Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 7

» Effect of Correlation on BER Performance of the FSO-MISO System With Repetition Coding Over Gamma–Gamma Turbulence
Abstract:
In free space optical (FSO) communication systems, atmospheric turbulence is the major cause of bit error rate (BER) performance degradation. The error performance of the system can be significantly improved with the help of spatial diversity by employing multiple transmit or receive apertures. However, correlation of channels under turbulence in the case of small separation between transmit apertures can substantially reduce the benefits of spatial diversity. Still, a thorough analysis of the system performance in terms of diversity order and coding gain for the FSO multiple-input single-output (MISO) system under turbulence influenced correlated channels has not been studied when the repetition coding is used to achieve improved BER performance. In this paper, we provide unique results of the BER performance analysis of the considered correlated FSO-MISO system over Gamma–Gamma distributed turbulence channel. Using the joint moment generating function of received signal-to-noise ratio (SNR), a novel generalized approximate BER expression is derived, followed by convergence test of the power series based BER expression using the Cauchy's ratio test. Then, an asymptotic analysis at high SNR is performed to obtain a novel closed-form expression for BER of FSO-MISO system. We also derive expressions for coding gain, diversity gain, and coding gain loss due to correlation in channels. Although the effect of correlation in channels on the BER performance of the system is analyzed under different scenarios, while it is observed that it does not affect the diversity order; it significantly degrades the coding gain of the considered system.
Autors: Richa Priyadarshani;Manav R. Bhatnagar;Zabih Ghassemlooy;Stanislav Zvanovec;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 15
Publisher: IEEE
 
» Effect of Human Brain Edema on Light Propagation: A Monte Carlo Modeling Based on the Visible Chinese Human Dataset
Abstract:
Brain edema originates from the excessive accumulation of cerebrospinal fluid (CSF) in the brain attributing to brain trauma or nontrauma diseases such as cancer, ischemic stroke, meningitis, and encephalitis. The high intracranial pressure could extrude the vessels in brain and block the blood circulation, yielding the risk of intracranial hemorrhage (ICH). In this study, we investigated the feasibility of utilizing functional near infrared spectroscopy (fNIRS) for brain edema inspection through Monte Carlo simulations over the head model of the Visible Chinese Human dataset. The outstanding influence of the development (4 levels) of edema and the occurrence of ICH on the light migration were observed. With the increase of CSF volume, the results show a strong linear relationship between the volumes of CSF and the intensities of the detected signal and the deeper penetration of photons. An outstanding contrast was also observed before and after the occurrence of ICH. The study revealed that fNIRS holds promise to be an easy and reliable solution for inspecting edema aggression inside brain through the observation on the variation of optical signals, and is very suitable for continuous bedside inspection.
Autors: Lanhui Wu;Yu Lin;Ting Li;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Effect of Outdated CSI on Handover Decisions in Dense Networks
Abstract:
We consider an ultra-dense network where each mobile is attached to the access point, which provides the best reference signal received power considering both path-loss and small-scale fading. In order to evaluate the effect of outdated channel state information (CSI) brought by feedback delay, we first derive the estimated and accurate handover probability according to outdated and perfect CSI, respectively. Furthermore, two metrics are proposed to measure the handover failure, i.e., false handover probability and miss handover probability. Simulations show that in sparse or ultra-dense networks, the imperfection of CSI is acceptable for handover decisions; however, in between, i.e., dense networks (medium-size networks), handover decisions are very sensitive to the user velocity and CSI imperfection.
Autors: Yinglei Teng;Mengting Liu;Mei Song;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2238 - 2241
Publisher: IEEE
 
» Effect of Structural Disorder on Photonic Crystal Logic Gates
Abstract:
In this paper, we study the effect of structural disorder on photonic crystals logic gates applying a new approach based on the evaluation of two metrics: the error rate (ER) and the mean absolute deviation of transmission of the error cases (MATEC). ER is the probability that a fabricated photonic crystal logic gate does not accomplish its logic function correctly, and MATEC measures the imperfection degree of the device through the transmission coefficient. The process consists in introducing disorder in specific regions in the boundary of the waveguides that form the logic gate structure. A significant number of simulations is randomly performed for each input combination of the logic gate. The ER and MATEC are calculated, and the process is replicated 20 times with different seed numbers. Finally, a statistical test T is carried out to establish the most critical regions for the device. We evaluate some photonic crystal logic gates with different lattice configurations using this approach. The results show that, for structures with a triangular lattice, regions in the corners and close to the output are more critical to ER and MATEC, respectively. For structures with a square lattice, we found that the intersection regions are the most sensitive for both metrics. As a final consideration, we remark that this methodology can be easily applied to evaluate other kinds of disorder and to analyze photonic crystals devices based on waveguides with different lattice configurations, and can guide the design of future robust gates.
Autors: Luis Eduardo Pedraza Caballero;Juan Pablo Vasco Cano;Paulo S. S. Guimarães;Omar Paranaiba Vilela Neto;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 15
Publisher: IEEE
 
» Effect of Surface Stresses on Microwave Surface Resistance and Its Impact for Cavity Perturbation Measurements
Abstract:
For microwave characterization of materials over a wide temperature range, it is often desirable to perform cavity perturbation measurements at elevated temperatures. Careful cavity design, involving the minimization of electrical contacts, ensures high measurement stability as the temperature varies. However, examining the Q-factor of a cylindrical cavity resonator during heating has shown that heat treatment can permanently modify the surface resistance of an aluminum surface. X-Ray diffraction measurements of Al-6082 confirm that the source of change can be due to changes in surface stress and the appearance of solution precipitates. Here we discuss the necessity to pretreat microwave cavities to stabilize their Q-factors in order to reliably measure material properties via cavity perturbation across a wide temperature range.
Autors: Nicholas Clark;Greg Shaw;Adrian Porch;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 939 - 941
Publisher: IEEE
 
» Effect of the Vegetation Fire on Backscattering: An Investigation Based on Sentinel-1 Observations
Abstract:
This paper aims at investigating the potential of Sentinel-1 C-band synthetic aperture radar (SAR) observations for detecting fire scars in vegetated areas at regional scale. A comprehensive analysis of the backscattering coefficients is carried out. The experimental analysis is conducted by analyzing the scenario of the Sardinia Island, which is one of the Italian regions most affected by fire events over the summer season. The detection capability of fire scars in such an environment is demonstrated by exploiting information extracted from dual-polarized SAR data. Our results reveal a significant decrease of the VH response over the fire-disturbed forests, thus, highlighting the effectiveness of such cross-polarized observations. In order to prove the validity of the proposed approach for the detection of fire scars in the vegetation layer, the results of the conducted experiments have been suitably compared with burned areas identified by using an existing fuzzy-based algorithm, which has been applied to multispectral Landsat-8 operational land imager data. This investigation opens the way to systematic methods for monitoring fire scars in heterogeneous environments, and in particular in fire-prone Mediterranean ecosystems.
Autors: Pasquale Imperatore;Ramin Azar;Fabiana Calò;Daniela Stroppiana;Pietro Alessandro Brivio;Riccardo Lanari;Antonio Pepe;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4478 - 4492
Publisher: IEEE
 
» Effective Current Model for Inverter-Transmission Gate Structure and Its Application in Circuit Design
Abstract:
In this paper, we present an effective switching current model () for inverter followed by a transmission gate structure (Inv-Tx) based on its switching trajectory. Unlike an inverter or NAND/NOR gates, where depends only on nMOSFET (pMOSFET) current for a falling (rising) transition, it is a function of both nMOSFET and pMOSFET currents for an Inv-Tx cell. The proposed model is verified against HSPICE simulations for a wide range of supply voltages and fan-outs at different technology nodes (e.g., 180, 130, and 65 nm). The model predicts the transition delay values with an average (maximum) error of 7% (11%) compared with HSPICE simulations. Synopsys TCAD Sentaurus simulations at 32-nm technology node are also used to validate the basic model assumptions. To demonstrate the utility of our model, design of some representative circuits while incorporating layout-dependent effects and inverse-narrow-width effect is presented. Finally, we show that a 256X1 multiplexer and a static D-flip-flop, with their transistor sizes and layout, optimized using the proposed model improves the performance of these circuits significantly over the conventional design methodologies.
Autors: Arvind Sharma;Naushad Alam;Anand Bulusu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4002 - 4010
Publisher: IEEE
 
» Effects of Armature Height and Position on the Performance of Induction Coil Launcher
Abstract:
Induction coil launcher (ICL) is an electromagnetic accelerator that uses Lorentz force to accelerate a projectile with a conducting armature. In this paper, the effects of the height and starting position of the armature on the performance of the ICL were analyzed. Launching experiments were conducted to verify the analysis results. The speed of the projectile converged to a saturated value as the armature height increased. We found that there exists an optimal starting position of the armature for the highest speed. The concept of inductance gradient was adopted to explain the analysis results. It was possible to predict the acceleration characteristics and to estimate the optimal starting position using this concept. Results show that the armature height should be longer than the drive coil height (, and the bottom of the armature should be positioned between and at the start to obtain the highest speed. The experimental results showed good agreement with the simulation analysis results.
Autors: Daehwan Kwak;Yun Sik Jin;Young Bae Kim;Jong Soo Kim;Chuhyun Cho;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2696 - 2700
Publisher: IEEE
 
» Effects of Bi(Zn2/3Nb1/3)O3 Modification on the Relaxor Behavior and Piezoelectricity of Pb(Mg1/3Nb2/3)O3–PbTiO3 Ceramics
Abstract:
Relaxor lead magnesium niobate (PMN)-based materials exhibit complex structures and unusual properties that have been puzzling researchers for decades. In this paper, a new ternary solid solution of Pb(Mg1/3Nb2/3)O3–PbTiO3–Bi(Zn2/3Nb1/3)O3 (PMN–PT–BZN) is prepared in the form of ceramics, and the effects of the incorporation of BZN into the PMN-PT binary system are investigated. The crystal structure favors a pseudocubic symmetry and the relaxor properties are enhanced as the concentration of BZN increases. The relaxor behavior and the related phase transformations are studied by dielectric spectroscopy. A phase diagram mapping out the characteristic temperatures and various states is established. Interestingly, the piezoelectricity of the PMN-PT ceramics is significantly enhanced by the BZN substitution, with an optimal value of reaching 826 pC/N for 0.96[0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3]-0.04Bi(Zn2/3Nb1/3)O3. This paper provides a better understanding of the relaxor ferroelectric behavior, and unveils a new relaxor-based ternary system as piezoelectric materials potentially useful for electromechanical transducer applications.
Autors: Zenghui Liu;Hua Wu;Alisa Paterson;Wei Ren;Zuo-Guang Ye;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1608 - 1616
Publisher: IEEE
 
» Effects of Image Quality on the Fundamental Limits of Image Registration Accuracy
Abstract:
For image-guided procedures, the imaging task is often tied to the registration of intraoperative and preoperative images to a common coordinate system. While the accuracy of this registration is a vital factor in system performance, there is a relatively little work that relates registration accuracy to image quality factors, such as dose, noise, and spatial resolution. To create a theoretical model for such a relationship, we present a Fisher information approach to analyze registration performance in explicit dependence on the underlying image quality factors of image noise, spatial resolution, and signal power spectrum. The model yields analysis of the Cramer–Rao lower bound (CRLB), in registration accuracy as a function of factors governing image quality. Experiments were performed in simulation of computed tomography low-contrast soft tissue images and high-contrast bone (head and neck) images to compare the measured accuracy [root mean squared error (RMSE) of the estimated transformations] with the theoretical lower bound. Analysis of the CRLB reveals that registration performance is closely related to the signal-to-noise ratio of the cross-correlation space. While the lower bound is optimistic, it exhibits consistent trends with experimental findings and yields a method for comparing the performance of various registration methods and similarity metrics. Further analysis validated a method for determining optimal post-processing (image filtering) for registration. Two figures of merit (CRLB and RMSE) are presented that unify models of image quality with registration performance, providing an important guide to optimizing intraoperative imaging with respect to the task of registration.
Autors: Michael D. Ketcha;Tharindu De Silva;Runze Han;Ali Uneri;Joseph Goerres;Matthew W. Jacobson;Sebastian Vogt;Gerhard Kleinszig;Jeffrey H. Siewerdsen;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 1997 - 2009
Publisher: IEEE
 
» Effects of Inclined Sidewall Structure With Bottom Metal Air Cavity on the Light Extraction Efficiency for AlGaN-Based Deep Ultraviolet Light-Emitting Diodes
Abstract:
An inclined sidewall scattering structure with air cavity characterized by a metal bottom and flat parallel top (Bottom_metal) is proposed to enhance the light extraction efficiency (LEE) for AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs). Compared to the reported sidewall metal inclined sidewall (Sidewall_metal) structure, the Bottom_metal structure can greatly enhance the LEE of DUV LEDs based on three-dimensional finite difference time domain simulations. Further analysis indicates that the existence of the air cavity promotes the Bottom_metal DUV LEDs to mainly utilize the total internal reflection and the Fresnel scattering to scatter the light into the escape cone, which avoids the light absorption from the sidewall metal mirror in the Sidewall_metal structure. Moreover, the unique air cavity having a bottom metal also enhances the scattering ability of the Bottom_metal DUV LEDs because any light within the cavity directing downward will be reflected back, and the parallel top interface of air cavity/AlGaN functions as additional out-light planes not limited by total internal reflection.
Autors: Yonghui Zhang;Ruilin Meng;Zi-Hui Zhang;Qiang Shi;Luping Li;Guoxu Liu;Wengang Bi;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Effects of Notch Filters on Imbalance Rejection With Heteropolar and Homopolar Magnetic Bearings in a 30-kW 60 000-r/min Motor
Abstract:
Active magnetic bearings (AMBs) have achieved great advantages in the high-speed and high-power-density rotating machine. Various vibration control strategies based on the notch filter have been reported to reduce the rotor imbalance vibration. But, the study is still insufficient to determine why the vibration gets reduced. This paper addresses a concise and direct explanation of the effects of notch filter on the rotor imbalance vibration with AMBs. An analytic solution for the synchronous response of rotor imbalance is introduced using the simple planar rotor model and general notch filter method. Then, combined with practical matters, the amplifier of a heteropolar radial AMB is further specified to uncover the effect of motion induced voltage to rotor self-centering, as a comparison with the homopolar radial AMB. Since the developed motor is equipped with both types of radial AMBs, a detailed control design is exhibited based on the dynamics of rigid body motion. The traditional simplification of two-plane separate control is improved, and a centralized controller is constructed. The effects of the rotor imbalance vibration rejection are demonstrated by the simulation results and experiments in a 30-kW 60000-r/min permanent magnet motor.
Autors: Jinxiang Zhou;Shiqiang Zheng;Bangcheng Han;Jiancheng Fang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8033 - 8041
Publisher: IEEE
 
