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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 4
» Enhancing Flatbed Printer Accuracy and Throughput: Optimal Rational Feedforward Controller Tuning Via Iterative Learning Control
Résumé:
Advanced control methods potentially enable performance improvements in printing systems for minor additional costs. The aim of this paper is to develop a control framework that is capable of delivering throughput and accuracy enhancements for an industrial flatbed inkjet printer. The proposed method involves iterative learning control with a rational feedforward parameterization to enable varying position references which are required for printing. Experimental results highlight the efficacy of the proposed method in a comparison with related pre-existing learning control approaches.
Auteurs: Joost Bolder;Jurgen van Zundert;Sjirk Koekebakker;Tom Oomen;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4207 - 4216
Editeur: IEEE
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» Enhancing Network Parameter Error Detection and Correction via Multiple Measurement Scans
Résumé:
Although the normalized Lagrange multiplier (NLM) method has been shown to be very effective for network parameter error identification, errors in parameters corresponding to insensitive NLMs still remain difficult to detect and correct. This paper proposes an enhanced method for detecting and correcting network parameter errors based on multiple measurement scans. The method is developed by first deriving the relationship between parameter errors and the associated Langrage multipliers in state estimation. This is then used to clarify the reason behind the sensitivity issue of NLMs and the improvements made by performing multiple scans. An approach for estimating the necessary number of scans for satisfying various detection requirements is also proposed. Moreover, a local parameter error correction procedure based on multiple scans is presented, with detailed discussion of the local network selection and the number of required measurement scans. Simulation results in a very large utility system in North America illustrate the effectiveness of the analysis and methods proposed in this paper.
Auteurs: Yuzhang Lin;Ali Abur;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2417 - 2425
Editeur: IEEE
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» Enhancing the Gaming Experience Using 3D Spatial User Interface Technologies
Résumé:
Three-dimensional (3D) spatial user interface technologies have the potential to make games more immersive and engaging and thus provide a better user experience. Although technologies such as stereoscopic 3D display, head tracking, and gesture-based control are available for games, it is still unclear how their use affects gameplay and if there are any user performance benefits. The authors have conducted several experiments on these technologies in game environments to understand how they affect gameplay and how we can use them to optimize the gameplay experience.
Auteurs: Arun Kulshreshth;Kevin Pfeil;Joseph J. LaViola;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 16 - 23
Editeur: IEEE
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» Entanglement-Assisted Capacities of Compound Quantum Channels
Résumé:
We study universal quantum codes for entanglement-assisted quantum communication over compound quantum channels. In this setting, sender and receiver do not know the specific channel that will be used for communication, but only know the set that the channel is selected from. We investigate different variations of the problem: uninformed users, informed receiver, informed sender, and feedback assistance. We derive single-letter formulas for all corresponding channel capacities. Our proofs are based on one-shot decoupling bounds and properties of smooth entropies.
Auteurs: Mario Berta;Hrant Gharibyan;Michael Walter;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3306 - 3321
Editeur: IEEE
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» Epileptic Focus Localization Using Discrete Wavelet Transform Based on Interictal Intracranial EEG
Résumé:
Over the past decade, with the development of machine learning, discrete wavelet transform (DWT) has been widely used in computer-aided epileptic electroencephalography (EEG) signal analysis as a powerful time-frequency tool. But some important problems have not yet been benefitted from DWT, including epileptic focus localization, a key task in epilepsy diagnosis and treatment. Additionally, the parameters and settings for DWT are chosen empirically or arbitrarily in previous work. In this work, we propose a framework to use DWT and support vector machine (SVM) for epileptic focus localization problem based on EEG. To provide a guideline in selecting the best settings for DWT, we decompose the EEG segments in seven commonly used wavelet families to their maximum theoretical levels. The wavelet and its level of decomposition providing the highest accuracy in each wavelet family are then used in a grid search for obtaining the optimal frequency bands and wavelet coefficient features. Our approach achieves promising performance on two widely-recognized intrancranial EEG datasets that are also seizure-free, with an accuracy of 83.07% on the Bern-Barcelona dataset and an accuracy of 88.00% on the UBonn dataset. Compared with existing DWT-based approaches in epileptic EEG analysis, the proposed approach leads to more accurate and robust results. A guideline for DWT parameter setting is provided at the end of the paper.
Auteurs: Duo Chen;Suiren Wan;Forrest Sheng Bao;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 413 - 425
Editeur: IEEE
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» Equipment Utilization Enhancement in Photolithography Area Through a Dynamic System Control Using Multi-Fidelity Simulation Optimization With Big Data Technique
Résumé:
Photolithographic (Photo) plays a key role in semiconductor manufacturing because of its importance to advanced process shrinking. Even with a small improvement in its operational efficiency, the cost competitiveness in production can be enhanced as a result of the huge amount of share capital cost. However, it is difficult to stabilize the throughput rhythm of Fabs, while keeping a high equipment utilization for Photo. In the light of Industry 4.0 and big data, a huge potential of maintaining a desired system performance by (near) real-time dynamic system control is highly anticipated. But it also poses challenges to intelligently handling mass data acquisition and allocating computing resources. This research aims to maximize the equipment utilization in Photo by an efficient multi-model simulation optimization approach with big data techniques in the era of Industry 4.0. dynamic Photo configurator and abnormality detector are the two critical units in our proposed system framework; the former can make a quick decision to optimize the system configuration while receiving the adjustment request from the latter. The results from an empirical study show the practical viability of proposed approach that the capacity loss in Photo has been effectively improved.
Auteurs: Liam Y. Hsieh;Edward Huang;Chun-Hung Chen;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 166 - 175
Editeur: IEEE
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» Ergodic Spectral Efficiency in MIMO Cellular Networks
Résumé:
This paper shows how the application of stochastic geometry to the analysis of wireless networks is greatly facilitated by: ( ${i}$ ) a clear separation of time scales; (ii) the abstraction of small-scale effects via ergodicity; and (iii) an interference model that reflects the receiver’s lack of knowledge of how each individual interference term is faded. These procedures render the analysis both more manageable and more precise, as well as more amenable to the incorporation of subsequent features. In particular, the paper presents analytical characterizations of the ergodic spectral efficiency of cellular networks with single-user multiple-input multiple-output and sectorization. These characterizations, in the form of easy-to-evaluate expressions, encompass the coverage, the distribution of spectral efficiency over the network locations, and the average thereof.
Auteurs: Geordie George;Ratheesh K. Mungara;Angel Lozano;Martin Haenggi;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2835 - 2849
Editeur: IEEE
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» Error-Resilient Integrated Clock Gate for Clock-Tree Power Optimization on a Wide Voltage IOT Processor
Résumé:
Energy-efficiency optimization occupies an important position in the Internet of Things application. The error-resilience technique has begun to emerge and brought the performance and energy benefits as a new vision for alternative computing, because it eliminates the overconstrained margin in current processor design flow and protects the system from process, supply voltage, temperature, and aging variations through an error-resilient mechanism rather than expensive guardbands. However, as a traditional clock-tree power optimization technique, the clock gating mechanism cannot work in such a system when it faces the timing violation problem. In this paper, we propose an error-resilient integrated clock gate (ERICG) and its automatic integration methodology in error detection and correction (EDAC) system design flow. ERICG can provide the ability of in situ timing EDAC with only four additional transistors compared with a conventional integrated clock gate. The SPICE simulation shows that it is a metastable-hardened cell and can work well in the wide voltage operation (0.5~ 1.1 V) including the near-threshold region. We implement it in a commercial C-SKY CK802 processor based on an SMIC 40-nm technology. The result shows that it improves the energy efficiency by 68% compared with the non-EDAC design and lowers the total power by 28.72% over the conventional EDAC design at 0.6 V.
Auteurs: Tao-Tao Zhu;Jian-Yi Meng;Xiao-Yan Xiang;Xiao-Lang Yan;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1681 - 1693
Editeur: IEEE
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» Error-Resilient Video Encoding Using Parallel Independent Signature Processing
Résumé:
Soft errors resulting from encoding video sequences on unreliable hardware can create significant artifacts in decoded video sequences, contributing to extreme video quality degradation. Modern systems are required to operate under increasingly challenging constraints, including smaller feature sizes and lower operating voltage, increasing the likelihood of soft errors in the video encoding hardware. These conditions are of particular concern for energy-limited battery-operated systems since they may be required to operate in nonideal environments and/or continue operating with a practically depleted energy source. The proposed parallel independent signature processing design performs error detection and mitigation in video encoding hardware, enabling a graceful degradation of quality when encoding by using unreliable hardware. The effects of soft errors are minimized by preventing the error propagation normally associated with errors in encoded video sequences. This allows for the recovery of quality when errors are present in the video encoding system. Conventional video encoding techniques are designed to handle worst case error rates by increasing gate sizes and/or increasing the operating voltage of the system. Such designs have error-rate limits, and when these limits are reached, the systems tend to fail catastrophically, resulting in an unrecoverable signal. The proposed design allows for single upset events to translate into single transient artifacts in a decoded video sequence.
Auteurs: Joshua W. Wells;Abhijit Chatterjee;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1077 - 1090
Editeur: IEEE
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» ESD Robust Fully Salicided 5-V Integrated Power MOSFET in Submicron CMOS
Résumé:
A novel high electrostatic discharge (ESD), robust fully salicided 5-V integrated CMOS power MOSFET design is developed and demonstrated without the use of conventional salicide blocking ballast resistor. This scheme builds the ballast resistors on the top of the source and drain, without any increase in silicon footprint unlike prior methods, while maintaining standard transistor parametric performance.
Auteurs: Jian-Hsing Lee;Natarajan Mahadeva Iyer;Manjunatha Prabhu;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 623 - 625
Editeur: IEEE
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» Estimate of Ocean Wind Vectors Inside Tropical Cyclones From Polarimetric Radiometer
Résumé:
Microwave polarimetry provides a distinctive opportunity to retrieve wind speed (WS) and wind direction (WD) inside tropical cyclones (TCs) due to the high atmospheric transmissivity through clouds and under rain conditions. A WS retrieval algorithm for WS above 20 m/s in TCs using brightness temperature at 6.8- and 10.7-GHz has been developed and a new set of parameters has been optimized from WindSat TB and the HWind analysis matches. This algorithm is estimated to have an encouraging degree of accuracy for retrieving WS in TCs. For WS above 20 m/s, the mean (std) of the differences between retrieved WS and HWind analysis for 17 TCs from 2003 to 2009 is 0.2 m/s (3.1 m/s). WD signals in the third (T3) and fourth Stokes (T4) parameters at 10.7-, 18.7- and 37-GHz for ocean surfaces in TCs under rain are presented. T3 observations from the WindSat 10.7-, 18.7-, and 37-GHz channels are collocated with the ocean-surface winds from the HWind analysis. The collocated data are binned as a function of WS and WD. The 10.7 GHz T3 data show clear 4-K peak-to-peak directional signals at 30–40 m/s WS after correction for the atmospheric attenuation. The data are fitted by harmonics of the relative azimuth angles between the HWind analysis and radiometer look directions. The new coefficients of WD harmonics are used to retrieve WD in TCs under rain using WindSat T3 and T4 channels. The rms difference between retrieved WD and HWind WD is 24.2.
Auteurs: Xiaobin Yin;Zhenzhan Wang;Qingtao Song;Yingzhu Huang;Ruanyu Zhang;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1701 - 1714
Editeur: IEEE
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» Estimating Sag and Wind-Induced Motion of Overhead Power Lines With Current and Magnetic-Flux Density Measurements
Résumé:
Overhead high-voltage transmission lines (HVTLs) extend over diverse geographic regions under uneven weather conditions, where sag and wind-induced conductor motion poses serious issues for uninterrupted power distribution by HVTLs. Sag reduces the ground clearance of the line, whereas conductor motion may result in phase to phase short circuit, and damage to support structure. A real-time estimate of these factors is deemed important to develop requisite prevention measures. In this paper, we present a novel method to cater for sag and motion estimation in real-world scenarios. Our method can detect a change in sag and conductor motion, whether it is symmetrical or unsymmetrical to one or more conductors. We require uniaxial magnetic-field (MF) sensors mounted at support tower, equal to conductors, and synchronized with current-transformer (CT) data at substation. The sensors provide noncontact MF measurements, which are time stamped and transmitted to the substation. The data are then simultaneously processed along with electric current readings from the CT. For processing, we developed a unified algorithm that first distinguishes variation in sag from motion in conductor. Then, it estimates the corresponding sag or motion in any of the conductors. The method is verified first by numerical simulations, and then with a scaled setup in laboratory. Different test cases were identified by the algorithm. Error remains \leq 1 % for unsymmetrical sag estimation. In addition, trajectory of a conductor in motion is retrieved. Where the root mean square error between actual and retrieved conductor amplitude was only 0.0833 for the observation window of 200 ms.
Auteurs: Arsalan Habib Khawaja;Qi Huang;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 897 - 909
Editeur: IEEE
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» Estimating Soil Salinity Under Various Moisture Conditions: An Experimental Study
Résumé:
Soil salinization is one of the most common land desertification processes that can be found worldwide. It is a certainly severe environment hazard and threatens the stability of ecosystems. As a rapid and inexpensive tool, remote sensing technology combining with the measurements of soil spectra has been widely concerned on identifying and mapping salt effect on lands. However, as effects of the soil moisture often immerge the effects of salt to soil reflectance spectra, soil moisture became a major factor to restrict soil salinity monitoring from soil reflectance. High soil moisture content will lead to failure on soil salinity estimation from soil reflectance data. In this paper, a semianalytical model using an exponent function was developed to estimate soil salt content (SSC) under different moisture levels based on a control laboratory experiment. And the root-mean-square error and mean relative error were 0.799 g/kg and 31.294%, respectively, when the model was applied to estimate SSCs by wet soil reflectance. To sum up, considering both effects of soil moisture and soil salt on soil reflectance, the semianalytical model reduced SSC estimated error. The approach presented in this paper provides a new way of estimating soil salinity from soil spectra under various soil moisture conditions, and it will be a potential application for large-scale SSC mapping.
Auteurs: Xiguang Yang;Ying Yu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2525 - 2533
Editeur: IEEE
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» Estimating the Accuracy Level Among Individual Detections in Clustered Microcalcifications
Résumé:
Computerized detection of clustered microcalcifications (MCs) in mammograms often suffers from the occurrence of false positives (FPs), which can vary greatly from case to case. We investigate how to apply statistical estimation to determine the number of FPs that are present in a detected MC lesion. First, we describe the number of true positives (TPs) by a Poisson–binomial probability distribution, wherein a logistic regression model is trained to determine the probability for an individual detected MC to be a TP based on its detector output. Afterward, we model the spatial occurrence of FPs in a lesion area by a spatial point process (SPP), of which the distribution parameters are estimated from the detections in the lesion and its surrounding region. Furthermore, to improve the estimation accuracy, we incorporate the Poisson–binomial distribution of the number of TPs into the SPP model using maximum a posteriori estimation. In the experiments, we demonstrated the proposed approach on the detection results from a set of 188 full-field digital mammography (FFDM) images (95 cases) by three existing MC detectors. The results showed that there was a strong consistency between the estimated and the actual number of TPs (or FPs) for these detectors. When the fraction of FPs in detection was varied from 20% to 50%, both the mean and median values of the estimation error were within 11% of the total number of detected MCs in a lesion. In particular, when the number of FPs increased to as high as 11.38 in a cluster on average, the error was 2.51 in the estimated number of FPs. In addition, lesions estimated to be more accurate in detection were shown to have better classification accuracy (for being malignant or benign) than those estimated to be less accurate.
