy has been applied to the 3-D model achieving a considerable reduction of computational time. In both 3-D models, the eddy currents in the laminations are fully modeled. Then, in order to avoid 3-D model, a 2-D model has been considered. In this case, eddy currents are included adopting a homogenization technique. In the 2-D case, both non-linear time domain simulations and small-signal strategy have been implemented. The results of the four considered simulation strategies are in very good agreement, proving that the small-signal simulation strategy can be profitably used in order to reduce significantly the computational cost. As an example, this paper considers a two-port mutual inductor as a test model.
Autors: Omar Bottesi;Luigi Alberti;Ruth V. Sabariego;Johan Gyselinck;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2017, volume: 53, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Finite Model Approximations and Asymptotic Optimality of Quantized Policies in Decentralized Stochastic Control
Abstract:
We consider finite model approximations of a large class of static and dynamic team problems where these models are constructed through uniform quantization of the observation and action spaces of the agents. The strategies obtained from these finite models are shown to approximate the optimal cost with arbitrary precision under mild technical assumptions. In particular, quantized team policies are asymptotically optimal. This result is then applied to Witsenhausen's celebrated counterexample and the Gaussian relay channel problem. For Witsenhausen's counterexample, our approximation approach provides, to our knowledge, the first rigorously established result that one can construct an -optimal strategy for any through a solution of a simpler problem.
Autors: Naci Saldi;Serdar Yüksel;Tamás Linder;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2360 - 2373
Publisher: IEEE
 
» Finite-Difference Modeling of Broadband Huygens’ Metasurfaces Based on Generalized Sheet Transition Conditions
Abstract:
An explicit time-domain finite-difference technique for modeling zero-thickness Huygens’ metasurfaces based on generalized sheet transition conditions (GSTCs) is proposed and demonstrated using full-wave simulations. The Huygens’ metasurface is modeled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens’ metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time domain. Identifying the exact equivalence between Huygens’ metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modeling techniques based on a finite-difference formulation. Several examples, including generalized refraction, are shown to illustrate the temporal evolution of scattered fields from the Huygens’ metasurface under plane-wave normal incidence, in both harmonic steady-state and broadband regimes. In particular, due to its inherent time-domain formulation, a significant strength of the methodology is its ability to model time-varying metasurfaces, which is demonstrated with a simple example of a pumped metasurface leading to new frequency generation and wave amplification.
Autors: Tom J. Smy;Shulabh Gupta;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2566 - 2577
Publisher: IEEE
 
» Finite-Difference Time-Domain Technique for Gyroelectric Material Structure Simulation Using Recursive Convolutions in Polarization
Abstract:
A gyrotropic material handling method is proposed. Our technique does not require modification of the finite-difference time-domain stepping algorithm, and the gyroelectric phenomenon can be treated as a variation of material polarization. The simulation of electromagnetic wave transmission through a test gyroelectric structure of a magnetized plasma layer is presented and compared with the analytical solution. An open source implementation is presented.
Autors: A. V. Friman;A. A. Gorbatsevich;P. P. Sverbil;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2745 - 2747
Publisher: IEEE
 
» Finite-Element Modeling of Metasurfaces With Generalized Sheet Transition Conditions
Abstract:
A modeling of metasurfaces in the finite-element method (FEM) based on generalized sheet transition conditions (GSTCs) is presented. The discontinuities in electromagnetic fields across a metasurface as represented by the GSTC are modeled by assigning nodes to both the sides of the metasurface. The FEM-GSTC formulation in both 1-D and 2-D domains is derived and implemented. The method is extended to handle more general bianistroptic metasurfaces. The formulations are validated by several illustrative examples.
Autors: Srikumar Sandeep;Jian-Ming Jin;Christophe Caloz;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2413 - 2420
Publisher: IEEE
 
» Finite-Length Linear Schemes for Joint Source-Channel Coding Over Gaussian Broadcast Channels With Feedback
Abstract:
In this paper, we study linear encoding for a pair of correlated Gaussian sources transmitted over a two-user Gaussian broadcast channel in the presence of unit-delay noiseless feedback, abbreviated as the GBCF. Each pair of source samples is transmitted using a linear transmission scheme in a finite number of channel uses. We investigate three linear transmission schemes: A scheme based on the Ozarow–Leung (OL) code, a scheme based on the linear quadratic Gaussian (LQG) code of Ardestanizadeh et al., and a novel scheme derived in this paper using a dynamic programming (DP) approach. For the OL and LQG schemes we present lower and upper bounds on the minimal number of channel uses needed to achieve a target mean-square error (MSE) pair. For the LQG scheme in the symmetric setting, we identify the optimal scaling of the sources, which results in a significant improvement of its finite horizon performance, and, in addition, characterize the (exact) minimal number of channel uses required to achieve a target MSE. Finally, for the symmetric setting, we show that for any fixed and finite number of channel uses, the DP scheme achieves an MSE lower than the MSE achieved by either the LQG or the OL schemes.
Autors: Yonathan Murin;Yonatan Kaspi;Ron Dabora;Deniz Gündüz;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2017, volume: 63, issue:5, pages: 2737 - 2772
Publisher: IEEE
 
» Finite-Time Fuzzy Sampled-Data Control for Nonlinear Flexible Spacecraft With Stochastic Actuator Failures
Abstract:
This paper deals with the problem of finite-time sampled-data control for nonlinear flexible spacecraft described by Takagi–Sugeno (T–S) fuzzy model with stochastic actuator failures. Different from the existing literatures, T–S fuzzy approach is used to model the nonlinear behaviors of flexible spacecraft for its good approximation performance. A novel and general input model related to Markovian variables is developed to depict the stochastic actuator failures, which is capable of covering various faulty modes. With the aid of stochastic analysis and convex optimization techniques, a novel fault-tolerant fuzzy switching controller is designed to carry out the finite-time attitude stabilization for flexible spacecraft with the existence of stochastic failures and sampled-data inputs, and an optimal performance level is ensured simultaneously. Finally, a practical example with simulation results are provided to validate the effectiveness of the developed control strategy.
Autors: Guanghui Sun;Shidong Xu;Zhan Li;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3851 - 3861
Publisher: IEEE
 
» Finite/Fixed-Time Stabilization for Nonlinear Interconnected Systems With Dead-Zone Input
Abstract:
The decentralized control problem is considered for a class of nonlinear time-varying interconnected systems. Each subsystem is with the dead-zone input and unmodeled dynamics. The interconnections are bounded by time-varying nonlinear functions, which relaxes the commonly used linear condition or time-invariant condition. Based on the recursive method, we design a new decentralized finite-time controller such that all the state variables reach zero in finite time. The reaching time is based on the design parameters and initial value of system state. Furthermore, the fixed time stability conditions are given and the constructed controller can guarantee the fixed-time stabilization of the system, in which the reaching time only depends the control design parameters. Finally, simulation results are presented to illustrate the effectiveness of proposed method.
Autors: Changchun Hua;Yafeng Li;Xinping Guan;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2554 - 2560
Publisher: IEEE
 

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