» Effects of Signal Saturation on QUS Parameter Estimates Based on High-Frequency-Ultrasound Signals Acquired From Isolated Cancerous Lymph Nodes
Abstract:
Choosing an appropriate dynamic range (DR) for acquiring radio frequency (RF) data from a high-frequency-ultrasound (HFU) system is challenging because signals can vary greatly in amplitude as a result of focusing and attenuation effects. In addition, quantitative ultrasound (QUS) results are altered by saturated data. In this paper, the effects of saturation on QUS estimates of effective scatterer diameter (ESD) and effective acoustic concentration (EAC) were quantified using simulated and experimental RF data. Experimental data were acquired from 69 dissected human lymph nodes using a single-element transducer with a 26-MHz center frequency. Artificially saturated signals ( were produced by thresholding the original unsaturated RF echo signals. Saturation severity was expressed using a quantity called saturate-signal-to-noise ratio (SSNR). Results indicated that saturation has little effect on ESD estimates. However, EAC estimates decreased significantly with decreasing SSNR. An EAC correction algorithm exploiting a linear relationship between EAC values over a range of SSNR values and -norm of (i.e., the sum of absolute values of the true RF echo signal) is developed. The maximal errors in EAC estimates resulting from saturation were −8.05, −3.59, and −0.93 dB/mm3 with the RF echo signals thresholded to keep 5, 6, and 7-bit from the original 8-bit DR, respectively. The EAC correction algorithm reduced maximal errors to −3.71, −0.89, and −0.26 dB/mm3 when signals were thresholded at 5, 6, and 7-bit, respectively.
Autors: Kazuki Tamura;Jonathan Mamou;Alain Coron;Kenji Yoshida;Ernest J. Feleppa;Tadashi Yamaguchi;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1501 - 1513
Publisher: IEEE
 
» Efficiency Enhancement for an Inductive Wireless Power Transfer System by Optimizing the Impedance Matching Networks
Abstract:
Inductive wireless power transfer (IWPT) is a promising power technology for implantable biomedical devices, where the power consumption is low and the efficiency is the most important consideration. In this paper, we propose an optimization method of impedance matching networks (IMN) to maximize the IWPT efficiency. The IMN at the load side is designed to achieve the optimal load, and the IMN at the source side is designed to deliver the required amount of power (no-more-no-less) from the power source to the load. The theoretical analyses and design procedure are given. An IWPT system for an implantable glaucoma therapeutic prototype is designed as an example. Compared with the efficiency of the resonant IWPT system, the efficiency of our optimized system increases with a factor of 1.73. Besides, the efficiency of our optimized IWPT system is 1.97 times higher than that of the IWPT system optimized by the traditional maximum power transfer method. All the discussions indicate that the optimization method proposed in this paper could achieve a high efficiency and long working time when the system is powered by a battery.
Autors: Zhidong Miao;Dake Liu;Chen Gong;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Oct 2017, volume: 11, issue:5, pages: 1160 - 1170
Publisher: IEEE
 
» Efficient Analysis of Metasurfaces in Terms of Spectral-Domain GSTC Integral Equations
Abstract:
We present a spectral-domain (SD) technique for the efficient analysis of metasurfaces. The metasurface is modeled by generalized sheet transition conditions (GSTCs) as a zero-thickness sheet creating a discontinuity in the electromagnetic field. The SD expression of these GSTCs for a specified incident field leads to a system of four surface integral equations for the reflected and transmitted fields, which are solved using the method of moments in the SD. Compared with the finite-difference and finite-element techniques that require meshing the entire computational domain, the proposed technique reduces the problem to the surface of the metasurface, hence eliminating one dimension and providing substantial benefits in terms of memory and speed. A monochromatic generalized-refractive metasurface and a polychromatic focusing metasurface are presented as illustrative examples.
Autors: Nima Chamanara;Karim Achouri;Christophe Caloz;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5340 - 5347
Publisher: IEEE
 
» Efficient Coded Cooperative Networks With Energy Harvesting and Transferring
Abstract:
In this paper, a multi-user multi-relay network with integrated energy harvesting and transferring (IEHT) strategy is studied. In our system, a simultaneous two-level cooperation, i.e., information- and energy-level cooperation is conducted for uplink data transmissions (from the users to a destination). Specifically, network coding is employed at the relays to facilitate the information-level cooperation; meanwhile, ET is adopted to share the harvested energy among the users for the energy-level cooperation. For generality purposes, the Nakagami- fading channels that are independent but not necessarily identically distributed (i.n.i.d.) are considered. The problem of energy efficiency maximization under constraints of the energy causality and a predefined outage probability threshold is formulated and shown to be non-convex. By exploiting fractional and geometric programming, a convex form-based iterative algorithm is developed to solve the problem efficiently. Close-to-optimal power allocation and energy cooperation policies across consecutive transmissions are found. Moreover, the effects of relay locations, wireless energy transmission efficiency, battery capacity as well as the existence of direct links are investigated. The performance comparison with the current state of solutions demonstrates that the proposed policies can manage the harvested energy more efficiently.
Autors: Nan Qi;Ming Xiao;Theodoros A. Tsiftsis;Lin Zhang;Mikael Skoglund;Huisheng Zhang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6335 - 6349
Publisher: IEEE
 
» Efficient Discrete Rate Assignment and Power Optimization in Optical Communication Systems Following the Gaussian Noise Model
Abstract:
Computationally efficient heuristics for solving the discrete-rate capacity optimization problem for optical fiber communication systems are investigated. In the Gaussian noise nonlinearity model regime, this class of problem is an NP-hard mixed integer convex problem. The proposed heuristic minimizes the number of calls required to solve the computationally intensive problem of determining the feasibility of proposed discrete rate allocations. In a live system, optimization using this algorithm minimizes the number of potential discrete rate allocations tested for feasibility while additional discrete system capacity is extracted. In exemplary point-to-point links at 50 Gbaud with 50 Gb/s rate steps, the mean lost capacity per modem is reduced from 24.5 Gb/s with truncation to 7.95 Gb/s with discrete-rate optimization. With 25 Gb/s rate steps, the mean lost capacity is reduced from 12.3 Gb/s to 2.07 Gb/s. An unbiased metric is proposed to extend the capacity optimization objective from point-to-point links to mesh networks. A gain of 13% in distance-times-capacity metric is obtained from discrete-rate optimization with 50 Gb/s rate steps, and a 7.5% gain is obtained with 25 Gb/s rate steps.
Autors: Ian Roberts;Joseph M. Kahn;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4425 - 4437
Publisher: IEEE
 
» Efficient Memory Partitioning for Parallel Data Access in FPGA via Data Reuse
Abstract:
Parallelizing the memory accesses in a nested loop is a critical challenge to facilitate loop pipelining. An effective approach for high-level synthesis on field-programmable gate array is to map these accesses to multiple on-chip memory banks using a memory partitioning technique. In this paper, we propose an efficient memory partitioning algorithm with low overhead and low time complexity for parallel data access via data reuse. We find that for most applications in image and video processing, a large amount of data can be reused among different iterations of a loop nest. Motivated by this observation, we propose to cache reusable data using on-chip registers, organized as register chains. The nonreusable data are then separated into several memory banks by a memory partitioning algorithm. We revise the existing padding method to cover cases occurring frequently in our method wherein certain components of partition vector are zeros. Experimental results have demonstrated that compared with the state-of-the-art algorithms, the proposed method is efficient in terms of execution time, resource overhead, and power consumption across a wide range of access patterns extracted from applications in image and video processing. As for the testing patterns, the execution time is typically less than one millisecond. And the number of required memory banks is reduced by 59.7% on average, which leads to an average reduction of 78.2% in look-up tables, 65.5% in flip-flops, 37.1% in DSP48Es, and therefore 74.8% reduction in dynamic power consumption. Moreover, the storage overhead incurred by the proposed method is zero for most widely used access patterns in image filtering.
Autors: Jincheng Su;Fan Yang;Xuan Zeng;Dian Zhou;Jie Chen;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1674 - 1687
Publisher: IEEE
 
» Efficient OCT Volume Reconstruction From Slitlamp Microscopes
Abstract:
Since its introduction 25 years ago, Optical Coherence Tomography (OCT) has contributed tremendously to diagnostic and monitoring capabilities of pathologies in the field of ophthalmology. Despite rapid progress in hardware and software technology however, the price of OCT devices has remained high, limiting their use in private practice, and in screening examinations. In this paper, we present a slitlamp-integrated OCT device, built with off-the-shelf components, which can generate high-quality volumetric images of the posterior eye segment. To do so, we present a novel strategy for 3D image reconstruction in this challenging domain that allows us for state-of-the-art OCT volumes to be generated at fast speeds. The result is an OCT device that can match current systems in clinical practice, at a significantly lower cost.
Autors: Stefanos Apostolopoulos;Raphael Sznitman;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2403 - 2410
Publisher: IEEE
 
» Efficient Ordinary Differential Equation-Based Discontinuous Galerkin Method for Viscoelastic Wave Modeling
Abstract:
We present an efficient nonconformal-mesh discontinuous Galerkin (DG) method for elastic wave propagation in viscous media. To include the attenuation and dispersion due to the quality factor in time domain, several sets of auxiliary ordinary differential equations (AODEs) are added. Unlike the conventional auxiliary partial differential equation-based algorithm, this new method is highly parallel with its lossless counterpart, thus requiring much less time and storage consumption. Another superior property of the AODE-based DG method is that a novel exact Riemann solver can be derived, which allows heterogeneous viscoelastic coupling, in addition to accurate coupling with purely elastic media and fluid. Furthermore, thanks to the nonconformal-mesh technique, adaptive hp-refinement and flexible memory allocation for the auxiliary variables are achieved. Numerical results demonstrate the efficiency and accuracy of our method.
Autors: Qiwei Zhan;Mingwei Zhuang;Qingtao Sun;Qiang Ren;Yi Ren;Yiqian Mao;Qing Huo Liu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5577 - 5584
Publisher: IEEE
 
» Efficient Privacy-Preserving Dual Authentication and Key Agreement Scheme for Secure V2V Communications in an IoV Paradigm
Abstract:
The Internet of Vehicles (IoV) aims to provide a new convenient, comfortable, and safe driving way, and in turn enables intelligent transportation through wireless communications among road-side units, on-board units (OBUs), phones, and other devices inside a vehicle. However, significantly increasing reliance on wireless communication, control, and computing technology makes IoV more vulnerable to potential attacks, such as remote intrusion, control, and trajectory tracking. Therefore, efficient authentication solutions preventing unauthorized visitors need to be addressed to cope with these issues. Hence, in this paper we focus on the security and privacy-preserving by developing a dual authentication scheme for IoV according to its different scenarios. First, the OBU self-generates an anonymous identity and temporary encryption key to open an authentication session. Second, the legitimacy of the vehicle’s real and anonymous identity can be verified by trust authority (TA). After that, the vehicle’s reputation is evaluated according to its history interactive behavior and the session key for V2V can be finally established. There are three major advantages, including privacy-preserving and security enhancement without a burden of key management in the condition of acceptable time delay range, introducing trust evaluation into authentication protocol, as well as considering the vehicle behavior attributes in the new reputation evaluation method. In addition, we also prove the correctness of this scheme using the Burrows–Abadi–Needham (BAN) logic, and the performance comparison against the existing schemes is given as well.
Autors: Yanbing Liu;Yuhang Wang;Guanghui Chang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2740 - 2749
Publisher: IEEE
 
» Efficient Retrieval of Bounded-Cost Informative Routes
Abstract:
The widespread location-aware applications produce a vast amount of spatio-textual data that contains both spatial and textual attributes. To make use of this enriched information for users to describe their preferences for travel routes, we propose a Bounded-Cost Informative Route (BCIR) query to retrieve the routes that are the most textually relevant to the user-specified query keywords subject to a travel cost constraint. BCIR query is particularly helpful for tourists and city explorers to plan their travel routes. We will show that BCIR query is an NP-hard problem. To answer BCIR query efficiently, we propose an exact solution with effective pruning techniques and two approximate solutions with performance guarantees. Extensive experiments over real data sets demonstrate that the proposed solutions achieve the expected performance.
Autors: Wengen Li;Jiannong Cao;Jihong Guan;Man Lung Yiu;Shuigeng Zhou;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2182 - 2196
Publisher: IEEE
 
» Electric Vehicle Route Selection and Charging Navigation Strategy Based on Crowd Sensing
Abstract:
This paper has proposed an electric vehicle (EV) route selection and charging navigation optimization model, aiming to reduce EV users’ travel costs and improve the load level of the distribution system concerned. Moreover, with the aid of crowd sensing, a road velocity matrix acquisition and restoration algorithm is proposed. In addition, the waiting time at charging stations is addressed based on the queue theory. The formulated objective of the presented model is to minimize the EV users’ travel time, charging cost or the overall cost based on the time of use price mechanism, subject to a variety of technical constraints such as path selections, travel time, battery capacities, and charging or discharging constraints, etc. Case studies are carried out within a real-scale zone in a city where there are four charging stations and the IEEE 33-bus distribution system. The effects of real-time traffic information acquisition and different decision targets on EV users’ travel route and effects of charging or discharging of EVs on the load level of the distribution system are also analyzed. The simulation results have demonstrated the feasibility and effectiveness of the proposed approach.
Autors: Hongming Yang;Youjun Deng;Jing Qiu;Ming Li;Mingyong Lai;Zhao Yang Dong;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2214 - 2226
Publisher: IEEE
 