Auteurs: María V. Sainz de Cea;Robert M. Nishikawa;Yongyi Yang;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 05.-2017, volume: 36, issue:5, pages: 1162 - 1171
Editeur: IEEE
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» Estimation and Attitude Control in CONASAT's Nominal Operation Mode: An Approach for SDRE Filter and PID Control
Résumé:
CubeSat attracted interest of international community with numerous studies being developed in some universities, schools or even space enthusiastic. Miniaturization of components and use of conventional electronics reduced costs with space projects, that previously restricted access to space to only a few nations at costs of several million dollars. So, governments and space agencies, especially in developing nations, has begun to invest in small satellite projects, because now they can have space missions at low cost. Thus, the National Institute for Space Research (INPE), in Brazil, has planning some CubeSat missions as an academic tool to spread the space technology across the country to universities and researches. One of the missions in development is the Nanosatellite Constellation for Environmental Data Collection (CONASAT). This project intends to launch at least two small satellites to replace the SCD1 and SCD2 satellites of the Brazilian's environmental data collection system. The main objective of this paper is to propose state estimation technique, known as State-Dependent Riccati Equation (SDRE), together with a PID controller based on attitude error given by the Euler angle and axis for nominal mode attitude control of CONASAT. Simulations were performed using an open computational tool for attitude and orbit simulation.
Auteurs: Brehme Dnapoli Reis de Mesquita;Helio Koiti Kuga;Valdemir Carrara;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 835 - 842
Editeur: IEEE
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» Estimation of Current and Sag in Overhead Power Transmission Lines With Optimized Magnetic Field Sensor Array Placement
Résumé:
Power distribution mechanism in smart grid necessitates the development of an easy-to-install and contactless sensing system to monitor the operational state of overhead high-voltage transmission lines. Here, we propose a robust phase current and sag estimation method at support structures. Novelty in our work is the use of dual-axis magnetic field (MF) sensors equal to the number of phase conductors. This is realized by installing an array of sensors optimally placed in the same vertical plane as of conductors on the tower. The optimal position of sensor array was found while minimizing the condition number of governing linear system close to unity. For any circuit configuration, our method processes the sensed MF vector projections through a linear system, which is based on the Biot–Savart law. It considers the practical factors, such as sag, span length, and sensor-to-conductor distance. An algorithm is then designed to estimate the electric current and sag by iterative comparison between the measured and calculated MF. The method is first tested by numerical simulations for a typical one-circuit configuration, which involves three scenarios of symmetrical and unsymmetrical sag in conductors. The algorithm converges to a maximum error of $le 1$ % within 300 iterations. We then experimentally verify our scheme on a scaled laboratory setup. Retrieved current and sag values were verified with the readings from ammeter and vernier caliper, respectively. The results prove the viability of our approach within $le 2.6$ % deviation for current and $le 1$ % for sag in all conductors.
Auteurs: Arsalan Habib Khawaja;Qi Huang;Jian Li;Zhenyuan Zhang;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 10
Editeur: IEEE
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» Estimation of Sparse Massive MIMO-OFDM Channels With Approximately Common Support
Résumé:
In this letter, we reveal that in the massive multiple-input multiple-output system with large bandwidth, sub-channels of orthogonal frequency division multiplexing share approximately sparse common support due to the frequency difference of subcarriers. We use the approximate message passing with nearest neighbor sparsity pattern learning (AMP-NNSPL) algorithm to adaptively learn the underlying structure for improving the accuracy of channel estimation, where the learning strategy is newly derived by solving an optimization problem. In addition, the performance of the AMP-NNSPL is well predicted by the state evolution. Simulation results demonstrate the superiority of the algorithm in systems with large bandwidth.
Auteurs: Xincong Lin;Sheng Wu;Linling Kuang;Zuyao Ni;Xiangming Meng;Chunxiao Jiang;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1179 - 1182
Editeur: IEEE
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» Estimation of the Lens Distortion Model by Minimizing a Line Reprojection Error
Résumé:
Most techniques for camera calibration that use planar calibration patterns require the computation of a lens distortion model and a homography. Both are simultaneously refined using a bundle adjustment that minimizes the reprojection error of a collection of points when projected from the scene onto the camera sensor. These points are usually the corners of the rectangles of a calibration pattern. However, if the lens shows a significant distortion, the location and matching of the corners can be difficult and inaccurate. To cope with this problem, instead of point correspondences, we propose to use line correspondences to compute the reprojection error. We have designed a fully automatic algorithm to estimate the lens distortion model and the homography by computing line correspondences and minimizing the line reprojection error. In the experimental setup, we focus on the analysis of the quality of the obtained lens distortion model. We present some experiments that show that the proposed method outperforms the results obtained by standard methods to compute lens distortion models based on line rectification.
Auteurs: Daniel Santana-Cedrés;Luis Gomez;Miguel Alemán-Flores;Agustín Salgado;Julio Esclarín;Luis Mazorra;Luis Alvarez;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2848 - 2855
Editeur: IEEE
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» Evaluating Gaussian and Rayleigh-Based Mathematical Models for T and P-waves in ECG
Résumé:
This paper presents a comparative study of modelling and segmentation of P and T waves in electrocardiograms, using three different mathematical models: Gaussian function, a composition of two Gaussian functions and Rayleigh probability density function (Rayleigh pdf). In order to evaluate the adaptability and the matching degree between each model and each characteristic wave, we compute the normalized root mean square (RMS) error, as well as the evolution of the fitting parameters related to each kernel throughout ECG records from the well-known QT database. Concerning the delineation of P and T-waves, we apply Wavelet Transform for estimating T-wave and P-wave peak locations and combine each developed model with an approach based on the computation of Trapezium's area to locate the end point of each T-wave and the beginning and end point of each P-wave. The composition of two Gaussian functions has produced the most accurate results concerning wave modelling, providing average values of normalized RMS errors equal to 9,15% and 18,70%, respectively for T-wave and P-wave. Rayleigh pdf provided the most stable fitting parameters. For T-wave end location, the most accurate results were computed when using the kernel composition of two Gaussian functions, for which the average time error was 4,49 ± 14,32 ms. For P-wave begin and P-wave end locations, the most accurate results were computed when using kernel Rayleigh pdf, for which the average time errors were, respectively, -4,23 ± 14,84 ms and 2,26 ± 13,14 ms.
Auteurs: Joao Paulo do Vale Madeiro;Elves Mauro Boa Esperanca dos Santos;Paulo Cesar Cortez;John Hebert da Silva Felix;Fernando Soares Schlindwein;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 843 - 853
Editeur: IEEE
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» Evaluating Generating Unit Unavailability Using Bayesian Power Priors
Résumé:
Generating unit unavailability assessment is an important task in the power system generation expansion planning aimed at managing an acceptable degree of security of supply. In the case of the newly installed or planned units, the sample size of the data for unavailability assessment is limited and inadequate to provide the desired accuracy in the unavailability estimation. A new concept based on the Bayesian power prior approach has been developed to utilize the data from similar generating units. The original contribution of the present work is a model that incorporates the data of unavailability from other generating units into the statistical analysis of unavailability of the analysed generating unit to improve the accuracy of the estimation. The empirical results show that for unavailability estimation, the power prior Bayesian approach exhibits better than the classical statistical approach in both the standard error of estimate and confidence interval as the measures of accuracy.
Auteurs: Ivan Lorencin;Miloš Pantoš;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2315 - 2323
Editeur: IEEE
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» Evaluation of 4-D Reaction Integrals in the Method of Moments: Coplanar Element Case
Résumé:
Recently, the benefits of simultaneously treating source and testing integrals in the numerical evaluation of 4-D reaction integrals have been reported. The reported schemes usually first transform the reaction integral to parametric coordinates, and some combination of radial, angular, and/or line segment integrals is then used to treat coincident, edge-adjacent, or vertex-adjacent triangular source and test element pairs. However, advantages of the reported approaches are tempered by their lack of generality and severely degraded performance on poorly shaped elements, the latter caused primarily by the parametric transformations’ severe distortion of the kernel’s circularly concentric level contours. Here, for coplanar element pairs and kernels with 1/ $R$ singularities, we apply the surface divergence theorem twice to obtain a novel formula for 4-D reaction integrals, generalizing earlier schemes while retaining their benefits and without distorting the original configuration space. Numerical results illustrate the method’s efficiency, which is improved by employing appropriate transformations to further smooth the resulting integrands and hence accelerate their convergence. The reaction integral formula can be extended to noncoplanar elements.
Auteurs: Donald R. Wilton;Francesca Vipiana;William A. Johnson;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2479 - 2493
Editeur: IEEE
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» Evaluation of Load Frequency Control Performance Based on Standard Deviational Ellipses
Résumé:
This paper discusses new criterion for the evaluation of load frequency control (LFC) performance. The proposed LFC performance evaluation is based on a standard deviational ellipse that characterizes a bivariate relationship between the frequency deviation and the area's interchange power variation. The standard deviational ellipse is evaluated using Tyler's maximum-likelihood estimator, which is distribution-free within the family of elliptical distributions. In addition, a target standard deviational ellipse is proposed, using predefined values for a target frequency bound and the area's frequency bias. The presented approach is based on the accordance of the estimated ellipse with the target ellipse, resulting in several grades for the LFC performance. A comparison of the proposed criterion is made with other LFC performance criteria known from the literature. Extensive measurements were applied, and the obtained results show the correctness of the proposed approach.
Auteurs: Boštjan Polajžer;Robert Brezovnik;Jožef Ritonja;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2296 - 2304
Editeur: IEEE
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» Evaluation of Potential and Impedance Integrals in Analysis of Axially Symmetric Metallic Structures to Prescribed Accuracy Up To Machine Precision
Résumé:
This paper presents a novel method for evaluating potential and impedance integrals appearing in the method of moment analysis of arbitrary axially symmetric metallic structures based on exact wire kernel and higher order bases. Due to new variable transforms proposed for singularity cancellation and smoothing the integrands, high accuracy up to machine precision is achieved using relatively small number of integration points. Simple formulas are determined for predicting a number of integration points needed for prescribed accuracy. Benefits of high-precision evaluation of impedance integrals are illustrated on a number of numerical examples.
Auteurs: Aleksandra J. Krneta;Branko M. Kolundzija;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2526 - 2539
Editeur: IEEE
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» Evaluation of the Range Accuracy and the Radiometric Calibration of Multiple Terrestrial Laser Scanning Instruments for Data Interoperability
Résumé:
Terrestrial laser scanning (TLS) data provide 3-D measurements of vegetation structure and have the potential to support the calibration and validation of satellite and airborne sensors. The increasing range of different commercial and scientific TLS instruments holds challenges for data and instrument interoperability. Using data from various TLS sources will be critical to upscale study areas or compare data. In this paper, we provide a general framework to compare the interoperability of TLS instruments. We compare three TLS instruments that are the same make and model, the RIEGL VZ-400. We compare the range accuracy and evaluate the manufacturer's radiometric calibration for the uncalibrated return intensities. Our results show that the range accuracy between instruments is comparable and within the manufacturer's specifications. This means that the spatial XYZ data of different instruments can be combined into a single data set. Our findings demonstrate that radiometric calibration is instrument specific and needs to be carried out for each instrument individually before including reflectance information in TLS analysis. We show that the residuals between the calibrated reflectance panels and the apparent reflectance measured by the instrument are greatest for highest reflectance panels (residuals ranging from 0.058 to 0.312).
Auteurs: Kim Calders;Mathias I. Disney;John Armston;Andrew Burt;Benjamin Brede;Niall Origo;Jasmine Muir;Joanne Nightingale;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2716 - 2724
Editeur: IEEE
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» Evaluation Scheme for EMI of Train Body Voltage Fluctuation on the BCU Speed Sensor Measurement
Résumé:
The voltage fluctuation between the train body (TB) and the train’s wheel axis (TB voltage fluctuation for short), might cause electromagnetic interference (EMI) on brake control unit (BCU) speed sensor in some high-speed trains (HSTs), which may cause faulty measurement of train speed and incorrect operation of train door. Using a relevant event that occurred in China railways high-speed 380CL-type train as case study, this paper presents an evaluation scheme for the EMI influence of TB voltage fluctuation on the speed measurement of BCU speed sensor. First, the EMI channels are researched, and a model representing the relation between TB voltage and voltage signal reflecting measured speed is deduced. Second, an evaluation scheme for speed measurement influenced by EMI is designed on this basis, where TB voltage and voltage signal reflecting measured speed are taken as the input and the output of model, respectively. The evaluation aimed at EMI is realized by judging the correctness of model output. Later, a real-life experiment is performed in the Chinese Nanjing station to verify the validity and feasibility of evaluation scheme. Last, some application studies are made to evaluate the presented scheme under multiple specific conditions, such as different TB contact conditions or different train speeds. The comparison results illustrate that the scheme can not only provide an opportunity to judge the correctness of speed measurement under the premise of collecting TB voltages, but also provide references in taking timely measures to prevent faulty speed measurement such as weakening TB voltage fluctuations.
Auteurs: Ke Huang;Zhigang Liu;Feng Zhu;Zongsheng Zheng;Ye Cheng;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 1046 - 1057
Editeur: IEEE
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» Event-Triggered Optimal Control for Partially Unknown Constrained-Input Systems via Adaptive Dynamic Programming
Résumé:
Event-triggered control has been an effective tool in dealing with problems with finite communication and computation resources. In this paper, we design an event-triggered control for nonlinear constrained-input continuous-time systems based on the optimal policy. Constraints on controls are handled using a bounded function. To learn the optimal solution with partially unknown dynamics, an online adaptive dynamic programming algorithm is proposed. The identifier network, the critic network, and the actor network are employed to approximate the unknown drift dynamics, the optimal value, and the optimal policy, respectively. The identifier is tuned based on online data, which further trains the critic and actor at triggering instants. A concurrent learning technique repeatedly uses past data to train the critic. Stability of the closed-loop system, and convergence of neural networks to the optimal solutions are proved by Lyapunov analysis. In the end, the algorithm is applied to the overhead crane system to observe the performance. The event-triggered optimal controller with constraints stabilizes the system and consumes much less sampling times.
Auteurs: Yuanheng Zhu;Dongbin Zhao;Haibo He;Junhong Ji;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4101 - 4109
Editeur: IEEE
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» Evidential Fusion Based Technique for Detecting Landslide Barrier Lakes From Cloud-Covered Remote Sensing Images
Résumé:
Landslide barrier lakes usually form quickly after disasters and require very timely remote sensing images to monitor the land-cover change. However, cloud-free images are not always available in emergency situations. This paper provides a method to fuse multitemporal cloud-covered images for change detection, based on the evidential fusion framework. First, the frame of discernment is defined by postclassification comparison results. Second, a way of measuring the basic belief assignment (BBA) is introduced based on the confusion matrixes. Next, a simple BBA redistribution process is proposed to deal with cloud coverage problems. Then, the complementary and redundant information from the input images can be fused following the evidence combination and decision making rules in the evidential fusion framework. Finally, the land-cover change map can be derived. Thanks to the Dempster–Shafer evidence theory, the proposed method can complete the change detection process—including data fusion and cloud removal—in an integrated manner. The proposed method is applied to detect the landslide barrier lake in a real case study, using a series of cloud-covered images from the GF-1 satellite. Result comparisons show that the proposed method is more effective than some basic fusion strategies that perform change detection and cloud removal in separate steps. Then, some approaches to improve the proposed method are discussed: introducing new evidence combination rule, improving the classification accuracy, and adding new evidences. All the results indicate the potential of evidential fusion for change detection from cloud-covered images.
Auteurs: Xi Chen;Jing Li;Yunfei Zhang;Weiguo Jiang;Liangliang Tao;Wei Shen;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1742 - 1757
Editeur: IEEE
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» Evolutionary Nonnegative Matrix Factorization Algorithms for Community Detection in Dynamic Networks
Résumé:
Discovering evolving communities in dynamic networks is essential to important applications such as analysis for dynamic web content and disease progression. Evolutionary clustering uses the temporal smoothness framework that simultaneously maximizes the clustering accuracy at the current time step and minimizes the clustering drift between two successive time steps. In this paper, we propose two evolutionary nonnegative matrix factorization (ENMF) frameworks for detecting dynamic communities. To address the theoretical relationship among evolutionary clustering algorithms, we first prove the equivalence relationship between ENMF and optimization of evolutionary modularity density. Then, we extend the theory by proving the equivalence between evolutionary spectral clustering and ENMF, which serves as the theoretical foundation for hybrid algorithms. Based on the equivalence, we propose a semi-supervised ENMF (sE-NMF) by incorporating a priori information into ENMF. Unlike the traditional semi-supervised algorithms, a priori information is integrated into the objective function of the algorithm. The main advantage of the proposed algorithm is to escape the local optimal solution without increasing time complexity. The experimental results over a number of artificial and real world dynamic networks illustrate that the proposed method is not only more accurate but also more robust than the state-of-the-art approaches.
Auteurs: Xiaoke Ma;Di Dong;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1045 - 1058
Editeur: IEEE
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» Evolutive Strategy to Inducing Chaos in a Gene Regulatory Network
Résumé:
In the present paper we propose an Evolutionary Strategy of Multiobjective Optimization like an alternative method to induce chaotic dynamics in a genetic regulatory network, called V-System, which was created by joining two systems of equations: one oscillating and one with a hysteresis dynamics. The genetic regulatory network is represented by four differential equations with seventeen parameters, which variables show the proteins concentrations. The multiobjective fitness function is built like a linear combination, involving a numerical approximation to Lyapunov exponents in the system, which is only dependent of the parameters fixed values. The optimization problem optimum represents the set of parameters values where the system is more chaotic. We present the numerical results of the evolutionary strategy and we show the convergence of the individuals in the population to the critical points in one of the subsystems in the V-System.
Auteurs: Hector Guardado Muro;Eunice Esther Ponce de Leon Senti;Aurora Torres Soto;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 916 - 921
Editeur: IEEE
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» Exact Moderate Deviation Asymptotics in Streaming Data Transmission
Résumé:
In this paper, a streaming transmission setup is considered, where an encoder observes a new message in the beginning of each block and a decoder sequentially decodes each message after a delay of $T$ blocks. In this streaming setup, the fundamental interplay between the coding rate, the error probability, and the blocklength in the moderate deviations regime is studied. For output symmetric channels, the moderate deviations constant is shown to improve over the block coding or non-streaming setup by exactly a factor of $T$ for a certain range of moderate deviations scalings. For the converse proof, a more powerful decoder, to which some extra information is fedforward is assumed. The error probability is bounded first for an auxiliary channel and this result is translated back to the original channel by using a newly developed change-of-measure lemma, where the speed of decay of the remainder term in the exponent is carefully characterized. For the achievability proof, a known coding technique that involves a joint encoding and decoding of fresh and past messages is applied with some manipulations in the error analysis.
Auteurs: Si-Hyeon Lee;Vincent Y. F. Tan;Ashish Khisti;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2726 - 2736
Editeur: IEEE
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» Experience With a Multidisciplinary, Team-Taught Smart Grid Cyber Infrastructure Course
Résumé:
Electric power systems are going through a major upgrade with the integration of advanced technologies to enable the smarter electric grid (SEG). The SEG will use information and communications technology to have enhanced controllability and will become more interactive. This ongoing change also necessitates educating professionals and future generation of engineers to manage evolving complexity of the electric grid. This paper presents experiences in the design and teaching of a unique multidisciplinary team-taught course on smart grid cyber infrastructure to provide a new generation of engineers with a solid foundation of smart grid concepts and their associated challenges. This paper identifies the course topics covered, learning objectives, and assessment activities for the class as well as lessons learned based on course evaluations obtained from multiple offerings. All of the course material is available in public domain and can be easily adopted at another educational institution.
Auteurs: Anurag K. Srivastava;Adam L. Hahn;Olusola O. Adesope;Carl H. Hauser;David E. Bakken;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2267 - 2275
Editeur: IEEE
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» Experimental Characterization of the Thermal Time Constants of GaN HEMTs Via Micro-Raman Thermometry
Résumé:
Gallium nitride (GaN) high-electron mobility transistors (HEMTs) are a key technology for realizing next generation high-power RF amplifiers and high-efficiency power converters. However, elevated channel temperatures due to self-heating often severely limit their power handling capability. Although the steady-state thermal behavior of GaN HEMTs has been studied extensively, significantly fewer studies have considered their transient thermal response. In this paper, we report a methodology for measuring the transient temperature rise and thermal time constant spectrum of GaN HEMTs via time-resolved micro-Raman thermometry with a temporal resolution of 30 ns. We measured a broad spectrum of time constants from $approx 130$ ns to $approx 3.2$ ms that contribute to the temperature rise of an ungated GaN-on-SiC HEMT due to aggressive, multidimensional heat spreading in the die and die-attach. Our findings confirm previous theoretical analysis showing that one or two thermal time constants cannot adequately describe the transient temperature rise and that the temperature reaches steady-state at $approx {16}L^{{2}}/pi ^{{2}}alpha $ , where $L$ and ${alpha }$ are the thickness and thermal diffusivity of the substrate. This paper provides a practical methodology for validating transient thermal models of GaN HEMTs and for obtaining experimental values of the thermal resistances and capacitances for compact electrothermal modeling.
Auteurs: Kevin R. Bagnall;Omair I. Saadat;Sameer Joglekar;Tomás Palacios;Evelyn N. Wang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2121 - 2128
Editeur: IEEE
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» Experimental Realization of Thermal Stability Enhancement of Nickel Germanide Alloy by Using TiN Metal Capping
Résumé:
In this paper, we demonstrated the enhancement of thermal stability of nickel germanide (NiGe) alloy up to 600 °C by using titanium nitride (TiN) metal capping. A high ${I}_{ mathrm{scriptscriptstyle ON}}/{I}_{ mathrm{scriptscriptstyle OFF}}$ ratio of $2.9 times 10^{5}$ was achieved by capping TiN metal on Ni for NiGe alloy formation at 600 °C. Detailed analyses were performed for realizing the mechanism for TiN capping on NiGe/Ge, including vertical element diffusion profile observation through depth-profiling X-ray photoelectron spectroscopy (XPS), element diffusion distribution by energy-dispersive X-ray spectroscopy mapping, and direct junction leakage current path detection by conductive atomic force microscopy. The experimental results indicated that TiN capping can reduce the risk of agglomeration and form a graded NiGe/Ge Schottky junction that is beneficial for suppressing the degradation of junction leakage. Subsequently, we compared the electrical performance of TiN/NiGe/n-Ge at various N/Ti ratios of TiNs. Based on the depth-profiling XPS results and electrical performance, TiN with an N/Ti ratio of approximately 1:1 can resist the Ni and Ge diffusion, which facilitates the suppression of the agglomeration process. However, the TiN capping layers with an N/Ti ratio of less than approximately 1:1 (Ti-rich) were not favorable for resisting Ni and Ge diffusion.
Auteurs: Chen-Han Chou;Yi-He Tsai;Chung-Chun Hsu;Yu-Hau Jau;Yu-Hsien Lin;Wen-Kuan Yeh;Chao-Hsin Chien;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2314 - 2320
Editeur: IEEE
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» Experimental Study of Electrically Compact Retrodirective Monopole Antenna Arrays
Résumé:
Auto-pointing and angular super-resolution properties of the radiation patterns generated by an electrically compact retrodirective monopole antenna array are demonstrated experimentally for the first time. The operation of electrically compact (element spacings less than one-fifth of the radiation wavelength) retrodirective antenna arrays that were theoretically considered in our previous work is confirmed by measurement. Particularly, it is shown that the direction-of-arrival information carried by an incident electromagnetic wave can be encoded into the evanescent near field of an electrically small resonant antenna array with a spatial rate higher than the spatial oscillation rate of the incident field in free space. This observation is supported by the near-field measurements, demonstrating that the magnitude of the scattered (evanescent) field in the array environment can exceed the magnitude of the incident field in free space by at least 6 dB. Retrodirective array antenna matching and the feasibility of a frequency-division full-duplex communication link based on the proposed antenna arrays are also discussed.
Auteurs: Oleksandr Malyuskin;Vincent F. Fusco;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2339 - 2347
Editeur: IEEE
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» Experimental Study on Deflection Behavior of Vacuum Arcs Under the Influence of External Transverse Magnetic Field
Résumé:
In real power system, when the three-phase short-circuit fault occurs, the vacuum arc in one phase will be influenced by the transverse magnetic field generated by neighbor phases and bus bars. This kind of effect is the main cause of the unstable arc and deflected erosion of contact plates, which leads to the failure of vacuum circuit breakers interruption. The objective of this paper is to get more insight into the influence of external transverse magnetic field (ETMF) on vacuum arc’s behavior. The experiments were conducted in a demountable vacuum chamber with pressure about $10^{-4}$ Pa. The cup-type axial magnetic field contacts were used, whose material was pure copper and the diameter is 35 mm. The uniform ETMF in the arc region was generated by two parallel bulk permanent magnets. The experiments were conducted under different ETMFs (0, 15, and 25 mT) and current levels (1-, 2.5-, and 4-kA rms) with different gap distances (6, 8.5, and 11 mm). The videos of arc column were recorded by a high-speed charge-coupled device camera. Under the action of ETMF, the vacuum arc got deflected. Due to the retrograde motion of cathode spots and Ampere force acting on arc column, the deflection behaviors during three typical periods (that is, initial, peak value, and close-to-current-zero period) were different. Moreover, the deflection level of vacuum arc at current peak value moment was greatly impacted by ETMF and gap distance. Larger the ETMF and gap distance were, higher the deflection level at current peak value moment was. The simulation results of arc deflection based on magnetic-hydrodynamic model were in agreement with experimental results in trends.
Auteurs: Shenli Jia;Zhonghao Qian;Lijun Wang;Wein Xin Shi;Jie Deng;Xiao Zhang;Zongqian Shi;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 868 - 874
Editeur: IEEE
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» Experimental Validation of a Fast Forward Model for Guided Wave Tomography of Pipe Elbows
Résumé:
Ultrasonic guided wave tomography (GWT) methods for the detection of corrosion and erosion damage in straight pipe sections are now well advanced. However, successful application of GWT to pipe bends has not yet been demonstrated due to the computational burden associated with the complex forward model required to simulate guided wave propagation through the bend. In a previous paper [Brath et al., IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 61, pp. 815–829, 2014], we have shown that the speed of the forward model can be increased by replacing the 3-D pipe bend with a 2-D rectangular domain in which guided wave propagation is formulated based on an artificially inhomogeneous and elliptically anisotropic (INELAN) acoustic model. This paper provides further experimental validation of the INLEAN model by studying the traveltime shifts caused by the introduction of shallow defects on the elbow of a pipe bend. Comparison between experiments and simulations confirms that a defect can be modeled as a phase velocity perturbation to the INLEAN velocity field with accuracy that is within the experimental error of the measurements. In addition, it is found that the sensitivity of traveltime measurements to the presence of damage decreases as the damage position moves from the interior side of the bend (intrados) to the exterior one (extrados). This effect is due to the nonuniform ray coverage obtainable when transmitting the guided wave signals with one ring array of sources on one side of the elbow and receiving with a second array on the other side.
Auteurs: Alex J. Brath;Francesco Simonetti;Peter B. Nagy;Geir Instanes;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 859 - 871
Editeur: IEEE
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» Exploiting Non-Orthogonal Multiple Access in Cooperative Relay Sharing
Résumé:
We propose and investigate a dual-hop cooperative relaying scheme using non-orthogonal multiple access (NOMA) (termed NOMA-RS), where two sources communicate with their corresponding destinations in parallel over the same frequency band via a common relay. In this scheme, after receiving symbols transmitted in parallel by both sources with different allocated powers, the relay forwards a super-position coded composite signal using NOMA to the destinations. One of the main benefits of NOMA-RS is that multiple (two) sources can share the same relay, unlike the previous works. Through the simulations and mathematical analysis, we demonstrate the effectiveness of the proposed protocol in terms of ergodic sum capacity by considering perfect and imperfect successive interference cancellation.
Auteurs: Md. Fazlul Kader;Muhammad Basit Shahab;Soo Young Shin;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1159 - 1162
Editeur: IEEE
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» Exploring Tag Distribution in Multi-Reader RFID Systems
Résumé:
Radio Frequency Identification (RFID) brings a revolutionary change in a range of applications by automatically monitoring and tracking products. With the proliferation of RFID-enabled applications, multiple readers are needed for ensuring the full coverage of numerous RFID tags. In this paper, we focus on the tag distribution problem in multi-reader RFID systems. The problem is to fast identify the tag set beneath each reader, which is a fundamental premise of efficient product inventory and management. Only with such tag set information can we localize specific tags in a reader and expedite the tag query information collection. As an RFID system usually contains a large number of tags and multiple readers, the traditional solution to identify tags by individual readers is highly time inefficient. We propose an Inference-Based protocol (IB) that identifies the tag distribution based on information inference rules and the aggregated physical signals to improve operational efficiency. In our protocol, three kinds of inference rules based on internal information reported by a single reader, external information shared by multiple readers, and history information retained by the system are fully exploited to infer tag distribution. With these rules, all readers can cooperatively work together and quickly obtain the tag distribution in the system. We also build a prototype RFID system using the USRP-based reader and WISP programmable tags, and then implement the IB protocol. The experimental results and extended simulations show that IB outperforms the state-of-the-art protocols.
Auteurs: Feng Zhu;Bin Xiao;Jia Liu;Bin Wang;Qingfeng Pan;Li-Jun Chen;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1300 - 1314
Editeur: IEEE
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» Extended Efficiency Range, Equal-Cell Doherty Amplifier Design Using Explicit Circuit Model
Résumé:
This letter presents the design of a symmetrical Doherty power amplifier (DPA) with extended high-efficiency range by using a new and explicit circuit model. Theoretical analysis reveals that by the adjustment of the electrical length of transmission line sections in the proposed circuit model, new DPA variants with simple circuitry and enhanced output back-off (OBO) are obtained. For experimental verification, a 42-dBm, 2-GHz DPA with OBO of 9.5 dB was designed and fabricated using identical GaN HEMT devices. Under continuous-wave stimulation, measurement results indicate good Doherty behavior can be obtained with 9.5-dB back-off efficiency of 51%–61% and saturation efficiency of 68%–72% over 1.85–2.1 GHz. Moreover, with single carrier WCDMA signal (centered at 2.1 GHz) and peak-to-average power ratio of 9.6 dB, the proposed design is found to deliver an average drain efficiency of 58% and adjacent channel leakage power of −47 dBc at an output power level of 32.5 dBm.