» Electric-Field-Controlled Interface Exchange Coupling in Cobalt–Chromia Thin Films
Abstract:
First-principle calculations are used to determine the interface exchange coupling in cobalt–chromia thin films as a function of the electric field. Both bilayer Co/Cr2O3 and trilayer Co/Pt/Cr2O3 are investigated. The sign and magnitude of the interface exchange depend on the thickness of the cobalt layer, and oscillatory sign changes of the interface exchange are found in the trilayer system. The electric field dependence of the exchange may be exploited in voltage-controlled spin-electronics applications.
Autors: Renu Choudhary;Ralph Skomski;Arti Kashyap;
Appeared in: IEEE Transactions on Magnetics
Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 4
Publisher: IEEE
 
» Electrical and Acoustic Parameters of Wire-Guided Discharges in Water: Experimental Determination and Phenomenological Scaling
Abstract:
This paper is focused on investigation of the electrical, hydrodynamic, and acoustic parameters of underwater plasma discharges, stabilized with thin copper wires. The experimental current and acoustic waveforms have been obtained using different combinations of the circuit capacitance, charging voltage, and wire length. The resistances of plasma discharges have been calculated for all combinations of electrical and topological parameters, based on the constant resistance approach. Phenomenological scaling relationships that link the plasma resistance and the total energy delivered to the plasma, the period of discharge cavity oscillation and the peak magnitude of the acoustic impulse have been obtained. These relationships can be used in optimization of the acoustic output from the wire-guided discharges for different practical applications.
Autors: Ying Sun;Igor V. Timoshkin;Scott J. MacGregor;Mark P. Wilson;Martin J. Given;Tao Wang;Nelly Bonifaci;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2648 - 2655
Publisher: IEEE
 
» Electricity Auction Simulation Platform for Learning Competitive Energy Markets
Abstract:
Considering that each energy market presents its own singularities according to its maturity, liquidity, generation matrix characteristics, and generation capacities, energy auctions are widely used to guarantee fair tariffs. These auctions also promote competition and the search for more efficient generation sources. The platform developed is designed to be an auxiliary tool for stimulating students in learning the processes of electricity market mechanisms. It enables students to develop a better sensitivity regarding energy auctions as they can train and see the results of those auctions. The energy auction platform developed in our work is easy to use and to update, and it can support the learning of electricity auctions. This platform also can be used in any computer and in almost all computer networks. It can be adapted to other kind of auctions and designed to address different electricity markets.
Autors: Edgar B. Xavier;David A.V. Goncalves;Bruno H. Dias;Bruno S.M.C. Borba;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 32 - 36
Publisher: IEEE
 
» Electromagnetic Inverse Problems [Guest Editorial]
Abstract:
Autors: Maokun Li;Aria Abubakar;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 9 - 115
Publisher: IEEE
 
» Electromagnetic Tomography for Detection, Differentiation, and Monitoring of Brain Stroke: A Virtual Data and Human Head Phantom Study.
Abstract:
Brain stroke is one of the leading causes of death and disability worldwide [1]. It can be classified as ischemic stroke (i-stroke), e.g., blood flow is restricted by a blood clot, or hemorrhagic stroke (h-stroke), e.g., a bleeding in the brain. Approximately 80% of total stroke cases are ischemic. The most common treatment for i-stroke to date is the use of thrombolytics: drugs that dissolve the blood clots. The clinical decision to apply a thrombolytic should be made within 3-4.5 h from the onset of the stroke symptoms (e.g., [2]), and it relies on imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI). Further evaluation of stroke evolution is done mainly by imaging to assess the extent of the ischemic injury and to correlate with the functional behavior of the patient. However, to date there is no accurate way to provide reliable information about the key components of i-stroke physiology that include the position and size of the acute stroke (arterial occlusion), the core infarct region that contains irreversibly injured tissues, and the ischemic penumbra, i.e., the tissue that could potentially be restored by rapid revascularization [1], [3].
Autors: Markus Hopfer;Ramon Planas;Abouzar Hamidipour;Tommy Henriksson;Serguei Semenov;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 86 - 97
Publisher: IEEE
 
» Electromagnetic Wave Propagation in the Turbulent Atmosphere With an Anisotropic Exponent of the Spectrum
Abstract:
In this communication, we propose a new model for describing the anisotropy of turbulence relative to the vertical and horizontal directions, through the anisotropy of the structure function exponent. Using the obtained anisotropy spectrum, we calculate various parameters such as log-amplitude variance for various atmospheric communication channels with comparison to the classical Kolmogorov model and newer models developed in previous works.
Autors: Elad Dakar;Ephim Golbraikh;Natan Kopeika;Arkadi Zilberman;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5654 - 5657
Publisher: IEEE
 
» Electromagnetically Induced Transparency in an All-Dielectric Metamaterial-Waveguide With Large Group Index
Abstract:
We investigate numerically an analog of electromagnetically induced transparency (EIT) in an all-dielectric metamaterial-waveguide (ADMW) that consists of a two-dimensional silicon rod array on quartz slab waveguide. The EIT-like response is achieved by the destructive interference between a broad magnetic resonance and a narrow guide mode resonance. By tailoring the guided mode through the thickness of the slab waveguide or the lattice period of the metamaterial, an EIT-like transmission window is achieved with both high Q-factor (>104) and high transmission (>94%). And the group refractive index at the EIT-like resonance of the ADMW can be up to several thousands. These results demonstrate that the proposed ADMW has potential applications in low-loss slow-light based devices, bio-chemical sensing, and optical modulations.
Autors: Chuanshuai Sui;Bingxin Han;Tingting Lang;Xiangjun Li;Xufeng Jing;Zhi Hong;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Electromigration-Aware Local-Via Allocation in Power/Ground TSVs of 3-D ICs
Abstract:
With increasing temperature and current density, electromigration (EM) becomes a major interconnect reliability concern for 3-D integrated-circuits (3-D ICs). In 3-D power delivery networks, local vias are used inside power/ground (P/G) through-silicon-vias (TSVs) for vertical power delivery, which are susceptible to EM effects. In order to improve the EM reliability of P/G TSVs, it is desirable to insert multiple local vias in each P/G TSV whereby the current density of each local via can be reduced. However, excessive local vias may consume too much routing area, which leads to exacerbated routing congestion and increased delay overhead. In this paper, we propose a design technique to handle this tradeoff between EM reliability of P/G TSVs and timing performance of 3-D ICs. By utilizing an integer-linear-programming formulation, the optimal local-via number in each P/G TSV can be determined to minimize the local via-induced routing congestion while satisfying the given requirement of EM reliability.
Autors: Shengcheng Wang;Mehdi B. Tahoori;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2881 - 2892
Publisher: IEEE
 
» Electrospun Iron-Based Fibers for Use in MEMS Sensors
Abstract:
This letter reports on the characterization of iron containing nanofibers using a polyvinyl alcohol (PVA)-based solution in a batch electrospinning processing method. Variation of iron content within the pre-fiber solution, and characterization of fiber size and porosity are important for the use of these nanomaterials in sensing. Simulated non-porous fibers are compared with nanofibers obtained utilizing this method. Pre-calcination (thermal) fibers had diameters of 243 nm on average with a standard deviation of ±43 nm and a standard error of ±4.53 nm. Fabrication of mesoporous iron-based nanofibers was achieved after the calcination of the iron/PVA fibers. With the calcination process, we produced fibers with 32-nm diameters, and a standard deviation of ±12 nm and a standard error of ±1.41 nm. The error between model and experimental results is 37.5% for producing Fe3O4 fibers. This error percentage and oversized dimensions suggest near total conversion to Fe3O4 occurring due to calcination as well as creating mesoporous fibers. [2017-0014]
Autors: Nicholas Groden;William Clower;Chester G. Wilson;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 987 - 989
Publisher: IEEE
 
» Embedded Deterministic Test Points
Abstract:
There is mounting evidence that automatic test pattern generation tools capable of producing tests with high coverage of defects occurring in the large semiconductor nanometer designs unprecedentedly inflate test sets and test application times. A design-for-test technique presented in this paper aims at reducing deterministic pattern counts and test data volume through the insertion of conflict-aware test points. This methodology identifies and resolves conflicts across internal signals allowing test generation to increase the number of faults targeted by a single pattern. This is complemented by a method to minimize silicon area needed to implement conflict-aware test points. The proposed approach takes advantage of the conflict analysis and reuses functional flip-flops as drivers of control points. Experimental results on industrial designs with on-chip test compression demonstrate that the proposed test points are effective in achieving, on average, an additional factor of – compression for stuck-at and transition patterns over the best up-to-date results provided by the embedded deterministic test (EDT)-based regular compression.
Autors: Cesar Acero;Derek Feltham;Yingdi Liu;Elham Moghaddam;Nilanjan Mukherjee;Marek Patyra;Janusz Rajski;Sudhakar M. Reddy;Jerzy Tyszer;Justyna Zawada;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2949 - 2961
Publisher: IEEE
 
» Embedding Learning on Spectral–Spatial Graph for Semisupervised Hyperspectral Image Classification
Abstract:
Scarcity of labeled samples is the main obstacle for hyperspectral image classification tasks when labeling data is considerably costly and time-consuming in real-world scenarios. To alleviate any underfitting problem that may occur due to lack of training data, semisupervised classification frameworks explore the intrinsic information of unlabeled samples and bridge labeled and unlabeled data. In this letter, we propose a novel framework that learns underlying manifold representation and semisupervised classifier simultaneously. It avoids explicit eigenvector decomposition and directly samples via iterating random walk on the similarity graph, which makes it feasible to implement on huge graphs. To verify the efficacy of embedding the learning process, we compare the proposed method with other dimensionality reduction and manifold-learning-based approaches. Experimental results show that compared to the methods using traditional semisupervised strategies, the graph embedding method gives a better result.
Autors: Jiayan Cao;Bin Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1805 - 1809
Publisher: IEEE
 
» Empirical Study of DSRC Performance Based on Safety Pilot Model Deployment Data
Abstract:
Dedicated short range communication (DSRC) was designed to provide reliable wireless communication for intelligent transportation system applications. Sharing information among cars and between cars and the infrastructure, pedestrians, or “the cloud” has great potential to improve safety, mobility, and fuel economy. DSRC is being considered by the U.S. Department of Transportation to be required for ground vehicles. In the past, their performance has been assessed thoroughly in the laboratories and limited field testing, but not on a large fleet. In this paper, we present the analysis of DSRC performance using data from the world’s largest connected vehicle test program—Safety Pilot Model Deployment lead by the University of Michigan. We first investigate their maximum and effective range, and then study the effect of environmental factors, such as trees/foliage, weather, buildings, vehicle travel direction, and road elevation. The results can be used to guide future DSRC equipment placement and installation, and can be used to develop DSRC communication models for numerical simulations.
Autors: Xianan Huang;Ding Zhao;Huei Peng;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2619 - 2628
Publisher: IEEE
 
» Enabling Anonymous Authorization and Rewarding in the Smart Grid
Abstract:
The smart grid leverages infrastructural support to achieve fine-grained power consumption monitoring in an attempt to offer higher efficiency, reliability, and security. Such functionality, however, requires the collection of fine-grained usage data which may raise serious concerns with respect to consumer privacy. Thus far, existing work has solely focused on the problem of privately aggregating energy measurements. However, these solutions do not allow the provider to acquire detailed energy measurements which are essential for maintaining the network, debugging configuration problems, etc. In this work, we address this problem and we propose an authentication scheme that allows a smart meter to anonymously interact with the utility provider when submitting detailed consumption data. We then move one step further, enabling the incorporation of anonymous rewarding mechanisms in the smart grid in exchange for detailed measurements that users report. We argue that such rewarding mechanisms provide solid incentives for users to accept the release of their detailed energy consumption; we show that our proposal does notleak any information about the identity of users-even when redeeming the rewards. Finally, we implement a prototype based on our proposal and we evaluate its performance in realistic deployment settings.
Autors: Tassos Dimitriou;Ghassan O. Karame;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 565 - 572
Publisher: IEEE
 
» End-to-End Backlog and Delay Bound Analysis for Multi-Hop Vehicular Ad Hoc Networks
Abstract:
Vehicular ad hoc network (VANET) is able to facilitate data exchange among vehicles and provides diverse data services. Intuitively, end-to-end backlog and delay bounds are considered significant metrics to evaluate the quality of service in VANETs. In order to analyze how the multi-hop transmission impacts the delay performance, we model the multi-hop service process into a virtualized single service in a min-plus convolution form. To obtain multi-hop end-to-end backlog and delay bound, we consider the stochastic network traffic characteristics and the highly dynamic channel environment under the static priority, first in first out, and earliest deadline first scheduling policies by applying the martingale theory. The IEEE 802.11p enhanced distributed channel access mechanism is also adopted to analyze the access performance in the MAC sub-layer. With three kinds of real wireless data traces, i.e., VoIP, gaming, and UDP, we verify our algorithm by considering the double Nakagami- fading channel model among vehicles. From the simulation results, we can see that the supermartingale end-to-end backlog and delay bound are remarkably tight to the real simulation results when compared with the existing standard bounds. The effect of the number of vehicles on the highway on the end-to-end backlog and delay performance is also investigated.
Autors: Yun Hu;Hongyan Li;Zheng Chang;Zhu Han;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6808 - 6821
Publisher: IEEE
 