Auteurs: Xiao-Hu Fang;Hao-Yu Liu;Kwok-Keung M. Cheng;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 497 - 499
Editeur: IEEE
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» Extrafoveal Video Extension for an Immersive Viewing Experience
Résumé:
Between the recent popularity of virtual reality (VR) and the development of 3D, immersion has become an integral part of entertainment concepts. Head-mounted Display (HMD) devices are often used to afford users a feeling of immersion in the environment. Another technique is to project additional material surrounding the viewer, as is achieved using cave systems. As a continuation of this technique, it could be interesting to extend surrounding projection to current television or cinema screens. The idea would be to entirely fill the viewer's field of vision, thus providing them with a more complete feeling of being in the scene and part of the story. The appropriate content can be captured using large field of view (FoV) technology, using a rig of cameras for 110 ^{\circ} to 360 ^{\circ} capture, or created using computer-generated images. The FoV is, however, rather limited in its use for existing (legacy) content, achieving between 36 to 90 degrees ( ^{\circ} ) field, depending on the distance from the screen. This paper seeks to improve this FoV limitation by proposing computer vision techniques to extend such legacy content to the peripheral (extrafoveal) vision without changing the original creative intent or damaging the viewer's experience. A new methodology is also proposed for performing user tests in order to evaluate the quality of the experience and confirm that the sense of immersion has been increased. This paper thus presents: i) an algorithm to spatially extend- the video based on human vision characteristics, ii) its subjective results compared to state-of-the-art techniques, iii) the protocol required to evaluate the quality of the experience (QoE), and iv) the results of the user tests.
Auteurs: Laura Turban;Fabrice Urban;Philippe Guillotel;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1520 - 1533
Editeur: IEEE
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» FabSquare: Fabricating Photopolymer Objects by Mold 3D Printing and UV Curing
Résumé:
The FabSquare system is a personal fabrication method that lets users fabricate objects by molding photopolymers inside a 3D printed mold. The molds are printed with UV-transparent materials that allow for UV curing--the polymerization and solidification of the fluid content. The molds can be repeatedly reused to fabricate identical objects or create new objects with identical geometry, but different components. Because the necessary equipment is easily obtainable and affordable, the FabSquare approach is suitable for ordinary users in nonspecialized labs, allowing them to rapidly fabricate a range of objects. https://extras.computer.org/extra/mcg2017030034s1.mp4https://extras.computer.org/extra/mcg2017030034s2.pdf
Auteurs: Vahid Babaei;Javier Ramos;Yongquan Lu;Guillermo Webster;Wojciech Matusik;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 34 - 42
Editeur: IEEE
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» Family of Enhanced ZCS Single-Stage Single-Phase Isolated AC–DC Converter for High-Power High-Voltage DC Supply
Résumé:
AC–DC power supply is essential equipment which builds the connection between the ac grid and the dc loads. In order to achieve high-power density and high efficiency, a family of enhanced zero-current-switched (ZCS) single-stage single-phase isolated ac–dc converters is proposed for high-power high-voltage dc application. Only one resonant capacitor is required for the proposed converters to realize ZCS operation. On the other hand, the over voltage problem which exists in former developed ZCS ac–dc topologies is eliminated. Thus, lower voltage rating IGBTs can be applied. Higher efficiency is realized. At the same time, these converters inherit the feature such as one-stage power conversion, low conduction loss, good total harmonics distortion performance, etc. A 3 kW prototype is built to verify the proposed converters. A comparison is made to show the efficiency improvement clearly.
Auteurs: Chushan Li;Dewei Xu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3629 - 3639
Editeur: IEEE
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» Fast and Accurate Computation of the Multilook Interferometric Phase Probability Density Function
Résumé:
This letter reports a method to compute the multilook interferometric phase probability density function (pdf) used in interferometric synthetic aperture radar (InSAR). The method is fast and accurate for at least 10 000 looks and the full range of interferometric correlations. This is accomplished by computing the products of large and small numbers in the underlying hypergeometric series logarithmically and by deriving a single-term recursion relation to accelerate the computation. This letter extends the usable range of inputs to the multilook interferometric phase pdf for radar systems with a large number of looks and the entire practical range of interferometric correlation.
Auteurs: Mark S. Haynes;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 769 - 772
Editeur: IEEE
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» Fast and Efficient Analysis of Radome-Enclosed Antennas in Receiving Mode by an Iterative-Based Hybrid Integral Equation/Modified Surface Integration Method
Résumé:
An iterative-based hybrid method, which combines the volume-surface integral equation (VSIE) and the modified surface integration (MSI) method, is presented to analyze the radome-enclosed antennas in receiving mode. Compared with the previously published hybrid approaches, this method improves computational accuracy by including the effects of shaded wall of the radome and the mutual interactions between antennas and radome during the numerical solution of the VSIE in an iterative manner. By embedding different parts of the antenna-radome structure (ARS) into three distinct oct-trees, the multilevel fast multipole algorithm (MLFMA) is used to accelerate both the VSIE solution and the surface/volume integrations in the MSI stage. The new method obtains more accurate results than its original version within less CPU time, and keeps good accuracy with much less memory usage and computational time when compared with the MLFMA-accelerated full-wave VSIE solution for the entire ARS.
Auteurs: Binbin Wang;Mang He;Jinbo Liu;Chuanfang Zhang;Houjun Sun;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2436 - 2445
Editeur: IEEE
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» Fast Grid Security Assessment With N − k Contingencies
Résumé:
The challenge of grid security assessment with $N- k$ contingencies lies in a huge amount of transmission security constraints and even for the modest values of N and k, the computational complexity would be very high. A new method for fast grid security assessment is presented in this paper for DC grid. The key idea is to construct a small number of representative constraints to equivalently “represent” the huge number of original security constraints. It is proved that applying the representative constraints is sufficient to assess grid security as the original security constraints do. An important feature of the new method is that the representative constraints need to be constructed only once offline. They are only related to the parameters of transmission network and do not change with power injections. Numerical testing is performed for IEEE-RTS 24-bus system, IEEE 118-bus system, and the Polish 2383-bus system. The number of representative constraints to be assessed is only 1.1%, 0.32%, and 0.27% of that of the original constraints, respectively, and the computational time of security assessment is greatly reduced.
Auteurs: Yafei Yang;Xiaohong Guan;Qiaozhu Zhai;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2193 - 2203
Editeur: IEEE
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» Fast Packet Classification Based on Hybrid Cutting
Résumé:
Most existing packet classification algorithms adopt only one cutting strategy. However, the proposed algorithm adopts a hybrid one that combines equi-sized cuttings with pivot-based cuttings, so it can significantly increase cutting efficiency. Therefore, it can have distinct features, such as smaller table size, larger supportable rule set, and higher classification performance compared with the existing competitors.
Auteurs: Jae-Hyeong Wee;Wooguil Pak;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1011 - 1014
Editeur: IEEE
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» FBG Thermal Sensing Features for Hot Spot Monitoring in Random Wound Electric Machine Coils
Résumé:
This paper investigates the key design and operational features of embedded fiber Bragg grating (FBG) sensing for thermal hot spot monitoring in random wound coils, such as used in low voltage electrical machines. To this end thermal experiments are performed on test wound coils embedded with FBG sensors to examine the vital application features of embedded sensor design, such as the sensor packaging material choice, in-situ calibration, sensitivity to vibration, and thermal response time. Measurement error rates are examined and quantified in representative practical tests. The reported results enable a much improved understanding of the performance implications of embedded FBG sensor design features and the attainable in-situ hot spot thermal monitoring performance in random wound coils.
Auteurs: Anees Mohammed;Siniša Djurović;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3058 - 3067
Editeur: IEEE
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» Feasibility Study of Using Electrically Conductive Concrete for Electromagnetic Shielding Applications as a Substitute for Carbon-Laced Polyurethane Absorbers in Anechoic Chambers
Résumé:
This paper investigates conductive concrete in electromagnetic shielding applications as a viable alternative to carbon-laced polyurethane, which is used as an absorber material in anechoic chambers. To greatly increase concrete’s electromagnetic shielding performance, carbon black, graphite powder, and steel fibers are introduced to its composition. Samples of conductive concrete have been prepared and its shielding effectiveness is evaluated. The test method is based on using power spectrum analysis to characterize the degree of shielding due to the different mechanisms of reflection and absorption. The tested samples are in the shape of anechoic chambers pyramidal cones, to provide gradual impedance gradient. Slabs with flat surface are also built and tested in order to compare the results. Measured data are then compared with published figures for commercial chamber performances. The range of frequency tested is from 1 to 5.5 GHz. The pyramidal conductive concrete samples yield an excellent shielding effectiveness of approximately 65 dB as opposed to the carbon-laced polyurethane performance of 50 dB.
Auteurs: Tuqa Khalid;Lutfi Albasha;Nasser Qaddoumi;Sherif Yehia;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2428 - 2435
Editeur: IEEE
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» Feature Constrained Multi-Task Learning Models for Spatiotemporal Event Forecasting
Résumé:
Spatial event forecasting from social media is potentially extremely useful but suffers from critical challenges, such as the dynamic patterns of features (keywords) and geographic heterogeneity (e.g., spatial correlations, imbalanced samples, and different populations in different locations). Most existing approaches (e.g., LASSO regression, dynamic query expansion, and burst detection) address some, but not all, of these challenges. Here, we propose a novel multi-task learning framework that aims to concurrently address all the challenges involved. Specifically, given a collection of locations (e.g., cities), forecasting models are built for all the locations simultaneously by extracting and utilizing appropriate shared information that effectively increases the sample size for each location, thus improving the forecasting performance. The new model combines both static features derived from a predefined vocabulary by domain experts and dynamic features generated from dynamic query expansion in a multi-task feature learning framework. Different strategies to balance homogeneity and diversity between static and dynamic terms are also investigated. And, efficient algorithms based on Iterative Group Hard Thresholding are developed to achieve efficient and effective model training and prediction. Extensive experimental evaluations on Twitter data from civil unrest and influenza outbreak datasets demonstrate the effectiveness and efficiency of our proposed approach.
Auteurs: Liang Zhao;Qian Sun;Jieping Ye;Feng Chen;Chang-Tien Lu;Naren Ramakrishnan;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1059 - 1072
Editeur: IEEE
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» Field Demonstration of a Real-Time 100-Gb/s PON Based on 10G-Class Optical Devices
Résumé:
We have demonstrated the first field trial of a real-time 100-Gb/s passive optical network with downstream/upstream data rates of 25/10-Gb/s/λ based on 10G-class optical devices supporting 0–40 km differential reach. We employ a single delay-interferometer (DI) to realize chirp management as well as frequency equalization to combat the chromatic dispersion during the fiber transmission and equalize the frequency response of the bandwidth-limited system. Owing to the periodical characteristic, DI can successfully manage the four downstream wavelengths simultaneously. As for the upstream transmission, a fiber Bragg grating is employed to compensate the dispersion of the four upstream channels. In addition, an optical amplification deployed at the optical line termination (OLT) is used to amplify the downstream optical power and pre-amplify the upstream signal for supporting more users. All the active and passive components except for transceivers are packaged into a single module in the OLT. The system stability is verified within 67-h real-time bit error rate measurement. We obtained a power budget of 33 dB with 0–40 km reach of standard single mode fiber based on non-return-to-zero on-off-keying modulation format for both downstream and upstream.
Auteurs: Honglin Ji;Lilin Yi;Zhengxuan Li;Lei Xue;Xiang Li;Qi Yang;Suyi Wang;Ying Yang;Shaohua Yu;Weisheng Hu;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1914 - 1921
Editeur: IEEE
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» Field Measurement and Analysis of Long-Reach and High-Splitting-Ratio 10G-EPON With Optical Amplifier in Central Office
Résumé:
It is important to economize the infrastructure of the access network and enhance its profitability because it represents the greatest part of network infrastructure cost. As 10G-EPON can be cost-effectively shared among various access services, it is one of the strong candidates to reduce the infrastructure cost of the next-generation access network. To further enhance cost effectiveness, it is useful to improve the acceptable link budget of access systems by using optical amplifiers (OAs), which can increase the splitting ratios and extend the reachable distance of the system. In this paper, we demonstrate an $N$:1 redundant 10G-EPON system with dual-rate central-office-set-type semiconductor optical amplifier (CO-SOA). Our 10G-EPON system reduces OPEX and CAPEX due to its extended reachable distance and elimination of intermediate offices while keeping its system reliability with the $N$ :1 protection system. Moreover, we also develop a method for estimating the total reachable distance of 10G-EPON systems with OAs in order to quantitatively evaluate the effect of extending reachable distance on various combinations of splitting ratio based on the results of actual demonstrations. Analyses of field measurement results clarify that the proposed system has sufficient design flexibility so as to satisfy the subscriber distribution requirements as regards the factors of splitting ratio and reachable distance. The results indicate that the $N$:1 optical subscriber unit protection with CO-SOAs is a promising approach to practical 10G-EPON systems that are cost effective and reliable.
Auteurs: Takuya Tsutsumi;Yoshihito Sakai;Toshihito Fujiwara;Hiroshi Ou;Yasutaka Kimura;Takeshi Sakamoto;Ken-Ichi Suzuki;Manabu Kubota;Akihiro Otaka;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1775 - 1784
Editeur: IEEE
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» Fin-Array Tunneling Trigger With Tunable Hysteresis on (001) Silicon Substrate
Résumé:
We report the fabrication and characterization of a GaAs fin-array tunneling trigger monolithically integrated on an exact (001) silicon substrate. A Schmitt-trigger-like behavior was observed under double sweep condition by connecting the tunnel diode with an on-chip load resistor. The tunneling trigger circuit was studied using load line analysis. Critical parameters of the circuit were extracted. We found that the circuit hysteresis can be tuned by tailoring of the diode dimensions and load resistor values.
Auteurs: Yu Han;Qiang Li;Kei May Lau;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 556 - 559
Editeur: IEEE
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» Finite Element Small-Signal Simulation of Electromagnetic Devices Considering Eddy Currents in the Laminations
Résumé:
This paper presents the validation of a small-signal finite-element simulation strategy comparing different simulation approaches. At first, a full 3-D non-linear model in the time domain is presented. Then, the small-signal strategy has been applied to the 3-D model achieving a considerable reduction of computational time. In both 3-D models, the eddy currents in the laminations are fully modeled. Then, in order to avoid 3-D model, a 2-D model has been considered. In this case, eddy currents are included adopting a homogenization technique. In the 2-D case, both non-linear time domain simulations and small-signal strategy have been implemented. The results of the four considered simulation strategies are in very good agreement, proving that the small-signal simulation strategy can be profitably used in order to reduce significantly the computational cost. As an example, this paper considers a two-port mutual inductor as a test model.
Auteurs: Omar Bottesi;Luigi Alberti;Ruth V. Sabariego;Johan Gyselinck;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 8
Editeur: IEEE
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» Finite Model Approximations and Asymptotic Optimality of Quantized Policies in Decentralized Stochastic Control
Résumé:
We consider finite model approximations of a large class of static and dynamic team problems where these models are constructed through uniform quantization of the observation and action spaces of the agents. The strategies obtained from these finite models are shown to approximate the optimal cost with arbitrary precision under mild technical assumptions. In particular, quantized team policies are asymptotically optimal. This result is then applied to Witsenhausen's celebrated counterexample and the Gaussian relay channel problem. For Witsenhausen's counterexample, our approximation approach provides, to our knowledge, the first rigorously established result that one can construct an $varepsilon$-optimal strategy for any $varepsilon > 0$ through a solution of a simpler problem.
Auteurs: Naci Saldi;Serdar Yüksel;Tamás Linder;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2360 - 2373
Editeur: IEEE
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» Finite-Difference Modeling of Broadband Huygens’ Metasurfaces Based on Generalized Sheet Transition Conditions
Résumé:
An explicit time-domain finite-difference technique for modeling zero-thickness Huygens’ metasurfaces based on generalized sheet transition conditions (GSTCs) is proposed and demonstrated using full-wave simulations. The Huygens’ metasurface is modeled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens’ metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time domain. Identifying the exact equivalence between Huygens’ metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modeling techniques based on a finite-difference formulation. Several examples, including generalized refraction, are shown to illustrate the temporal evolution of scattered fields from the Huygens’ metasurface under plane-wave normal incidence, in both harmonic steady-state and broadband regimes. In particular, due to its inherent time-domain formulation, a significant strength of the methodology is its ability to model time-varying metasurfaces, which is demonstrated with a simple example of a pumped metasurface leading to new frequency generation and wave amplification.
Auteurs: Tom J. Smy;Shulabh Gupta;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2566 - 2577
Editeur: IEEE
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» Finite-Difference Time-Domain Technique for Gyroelectric Material Structure Simulation Using Recursive Convolutions in Polarization
Résumé:
A gyrotropic material handling method is proposed. Our technique does not require modification of the finite-difference time-domain stepping algorithm, and the gyroelectric phenomenon can be treated as a variation of material polarization. The simulation of electromagnetic wave transmission through a test gyroelectric structure of a magnetized plasma layer is presented and compared with the analytical solution. An open source implementation is presented.
Auteurs: A. V. Friman;A. A. Gorbatsevich;P. P. Sverbil;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2745 - 2747
Editeur: IEEE
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» Finite-Element Modeling of Metasurfaces With Generalized Sheet Transition Conditions
Résumé:
A modeling of metasurfaces in the finite-element method (FEM) based on generalized sheet transition conditions (GSTCs) is presented. The discontinuities in electromagnetic fields across a metasurface as represented by the GSTC are modeled by assigning nodes to both the sides of the metasurface. The FEM-GSTC formulation in both 1-D and 2-D domains is derived and implemented. The method is extended to handle more general bianistroptic metasurfaces. The formulations are validated by several illustrative examples.
Auteurs: Srikumar Sandeep;Jian-Ming Jin;Christophe Caloz;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2413 - 2420
Editeur: IEEE
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» Finite-Length Linear Schemes for Joint Source-Channel Coding Over Gaussian Broadcast Channels With Feedback
Résumé:
In this paper, we study linear encoding for a pair of correlated Gaussian sources transmitted over a two-user Gaussian broadcast channel in the presence of unit-delay noiseless feedback, abbreviated as the GBCF. Each pair of source samples is transmitted using a linear transmission scheme in a finite number of channel uses. We investigate three linear transmission schemes: A scheme based on the Ozarow–Leung (OL) code, a scheme based on the linear quadratic Gaussian (LQG) code of Ardestanizadeh et al., and a novel scheme derived in this paper using a dynamic programming (DP) approach. For the OL and LQG schemes we present lower and upper bounds on the minimal number of channel uses needed to achieve a target mean-square error (MSE) pair. For the LQG scheme in the symmetric setting, we identify the optimal scaling of the sources, which results in a significant improvement of its finite horizon performance, and, in addition, characterize the (exact) minimal number of channel uses required to achieve a target MSE. Finally, for the symmetric setting, we show that for any fixed and finite number of channel uses, the DP scheme achieves an MSE lower than the MSE achieved by either the LQG or the OL schemes.
Auteurs: Yonathan Murin;Yonatan Kaspi;Ron Dabora;Deniz Gündüz;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2737 - 2772
Editeur: IEEE
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» Finite-Time Fuzzy Sampled-Data Control for Nonlinear Flexible Spacecraft With Stochastic Actuator Failures
Résumé:
This paper deals with the problem of finite-time sampled-data control for nonlinear flexible spacecraft described by Takagi–Sugeno (T–S) fuzzy model with stochastic actuator failures. Different from the existing literatures, T–S fuzzy approach is used to model the nonlinear behaviors of flexible spacecraft for its good approximation performance. A novel and general input model related to Markovian variables is developed to depict the stochastic actuator failures, which is capable of covering various faulty modes. With the aid of stochastic analysis and convex optimization techniques, a novel fault-tolerant fuzzy switching controller is designed to carry out the finite-time attitude stabilization for flexible spacecraft with the existence of stochastic failures and sampled-data inputs, and an optimal $H_infty$ performance level is ensured simultaneously. Finally, a practical example with simulation results are provided to validate the effectiveness of the developed control strategy.
Auteurs: Guanghui Sun;Shidong Xu;Zhan Li;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3851 - 3861
Editeur: IEEE
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» Finite/Fixed-Time Stabilization for Nonlinear Interconnected Systems With Dead-Zone Input
Résumé:
The decentralized control problem is considered for a class of nonlinear time-varying interconnected systems. Each subsystem is with the dead-zone input and unmodeled dynamics. The interconnections are bounded by time-varying nonlinear functions, which relaxes the commonly used linear condition or time-invariant condition. Based on the recursive method, we design a new decentralized finite-time controller such that all the state variables reach zero in finite time. The reaching time is based on the design parameters and initial value of system state. Furthermore, the fixed time stability conditions are given and the constructed controller can guarantee the fixed-time stabilization of the system, in which the reaching time only depends the control design parameters. Finally, simulation results are presented to illustrate the effectiveness of proposed method.
Auteurs: Changchun Hua;Yafeng Li;Xinping Guan;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2554 - 2560
Editeur: IEEE
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» First Principles Optimization of Opto-Electronic Communication Links
Résumé:
We introduce a first principles, end-to-end analysis of opto-electronic communication links which incorporates a thorough model of the receiver circuitry, in addition to the more familiar laser transmitter optimization. In particular, we optimize receiver sensitivity and power by studying their dependence on front-end design as well as follow-on digital sampler requirements. We find that the photo-receiver sensitivity is the most important factor in controlling the overall link power consumption. Our physical model and circuit optimization principles are applied to a heterogenous-integrated photonic+CMOS platform, where we show state-of-the-art performance through this physics-based rapid-design protocol. Incidentally this greatly simplifies the design process. Lastly, we apply this approach to extrapolate future performance trends, platform bottlenecks, and fundamental limits in optical link design while showcasing the potential for sub-1fJ/bit system efficiency at high speeds.
Auteurs: Krishna T. Settaluri;Christopher Lalau-Keraly;Eli Yablonovitch;Vladimir Stojanović;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1270 - 1283
Editeur: IEEE
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» First-Principles-Based Quantum Transport Simulations of Monolayer Indium Selenide FETs in the Ballistic Limit
Résumé:
We investigate the ballistic performance of monolayer indium selenide (InSe) n-type FETs, benchmarking with monolayer WS2, WSe2, and black phosphorus FETs. We utilize first-principles-based quantum transport simulations employing density functional theory and nonequilibrium Green’s function. The transfer characteristics, subthreshold swing, and drain-induced barrier lowering of InSe FETs are assessed and compared with those of the benchmarks. Our comparison of InSe FETs to the benchmark transistors reveals that InSe transistors are competitive in ON-state performance, but the short-channel effects in ultrascaled InSe FETs need to be suppressed. InSe FETs are favorable for high-performance applications rather than low power ones.
Auteurs: Yongsoo Ahn;Mincheol Shin;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2129 - 2134
Editeur: IEEE
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» Flat Panel Light-Field 3-D Display: Concept, Design, Rendering, and Calibration
Résumé:
Recent autostereoscopic 3-D (A3D) displays suffer from many limitations such as narrow viewing angle, low resolution, and shallow depth effects. As these limitations mainly originate from the insufficiency of pixel resources, it is not easy to obtain a feasible solution that can solve all the limitations simultaneously. In many cases, it will be better to find a good compromising design. Generally, the multiview display and the integral imaging display are the representative designs of A3D. However, as they are too canonical and lack flexibility in design, they tend to be a tradeoff. To address these design issues, we have analyzed the multiview display and the integral image display in a light-field coordinate and developed a 3-D display design framework in a light-field space. The developed framework does not use the “view” concept anymore. Instead, it considers the spatial distribution of rays of the 3-D display and provides more flexible and sophisticated design methods. In this paper, the developed design method is explained using a new pixel value assigning algorithm, called the light-field rendering, and vision-based parameter calibration methods for 3-D displays. We have also analyzed the blur effects caused by the depth and display characteristics. By implementing the proposed method, we have designed a 65-in 96-view display with a 4K panel. The developed prototype has showed almost seamless parallax with a high-resolution comparable to the conventional four to five views displays. This paper will be useful to readers interested in A3D displays, especially in the multiview and the integral imaging displays.
Auteurs: Dongkyung Nam;Jin-Ho Lee;Yang Ho Cho;Young Ju Jeong;Hyoseok Hwang;Du Sik Park;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 876 - 891
Editeur: IEEE
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» Flexibility Is Key in New York: New Tools and Operational Solutions for Managing Distributed Energy Resources
Résumé:
New York State is pioneering a new approach to regulating its electric utility companies that is expected to usher in the distributed energy system of tomorrow. Among the goals of the New York REV (Reforming the Energy Vision) proceeding launched in 2015 are a 40% reduction in greenhouse gas emissions from 1990 levels and a mandate for 50% of the state's electricity to be generated from renewable resources by 2030. In 2014, 25% of New York's electric generation was produced by renewables, of which 80% was from hydropower. In addition to these and other objectives, the New York Public Service Commission has identified the need to establish a distributed system platform provider (DSPP), which will facilitate new markets to accelerate adoption and realize the value of distributed energy resources (DERs). To do this, the incumbent utilities will perform the role of the DSPP and create and operate the distributed system platform (DSP). Building the DSP is a big task, and each of the New York utilities is in the process of deploying it according to their distribution system implementation plans (DSIPs).
Auteurs: Bob Currie;Chad Abbey;Graham Ault;Jeff Ballard;Brian Conroy;Ryan Sims;Chris Williams;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 20 - 29
Editeur: IEEE
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» Flexible and Stretchable Microwave Microelectronic Devices and Circuits
Résumé:
Electronic systems built on flexible plastic films and stretchable rubber sheets have attracted new applications in many emerging fields. Integration of high-speed electronics such as microwave power amplifiers and switches can extend the applications even further with wireless capabilities. As such, flexible and stretchable microwave electronics represent opportunities for future electronics where remote capabilities are desired. Here, we review advances in numerous types of microelectronic devices used for fast, flexible, and stretchable electronic devices, as well as flexible and stretchable passive elements and circuitries. We first introduce the challenges associated with design and fabrication, and the characteristics required for high-frequency operation of the devices on foreign substrates. Second, we review the recent efforts that were made utilizing different types of high-performance semiconductors, which are ideal for high-speed flexible and stretchable electronics, such as silicon, compound semiconductors, and 1-D and 2-D materials. Third, passive electronic components fabricated on such substrates, including inductors, capacitors, and transmission lines, are reviewed. Finally, we discuss the flexible and stretchable microwave electronics at the circuit level and review the recent advances in making numerous types of flexible and stretchable microwave circuits for diverse applications.
Auteurs: Yei Hwan Jung;Huilong Zhang;Sang June Cho;Zhenqiang Ma;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1881 - 1893
Editeur: IEEE
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» Flexible Capacitive Hydrogel Tactile Sensor With Adjustable Measurement Range Using Liquid Crystal and Carbon Nanotubes Composites
Résumé:
In this paper, we present a $4times4$ capacitive pressure tactile sensor fabricated with new materials, which consists of one dielectric layer and two electrode layers. The dielectric layer is composed of carbon nanotubes dispersed in liquid crystal, which is surrounded by a hydrogel elastomeric membrane. An upper Au parylene film and a lower Au parylene film taped on the kapton tapes are served as the electrode layers. The properties of the devices are well characterized and the capability of adjustable measurement range is successfully realized. Experimental results demonstrate that the capacitance will change with the different driving frequency and voltage accordingly.
Auteurs: Lixin Chen;Jingquan Liu;Xiaolin Wang;Bowen Ji;Xiang Chen;Bin Yang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1968 - 1972
Editeur: IEEE
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» Flexible Optoelectric Neural Interface Integrated Wire-Bonding $mu$ LEDs and Microelectrocorticography for Optogenetics
Résumé:
As an advanced brain–computer interface, the flexible surface electrode array has been used for spatiotemporal localization of neural interactions by recording electrocorticography (ECoG) signals over brain cortical areas. Compared with the electrical stimulation, optogenetics provides a potentially ideal way to stimulate the genetically modified brain tissue by light. In this paper, we developed an optoelectric neural interface combining a micro ECoG ( $mu $ ECoG) recording electrode array and a microlight-emitting diode ( $mu $ LED) array. Three $mu $ LED chips were connected to a flexible polyimide substrate by a unique wire bonding method, and their light-emitting surfaces were downward and in the same plane with the substrate’s lower surface, which allowed blue light directly going through the aligned holes on substrate with barely no loss. In addition, the recording electrodes were modified with electroplated platinum black or activated iridium oxide, and their stability was proved well after repetitive pressures. Mechanical strength and conformality of two $mu $ ECoG arrays with 5 and $10~mu text{m}$ thicknesses were tested. Finally, this bidirectional neural interface was proved to be effective by an acute in vivo experiment performed by attaching two devices with varied thicknesses to the cortical surface of a mouse expressing Channelrhodopsin-2.
Auteurs: Bowen Ji;Minghao Wang;Xiaoyang Kang;Xiaowei Gu;Chengyu Li;Bin Yang;Xiaolin Wang;Jingquan Liu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2008 - 2015
Editeur: IEEE
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» Flexible Organic Amplifiers
Résumé:
Signal processing is fundamental to the modern information society. Sensing and signal processing of various biological signals using human body conformable flexible organic integrated circuits have been actively researched to enable continuous health condition monitoring via wearable devices. To amplify very small electrical biological signals from humans, high performance flexible organic amplifiers are required. In this paper, we briefly review the principles and recent progresses of printable organic amplifiers, including materials, processes, and circuits.
Auteurs: Huabin Sun;Yong Xu;Yong-Young Noh;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1944 - 1954
Editeur: IEEE
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» Flicker Noise Performance on Thick and Thin Oxide FinFETs
Résumé:
1/f noise was characterized on Fin Field-Effect Transistors (FinFETs) to compare noise performance of CORE and IO devices of a technology node. Thin FinFETs (CORE devices with Equivalent Oxide Thickness (EOT) <1.5 nm and channel length L < 28 nm) were compared to thick FinFETs (IO devices with EOT > 3 nm and long channel L > 100 nm). At low gate bias condition [( $mathsf {V_{g}} -mathsf{V_{{{{th}}}}} le 0.15$ V), after normalization with respect to device area and EOT], noise level of thin FinFETs shows almost tenfold larger than that of thick FinFETs. Moreover, it is found that the discrepancy of noise measured at linear and saturation condition is more significant for FinFETs with shorter channel length. The bias-dependent noise was well fitted by unified model. The extracted defects concentration of thin FinFETs is ~10 times larger than that of thick FinFETs. Finally, flicker noise spectra measured after bias temperature instability stress were compared to that of before stress, the trap concentrations were calculated, and found that defects primarily presents in the metal/high-k interface and have more impact on noise performance if EOT is decreased.