» Energy Consume Analysis for Ring-Topology TWDM-PON Front-Haul Enabled Cloud RAN
Abstract:
Cloud radio access network (C-RAN) is a new architecture to meet the ever increasing internet data traffic. In particular, the operating expense (OPEX), mainly the energy consumption, of C-RAN is an issue of common concern. Several former works in this area lacked the essential consideration for the optical front-haul part, as a result that it cannot provide overall energy consumption study for the whole system. In this paper, we analyze the energy consume problem in a new C-RAN architecture, i.e., the ring-topology time-wavelength division multiplexing (TWDM) passive optical network (PON) front-haul enabled C-RAN, considering the requirements for large transmission capacity, high energy efficiency, and the appropriate utilization in the large-scale and densely populated cities. After bringing in this optical front-haul and considering the quality of service, a network traffic modeling is provided to analyze the energy problem based on queueing theory. We also conduct the network optimization to ensure that the system works in the most energy-efficient state. Besides, the energy comparisons among the ring-topology TWDM-PON front-haul enabled C-RAN, the time division multiplexing (TDM) PON enabled C-RAN and the ring-topology TWDM-PON-LTE architecture have also been made. According to the numerical results, the new C-RAN, after energy optimization, can save up to 58.1% energy compared with the TWDM-PON-LTE architecture, and also has a slight advantage over the TDM-PON enabled C-RAN (saving more than 2% energy), demonstrating its broad application prospects and large potential in the future.
Autors: Zhongwei Tan;Chuanchuan Yang;Ziyu Wang;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4526 - 4534
Publisher: IEEE
 
» Energy Storage in Microgrids: Compensating for Generation and Demand Fluctuations While Providing Ancillary Services
Abstract:
Driven by global environmental emission issues, energy access in remote communities, and tighter requirements for system resilience and reliability, electricity production is shifting from a centralized paradigm to a decentralized one. In this context, renewable energy sources (RESs) have proliferated over the past decade, exhibiting a steadily increasing trend. Thus, today, a large number of wind turbines and photovoltaic (PV) panels are connected to medium- (1-69 kV) and low-voltage (=1 kV) grids, with traditional integrated bulk power systems becoming decentralized in the presence of active distribution networks, where the flow of power is bidirectional between generators and "prosumers." In particular, with decreasing RES s costs, these technologies are becoming attractive solutions to bring energy to remote communities and/or replace expensive fossil-fuel-based generators. However, RES s such as wind and solar are intermittent sources of energy, difficult to predict, and prone to large output fluctuations-therefore, significantly affecting system voltage and frequency.
Autors: Mostafa Farrokhabadi;Bharatkumar V. Solanki;Claudio A. Canizares;Kankar Bhattacharya;Sebastian Koenig;Patrick S. Sauter;Thomas Leibfried;Sören Hohmann;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 81 - 91
Publisher: IEEE
 
» Energy Storage Systems: Applications, Regulations, & Renewable Resources [From the Editor]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Michael Henderson;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 4 - 8
Publisher: IEEE
 
» Energy Storage: From Holywood Stunt Double to Action Hero [In My View]
Abstract:
Discusses the growing market for advanced battery-based energy storage systems and reports on applications for their use.
Autors: J. Chris Shelton;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 112 - 108
Publisher: IEEE
 
» Energy trading for fun and profit buy your neighbor's rooftop solar power or sell your own-it'll all be on a blockchain
Abstract:
Would you pay slightly more for your electricity if you knew it was sourced from photovoltaic panels on your neighbor's roof? Or, if you are that neighbor, would you use your solar power to charge a battery and dump that energy back onto the grid at peak hours, when the price was highest? The answers to these questions-which depend on how people would behave in an open energy market-are unknown, because that market does not exist. Net metering and feed-in tariff programs, the two dominant schemes for reimbursing residential energy production, pay out at a fixed rate, effectively decoupling producers from the price signals that might otherwise direct their behavior. But that may be changing. And we may have the blockchain to thank. Multiple projects are now under way to use technology that was originally intended to account for transactions in digital currency to track electricity production and put it up for sale.
Autors: Morgen E. Peck;David Wagman;
Appeared in: IEEE Spectrum
Publication date: Oct 2017, volume: 54, issue:10, pages: 56 - 61
Publisher: IEEE
 
» Energy-Efficient Near-Threshold Parallel Computing: The PULPv2 Cluster
Abstract:
This article presents an ultra-low-power parallel computing platform and its system-on-chip (SoC) embodiment, targeting a wide range of emerging near-sensor processing tasks for Internet of Things (IoT) applications. The proposed SoC achieves 193 million operations per second (MOPS) per mW at 162 MOPS (32 bits), improving the first-generation Parallel Ultra-Low-Power (PULP) architecture by 6.4 and 3.2 times in performance and energy efficiency, respectively.
Autors: Davide Rossi;Antonio Pullini;Igor Loi;Michael Gautschi;Frank Kağan Gürkaynak;Adam Teman;Jeremy Constantin;Andreas Burg;Ivan Miro-Panades;Edith Beignè;Fabien Clermidy;Philippe Flatresse;Luca Benini;
Appeared in: IEEE Micro
Publication date: Oct 2017, volume: 37, issue:5, pages: 20 - 31
Publisher: IEEE
 
» Energy-Efficient Reconfigurable SRAM: Reducing Read Power Through Data Statistics
Abstract:
This paper introduces a framework for designing data-dependent SRAMs taking advantage of statistical dependencies present in the binary values processed and stored in the intermediary stages of various algorithms. To demonstrate the framework, a reconfigurable conditional precharge (CP) SRAM is designed in a 28-nm fully-depleted silicon-on-insulator CMOS process. To reduce read power consumption, the SRAM reconfigures its prediction scheme for each column as the data statistics evolve. A 10T bit cell, a prediction-based CP circuit, and a compact column circuit implemented in a 16-kbit SRAM test chip demonstrate the power savings of 63%, 50%, and up to 69% for the applications sparse fast Fourier transform, object detection, and motion estimation, respectively, as compared with similar memories with naive prediction. Analysis tools for optimal prediction selection for the presented class of low-power memories are also provided.
Autors: Chuhong Duan;Andreas J. Gotterba;Mahmut E. Sinangil;Anantha P. Chandrakasan;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Oct 2017, volume: 52, issue:10, pages: 2703 - 2711
Publisher: IEEE
 
» Energy-Efficient Resource Allocation in Buffer-Aided Wireless Relay Networks
Abstract:
In this paper, we study energy-efficient resource allocation in the downlink of buffer-aided wireless relay networks. We aim at maximizing the system average energy efficiency while maintaining the queue stability at both the base station (BS) and relays. We formulate the resource allocation design as a novel stochastic network optimization problem and based on the well-known Lyapunov drift-plus-penalty policy and the system constraints, we transform it to an instantaneous non-convex optimization problem to be solved in each time slot. We analyze the instantaneous utility function and propose a novel algorithm to find its optimum point. Based on that, we present an effective distributed strategy to get the globally optimal solution for channel and power allocation. Furthermore, we show that the proposed algorithm can be used as a building block for energy-efficient resource allocation in conventional relay networks, where the relays do not have buffering capability, but the BS queues need to be stabilized. Using extensive simulations, we show that the proposed algorithm is able to provide higher energy efficiency compared with the existing algorithms, while keeping the system queues stable.
Autors: Javad Hajipour;Javad Musevi Niya;Derrick Wing Kwan Ng;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6648 - 6659
Publisher: IEEE
 
» Enhanced Autofocusing in Optical Scanning Holography Based on Hologram Decomposition
Abstract:
Optical scanning holography is a compact and powerful method for capturing hologram of a wide three-dimensional (3-D) view scene. After a hologram has been taken, it is often necessary to determine the locations of the focal plane on which the objects are residing, so that the 3-D scene can be numerically reconstructed for further analysis or processing. Recent research has shown that automatic detection of the depth (focal plane) of objects represented in a hologram can be conducted with entropy minimization method. Despite the success, the method could fail if the entropy information of objects in a hologram are interfering with each other. In this paper, we propose a method based on the hologram decomposition to overcome this problem. Briefly, the hologram is decomposed into subholograms and the focal plane distance is determined separately for each subobject. Simulation results reveal that our proposed method has good accuracy and reliability.
Autors: Shuming Jiao;Peter Wai Ming Tsang;Ting-Chung Poon;Jung-Ping Liu;Wenbin Zou;Xia Li;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2455 - 2463
Publisher: IEEE
 
» Enhanced Negative Bias Stress Degradation in Multigate Polycrystalline Silicon Thin-Film Transistors
Abstract:
In this brief, a negative bias stress (NBS) induced degradation in n-type multigate polycrystalline silicon (poly-Si) thin-film transistor (TFT) is investigated. It is observed that after NBS the transfer characteristic curves shift to the negative gate bias direction and multigate TFTs degrade more than the single-gate TFTs with the same effective channel length. The observed degradation phenomenon is explained with short channel effect that is resulted from the diffusion and distribution of hole carriers in the channel, which are generated in the source/drain depletion region and swept into the channel when the junctions are reversely biased during NBS. Pronounced NBS degradation caused by increased hole carriers in the channel is also verified in NBS experiment with light illumination.
Autors: Dongli Zhang;Mingxiang Wang;Huaisheng Wang;Yilin Yang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4363 - 4367
Publisher: IEEE
 
» Enhanced Output Power of Light-Emitting Diodes With Embedded Air-Gap Photonic Crystals by Nanosphere Lithography
Abstract:
Large-scale two-dimensional air-gap photonic crystals (PhCs) were embedded in an n-type GaN layer to enhance the light emission of GaN-based light-emitting diodes (LEDs). The embedded-PhCs were obtained through overgrowth on n-GaN templates, which had air holes array previously fabricated by using nanosphere lithography technology. The effects of the distance D from active region to PhCs on the light extraction efficiency (LEE) of LEDs are investigated by experiments and finite difference-time domain simulation. The PhC LEDs with D = 2370 nm showed an improved light output power by 80.8% on average at forward current of 350 mA without degradation of electrical performance compared to conventional LEDs. It is mainly attributed to the improved LEE by enhancing the interaction of the guided modes and the embedded air-gap PhCs.
Autors: Chengxiao Du;Wanrong Zhang;Tongbo Wei;Xiaoli Ji;Jinmin Li;Chong Geng;Qingfeng Yan;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7
Publisher: IEEE
 
» Enhanced UV Photodetector Response of ZnO/Si With AlN Buffer Layer
Abstract:
Studies have been carried out on the enhancement of responsivity and detectivity of the ZnO thin-films-based ultraviolet photodetectors by introducing an AlN buffer layer on silicon substrate. The ZnO film grown with AlN buffer layer established an epitaxial relation with the substrate and was found to show improved crystallinity with excellent optical properties. A strong and narrow photoluminescence emission was observed on the ZnO film grown with buffer layer, while a defect related broad emission was dominated on the film without buffer layer. The photodetectors showed a higher responsivity () of A/W with a specific detectivity () of at an applied bias of 3 V due to their excellent crystal quality.
Autors: Basanta Roul;Rohit Pant;Saraswathi Chirakkara;Greeshma Chandan;K. K. Nanda;S. B. Krupanidhi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4161 - 4166
Publisher: IEEE
 
» Enhancement-Mode AlGaN/GaN Nanowire Channel High Electron Mobility Transistor With Fluorine Plasma Treatment by ICP
Abstract:
This letter reports on a novel enhancement-mode (E-mode) AlGaN/GaN high electron mobility transistor (HEMT) that combines nanowire channel and fluorine plasma treatment using inductively coupled plasma (ICP). Compared with the conventional HEMTs, the threshold voltage of E-mode HEMT shifts from −2.8 to +0.7 V, and the Schottky reverse leakage current is reduced by one order of magnitude. The device exhibits a superior performance with a drain current of 460 mA/mm at - V. High ratio of approximately and high breakdown voltage of 138 V with are obtained, i.e., the breakdown voltage of E-mode HEMT is improved by 25% than that in conventional HEMTs. The drain induced barrier lowering (DIBL) is as low as 4 mV/V, and the subthreshold swing (SS) of 70 mV/decade is achieved. The device exhibits an intrinsic current gain cutoff frequency of 22 GHz and a maximum oscillation frequency of 60 GHz.
Autors: Yunlong He;Minhan Mi;Chong Wang;Xuefeng Zheng;Meng Zhang;Hengshuang Zhang;Ji Wu;Ling Yang;Peng Zhang;Xiaohua Ma;Yue Hao;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1421 - 1424
Publisher: IEEE
 
» Enhancing QoE-Aware Wireless Edge Caching With Software-Defined Wireless Networks
Abstract:
Software-defined networking and in-network caching are promising technologies in the next generation wireless networks. In this paper, we propose enhancing the quality of experience (QoE)-aware wireless edge caching with bandwidth provisioning in software-defined wireless networks (SDWNs). Specifically, we design a novel mechanism to jointly provide proactive caching, bandwidth provisioning, and adaptive video streaming. The caches are requested to retrieve data in advance dynamically according to the behaviors of users, the current traffic, and the resource status. Then, we formulate a novel optimization problem regarding the QoE-aware bandwidth provisioning in SDWNs with jointly considering in-network caching strategy. The caching problem is decoupled from the bandwidth provisioning problem by deploying the dual-decomposition method. Additionally, we relax the binary variables to real numbers so that those two problems are formulated as a linear problem and a convex problem, respectively, which can be solved efficiently. Simulation results are presented to show that the latency is decreased and the utilization of caches is improved in the proposed scheme.
Autors: Chengchao Liang;Ying He;F. Richard Yu;Nan Zhao;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6912 - 6925
Publisher: IEEE
 
» Enhancing the Light-Extraction Efficiency of an AlGaN Nanowire Ultraviolet Light-Emitting Diode by Using Nitride/Air Distributed Bragg Reflector Nanogratings
Abstract:
The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction efficiency (LEE) due to the intrinsic material properties of AlGaN. Here, to enhance the LEE of the device, we demonstrate an AlGaN nanowire light-emitting diode (NW-LED) integrated with nitride/air distributed Bragg reflector (DBR) nanogratings. Compared to a control device (only mesa), the AlGaN NW-LED with the nitride/air DBR nanogratings exhibits enhancement in the light output power and external quantum efficiency (EQE) by a factor of ∼1.67. The higher light output power and EQE are attributed mainly to the multiple reflectances laterally for the transverse magnetic (TM)-polarized light and scattering introduced by the nanogratings. To further understand the LEE enhancement, the electrical field distribution, extraction ratio, and polar pattern of the AlGaN NW-LED with and without the nitride/air DBR nanogratings were analyzed using the finite-difference time-domain method. It was observed that the TM-field emission was confined and scattered upward, whereas the polar pattern was intensified for the AlGaN NW-LED with the nanogratings. Our approach to enhance the LEE via the nitride/air DBR nanogratings can provide a promising route for increasing the efficiency of AlGaN-based LEDs, also, to functioning as facet mirror for AlGaN-based laser diodes.
Autors: Mohd Sharizal Alias;Bilal Janjua;Chao Zhao;Davide Priante;Abdullah A. Alhamoud;Malleswararao Tangi;Lafi M. Alanazi;Abdullah A. Alatawi;Abdulrahman M. Albadri;Ahmed Y. Alyamani;Tien Khee Ng;Boon S. Ooi;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Enriching Triangle Mesh Animations with Physically Based Simulation
Abstract:
We present a system to combine arbitrary triangle mesh animations with physically based Finite Element Method (FEM) simulation, enabling control over the combination both in space and time. The input is a triangle mesh animation obtained using any method, such as keyframed animation, character rigging, 3D scanning, or geometric shape modeling. The input may be non-physical, crude or even incomplete. The user provides weights, specified using a minimal user interface, for how much physically based simulation should be allowed to modify the animation in any region of the model, and in time. Our system then computes a physically-based animation that is constrained to the input animation to the amount prescribed by these weights. This permits smoothly turning physics on and off over space and time, making it possible for the output to strictly follow the input, to evolve purely based on physically based simulation, and anything in between. Achieving such results requires a careful combination of several system components. We propose and analyze these components, including proper automatic creation of simulation meshes (even for non-manifold and self-colliding undeformed triangle meshes), converting triangle mesh animations into animations of the simulation mesh, and resolving collisions and self-collisions while following the input.
Autors: Yijing Li;Hongyi Xu;Jernej Barbič;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Oct 2017, volume: 23, issue:10, pages: 2301 - 2313
Publisher: IEEE
 
» Enumerating Maximal Bicliques from a Large Graph Using MapReduce
Abstract:
We consider the enumeration of maximal bipartite cliques (bicliques) from a large graph, a task central to many data mining problems arising in social network analysis and bioinformatics. We present novel parallel algorithms for the MapReduce framework, and an experimental evaluation using Hadoop MapReduce. Our algorithm is based on clustering the input graph into smaller subgraphs, followed by processing different subgraphs in parallel. Our algorithm uses two ideas that enable it to scale to large graphs: (1) the redundancy in work between different subgraph explorations is minimized through a careful pruning of the search space, and (2) the load on different reducers is balanced through a task assignment that is based on an appropriate total order among the vertices. We show theoretically that our algorithm is work optimal, i.e., it performs the same total work as its sequential counterpart. We present a detailed evaluation which shows that the algorithm scales to large graphs with millions of edges and tens of millions of maximal bicliques. To our knowledge, this is the first work on maximal biclique enumeration for graphs of this scale.
Autors: Arko Provo Mukherjee;Srikanta Tirthapura;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 771 - 784
Publisher: IEEE
 
» Environmental Sensors-Based Occupancy Estimation in Buildings via IHMM-MLR
Abstract:
Occupancy estimation in buildings can benefit various applications such as heating, ventilation, and air-conditioning control, space monitoring, and emergency evacuation. Due to the consideration of temporal dependency in occupancy data, hidden Markov model (HMM) has been shown to be effective in occupancy estimation. However, the conventional HMM that assumes invariant temporal dependency of occupancy dynamics for different time instances is unrealistic. Moreover, the performance of the conventional HMM that utilizes mixture of Gaussian for emission probability in terms of continuous observations can be easily affected by the noise in sensory data. To address these problems, in this paper, we propose a new architecture, i.e., inhomogeneous hidden Markov model with multinomial logistic regression (IHMM-MLR), for building occupancy estimation using nonintrusive environmental sensors. Instead of using the time-invariant transition probability matrix, we apply a time-dependent (inhomogeneous) transition probability matrix which can capture the temporal dependency for different time instances. Meanwhile, we employ an efficient probabilistic model, i.e., MLR, for emission probability. Online and offline occupancy estimation schemes are presented for real-time and accurate long-term applications respectively. Real experiments have indicated the effectiveness of our proposed approach.
Autors: Zhenghua Chen;Qingchang Zhu;Mustafa Khalid Masood;Yeng Chai Soh;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2184 - 2193
Publisher: IEEE
 
» Equivalence of Finite Dimensional Input–Output Models of Solute Transport and Diffusion in Geosciences
Abstract:
We show that for a large class of finite dimensional input–output positive systems that represent networks of transport and diffusion of solute in geological media, there exist equivalent multirate mass transfer and multiple interacting continua representations, which are quite popular in geosciences. Moreover, we provide explicit methods to construct these equivalent representations. The proofs show that controllability property is playing a crucial role. These results contribute to our fundamental understanding on the effect of fine-scale geological structures on the transfer and dispersion of solute.
Autors: Alain Rapaport;Alejandro Rojas-Palma;Jean-Raynald de Dreuzy;Hector C. Ramírez;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5470 - 5477
Publisher: IEEE
 
» Error Characterization of Soil Moisture Satellite Products: Retrieving Error Cross-Correlation Through Extended Quadruple Collocation
Abstract:
The triple collocation (TC) technique is being increasingly used to validate soil moisture retrievals derived from different systems, like satellites, hydrological models, or in situ probes. In recent years, several extensions of this method were proposed in order to evaluate the error standard deviations of more than three systems and to soften the TC hypothesis. In this paper, a novel extended quadruple collocation (E-QC) method is proposed, in order to consider the possibility of a cross correlation between product errors, identifying automatically the couple of error cross-correlated systems. The method is applicable even to a larger number of collocated datasets, although it may be unfeasible to collect them in practice. A synthetic experiment showed promising results, concluding that the E-QC is able to individuate (if any) the pair of systems with cross-correlated errors. It correctly compensates for the latter contribution and accurately retrieves error standard deviations of each system, otherwise biased if cross correlation is not taken into account. The E-QC was applied to soil moisture retrievals provided by satellite (SMOS, ASCAT, and SMAP), model (ERA Interim), and in situ probes (ISMN). The E-QC method identified the presence of error cross-correlation between the satellite products. This was also confirmed by analyzing the five datasets all together. E-QC showed fair performances of satellite products, especially of SMAP, although not as good as in case the presence of error correlation is not correctly taken into account.
Autors: Nazzareno Pierdicca;Fabio Fascetti;Luca Pulvirenti;Raffaele Crapolicchio;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4522 - 4530
Publisher: IEEE
 
» Error-Voltage-Based Open-Switch Fault Diagnosis Strategy for Matrix Converters with Model Predictive Control Method
Abstract:
This paper proposes an error-voltage-based open-switch fault-diagnosis a strategy for a matrix converter (MC). A finite control set model predictive control method is used to operate the MC. The MC system performances under normal operation and under a single open-switch fault operation are analyzed. A fault-diagnosis strategy has also been implemented in two steps. First, the faulty phase is detected and identified based on a comparison of the reference and estimated output line-to-line voltages. Then, the faulty switch is located by considering the switching states of the faulty phase. The proposed fault-diagnosis method is able to locate the faulty switch accurately and quickly without additional voltage sensors. Simulation and experimental results are presented to demonstrate the feasibility and effectiveness of the proposed strategy.
Autors: Hanbing Dan;Tao Peng;Mei Su;Hui Deng;Qi Zhu;Ziyi Zhao;Patrick Wheeler;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4603 - 4612
Publisher: IEEE
 
» Estimating Circuit Aging Due to BTI and HCI Using Ring-Oscillator-Based Sensors
Abstract:
The performance of nanometer-scale circuits is adversely affected by aging induced by bias temperature instability (BTI) and hot carrier injection (HCI). Both BTI and HCI impact transistor electrical parameters at a level that depends on the operating environment and usage of the circuit. This paper presents a novel method, using on-chip sensors based on ring oscillators (ROSCs), to detect the delay shifts in circuits as a result of aging. Our method uses presilicon analysis of the circuit to compute calibration factors that can translate BTI- and HCI-induced delay shifts in the ROSC to those in the circuit of interest. Our simulations show that the delay estimates are within 1% of the true values from presilicon analysis. Further, for post-silicon analysis, a refinement strategy is proposed where sensor measurements can be amalgamated with infrequent online delay measurements on the monitored circuit to partially capture its true workloads. This leads to about 8% lower delay guardbanding overheads compared to the conventional methods as demonstrated using benchmark circuits.
Autors: Deepashree Sengupta;Sachin S. Sapatnekar;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1688 - 1701
Publisher: IEEE
 
» Estimating Cortical Feature Maps with Dependent Gaussian Processes
Abstract:
A striking example of brain organisation is the stereotyped arrangement of cell preferences in the visual cortex for edges of particular orientations in the visual image. These “orientation preference maps” appear to have remarkably consistent statistical properties across many species. However fine scale analysis of these properties requires the accurate reconstruction of maps from imaging data which is highly noisy. A new approach for solving this reconstruction problem is to use Bayesian Gaussian process methods, which produce more accurate results than classical techniques. However, so far this work has not considered the fact that maps for several other features of visual input coexist with the orientation preference map and that these maps have mutually dependent spatial arrangements. Here we extend the Gaussian process framework to the multiple output case, so that we can consider multiple maps simultaneously. We demonstrate that this improves reconstruction of multiple maps compared to both classical techniques and the single output approach, can encode the empirically observed relationships, and is easily extendible. This provides the first principled approach for studying the spatial relationships between feature maps in visual cortex.
Autors: Nicholas J. Hughes;Geoffrey J. Goodhill;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 1918 - 1928
Publisher: IEEE
 
» Estimating Fractional Vegetation Cover From Landsat-7 ETM+ Reflectance Data Based on a Coupled Radiative Transfer and Crop Growth Model
Abstract:
Fractional vegetation cover (FVC) is an important parameter for earth surface process simulations, climate modeling, and global change studies. Currently, several FVC products have been generated from coarse resolution (~1 km) remote sensing data, and have been widely used. However, coarse resolution FVC products are not appropriate for precise land surface monitoring at regional scales, and finer spatial resolution FVC products are needed. Time-series coarse spatial resolution FVC products at high temporal resolutions contain vegetation growth information. Incorporating such information into the finer spatial resolution FVC estimation may improve the accuracy of FVC estimation. Therefore, a method for estimating finer spatial resolution FVC from coarse resolution FVC products and finer spatial resolution satellite reflectance data is proposed in this paper. This method relies on the coupled PROSAIL radiative transfer model and a statistical crop growth model built from the coarse resolution FVC product. The performance of the proposed method is investigated using the time-series Global LAnd Surface Satellite FVC product and Landsat-7 Enhanced Thematic Mapper Plus reflectance data in a cropland area of the Heihe River Basin. The direct validation of the FVC estimated using the proposed method with the ground measured FVC data (, RMSE =0.0884), compared with the widely used dimidiate pixel model (, RMSE = 0.1575), shows that the proposed method is feasible for estimating finer spatial resolution FVC with satisfactory accuracy, and it has the potential to be applied at a large scale.
Autors: Xiaoxia Wang;Kun Jia;Shunlin Liang;Qiangzi Li;Xiangqin Wei;Yunjun Yao;Xiaotong Zhang;Yixuan Tu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5539 - 5546
Publisher: IEEE
 
» Estimation of Significant Wave Height From X-Band Marine Radar Images Based on Ensemble Empirical Mode Decomposition
Abstract:
In this letter, an ensemble empirical mode decomposition (EEMD)-based method is proposed to estimate significant wave height (SWH) from the X-band marine radar sea surface images. First, the data sequence in each radial direction of a radar subimage is decomposed by the EEMD into several intrinsic mode functions (IMFs). A normalization scheme is then applied to the IMFs to obtain their amplitude modulation components. Finally, by adopting a linear model, the SWH is estimated from the sum of the amplitudes from the second to the fifth modes. The method is tested using radar and buoy data collected in a sea trial off the east coast of Canada. The root-mean-square differences with respect to the buoy reference for the SWH estimations using the traditional signal-to-noise-based method, a recent shadowing-based method, and the proposed technique are 0.78, 0.48, and 0.36 m, respectively. The result indicates that the proposed technique produces improvement in the SWH measurements.
Autors: Xinlong Liu;Weimin Huang;Eric W. Gill;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1740 - 1744
Publisher: IEEE
 
» Evaluating Scattering Contributions to C-Band Radar Backscatter From Snow-Covered First-Year Sea Ice at the Winter–Spring Transition Through Measurement and Modeling
Abstract:
In this paper, we present model and measurement results for time-series angular dependencies of C-band HH and VV normalized radar cross-sections (NRCS) over first-year snow-covered sea ice during a winter–spring transition period. Experimental scatterometer and physical data were collected near Cambridge Bay, Nunavut, Canada, between May 20 and May 28, 2014, covering a severe storm event on May 25. We use the small perturbation scattering theory to model small-scale surface scattering, the Mie scattering theory to estimate the level of volume scattering in snow, and the Kirchhoff physical optics model to compute the large-scale surface scattering component. We observed good agreement between the model and experimental HH and VV NRCS. Before the storm, between model and experimental NRCS was 0.88 and 0.82 for VV and HH, respectively. After the storm, was 0.81 and 0.78 for VV and HH, respectively. Our model results suggest an overall increase in surface roughness after the storm event, supported by LiDAR measurements of the snow surface topography. Before the storm, the large-scale and small-scale surface scattering from the air-snow interface as well as volume scattering components dominated. After the storm, the large- and small-scale scattering contributions increased, while the volume scattering component considerably dropped. We attribute these effects to the increase in surface roughness and snow moisture content during the poststorm period. Our results could aid in interpretation of time-series synthetic aperture radar images with respect to physical properties of snow and ice during the winter–spring transition period.
Autors: Alexander S. Komarov;Jack C. Landy;Sergey A. Komarov;David G. Barber;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5702 - 5718
Publisher: IEEE
 