Auteurs: Yi Ming Ding;Durgamadhab Durga Misra;Purushothaman Srinivasan;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2321 - 2325
Editeur: IEEE
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» Floating Gate Nonvolatile Memory Using Individually Cladded Monodispersed Quantum Dots
Résumé:
This paper presents nonvolatile memory characteristics of a quantum dot gate floating gate nonvolatile memory (QDNVM) that employs SiOx-cladded silicon quantum dots as discrete charge storage nodes of the floating gate. The cladding of Si quantum dots and control of their size are shown to result in a faster access and improved retention time. The floating gate is formed by site-specific self-assembly of SiOx-Si quantum dots on the tunnel oxide layer over the p-region between source and drain of an n-channel field-effect transistor (FET). Experimental data on fabricated long channel devices show threshold voltage shift as a function of duration and magnitude of the electrical stress applied during the “Write” operation. Current–voltage characteristics ( $I_{mathrm {D}}$ $V_{mathrm {D}}$ and $I_{D}$ $V_{G})$ are presented before and after stress. The electrical characteristics are explained using a quantum dot gate FET model which includes the threshold voltage shift ( $Delta text{V}_{mathrm { {TH}}})$ as a function of charge on the floating gate quantum dots due to applied electrical stress.
Auteurs: Ravi Shankar R. Velampati;El-Sayed Hasaneen;E. K. Heller;Faquir C. Jain;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1774 - 1781
Editeur: IEEE
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» Fluorescence Diffusion in the Presence of Optically Clear Tissues in a Mouse Head Model
Résumé:
Diffuse Optical Tomography commonly neglects or assumes as insignificant the presence of optically clear regions in biological tissues, estimating their contribution as a small perturbation to light transport. The inaccuracy introduced by this practice is examined in detail in the context of a complete, based on realistic geometry, virtual fluorescence Diffuse Optical Tomography experiment where a mouse head is imaged in the presence of cerebral spinal fluid. Despite the small thickness of such layer, we point out that an error is introduced when neglecting it from the model with possibly reduction in the accuracy of the reconstruction and localization of the fluorescence distribution within the brain. The results obtained in the extensive study presented here suggest that fluorescence diffuse neuroimaging studies can be improved in terms of quantitative and qualitative reconstruction by accurately taking into account optically transparent regions especially in the cases where the reconstruction is aided by the prior knowledge of the structural geometry of the specimen. Thus, this has only recently become an affordable choice, thanks to novel computation paradigms that allow to run Monte Carlo photon propagation on a simple graphic card, hence speeding up the process a thousand folds compared to CPU-based solutions.
Auteurs: Daniele Ancora;Athanasios Zacharopoulos;Jorge Ripoll;Giannis Zacharakis;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 05.-2017, volume: 36, issue:5, pages: 1086 - 1093
Editeur: IEEE
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» Foreword
Résumé:
“Flexible electronics” has been thriving in the scholarly world as a buzz phrase for nearly two decades. A flourishing industry focusing on such physically bendable electronics is also growing rapidly. Specially, two major consumer electronics giants, Samsung and LG, have announced the arrival of organic light-emitting diode-based displays. Still, the focus is dominated by innovation in materials—more specifically, organic molecules, 1-D nanowires and nanotubes, and, more recently, 2-D atomic-scale materials like graphene and dichalcogenide materials. The focus of research on flexible electronics is presently geared toward materials and proof-of-concept-level exciting applications. Materials research is focusing on energy harvesting and energy storage, and applications are mostly concentrated on sensing-based advanced health care technology (wearable and implantable electronics). Although they are all compelling visions, still advances in pragmatic fully integrated systems are rare. As we know, a fully integrated autonomous system for in vivo or in vitro applications requires a variety of electronics: power supply, power management circuitry, interface circuit components, high-performance microprocessor or small-scale data-processing unit, and active and passive communication components. Therefore, the main objective of this dedicated issue is to engage the Electron Devices Community in a serious discussion, with their scholarly contributions specifically focused on solving major challenges in the general area of flexible electronics.
Auteurs: Yong-Young Noh;Xiaojun Guo;Muhammad Mustafa Hussain;Zhenqiang Jack Ma;Deji Akinwande;Mario Caironi;Thomas D. Anthopoulos;Tse Nga Tina Ng;Ryoichi Ishihara;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1878 - 1880
Editeur: IEEE
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» FPGA-Based System for In-Line Measurement of Velocity Profiles of Fluids in Industrial Pipe Flow
Résumé:
The rheology of a fluid flowing in an industrial process pipe can be calculated by combining the pressure drop and the velocity profile that the fluid develops across the tube diameter. The profile is obtained noninvasively through an ultrasound Doppler investigation. Unfortunately, at present, no system capable of real-time velocity profile assessment is available for in-line industrial rheological measurements, and tests are operated by manually moving fluid specimens to specialized laboratories. In this work, we present an embedded system capable of in-line and real-time measurement of velocity profile and pressure drop, which enables the automatic rheological characterization of non-Newtonian fluids in process pipes. The system includes all the electronics for the ultrasound front-end, as well as the digital devices for the real-time calculation of the velocity profile. The proposed system is highly programmable, low-noise, and specifically targeted for industrial use. It is shown capable of producing, for example, 512-point velocity profiles at 45 Hz rate. An application is presented where a sludge fluid, flowing at 600 L/min in a 48 mm diameter high-grade stainless steel pipe, is characterized in real-time with a ±5% accuracy.
Auteurs: Stefano Ricci;Valentino Meacci;Beat Birkhofer;Johan Wiklund;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3997 - 4005
Editeur: IEEE
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» Fractional Hilbert Transform Sampling Method and Its Filter Bank Reconstruction
Résumé:
In this paper, conventional Hilbert transform sampling method is generalized to fractional Hilbert transform sampling method. First, a frequency-domain analysis method is applied to derive the fractional Hilbert transform sampling theorem of a band-limited signal. Then, an analog filter bank method is presented to recover the original continuous-time signal from the discrete-time sampled signals. Because the analog filter bank is not easy to be implemented, a digital filter bank method is proposed to solve the reconstruction problem. Next, a sparse design of digital reconstruction filters is studied to reduce the arithmetic implementation complexity using sparse FIR filter design techniques. Finally, several numerical examples are illustrated to show the effectiveness of the proposed fractional Hilbert transform sampling method and its filter bank reconstruction.
Auteurs: Chien-Cheng Tseng;Su-Ling Lee;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1214 - 1224
Editeur: IEEE
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» Freeform Compliant CMOS Electronic Systems for Internet of Everything Applications
Résumé:
The state-of-the-art electronics technology has been an integral part of modern advances. The prevalent rise of the mobile device and computational technology in the age of information technology offers exciting applications that are attributed to sophisticated, enormously reliable, and most mature CMOS-based electronics. We are accustomed to high performance, cost-effective, multifunctional, and energy-efficient scaled electronics. However, they are rigid, bulky, and brittle. The convolution of flexibility and stretchability in electronics for emerging Internet of Everything application can unleash smart application horizon in unexplored areas, such as robotics, healthcare, smart cities, transport, and entertainment systems. While flexible and stretchable device themes are being remarkably chased, the realization of the fully compliant electronic system is unaddressed. Integration of data processing, storage, communication, and energy management devices complements a compliant system. Here, a comprehensive review is presented on necessity and design criteria for freeform (physically flexible and stretchable) compliant high-performance CMOS electronic systems.
Auteurs: Sohail F. Shaikh;Mohamed T. Ghoneim;Galo A. Torres Sevilla;Joanna M. Nassar;Aftab M. Hussain;Muhammad M. Hussain;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1894 - 1905
Editeur: IEEE
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» Frequency Dependence of Magnetic Dissipation in Microwave Garnet Films
Résumé:
A frequency dependence of the magnetic dissipation parameter (half-linewidth) $Delta {H}$ for films of yttrium–iron garnet (YIG) was experimentally investigated in the interval of microwave frequencies 1.7–26 GHz. The $Delta {H}$ value did not change over a frequency range of 2.2–26 GHz. The effect of conducting screens placed near a YIG film on the $Delta {H}$ value was also studied experimentally. For a screened film, the value of $Delta {H}$ exceeds $Delta {H}$ for an unscreened film when the distance between the film and the metal screen was less than 40– $70~mu text{m}$ .
Auteurs: Boris A. Kalinikos;Nikolai G. Kovshikov;Pavel A. Kolodin;Ivan P. Panchurin;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 2
Editeur: IEEE
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» Frequency Selective Surface Structure Miniaturization Using Interconnected Array Elements on Orthogonal Layers
Résumé:
Traditionally, the element of a frequency selective surface (FSS) is rotationally symmetrical and the element arrays in a multilayer FSS are aligned with each other. A new approach to miniaturize the size of the FSS array element is proposed in this paper by interconnecting the array elements only in one direction in a two-layer FSS structure. One layer acts as an enhanced inductor while the other layer provides capacitance. The interconnection between the adjacent array elements changes the equivalent circuit and produces a strong cross-layer capacitance, which lowers the resonant frequency significantly. The dimensions of the miniaturized FSS element are much smaller than the wavelength at the resonant frequency (periodicity $ll lambda )$ . The element can also have a low profile since the cross-layer capacitance is stronger with a thinner substrate. The sensitivity to the incident angle of the proposed structure is comparable with traditional ones. A theoretical equivalent circuit model is developed to characterize the structure, based on the analysis of the geometrical configuration of the FSS structure and the electric field distribution on it. The theory was verified by the experimental results.
Auteurs: Muaad Naser Hussein;Jiafeng Zhou;Yi Huang;Muayad Kod;Abed Pour Sohrab;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2376 - 2385
Editeur: IEEE
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» Frequency-Dependent Directive Radiation of Monopole-Dielectric Resonator Antenna Using a Conformal Frequency Selective Surface
Résumé:
Development of a conformal frequency selective surface (FSS) for radiation diversity of hybrid monopole-dielectric resonator antenna has been demonstrated in this paper. In the proposed method, a planar FSS screen with meandered unit cell is designed to be reflective at 5 GHz followed by its mapping on a cylindrical surface of flexible dielectric material. The proposed conformal reflector when kept at a specific distance from the radiating element improves the bandwidth of the antenna from 26.8% to 53.67% in 4–6 GHz band. A significant enhancement of 5–6 dBi in gain is also achieved over this band. Gain of the antenna with reflector is maintained around 9.5 dBi with a variation of ±1.5 dB. On the other hand, omni-directional radiation of the antenna is maintained at an upper band of 7–9 GHz. Simulations have been performed using ANSYS High Frequency Structure Simulator (HFSS). Experimental measurements of the fabricated prototype have been provided. The proposed design is useful to achieve pattern diversity in multiband antenna system.
Auteurs: Ayan Chatterjee;Susanta Kumar Parui;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2233 - 2239
Editeur: IEEE
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» Frequency-Domain Transient Imaging
Résumé:
A transient image is the optical impulse response of a scene, which also visualizes the propagation of light during an ultra-short time interval. In contrast to the previous transient imaging which samples in the time domain using an ultra-fast imaging system, this paper proposes transient imaging in the frequency domain using a multi-frequency time-of-flight (ToF) camera. Our analysis reveals the Fourier relationship between transient images and the measurements of a multi-frequency ToF camera, and identifies the causes of the systematic error-non-sinusoidal and frequency-varying waveforms and limited frequency range of the modulation signal. Based on the analysis we propose a novel framework of frequency-domain transient imaging. By removing the systematic error and exploiting the harmonic components inside the measurements, we achieves high quality reconstruction results. Moreover, our technique significantly reduces the computational cost of ToF camera based transient image reconstruction, especially reduces the memory usage, such that it is feasible for the reconstruction of transient images at extremely small time steps. The effectiveness of frequency-domain transient imaging is tested on synthetic data, real data from the web, and real data acquired by our prototype camera.
Auteurs: Jingyu Lin;Yebin Liu;Jinli Suo;Qionghai Dai;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 937 - 950
Editeur: IEEE
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» Frequency-Hopping Pulse Position Modulation Ultrawideband Receiver
Résumé:
Pulse position modulation (PPM) has been used in the radio-frequency (RF) domain to achieve both low-dissipation requirements and provide precision ranging. In ultrawideband (UWB) architectures, it underpins an asynchronous receiver, multiple access environments, and interference-resistant transmission. When combined with frequency hopping (FH), it allows for an additional level of immunity to jamming and low probability of intercept. Realization of a FH-PPM transceiver poses a practical challenge, particularly in the UWB RF range. With UWB pulses reaching the multi-gigahertz range, FH adds to the effective bandwidth at which the receiver must be operated, exceeding the performance of a modern quantizer and digital demodulation backplane. This study describes a new photonics-assisted FH-PPM receiver architecture that rests on mutually coherent frequency combs. The performance of the new receiver was characterized by receiving and decoding an 80–Mb/s rate FH-PPM UWB signal.
Auteurs: Daniel J. Esman;Vahid Ataie;Bill P.-P. Kuo;Nikola Alic;Stojan Radic;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1894 - 1899
Editeur: IEEE
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» Friction Compensation Based on Time-Delay Control and Internal Model Control for a Gimbal System in Magnetically Suspended CMG
Résumé:
Nonlinear friction torque is an important factor affecting the angular velocity precision of a gimbal system in double gimbal magnetically suspended control moment gyro. To effectively eliminate the influence of friction torque and implement high precision control of the gimbal system, a method that combines time delay control (TDC) with two-degree-of-freedom (2-DOF) internal model control (IMC) is proposed. First, nonlinear friction torque of the gimbal system is estimated via time-delay estimation. Second, to independently adjust the tracking performance and disturbance rejection performance, and to enhance the robustness of TDC, 2-DOF IMC is introduced. Simulation and experimental results indicate that the proposed control method not only improves the compensation performance of the gimbal system with nonlinear friction torque, but also enhances the robustness and realizes the high precision control of the gimbal servo system.
Auteurs: Peiling Cui;Dachuan Zhang;Shan Yang;Haitao Li;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3798 - 3807
Editeur: IEEE
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» From Available Synchrophasor Data to Short-Circuit Fault Identity: Formulation and Feasibility Analysis
Résumé:
This paper proposes a novel formulation for determining the short-circuit fault identity, that is the fault type, faulted line, and exact fault distance on it, by using available synchrophasor data. A simple and yet quite effective procedure is developed to model the fault area as a stand-alone sub-system. Thanks to phasor measurement units (PMUs), the proposed technique does not require the operating point and model of the portions being replaced. This greatly alleviates the complexity and technical problems involved in modeling the entire power system, as enforced by existing wide-area methods. A couple of effective theorems in Circuit Theory are exploited in a way as to make the prefault bus impedance matrix applicable in the postfault condition. The obtained fault equations are readily solved by the least-squares method to provide a closed-form solution for the fault distance. Two necessary and sufficient conditions are introduced to assess the fault location feasibility by any given set of PMUs. High accuracy is achieved since the calculations merely involve sound equations remaining after removing erroneous measurements of instrument transformers. The proposed method is successfully validated by more than 10 000 simulation cases conducted on the New England 39-bus and 118-bus test systems.
Auteurs: Sadegh Azizi;Majid Sanaye-Pasand;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2062 - 2071
Editeur: IEEE
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» From Higher Education to Open Education: Challenges in the Transformation of an Online Traditional Course
Résumé:
Open education has revolutionized the educational environment. Massive open online courses have become the main showcase for open educational resources, but the competition to establish a position in this movement has led to the rapid publication of many courses of arguable quality. This paper presents and analyzes the process of creating a small private online course that meets the requirements to be offered as a massive course. The starting point was an online higher education course that had previously been published as OpenCourseWare. In this paper, data were examined from 112 students enrolled in four different academic years, during which changes were progressively incorporated to transform the traditional course to an open course. The results show an improvement in students’ perceptions of resources and assessments and in their overall satisfaction. New assessment tools were developed and validated, without affecting the academic results. The process had positive effects on the instructional design of the final course, but some risks were identified when the course was adapted as a massive course. The final course provides useful input for future developments and a more effective student-focused methodology.