» Evaluating the Performance of Digital Modular Protection for Grid-Connected Permanent-Magnet-Generator-Based Wind Energy Conversion Systems With Battery Storage Systems
Abstract:
This paper develops and tests a new method for managing the responses of multiple digital relays employed in interconnected permanent-magnet generator (PMG)-based wind energy conversion systems (WECSs) with battery storage. The developed method utilizes digital relays (modules), each of which provides protection for a specific location of the PMG-based WECS and battery storage. The outputs of the developed digital protection scheme are trip signals to operate circuit breakers in PMG-based WECS, battery storage, and point-of-common-coupling. The modular digital protection is implemented for experimental testing on a 5-kW PMG-based WECS that has a 2.3-kW battery storage. Test results show that the developed protection can offer fast, accurate, and reliable responses to faults occurring in different parts of the tested WECS and battery storage. In addition, test results show that the modular digital protection has minor sensitivity to the location of faults, charge/discharge cycles of the battery storage, and/or levels of power delivery to the host grid.
Autors: S. A. Saleh;Ryan Meng;Ryan McSheffery;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4186 - 4200
Publisher: IEEE
 
» Evaluation of Negative Capacitance Ferroelectric MOSFET for Analog Circuit Applications
Abstract:
Negative capacitance ferroelectric (FE) field-effect transistor (FeFET) is promising to address the issue of the increasing power density in digital circuit by realizing sub-60 mV/decade subthreshold swing. This inspires us to evaluate its applications in analog circuit. In this paper, the evaluation is performed based on the equivalent circuit model and through device- and circuit-level benchmarking against MOSFET counterpart. It is found that the selection of FE thickness is important to balance current amplification and saturated output characteristics. As compared with MOSFET, FeFET exhibits a larger current, transconductance, and current-to-transconductance generation efficiency. Its output resistance is smaller in the linear region and larger in the saturation region. It also has less variation in threshold voltage with temperature. When implementing FeFETs into various analog circuit applications, we find that a node capacitor could be discharged within shorter time to increase circuit speed; A better analog switch consisting of complementary FeFETs exhibits a lower and more linear on-resistance; Differential amplifier provides larger voltage amplification to small input signal; Current mirror transfers a more precise output current to the reference one.
Autors: Yang Li;Yuye Kang;Xiao Gong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4317 - 4321
Publisher: IEEE
 
» Evaluation of Segmentation Quality via Adaptive Composition of Reference Segmentations
Abstract:
Evaluating image segmentation quality is a critical step for generating desirable segmented output and comparing performance of algorithms, among others. However, automatic evaluation of segmented results is inherently challenging since image segmentation is an ill-posed problem. This paper presents a framework to evaluate segmentation quality using multiple labeled segmentations which are considered as references. For a segmentation to be evaluated, we adaptively compose a reference segmentation using multiple labeled segmentations, which locally matches the input segments while preserving structural consistency. The quality of a given segmentation is then measured by its distance to the composed reference. A new dataset of 200 images, where each one has 6 to 15 labeled segmentations, is developed for performance evaluation of image segmentation. Furthermore, to quantitatively compare the proposed segmentation evaluation algorithm with the state-of-the-art methods, a benchmark segmentation evaluation dataset is proposed. Extensive experiments are carried out to validate the proposed segmentation evaluation framework.
Autors: Bo Peng;Lei Zhang;Xuanqin Mou;Ming-Hsuan Yang;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 1929 - 1941
Publisher: IEEE
 
» Evaluation of SiC Schottky Diodes Using Pressure Contacts
Abstract:
The thermomechanical reliability of SiC power devices and modules is increasingly becoming of interest especially for high-power applications, where power cycling performance is critical. Press-pack assemblies are a trusted and reliable packaging solution that has traditionally been used for high-power thyristor-based applications in FACTS/HVDC, although press-pack IGBTs have become commercially available more recently. These press-pack IGBTs require antiparallel PiN diodes for enabling reverse conduction capability. In these high-power applications, paralleling chips for high current conduction capability is a requirement, hence, electrothermal stability during current sharing is critical. SiC Schottky diodes not only exhibit the advantages of wide bandgap technology compared to silicon PiN diodes, but they have significantly lower zero temperature coefficient (ZTC), meaning they are more electrothermally stable. The lower ZTC is due to the unipolar nature of SiC Schottky diodes as opposed to the bipolar nature of PiN diodes. This paper investigates the implementation and reliability of SiC Schottky diodes in press-pack assemblies. The impact of pressure loss on the electrothermal stability of parallel devices is investigated.
Autors: Jose Ortiz Gonzalez;Olayiwola Alatise;Attahir Murtala Aliyu;Pushparajah Rajaguru;Alberto Castellazzi;Li Ran;Philip A. Mawby;Chris Bailey;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8213 - 8223
Publisher: IEEE
 
» Event-Based Energy Disaggregation Algorithm for Activity Monitoring From a Single-Point Sensor
Abstract:
The massive deployment of smart meters and other customized meters has motivated the development of nonintrusive load monitoring (NILM) systems. This is the process of disaggregating the total energy consumption in a building into individual electrical loads using a single-point sensor. Most literature is oriented to energy saving. Nevertheless, activity of daily livings monitoring through NILM is recently receiving much interest. This proposal presents an event-based NILM algorithm of high performance for activity monitoring applications. This is divided into two stages: 1) an event detector and 2) an event classification algorithm. The first one does not need to be trained and shows a detection rate up to 94%. The event classification algorithm uses a novel load signature based on trajectories of active, reactive, and distortion power (PQD) to obtain general models of appliance classes using principal component analysis. The F1 score and the F0.5 score (the last one is more relevant to activity monitoring) draw values of 90.6% and 98.5, respectively.
Autors: José Alcalá;Jesús Ureña;Álvaro Hernández;David Gualda;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2615 - 2626
Publisher: IEEE
 
» Event-Driven Nonlinear Discounted Optimal Regulation Involving a Power System Application
Abstract:
By employing neural network approximation architecture, the nonlinear discounted optimal regulation is handled under event-driven adaptive critic framework. The main idea lies in adopting an improved learning algorithm, so that the event-driven discounted optimal control law can be derived via training a neural network. The stability guarantee and simulation illustration are also included. It is highlighted that the initial stabilizing control policy is not required during the implementation process with the combined learning rule. Moreover, the closed-loop system is formulated as an impulsive model. Then, the related stability issue is addressed by using the Lyapunov approach. The simulation studies, including an application to a power system, are also conducted to verify the effectiveness of the present design method.
Autors: Ding Wang;Haibo He;Xiangnan Zhong;Derong Liu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8177 - 8186
Publisher: IEEE
 
» Event-Triggered Control of Multiagent Systems for Fixed and Time-Varying Network Topologies
Abstract:
A decentralized controller that uses event-triggered communication scheduling is developed for the leader-follower consensus problem under fixed and switching communication topologies. To eliminate continuous interagent communication, state estimates of neighboring agents are designed for control feedback and are updated via communication to reset growing estimate errors. The communication times are based on an event-triggered approach and are adapted based on the trade-off between the control system performance and the desire to minimize the amount of communication. An important aspect of the developed event trigger strategy is that communication is not required to determine when a state update is needed. Since the control strategy produces switched dynamics, analysis is provided to show that Zeno behavior is avoided by developing a positive constant lower bound on the minimum inter-event interval. A Lyapunov-based convergence analysis is also provided to indicate bounded convergence of the developed control methodology.
Autors: Teng-Hu Cheng;Zhen Kan;Justin R. Klotz;John M. Shea;Warren E. Dixon;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5365 - 5371
Publisher: IEEE
 
» Event-Triggered Suboptimal Tracking Controller Design for a Class of Nonlinear Discrete-Time Systems
Abstract:
In this paper, using the state-dependent Riccati equation approach, an event-triggered technique is proposed to solve the tracking problem for a broad class of nonlinear discrete-time networked control systems. It is shown that the proposed tracking controller leads to an asymptotically stable system, while the information exchange between the controller and the actuator can be directly affected with predictable results by changing a parameter of the controller called the triggering factor. The proposed method is experimentally validated on a laboratory three-tank system. The obtained results demonstrate the effectiveness of the proposed event-triggered technique for solving the tracking problem of a nonlinear system in a networked control framework.
Autors: Yazdan Batmani;Mohammadreza Davoodi;Nader Meskin;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8079 - 8087
Publisher: IEEE
 
» Ex-Post Max-Min Fairness of Generalized AGV Mechanisms
Abstract:
We generalize the standard Arrow-d'Aspremont-Gerard-Varet (AGV) mechanism to balance the net payoffs received by all agents, while maintaining Bayesian incentive compatibility, ex-post efficiency, and ex-post budget balance of the standard AGV mechanism. In a private-value setting with independent agents' types and the principal's cost, we formulate a convex optimization problem to find the mechanism (that achieves ex-post max-min fairness) over a set of parameterized generalized AGV mechanisms, through maximizing the expected value of the minimum ex-post net payoff. We reformulate the convex program as a linear program that can be effectively solved when the number of agents is small. When the number of agents is large, we propose to solve the formulated convex program through the incremental subgradient method. Numerical results on two action models show that the proposed mechanism significantly outperforms the standard AGV mechanism in terms of the expected minimum ex-post payoff.
Autors: Tao Wang;Yunjian Xu;Selin Damla Ahipasaoglu;Costas Courcoubetis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5275 - 5281
Publisher: IEEE
 
» Example-Based Subspace Stress Analysis for Interactive Shape Design
Abstract:
Stress analysis is a crucial tool for designing structurally sound shapes. However, the expensive computational cost has hampered its use in interactive shape editing tasks. We augment the existing example-based shape editing tools, and propose a fast subspace stress analysis method to enable stress-aware shape editing. In particular, we construct a reduced stress basis from a small set of shape exemplars and possible external forces. This stress basis is automatically adapted to the current user edited shape on the fly, and thereby offers reliable stress estimation. We then introduce a new finite element discretization scheme to use the reduced basis for fast stress analysis. Our method runs up to two orders of magnitude faster than the full-space finite element analysis, with average estimation errors less than 2 percent and maximum errors less than 6 percent. Furthermore, we build an interactive stress-aware shape editing tool to demonstrate its performance in practice.
Autors: Xiang Chen;Changxi Zheng;Kun Zhou;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Oct 2017, volume: 23, issue:10, pages: 2314 - 2327
Publisher: IEEE
 
» Exchangeability Characterizes Optimality of Sequential Normalized Maximum Likelihood and Bayesian Prediction
Abstract:
We study online learning under logarithmic loss with regular parametric models. In this setting, each strategy corresponds to a joint distribution on sequences. The minimax optimal strategy is the normalized maximum likelihood (NML) strategy. We show that the sequential NML (SNML) strategy predicts minimax optimally (i.e., as NML) if and only if the joint distribution on sequences defined by SNML is exchangeable. This property also characterizes the optimality of a Bayesian prediction strategy. In that case, the optimal prior distribution is Jeffreys prior for a broad class of parametric models for which the maximum likelihood estimator is asymptotically normal. The optimal prediction strategy, NML, depends on the number of rounds of the game, in general. However, when a Bayesian strategy is optimal, NML becomes independent of . Our proof uses this to exploit the asymptotics of NML. The asymptotic normality of the maximum likelihood estimator is responsible for the necessity of Jeffreys prior.
Autors: Fares Hedayati;Peter L. Bartlett;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6767 - 6773
Publisher: IEEE
 
» Expanding Acquisition and Clutter Filter Dimensions for Improved Perfusion Sensitivity
Abstract:
A method is explored for increasing the sensitivity of power-Doppler imaging without contrast enhancement. We acquire 1–10 s of echo signals and arrange it into a 3-D spatiotemporal data array. An eigenfilter developed to preserve all three dimensions of the array yields power estimates for blood flow and perfusion that are well separated from tissue clutter. This method is applied at high frequency (24-MHz pulses) to a murine model of an ischemic hindlimb. We demonstrate enhancements to tissue perfusion maps in normal and ischemic tissues. The method can be applied to data from any ultrasonic instrument that provides beamformed RF echo data.
Autors: MinWoo Kim;Craig K. Abbey;Jamila Hedhli;Lawrence W. Dobrucki;Michael F. Insana;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Oct 2017, volume: 64, issue:10, pages: 1429 - 1438
Publisher: IEEE
 
» Experimental Analysis of Small Drone Polarimetry Based on Micro-Doppler Signature
Abstract:
We present a polarimetric analysis of small drones from different aspect angles. Polarimetric analysis can provide more information of a target, since the returned radar signal is affected by different wave polarization. The analysis is performed with micro-Doppler signature (MDS) to investigate micromotions of the drone detected by the radar. We measured operating small drones in an anechoic chamber from two aspect angles, 0° and 90°. An outdoor experiment was carried out with metal clutters for verification in real environment. The indoor analysis result shows that copolarized antenna receives signals better than cross polarized when the aspect angle is 0°, and vice versa. We also verified that cross-polarized antenna receives MDS from the drone better than copolarized antenna, from outdoors when an aspect angle is almost 90°. By utilizing the polarimetric characteristic of the drone at this frequency band, it is preferable to use a polarimetric radar for drone detection.
Autors: Byung Kwan Kim;Hyun-Seong Kang;Seong-Ook Park;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1670 - 1674
Publisher: IEEE
 