Auteurs: José Luis Martín Núñez;Edmundo Tovar Caro;José Ramón Hilera González;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 134 - 142
Editeur: IEEE
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» From Random Matrix Theory to Coding Theory: Volume of a Metric Ball in Unitary Group
Résumé:
Volume estimates of metric balls in manifolds find diverse applications in information and coding theory. In this paper, new results for the volume of a metric ball in unitary group are derived via tools from random matrix theory. The first result is an integral representation of the exact volume, which involves a Toeplitz determinant of Bessel functions. A simple but accurate limiting volume formula is then obtained by invoking Szegő’s strong limit theorem for large Toeplitz matrices. The derived asymptotic volume formula enables analytical evaluation of some coding-theoretic bounds of unitary codes. In particular, the Gilbert–Varshamov lower bound and the Hamming upper bound on the cardinality as well as the resulting bounds on code rate and minimum distance are derived. Moreover, bounds on the scaling law of code rate are found. Finally, a closed-form bound on the diversity sum relevant to unitary space-time codes is obtained, which was only computed numerically in the literature.
Auteurs: Lu Wei;Renaud-Alexandre Pitaval;Jukka Corander;Olav Tirkkonen;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2814 - 2821
Editeur: IEEE
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» From the editors' desk
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Ed Cherney;Robert Fleming;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 05.-2017, volume: 33, issue:3, pages: 6 - 7
Editeur: IEEE
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» Full Wave Analysis of Plasma Loaded Coaxial Gyrotron Cavity With Triangular Corrugations on the Insert
Résumé:
The presence of plasma inside the gyrotron interaction structure alters the mode field. The presence of a magnetic field changes the plasma to an anisotropic media. Field analysis of a plasma loaded coaxial gyrotron cavity with triangular corrugations on the insert is undertaken using full wave approach. Modes inside a plasma loaded interaction structure have all six nonzero field components and hence are hybrid modes. Plasma modes (space charge modes), cyclotron modes, and waveguide EH and HE modes are the three families of modes that can exist in plasma loaded waveguide. Inside the gyrotron interaction structure, the cyclotron mode and the desired mode (HE) couple and this coupling leads to change in the eigenvalue of the modes. In this paper, a full wave approach has been used to analyze the dispersion relation and calculate eigenvalue of the desired HE mode.
Auteurs: Sukwinder Singh;M. V. Kartikeyan;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2369 - 2375
Editeur: IEEE
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» Full-Duplex MIMO in Cellular Networks: System-Level Performance
Résumé:
This paper characterizes, through a stochastic geometry analysis, the increase in spectral efficiency that full-duplex transmission brings about in wireless networks. While, on isolated links, full-duplex promises a doubling of the spectral efficiency, in the context of a network this is weighted down by the corresponding rise in interference, and our characterization captures the balance of these effects. The analysis encompasses both the forward link (FL) and the reverse link (RL) with single-user and multiuser transmissions. And, as a complement to the analysis, Monte-Carlo simulations on a Vodafone LTE field test network are also presented. In the FL, the rise in interference is found to have minor impact and a doubling in spectral efficiency can indeed be approached, especially in microcellular networks. In the RL, however, a major difficulty arises in the form of exceedingly strong interference among base stations. This renders full-duplex transmission all but unfeasible in macrocellular networks (unless major countermeasures could be implemented) and undesirable in dense microcellular networks. Only in microcells with sufficient spacing among base stations does RL full-duplex pay off. Thus, full-duplex is seen not to blend easily with densification.
Auteurs: Ratheesh K. Mungara;Ilaria Thibault;Angel Lozano;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3124 - 3137
Editeur: IEEE
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» Full-Duplex Regenerative Relaying and Energy-Efficiency Optimization Over Generalized Asymmetric Fading Channels
Résumé:
This paper is devoted to the end-to-end performance analysis, optimal power allocation (OPA), and energy-efficiency (EE) optimization of decode-and-forward (DF)-based full-duplex relaying (FDR) and half-duplex relaying (HDR) systems. Unlike existing analyses and works that assume simplified transmission over symmetric fading channels, we consider the more realistic case of asymmetric multipath fading and shadowing conditions. To this end, exact and asymptotic analytic expressions are first derived for the end-to-end outage probabilities (OPs) of the considered DF-FDR set ups. Based on these expressions, we then formulate the OPA and EE optimization problems under given end-to-end target OP and maximum total transmit power constraints. It is shown that OP in FDR systems is highly dependent upon the different fading parameters and that OPA provides substantial performance gains, particularly, when the relay self-interference (SI) level is strong. Finally, the FDR is shown to be more energy-efficient than its HDR counterpart, as energy savings beyond 50% are feasible even for moderate values of the SI levels, especially at larger link distances, under given total transmit power constraints and OP requirements.
Auteurs: Paschalis C. Sofotasios;Mulugeta K. Fikadu;Sami Muhaidat;Qimei Cui;George K. Karagiannidis;Mikko Valkama;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3232 - 3251
Editeur: IEEE
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» Full-Parallax Holographic Light-Field 3-D Displays and Interactive 3-D Touch
Résumé:
A light-field 3-D display (LFD) reproduces light rays or wavefront as if there are real objects, and a perfect 3-D display that satisfies all the depth cues in human vision becomes possible. By reproducing both horizontal and vertical parallaxes, i.e., full-parallax, an LFD reconstructs a real or virtual image in 3-D space. A rich 3-D experience can be provided to viewers, and moreover, multiple viewers can share the same reproduced 3-D image. A technology called holographic stereogram (HS) is the integration of ray-based and wavefront-based methods, and has been applied to LFD. Hardcopy HS has already been commercialized. The technology of HS is helpful also for an interactive LFD; a full-parallax LFD using a projector and a holographic screen that modulates the directions of light rays is based on the principle of HS. In this case, accurate registration between the projected image and the holographic screen is necessary, and it is achieved by projecting some test patterns and capturing them with a calibration camera. As a full-parallax LFD can reproduce real images in midair between the screen and viewers, it is possible to realize interactive 3-D touch interface. If a user touches the 3-D real image floating in the air, the reproduced light is scattered by the user’s fingertip. The scattered light is detected by a color image sensor placed behind the holographic screen, and can be employed to detect the user’s touch. In this system, the reproduced 3-D images and the 3-D touch detection are associated with each other, and thus, we do not have to worry about the complicated registration between them. The identification of the user’s interaction is simple, because the color information of the 3-D image can be used for this purpose. Some experimental results of the 3-D touch-sensing display are introduced, and possible applications of this technology are discussed as well.
Auteurs: Masahiro Yamaguchi;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 947 - 959
Editeur: IEEE
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» Full-Sphere Angle of Arrival Detection using CMRCLEAN
Résumé:
Extraneous signals propagating into the quiet zone (QZ) of an antenna measurement chamber pose a large contribution to the error of measurements therein. From the angle of arrival (AoA) of these extraneous signals, the locations of the reflective points, from which these signals originate, can be determined. If the location of a reflection point is known, it can be treated, and thus the level of the extraneous signal can be reduced or even completely mitigated. The combining mode rotation with CLEAN (CMRCLEAN) algorithm has shown that it is capable of detecting the AoA of closely spaced reflective sources, even in the presence of a strong signal such as the main beam illuminating the QZ. In this communication, the CMRCLEAN algorithm is further improved to allow a better discrimination of signals and their amplitude. Furthermore, this communication will show the ability of the improved algorithm to detect reflections from opposing directions, such as those originating from the back wall, which is opposite to the much stronger range illumination.
Auteurs: Marc Dirix;Dirk Heberling;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2769 - 2772
Editeur: IEEE
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» Fundamental Limits of Cache-Aided Interference Management
Résumé:
We consider a system, comprising a library of $N$ files (e.g., movies) and a wireless network with a $K_{T}$ transmitters, each equipped with a local cache of size of $M_{T}$ files and a $K_{R}$ receivers, each equipped with a local cache of size of $M_{R}$ files. Each receiver will ask for one of the $N$ files in the library, which needs to be delivered. The objective is to design the cache placement (without prior knowledge of receivers’ future requests) and the communication scheme to maximize the throughput of the delivery. In this setting, we show that the sum degrees-of-freedom (sum-DoF) of $min left {{frac {K_{T} M_{T}+K_{R} M_{R}}{N},K_{R}}right }$ is achievable, and this is within a factor of 2 of the optimum, under uncoded prefetching and one-shot linear delivery schemes. This result shows that (i) the one-shot sum-DoF scales linearly with the aggregate cache size in the network (i.e., the cumulative memory available at all nodes), (ii) the transmitters’ caches and receivers’ caches contribute equally in the one-shot sum-DoF, and (iii) caching can offer a throughput gain that scales linearly with the size of the network. To prove the result, we propose an achievable scheme that exploits the redundancy of the content at transmitter’s caches to cooperatively zero-force some outgoing interference, and availability of the unint- nded content at the receiver’s caches to cancel (subtract) some of the incoming interference. We develop a particular pattern for cache placement that maximizes the overall gains of cache-aided transmit and receive interference cancellations. For the converse, we present an integer optimization problem which minimizes the number of communication blocks needed to deliver any set of requested files to the receivers. We then provide a lower bound on the value of this optimization problem, hence leading to an upper bound on the linear one-shot sum-DoF of the network, which is within a factor of 2 of the achievable sum-DoF.
Auteurs: Navid Naderializadeh;Mohammad Ali Maddah-Ali;Amir Salman Avestimehr;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3092 - 3107
Editeur: IEEE
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» Fundamental Limits of Cache-Aided Wireless BC: Interplay of Coded-Caching and CSIT Feedback
Résumé:
Building on the recent coded-caching breakthrough by Maddah-Ali and Niesen, the work here considers the $K$ -user cache-aided wireless multi-antenna symmetric broadcast channel with random fading and imperfect feedback, and analyzes the throughput performance as a function of feedback statistics and cache size. In this setting, this paper identifies the optimal cache-aided degrees-of-freedom (DoF) within a factor of 4, by identifying near-optimal schemes that exploit a new synergy between coded caching and delayed CSIT, as well as by exploiting the unexplored interplay between caching and feedback-quality. The DoF expressions reveal an initial gain due to current CSIT, and an additional gain due to coded caching, which is exponential in the sense that any linear decrease in the required DoF performance, allows for an exponential reduction in the required cache size. In the end, this paper reveals three new aspects of caching: a synergy between memory and delayed feedback, a tradeoff between memory and current CSIT, and a powerful ability to provide cache-aided feedback savings.
Auteurs: Jingjing Zhang;Petros Elia;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3142 - 3160
Editeur: IEEE
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» Fundamental Limits of Photonic RF Phase-Shift Amplification by RF Interferometry
Résumé:
The fundamental limits posed by classical noise on Photonic RF Phase amplification by RF Interferometry (PARFI) are modeled theoretically and verified experimentally. With 320-MHz modulated light and a phase-shift amplification of 3000, we demonstrate a phase-shift resolution of $1.6 cdot {10^{ - 4}}^{circ}$ and 200-nm distance resolution. Based on these results, we postulate that single-nanometer distance resolution can be achieved with PARFI.
Auteurs: Moshe Ben Ayun;Seva Rosenberg;Daniel Gotliv;Shmuel Sternklar;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1906 - 1913
Editeur: IEEE
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» Fundamentals of Modeling Finite Wireless Networks Using Binomial Point Process
Résumé:
Modeling the locations of nodes as a uniform binomial point process, we present a generic mathematical framework to characterize the performance of an arbitrarily located reference receiver in a finite wireless network. Different from most of the prior works where the serving transmitter (TX) is located at the fixed distance from the reference receiver, we consider two general TX-selection policies: 1) uniform TX-selection: the serving node is chosen uniformly at random from amongst all transmitting nodes and 2) $k$ -closest TX-selection: the serving node is the $k$ th closest node (out of all transmitting nodes) to the reference receiver. The key intermediate step in our analysis is the derivation of a new set of distance distributions that lead not only to the tractable analysis of coverage probability but also enable the analysis of wide range of classical and currently trending problems in wireless networks. Using this new set of distance distributions, we further investigate the diversity loss due to $mathtt {SIR}$ correlation in a finite network. We then obtain the optimal number of links that can be simultaneously activated to maximize network spectral efficiency. Finally, we evaluate optimal caching probability to maximize the total hit probability in cache-enabled finite networks.
Auteurs: Mehrnaz Afshang;Harpreet S. Dhillon;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3355 - 3370
Editeur: IEEE
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» GaN Nanowire Schottky Barrier Diodes
Résumé:
A new concept of vertical gallium nitride (GaN) Schottky barrier diode based on nanowire (NW) structures and the principle of dielectric REduced SURface Field (RESURF) is proposed in this paper. High-threading dislocation density in GaN epitaxy grown on foreign substrates has hindered the development and commercialization of vertical GaN power devices. The proposed NW structure, previously explored for LEDs offers an opportunity to reduce defect density and fabricate low cost vertical GaN power devices on silicon (Si) substrates. In this paper, we investigate the static characteristics of high-voltage GaN NW Schottky diodes using 3-D TCAD device simulation. The NW architecture theoretically achieves blocking voltages upward of 700 V with very low specific on-resistance. Two different methods of device fabrication are discussed. Preliminary experimental results are reported on device samples fabricated using one of the proposed methods. The fabricated Schottky diodes exhibit a breakdown voltage of around 100 V and no signs of current collapse. Although more work is needed to further explore the nano-GaN concept, the preliminary results indicate that superior tradeoff between the breakdown voltage and specific on-resistance can be achieved, all on a vertical architecture and a foreign substrate. The proposed NW approach has the potential to deliver low cost reliable GaN power devices, circumventing the limitations of today’s high electron mobility transistors (HEMTs) technology and vertical GaN on GaN devices.
Auteurs: Gourab Sabui;Vitaly Z. Zubialevich;Mary White;Pietro Pampili;Peter J. Parbrook;Mathew McLaren;Miryam Arredondo-Arechavala;Z. John Shen;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2283 - 2290
Editeur: IEEE
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» Gas Spectroscopy System for Breath Analysis at mm-wave/THz Using SiGe BiCMOS Circuits
Résumé:
The unique fingerprint spectra of volatile organic compounds for breath analysis and toxic industrial chemicals make an mm-wave (mmW)/THz gas sensor very specific and sensitive. This paper reviews and updates results of our recent work on sensor systems for gas spectroscopy based on integrated transmitter (TX) and receiver (RX), which are developed and fabricated in IHP’s $0.13~mu text{m}$ SiGe BiCMOS technology. In this paper, we present an mmW/THz spectroscopic system including a folded gas absorption cell of 1.9 m length between the TX and RX modules. We discuss the results and specifications of our sensor system based on integrated TX and RX. We demonstrate TXs and RXs with integrated antennas for spectroscopy at 238–252 GHz and 494–500 GHz using integer- $N$ phase-locked loops (PLLs). We present a compact system by using fractional- ${N}$ PLLs allowing frequency ramps for the TX and RX, and for TX with superimposed frequency shift keying or reference frequency modulation. In another configuration, the voltage controlled oscillators of the TX and RX local oscillator are tuned directly without PLLs by applying external voltages. Further developments of our system are aimed at realizing an even wider frequency span by switching between frequency bands, and to use a more compact gas absorption cell.