» Experimental Demonstration of the Distributed Feedback Semiconductor Laser With S-Bent Waveguide and Sampled Grating
Abstract:
A distributed feedback (DFB) semiconductor laser based on s-bent waveguide and sampled grating is theoretically studied and experimentally demonstrated. The proposed laser operates with a high side mode suppression ratio (SMSR) when the bias current is changed from 50 to 130 mA. When the bias current is fixed at 130 mA, the SMSR is larger than 55 dB, which is benefit from the suppressed spatial hole burning, while the SMSR of the equivalent phase shifted DFB laser decreases to 39 dB. The wavelength spacing error between two proposed DFB lasers is measured to be 0.089 nm compared with the designed value. When temperature is increased from 20 °C to 42 °C, the presented DFB laser achieves stable single longitudinal mode (SLM) operation with SMSR >51 dB and the wavelength varies from 1562.24 to 1564.6 nm with a slope of 0.11 nm/°C. The s-bent waveguide and sampled grating can be fabricated simply by the common holography exposure and photolithograph technique resulting in a low cost. Besides, the wavelength accuracy and SLM yield can be improved significantly, which is very beneficial for the multiwavelength DFB laser array.
Autors: Yunshan Zhang;Yuechun Shi;Lianyan Li;Zhengpeng Zou;Jun Lu;Yinchao Du;Wenxuan Wang;Yating Zhou;Xin Chen;Jilin Zheng;Xiangfei Chen;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Experimental Investigation of a New Tribo-Aeroelectrostatic Separation Process for Micronized Plastics From WEEE
Abstract:
Tribo-electrostatic separation of mm-size granular insulating materials is a process widely used in the plastics recycling industry. However, the separation of micronized plastics is still inefficient because of their tendency to aggregate. The paper is aimed at validating the feasibility of a new tribo-aero-electrostatic separation process for micronized mixed plastics originating from waste electric and electronic equipment. The separation process is based on a fluidized bed tribocharging system equipped with rotating roll electrode connected to a dc high-voltage supply. The micronized insulating materials to be separated (white and grey polyvinyl chloride particles of average size 20 µm) were tribocharged using the fluidization air provided by a variable-speed blower. The charged particles were pinned to the rotating electrode of opposite polarity. This process enabled the sorting of one product while the other materials were left in the fluidized bed. The new electrode configuration has the merit to significantly reduce the particle aggregation problem that affects the operation of other fluidized-bed-type tribocharging devices. The separation outcome, in terms of recovery and purity, depended on several factors, and was found to be optimal for a voltage of 35 kV and a rotation speed of roll electrode of 60 r/min. This new process was also tested for ternary mixtures of granular plastics and the obtained results demonstrate its effectiveness for recovering a targeted product, according to the voltage polarity, leaving the other products in the fluidized bed.
Autors: Mohamed El-Mouloud Zelmat;Amar Tilmatine;Seddik Touhami;Abdelber Bendaoud;Karim Medles;Rabah Ouiddir;Lucian Dascalescu;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4950 - 4956
Publisher: IEEE
 
» Experimental Investigation on Improved Predistortion Circuit for Directly Modulated Radio Over Fiber System
Abstract:
An extension of the conventional dual Schottky diode-based predistortion circuit (PDC) is proposed to linearize directly modulated radio over fiber (RoF) system. The main advantages of the proposed PDC are simple configuration, excellent distortion suppression, and broad bandwidth from dc to 6 GHz. By using the proposed cascaded Schottky diodes-based PDC, the condition of third-order intermodulation nonlinearities suppression can be more easily satisfied and the optimal linearization effect can be achieved due to the fact that it has more circuit adjustment parameters. The experimental results show that by using the proposed PDC, the spurious-free dynamic range (SFDR) @2 GHz of the optical transceiver which is designed by ourselves can be improved from 93.8 dB·Hz2/3 to 112.1 dB·Hz4/5 in a 1-Hz bandwidth, corresponding to 7.21% error vector magnitude performance improvement for 20 MHz 64QAM-OFDM @2 GHz signal transmission over 10 km standard single mode fiber. The linearity improvement by using the proposed PDC has also been verified in a commercial optical transceiver based RoF system, and the achieved SFDR @ 2 GHz can be increased from 102.8 dB·Hz2/3 to 121.6 dB·Hz4/5 in a 1-Hz bandwidth.
Autors: Shichao Chen;Lei Deng;Yao Ye;Xiaoman Chen;Mengfan Cheng;Ming Tang;Songnian Fu;Fengguang Luo;Deming Liu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Experimental Study on Microsecond Pulse Breakdown Characteristics of Propylene Carbonate Modified by Al Nanoparticles
Abstract:
Liquid dielectrics are very important and useful in pulsed power systems, due to their unique characteristics of large energy storage densities, ease of circulation, and low cost. They are applicable to power systems which have complex geometries. Propylene carbonate (PC), as a kind of polar liquids, shows bright prospects in compact pulsed power sources because of its great permittivity, high electrical breakdown stress, and broad environmental operating ability. In this paper, a dielectric breakdown experiments were conducted with a microsecond pulsed power source and a test cell with spherical electrodes. The breakdown properties of PC and PC-based nanofluids (NFs) were investigated by changing the increasing rate of the charging voltage. Besides, the influence of nanoparticles on the dielectric breakdown characteristics of PC was analyzed. Results show that with a slow increasing rate of the charging voltage, the introduction of nanoparticles greatly improved the breakdown stability of PC; while with a fast increasing rate of the charging voltage, NFs exhibited much larger mean breakdown voltage. We also demonstrated that the improvement effect of NFs’ dielectric performance could be explained by the energy band theory very well.
Autors: Binbin Xu;Zicheng Zhang;Yanpan Hou;Hongwei Liu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2691 - 2695
Publisher: IEEE
 
» Experimental Validation of 3-D Magnet Eddy Current Loss Prediction in Surface-Mounted Permanent Magnet Machines
Abstract:
This paper presents the experimental validation of three-dimensional (3-D) Fourier method employed for predicting magnet eddy current loss in surface-mounted permanent magnet (SPM) machines. The magnet loss is measured for a 12-slot 14-pole SPM machine from experimental tests when the machine is operated with inverter under locked rotor conditions by repeating tests with two rotors, one with magnets and one without. The eddy current loss associated with each significant harmonic in the captured armature currents is predicted separately employing the developed method and the total magnet loss is evaluated by applying the principle of superposition. The magnet loss at real operating conditions of the machine is predicted from the method using the phase current captured when the SPM is operating at its maximum speed conditions. The result is used as an example to devise an effective means of further reduction in the total magnet loss.
Autors: Sreeju Sreedharan Nair;Jiabin Wang;Tianfu Sun;Liang Chen;Robert Chin;Minos Beniakar;Dmitry Svechkarenko;Iakovos Manolas;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4380 - 4388
Publisher: IEEE
 
» Experimental Validation of a Wideband Metasurface for Wide-Angle Scanning Leaky-Wave Antennas
Abstract:
Beam scanning arrays typically suffer from scan loss; an increasing degradation in gain as the beam is scanned from broadside toward the horizon in any given scan plane. Here, a metasurface is presented that reduces the effects of scan loss for a leaky-wave antenna (LWA). The metasurface is simple, being composed of an ultrathin sheet of subwavelength split-ring resonators. The leaky-wave structure is balanced, scanning from the forward region, through broadside, and into the backward region, and designed to scan in the magnetic plane. The metasurface is effectively invisible at broadside, where balanced LWAs are most sensitive to external loading. It is shown that the introduction of the metasurface results in increased directivity, and hence, gain, as the beam is scanned off broadside, having an increasing effect as the beam is scanned to the horizon. Simulations show that the metasurface improves the effective aperture distribution at higher scan angles, resulting in a more directive main beam, while having a negligible impact on cross-polarization gain. Experimental validation results show that the scan range of the antenna is increased from to , when loaded with the metasurface, demonstrating a flattened gain profile over a 135° range centered about broadside. Moreover, this scan range occurs over a frequency band spanning from 9 to 15.5 GHz, demonstrating a relative bandwidth of 53% for the metasurface.
Autors: Trevor R. Cameron;George V. Eleftheriades;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5245 - 5256
Publisher: IEEE
 
» Experimental Validation of Leak and Water-Ingression Detection in Low-Pressure Gas Pipeline Using Pressure and Flow Measurements
Abstract:
In underground low-pressure gas distribution pipelines, ground water enters the pipeline through cracks. This is known as the water ingress problem, and it occurs predominantly in the monsoon season, when the water table is high. This issue is currently detected based on complaints from the users. In order to arrive at an efficient and reliable processing technique, experimental results of pressure and flow on an existing low-pressure gas pipeline are reported in this paper. Several experiments for leak location, severity of the leak, water ingression with various volumes of water followed by removal of water are conducted. Healthy network loading data collected over a 24 h period is used to verify the robustness of the derived parameters for water ingression detection. The present technique can detect leaks easily with a leak valve opening of 30o. Robust detection of water ingression with more than 10% of pipe volume is possible.
Autors: Sugunakar Reddy Ravula;Srivathsan Chakaravarthi Narasimman;Libo Wang;Abhisek Ukil;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6734 - 6742
Publisher: IEEE
 
» Explicit Constructions of Optimal-Access MDS Codes With Nearly Optimal Sub-Packetization
Abstract:
An maximum distance separable (MDS) array code of length , dimension , and sub-packetization is formed of matrices over a finite field , with every column of the matrix stored on a separate node in the distributed storage system and viewed as a coordinate of the codeword. Repair of a failed node (recovery of one erased column) can be performed by accessing a set of surviving (helper) nodes. The code is said to have the optimal access property if the amount of data accessed at each of the helper nodes meets a lower bound on this quantity. For optimal-access MDS codes with , the sub-packetization satisfies the bound . In our previous work (IEEE Trans. Inf. Theory, vol. 63, no. 4, 2017), for any and , we presented an explicit construction of optimal-access MDS codes with sub-packetization . In this paper, we take up the question of reducing the sub-packetization value , which differs from the optimal value by at most a factor of . These codes can be constructed over any finite field as long as , and afford low-complexity encoding and decoding procedures. We also define a version of the repair problem that bridges the context of regenerating codes and codes with locality constraints (LRC codes), which we call group repair with optimal access. In this variation, we assume that the set of nodes is partitioned into repair groups of size , and require that the amount of accessed data for repair is the smallest possible whenever the helper nodes include all the other nodes from the same group as the failed node. For this problem, we construct a family of codes with the group optimal access property. These codes can be constructed over any field of size , and also afford low-complexity encoding and decoding procedures.
Autors: Min Ye;Alexander Barg;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6307 - 6317
Publisher: IEEE
 
» Exploiting Data Reliability and Fuzzy Clustering for Journal Ranking
Abstract:
Journal impact indicators are widely accepted as possible measurements of academic journal quality. However, much debate has recently surrounded their use, and alternative journal impact evaluation techniques are desirable. Aggregation of multiple indicators offers a promising method to produce a more robust ranking result, avoiding the possible bias caused by the use of a single impact indicator. In this paper, fuzzy aggregation and fuzzy clustering, especially the ordered weighted averaging (OWA) operators are exploited to aggregate the quality scores of academic journals that are obtained from different impact indicators. Also, a novel method for linguistic term-based fuzzy cluster grouping is proposed to rank academic journals. The paper allows for the construction of distinctive fuzzy clusters of academic journals on the basis of their performance with respect to different journal impact indicators, which may be subsequently combined via the use of the OWA operators. Journals are ranked in relation to their memberships in the resulting combined fuzzy clusters. In particular, the nearest-neighbor guided aggregation operators are adopted to characterize the reliability of the indicators, and the fuzzy clustering mechanism is utilized to enhance the interpretability of the underlying ranking procedure. The ranking results of academic journals from six subjects are systematically compared with the outlet ranking used by the Excellence in Research for Australia, demonstrating the significant potential of the proposed approach.
Autors: Pan Su;Changjing Shang;Tianhua Chen;Qiang Shen;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Oct 2017, volume: 25, issue:5, pages: 1306 - 1319
Publisher: IEEE
 
» Exploiting Multiple-Antenna Techniques for Non-Orthogonal Multiple Access
Abstract:
This paper aims to provide a comprehensive solution for the design, analysis, and optimization of a multiple-antenna non-orthogonal multiple access (NOMA) system for multiuser downlink communication with both time duplex division and frequency duplex division modes. First, we design a new framework for multiple-antenna NOMA, including user clustering, channel state information (CSI) acquisition, superposition coding, transmit beamforming, and successive interference cancellation. Then, we analyze the performance of the considered system, and derive exact closed-form expressions for average transmission rates in terms of transmit power, CSI accuracy, transmission mode, and channel conditions. For further enhancing the system performance, we optimize three key parameters, i.e., transmit power, feedback bits, and transmission mode. Especially, we propose a low-complexity joint optimization scheme, so as to fully exploit the potential of multiple-antenna techniques in NOMA. Moreover, through asymptotic analysis, we reveal the impact of system parameters on average transmission rates, and hence present some guidelines on the design of multiple-antenna NOMA. Finally, simulation results validate our theoretical analysis, and show that a substantial performance gain can be obtained over traditional orthogonal multiple access technology under practical conditions.
Autors: Xiaoming Chen;Zhaoyang Zhang;Caijun Zhong;Derrick Wing Kwan Ng;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2207 - 2220
Publisher: IEEE
 
» Exploring Consensus RNA Substructural Patterns Using Subgraph Mining
Abstract:
Frequently recurring RNAquery id="Q1"> structural motifs play important roles in RNA folding process and interaction with other molecules. Traditional index-based and shape-based schemas are useful in modeling RNA secondary structures but ignore the structural discrepancy of individual RNA family member. Further, the in-depth analysis of underlying substructure pattern is insufficient due to varied and unnormalized substructure data. This prevents us from understanding RNAs functions and their inherent synergistic regulation networks. This article thus proposes a novel labeled graph-based algorithm RnaGraph to uncover frequently RNA substructure patterns. Attribute data and graph data are combined to characterize diverse substructures and their correlations, respectively. Further, a top-k graph pattern mining algorithm is developed to extract interesting substructure motifs by integrating frequency and similarity. The experimental results show that our methods assist in not only modelling complex RNA secondary structures but also identifying hidden but interesting RNA substructure patterns.
Autors: Qingfeng Chen;Chaowang Lan;Baoshan Chen;Lusheng Wang;Jinyan Li;Chengqi Zhang;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1134 - 1146
Publisher: IEEE
 
» Exploring High Quality Chaotic Signal Generation in a Mutually Delay Coupled Semiconductor Lasers System
Abstract:
High quality chaotic signal generation in a mutually delay coupled semiconductor lasers (MDC-SLs) system is numerically explored by evaluating the time-delay signature (TDS) and complexity of chaotic signals. Autocorrelation function is utilized for quantitatively identifying the TDS of chaotic signal, and Kolmogorov–Sinai entropy and Kaplan–York dimensions are applied to estimate the complexity of chaotic signal. The results show that, under suitable parameters, two sets of chaotic signals with weak TDS and high complexity can be obtained simultaneously. By analyzing the influences of the mutual coupling strength and frequency detuning between the two MDC-SLs on the TDS and complexity of chaotic signals, the optimized parameter regions are specified for simultaneously generating two sets of high quality chaotic signals based on the MDC-SLs system.
Autors: Yu-Shuang Hou;Li-Lin Yi;Guang-Qiong Xia;Zheng-Mao Wu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Exploring the LCL Characteristics in GaN-Based Single-L Quasi-Z-Source Grid-Tied Inverters
Abstract:
As more widebandgap (WBG) devices are becoming commercially available, it is beneficial to use WBG device to increase the switching frequency in order to reduce the passive components. For quasi-Z-Source (qZS) grid-tied inverters, the reduction of passive components raises stability concerns as the coupling effect between the dc side and ac side of qZS inverter will increase. In this paper, the coupling effect between qZS impedance network and the output filter is analyzed by modeling both dc and ac sides. Analysis reveals the resonant characteristic of the qZS inverter. Controller parameter boundaries are derived, and a design method to improve stability is then proposed. Case studies for a 2.5-kW 10-kHz Si-based qZS inverter and a 1-kW 100-kHz GaN-based qZS inverter are presented. Circuit simulations and experimental verifications results are provided to assess analysis and the control design.
Autors: Yanjun Shi;Thierry Kayiranga;Yuan Li;Hui Li;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7758 - 7768
Publisher: IEEE
 
» Exploring Viewer Gazing Patterns for Touch-Based Mobile Gamecasting
Abstract:
Recent years have witnessed an explosion of gamecasting applications, in which game players (or gamers in short) broadcast game playthroughs by their personal devices in real time. Such pioneer platforms, such as YouTube Gaming, Twitch, and Mobcrush, have attracted a massive number of online broadcasters, and each of them can have hundreds or thousands of fellow viewers. The growing number, however, has created significant challenges to the network and end-devices, particularly considering that bandwidth- and battery-limited smartphones or tablets are becoming dominating for both gamers and viewers. Yet the unique touch operations of the mobile interface offer opportunities, too. In this paper, our measurements based on the real traces from gamers and viewers reveal that strong associations exist between the gamers’ touch interactions and the viewers’ gazing patterns. Motivated by this, we present a novel interaction-aware optimization framework to improve the energy utilization and stream quality for mobile gamecasting. Our framework incorporates a touch-assisted prediction module to extract association rules for gazing pattern prediction and a tile-based optimization module to utilize energy on mobile devices efficiently. Trace-driven simulations illustrate the effectiveness of our framework in terms of energy consumption and stream quality. Our user study experiments also demonstrate much improved (3%–13%) quality satisfaction over the state-of-the-art solution with similar network resources.
Autors: Cong Zhang;Qiyun He;Jiangchuan Liu;Zhi Wang;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2333 - 2344
Publisher: IEEE
 
» Extended Kalman Filter for Multichannel InSAR Height Reconstruction
Abstract:
One of the main challenges in Interferometric Synthetic Aperture Radar (SAR) is the accurate height reconstruction of the observed scene. Recently, approaches based on Extended Kalman Filter (EKF) have been proposed. Most of them are based on the hypothesis of height profile continuity. Such condition greatly reduces their applicability, being only valid for particular scenarios. Within this paper, we present a novel Kalman-based height reconstruction approach, specifically designed to work with multichannel data related to any type of scenario, both smooth or sharp. The novelty of the technique consists in its ability in detecting and correctly handling sharp height discontinuities while regularizing smooth areas. The approach is able to maintain the high computational efficiency typical of EKF and to work in an almost unsupervised way. The methodology has been tested and validated on both simulated and real X-band (TerraSAR-X and COSMO-SkyMed) high-resolution data sets. Reported results are encouraging and interesting, showing the correctness and the validity of the proposed approach.
Autors: Roberto Ambrosino;Fabio Baselice;Giampaolo Ferraioli;Gilda Schirinzi;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5854 - 5863
Publisher: IEEE
 
» Fabrication and Electromechanical Modeling of a Flexural-Mode MEMS Piezoelectric Transformer in AlN
Abstract:
This paper presents the fabrication and electromechanical characterization of a novel AlN-based microelectromechanical systems (MEMS) flexural-mode piezoelectric transformer (PT) realized in a silicon-on-insulator bulk-micromachining process with segmented electrodes at the secondary side, which are series-connected in order to increase the output voltage. The goal of this work is to propose a MEMS-based alternative to inductors and magnetic transformers for power management in micro-power mm-scale electronic systems. The fabricated device is fully modeled by means of the Butterworth-Van Dyke (BVD) two-port network. The device is modeled analytically with the classic equations of a fully clamped-edge membrane and through finite-element method simulations. Characterization is performed through impedance measurements and an alternative empirical method suitable for MEMS devices is proposed for directly extracting its lumped parameters electromechanical circuit. Finally, the effect of the feed-through capacitance is fully analytically modeled, and this paper presents a variant of the BVD network of the PT with an inner BVD circuit, allowing an easier estimation of the effects of the complex zeros introduced by the feed-forward capacitance. The presented device achieves a measured maximum voltage gain of 58mV/V at ~36.3 kHz and maximum efficiency of ~75%.
Autors: Antonio Camarda;Guido Sordo;Jacopo Iannacci;Michael Schneider;Ulrich Schmid;Marco Tartagni;Aldo Romani;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 1110 - 1121
Publisher: IEEE
 
» Fabrication, Characterization, and Analysis of Ge/GeSn Heterojunction p-Type Tunnel Transistors
Abstract:
We present a detailed study on fabrication and characterization of Ge/GeSn heterojunction p-type tunnel-field-effect-transistors (TFETs). Critical process modules as high-k stack and p-i-n diodes are addressed individually. As a result an ultrathin equivalent oxide thickness of 0.84 nm with an accumulation capacitance of /cm2 was achieved on an extremely scaled tri-layer stack of GeSnOx/Al2O3/HfO2 deposited by atomic-layer deposition monitored in situ by spectroscopic ellipsometry. Combining these process modules, Ge/GeSn heterojunction pTFETs are fabricated and characterized to demonstrate the best in-class pTFET performance in the GeSn material system. The transfer characteristics of the TFETs show signatures of the trap-assisted thermal generation in the subthreshold regime which is explained by a modified Shockley–Read–Hall model. For the ON-state current, we used band-to-band tunneling models calculated using parameters from the density functional theory. We then use the calibrated model to project performance of GeSn pTFETs with increased Sn content (lower bandgap), reduced trap density and ultrathin body geometry. Both experimental and projected results are benchmarked against state-of-the art III–V (e.g., In0.65Ga0.35/GaAs0.4Sb0.6) pTFETs. We demonstrate the ability of GeSn to achieve superior performance with both high ON-current and sub-60mV/decade switching benefiting from the small and direct bandgap for higher Sn contents.
Autors: Christian Schulte-Braucks;Rahul Pandey;Redwan Noor Sajjad;Mike Barth;Ram Krishna Ghosh;Ben Grisafe;Pankaj Sharma;Nils von den Driesch;Anurag Vohra;Gilbert Bruce Rayner;Roger Loo;Siegfried Mantl;Dan Buca;Chih-Chieh Yeh;Cheng-Hsien Wu;Wilman Tsai;Dimit
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4354 - 4362
Publisher: IEEE
 
» Facilitating the Integration of Renewables in Latin America: The Role of Hydropower Generation and Other Energy Storage Technologies
Abstract:
It is well known that storage facilities can provide value to various electricity sectors through several services, which we group into five main classes.
Autors: Rodrigo Moreno;Rafael Ferreira;Luiz Barroso;Hugh Rudnick;Eduardo Pereira;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 68 - 80
Publisher: IEEE
 
» Facilitating Time Critical Information Seeking in Social Media
Abstract:
Social media plays a major role in helping people affected by natural calamities. These people use social media to request information and help in situations where time is a critical commodity. However, generic social media platforms like Twitter and Facebook are not conducive for obtaining answers promptly. Algorithms to ensure prompt responders for questions in social media have to understand and model the factors affecting their response time. In this paper, we draw from sociological studies on information seeking and organizational behavior to identify users who can provide timely and relevant responses to questions posted on social media. We first draw from these theories to model the future availability and past response behavior of the candidate responders and integrate these criteria with user relevance. We propose a learning algorithm from these criteria to derive optimal rankings of responders for a given question. We present questions posted on Twitter as a form of information seeking activity in social media and use them to evaluate our framework. Our experiments demonstrate that the proposed framework is useful in identifying timely and relevant responders for questions in social media.
Autors: Suhas Ranganath;Suhang Wang;Xia Hu;Jiliang Tang;Huan Liu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2197 - 2209
Publisher: IEEE
 
» Falling Water, Rising Power
Abstract:
Hydropower is the production of electricity utilizing the force of falling water. Hydroelectric generators typically found in the United States range greatly in capacity from microhydro units rated between 5 kW-100 kW up to the large units at Grand Coulee Dam in Washington state, which are rated at 805 MW. The newly constructed Three Gorges Dam in China houses 32 units rated at 700 MW as well as two units rated at 50 MW to power the plant itself. Three Gorges is the world's largest hydroelectric power plant in terms of installed electrical generating capacity. Hydropower production can vary throughout the year as water supplies fluctuate. Peak hydropower generation typically occurs during the spring and summer months during snow melt and rain run-off season.
Autors: Mark Skoric;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 30 - 31
Publisher: IEEE
 
» Fano Resonance in a Metasurface Composed of Graphene Ribbon Superlattice
Abstract:
We present a metasurface composed of graphene ribbon superlattice that supports plasmonic Fano resonance in a simple symmetric configuration. Without the necessity of changing the geometry size of graphene ribbons, we tune the Fano resonance of the metasurface containing identical graphene ribbons by simply changing the global or local periods of the superlattice. The increase of the global period of the superlattice leads to a blue-shift of the broad resonance of the bright mode, while the increase of the local period leads to simultaneous shifts of the broad resonance of the bright mode and the sharp resonance of the dark mode toward opposite direction with respect to each other. The resonance shift mechanism can be well explained by the restoring force model for longitudinal dipole arrays. In addition, the overall spectral position of the Fano resonance can be actively tuned by the fermi level of graphene ribbons. Our methods provide a simple and flexible pathway to tune the plasmonic Fano resonance, which holds great potentials for tunable biosensing and slow light applications with improved performance.
Autors: Zi-Lan Deng;Xiangping Li;Tao Fu;Guo Ping Wang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7
Publisher: IEEE
 
» Fast and Accurate Frequency-Dependent Behavioral Model of Bonding Wires
Abstract:
A proposed model of bonding wires is presented in this paper. For a regular double-π bonding-wire model considering the skin effect, nine parameters should be determined, including inductance , series parasitic resistances , shunt parasitic capacitances , and parameters for skin effects , so procedures to extract the design parameters for a bonding-wire model are complicated. To reduce the complexity, a proposed model is presented. Introducing a frequency-dependent resistor can significantly reduce the number of design parameters for a bonding-wire model considering the skin effect from nine to five. This can resolve the design complexity of the bonding wires and cables. Moreover, it is suitable for industrial applications. In addition, the proposed design methodology is presented and the mechanisms are validated by experiments. According to experimental results, the model accuracy with 10% difference in magnitude between measured and modeled of the 2, 4, 6, and 8 mm aluminum bonding wires is at the frequencies of 5.9, 5.0, 3.5, and 2.9 GHz, respectively.
Autors: To-Po Wang;You-Fu Lu;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2389 - 2396
Publisher: IEEE
 
» Fast Antenna Far-Field Characterization via Sparse Spherical Harmonic Expansion
Abstract:
A procedure is proposed to significantly reduce the amount of time to characterize 3-D antenna far-field patterns. The measured far field is expanded into spherical harmonics, and a sparse recovery algorithm is used to recover the spherical wave coefficients giving access to the field radiated by the antenna everywhere. A small number of measurement points are required, since the relevant information of the most antenna patterns is concentrated in only a few spherical wave coefficients. Sampling strategies enabling fast spherical scans are discussed, which makes the approach both efficient and easy to implement in existing far-field measurement facilities. Simulations are first provided to show the potentialities of this compressive sensing-based approach. The proposed strategy is then applied to characterize 3-D far-field patterns radiated by several antennas operating in different frequency bands measured in far field in direct line of sight configuration and in a compact antenna test range. Experimental results show that a saving in the number of measurement points up to 70% can be achieved compared with standard approaches. These results pave the way to a more efficient use of far-field measurement facilities.
Autors: Benjamin Fuchs;Laurent Le Coq;Sébastien Rondineau;Marco Donald Migliore;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5503 - 5510
Publisher: IEEE
 
» Fast Background Calibration of Sampling Timing Skew in SHA-Less Pipeline ADCs
Abstract:
This brief presents a digital calibration technique for compensating timing-skew errors between the sub-ADC and the MDAC in the first stage of sample-and-hold amplifier (SHA)-less pipeline ADCs. In the presence of clock-skew errors, sub-ADC comparators produce time-variant offsets depending on the input-signal slope at the sampling instants. These increase residue excursions at the MDAC output, potentially causing overranging and an increment in nonlinear errors. This paper derives close analytical expressions for these effects. The proposed method uses the overranging information to perform a low-cost estimation and correction of the skew error with the following features: 1) very fast convergence (in the order of 1-k input samples); 2) indirect evaluation of the skew error signal, without any previous knowledge of the input signal’s frequency distribution; and 3) relatively simple digital logic—basically, two digital comparators and one small accumulator. The method was verified in behavioral and transistor-level simulations. As a demonstrator, its implementation in a 1.8-V 80-dB SNDR 100-Msps SHA-less pipeline ADC in a 0.18- CMOS process is shown.
Autors: A. J. Ginés;E. J. Peralías;A. Rueda;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2966 - 2970
Publisher: IEEE
 

Publication archives by date

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

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

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

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

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

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

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

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

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

 
0-C     D-L     M-R     S-Z