Auteurs: Klaus Schmalz;Nick Rothbart;Philipp F.-X. Neumaier;Johannes Borngräber;Heinz-Wilhelm Hübers;Dietmar Kissinger;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1807 - 1818
Editeur: IEEE
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» Gas-Liquid Two-Phase Flow Measurement Using Coriolis Flowmeters Incorporating Artificial Neural Network, Support Vector Machine, and Genetic Programming Algorithms
Résumé:
Coriolis flowmeters are well established for the mass flow measurement of single-phase flow with high accuracy. In recent years, attempts have been made to apply Coriolis flowmeters to measure two-phase flow. This paper presents data driven models that are incorporated into Coriolis flowmeters to measure both the liquid mass flowrate and the gas volume fraction of a two-phase flow mixture. Experimental work was conducted on a purpose-built two-phase flow test rig on both horizontal and vertical pipelines for a liquid mass flowrate ranging from 700 to 14500 kg/h and a gas volume fraction between 0% and 30%. Artificial neural network (ANN), support vector machine (SVM), and genetic programming (GP) models are established through training with the experimental data. The performance of backpropagation-ANN (BP-ANN), radial basis function-ANN (RBF-ANN), SVM, and GP models is assessed and compared. Experimental results suggest that the SVM models are superior to the BP-ANN, RBF-ANN, and GP models for two-phase flow measurement in terms of robustness and accuracy. For liquid mass flowrate measurement with the SVM models, 93.49% of the experimental data yield a relative error less than ±1% on the horizontal pipeline, while 96.17% of the results are within ±1% on the vertical installation. The SVM models predict the gas volume fraction with a relative error less than ±10% for 93.10% and 94.25% of the test conditions on the horizontal and vertical installations, respectively.
Auteurs: Lijuan Wang;Jinyu Liu;Yong Yan;Xue Wang;Tao Wang;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 852 - 868
Editeur: IEEE
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» Gaussian Multiple Access via Compute-and-Forward
Résumé:
Lattice codes used under the compute-and-forward paradigm suggest an alternative strategy for the standard Gaussian multiple-access channel (MAC): the receiver successively decodes the integer linear combinations of the messages until it can invert and recover all messages. In this paper, a multiple-access technique called compute-forward multiple access (CFMA) is proposed and analyzed. For the two-user MAC, it is shown that without time-sharing, the entire capacity region can be attained using CFMA with a single-user decoder as soon as the signal-to-noise ratios are above $1+sqrt {2}$ . A partial analysis is given for more than two users. Finally, the strategy is extended to the so-called dirty MAC, where two interfering signals are known non-causally to the two transmitters in a distributed fashion. Our scheme extends the previously known results and gives new achievable rate regions.
Auteurs: Jingge Zhu;Michael Gastpar;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2678 - 2695
Editeur: IEEE
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» General Stochastic Convergence Theorem and Stochastic Adaptive Output-Feedback Controller
Résumé:
This paper is devoted to the analysis methods/tools to stochastic convergence and stochastic adaptive output-feedback control. As the first contribution, a general stochastic convergence theorem is proposed for stochastic nonlinear systems. The theorem doesn't necessarily involve a positive-definite function of the system states with negative-semidefinite infinitesimal, essentially different from stochastic LaSalle's theorem (see e.g., [1]), and hence can provide more opportunities to achieve stochastic convergence. Moreover, as a direct extension of the convergence theorem, a general version of stochastic Barb ă lat's lemma is obtained, which requires the concerned stochastic process to be almost surely integrable, rather than absolutely integrable in the sense of expectation, unlike in [2]. As the second contribution, supported by the general stochastic convergence theorem, an adaptive output-feedback control strategy is established for the global stabilization of a class of stochastic nonlinear systems with severe parametric uncertainties coupled to unmeasurable states. Its feasibility analysis takes substantial effort, and is largely based on the general stochastic convergence theorem. Particularly, for the resulting closed-loop system, certain stochastic boundedness and integrability are shown by the celebrated nonnegative semimartingale convergence theorem, and furthermore, the desired stochastic convergence is achieved via the general stochastic convergence theorem.
Auteurs: Fengzhong Li;Yungang Liu;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2334 - 2349
Editeur: IEEE
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» Generalized Coprime Planar Array Geometry for 2-D DOA Estimation
Résumé:
In this letter, we propose a generalized coprime planar array (GCPA) geometry for 2-D direction of arrival (DOA) estimation, where two rectangular uniform planar subarrays are used. The proposed geometry allows a more flexible array layout and extends the array aperture to achieve a great performance improvement. We verify that GCPA can obtain a higher degree of freedom (DOF) than square coprime planar array and we derive the principle for array layout of GCPA to obtain the maximum DOF. The superiority of GCPA are revealed by numerical simulations with the classical DOA methods.
Auteurs: Wang Zheng;Xiaofei Zhang;Hui Zhai;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1075 - 1078
Editeur: IEEE
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» Generalized Line Loss Relaxation in Polar Voltage Coordinates
Résumé:
It is common for power system behavior to be expressed in terms of polar voltage coordinates. When applied in optimization settings, loss formulations in polar voltage coordinates typically assume that voltage magnitudes are fixed. In reality, voltage magnitudes vary and may have an appreciable effect on losses. This paper proposes a systematic approach to incorporating the effects of voltage magnitude changes into a linear relaxation of the losses on a transmission line. This approach affords greater accuracy when describing losses around a base voltage condition as compared to previous linear and piecewise linear methods. It also better captures the true behavior of losses at conditions away from the flat voltage profile.
Auteurs: Jonathon A. Martin;Ian A. Hiskens;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1980 - 1989
Editeur: IEEE
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» Generalized Primitive Stamps for Nonlinear Circuit-Field Coupling in the Transient Case
Résumé:
The simultaneous solution of circuit and field equations is often required in the analysis of magnetic devices. Although schemes for the solution of this coupled problem have been proposed, the existing formulations are usually tied to specific time discretization or nonlinear iteration expressions and therefore lack generality. In this paper, a highly systematized approach is proposed for strong circuit-field coupling in a transient finite element context, by identifying primitive stamps for field elements, circuit elements, and circuit-field couplings. The filamentary and solid conductors of the field model are the key elements for systematic interconnection using generalized stamps and modified nodal analysis. As a result, the coupling equations are treated just as any other circuit element, simplifying the implementation and providing a unified framework for circuit-field analysis. Both circuit and field stamps are independent of the time discretization and nonlinear solving procedure. With the proposed scheme, the finite element equations can be linked to circuits of arbitrary topology. The theory is developed for the axisymmetric and Cartesian 2-D cases and several examples are then solved to show the effectiveness of our new approach. Solutions are compared with those produced by well-known and validated commercial software packages which implement different, proprietary, and/or undisclosed circuit-field coupling methods.
Auteurs: Enrique Melgoza-Vazquez;Rafael Escarela-Perez;Jose L. Guardado;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 9
Editeur: IEEE
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» Generating Ambiguous Figure-Ground Images
Résumé:
Ambiguous figure-ground images, mostly represented as binary images, are fascinating as they present viewers a visual phenomena of perceiving multiple interpretations from a single image. In one possible interpretation, the white region is seen as a foreground figure while the black region is treated as shapeless background. Such perception can reverse instantly at any moment. In this paper, we investigate the theory behind this ambiguous perception and present an automatic algorithm to generate such images. We model the problem as a binary image composition using two object contours and approach it through a three-stage pipeline. The algorithm first performs a partial shape matching to find a good partial contour matching between objects. This matching is based on a content-aware shape matching metric, which captures features of ambiguous figure-ground images. Then we combine matched contours into a compound contour using an adaptive contour deformation, followed by computing an optimal cropping window and image binarization for the compound contour that maximize the completeness of object contours in the final composition. We have tested our system using a wide range of input objects and generated a large number of convincing examples with or without user guidance. The efficiency of our system and quality of results are verified through an extensive experimental study.
Auteurs: Ying-Miao Kuo;Hung-Kuo Chu;Ming-Te Chi;Ruen-Rone Lee;Tong-Yee Lee;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1534 - 1545
Editeur: IEEE
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» Generation of Duplicated Off-Line Signature Images for Verification Systems
Résumé:
Biometric researchers have historically seen signature duplication as a procedure relevant to improving the performance of automatic signature verifiers. Different approaches have been proposed to duplicate dynamic signatures based on the heuristic affine transformation, nonlinear distortion and the kinematic model of the motor system. The literature on static signature duplication is limited and as far as we know based on heuristic affine transforms and does not seem to consider the recent advances in human behavior modeling of neuroscience. This paper tries to fill this gap by proposing a cognitive inspired algorithm to duplicate off-line signatures. The algorithm is based on a set of nonlinear and linear transformations which simulate the human spatial cognitive map and motor system intra-personal variability during the signing process. The duplicator is evaluated by increasing artificially a training sequence and verifying that the performance of four state-of-the-art off-line signature classifiers using two publicly databases have been improved on average as if we had collected three more real signatures.
Auteurs: Moises Diaz;Miguel A. Ferrer;George S. Eskander;Robert Sabourin;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 951 - 964
Editeur: IEEE
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» Geometric Calibration of an Aerial Multihead Camera System for Direct Georeferencing Applications
Résumé:
An aerial multihead camera consists of a photogrammetric system composed of multiple cameras, which are mounted together in a main structure. By combining the images acquired simultaneously from each camera, a single synthetic image with much larger coverage can be generated. Such systems are usually integrated with a position and orientation system (POS) to perform direct georeferencing (DG) or integrated sensor orientation (ISO). However, to obtain mapping products with high accuracy through a DG procedure, it is essential the implementation of the system geometric calibration. Usually, the aerial multihead camera manufacturers perform the geometric calibration using laboratory methods and only the camera interior orientation parameters (IOPs) and their relative orientation parameters (ROPs) are determined to generate the synthetic image (process known as “platform calibration”). The mounting parameters (lever arms and boresight misalignment angles) relating the synthetic image and GNSS/INS reference systems are usually defined using nominal installation values. The objective of this paper is to present an in-flight calibration methodology for multihead camera systems and its assessment for DG applications. The introduced methodology involves three steps: 1) determination of the cameras’ IOPs and their ROPs; 2) synthetic image generation; and 3) refinement of the IOPs of the synthetic image and the mounting parameters determination between the synthetic image and GNSS/INS reference systems using different methods. The results of the experiments shown the viability of the proposed methodology for DG applications involving photogrammetric procedures for large-scale mapping requirements.
Auteurs: Leonardo E. Filho;Edson A. Mitishita;Ana Paula B. Kersting;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1926 - 1937
Editeur: IEEE
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» Geometrically Modified Einzel Lenses, From the Conventional Cylindrical Einzel Lens to Cubic and Continuous Einzel Lens
Résumé:
New geometrical counterparts to the conventional Einzel lens, cubic, and the continuous body electrostatic (CBE) lenses are introduced and their performances are investigated in terms of different aberrations and input beam properties. Design curves for the continuous body electrostatic lens are presented. Relative sensitivity is proposed as a figure of merit, based on which the focusing characteristics of the two new lenses are compared with that of a conventional Einzel, and a quadrupole lenses of the same size, as well. Moreover, performance and characteristics of the lenses are compared in terms of their corresponding sensitivities to the applied voltage and the incidence beam nonidealities. Electric field distributions of the lenses are studied, and different aberrations are discussed. It is shown that considering chromatic nonparaxial beams, the CBE lens outperforms the conventional Einzel lens in terms of the sensitivity and the absolute value of the lens demagnification.
Auteurs: Arash Riazi;Navid Yasrebi;Hossein Monjezi;Bizhan Rashidian;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 828 - 835
Editeur: IEEE
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» Global EDF Schedulability Analysis for Parallel Tasks on Multi-Core Platforms
Résumé:
With the widespread adoption of multi-core architectures, it is becoming more important to develop software in ways that takes advantage of such parallel architectures. This particularly entails a shift in programming paradigms towards fine-grained, thread-parallel computing. Many parallel programming models have been introduced for targeting such intra-task thread-level parallelism. However, most successful results on traditional multi-core real-time scheduling are focused on sequential programming models. For example, thread-level parallelism is not properly captured into the concept of interference, which is key to many schedulability analysis techniques. Thereby, most interference-based analysis techniques are not directly applicable to parallel programming models. Motivated by this, we extend the notion of interference to capture thread-level parallelism more accurately. We then leverage the proposed notion of parallelism-aware interference to derive efficient EDF schedulability tests that are directly applicable to parallel task models, including DAG models, on multi-core platforms, without knowing an optimal schedule. Our evaluation results indicate that the proposed analysis significantly advances the state-of-the-art in global EDF schedulability analysis for parallel tasks. In particular, we identify that our proposed schedulability tests are adaptive to different degrees of thread-level parallelism and scalable to the number of processors, resulting in substantial improvement of schedulability for parallel tasks on multi-core platforms.
Auteurs: Hoon Sung Chwa;Jinkyu Lee;Jiyeon Lee;Kiew-My Phan;Arvind Easwaran;Insik Shin;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1331 - 1345
Editeur: IEEE
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» Global Parametric Polynomial Approximation of Static Voltage Stability Region Boundaries
Résumé:
A novel method for globally approximating the static voltage stability region boundaries (SVSRBs) of power systems is proposed by applying parametric polynomial approximation to the criterion equation which defines the SVSRB. Known as the Galerkin method, the implicit function portraying the SVSRB is described as a linear combination of basis polynomial functions, and the coefficients of the basis functions are obtained by projecting the SVSRB criterion onto each basis function. The approximation guarantees high precision globally in the whole domain of the parameter of interest rather than only in the neighborhood of a point, and the error can be controlled by the degree of polynomial basis functions. In the meantime, analytical expression of the left or right eigenvector of the system's Jacobian matrix corresponding to the zero eigenvalue is obtained in the form of polynomial, which provides valuable information for online voltage stability control or monitoring. Case studies in a 10-bus test system and IEEE 118-bus test system verifies the validity, accuracy, and flexibility of the proposed method.
Auteurs: Yiwei Qiu;Hao Wu;Yongzhi Zhou;Yonghua Song;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2362 - 2371
Editeur: IEEE
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» GPU-Accelerated Simulation of Small Delay Faults
Résumé:
Delay fault simulation is an essential task during test pattern generation and reliability assessment of electronic circuits. With the high sensitivity of current nano-scale designs toward even smallest delay deviations, the simulation of small gate delay faults has become extremely important. Since these faults have a subtle impact on the timing behavior, traditional fault simulation approaches based on abstract timing models are not sufficient. Furthermore, the detection of these faults is compromised by the ubiquitous variations in the manufacturing processes, which causes the actual fault coverage to vary from circuit instance to circuit instance, and makes the use of timing accurate methods mandatory. However, the application of timing accurate techniques quickly becomes infeasible for larger designs due to excessive computational requirements. In this paper, we present a method for fast and waveform-accurate simulation of small delay faults on graphics processing units with exceptional computational performance. By exploiting multiple dimensions of parallelism from gates, faults, waveforms, and circuit instances, the proposed approach allows for timing-accurate and exhaustive small delay fault simulation under process variation for designs with millions of gates.
Auteurs: Eric Schneider;Michael A. Kochte;Stefan Holst;Xiaoqing Wen;Hans-Joachim Wunderlich;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 829 - 841
Editeur: IEEE
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» Grades of IEEE Membership [The Way Ahead]
Résumé:
Presents information on the different grades of IEEE membership.
Auteurs: J. Patrick Donohoe;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 4 - 4
Editeur: IEEE
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» Graphical Representation of the Power Transfer Efficiency of Lumped-Element Circuits Based on Hyperbolic Geometry
Résumé:
By adding a passive element to a power source, an inevitable power attenuation caused by the dissipative loss occurs. It is important for some applications to reduce this undesirable attenuation. A representative example of one of these kinds of applications is impedance matching, for which we transform the source's impedance to a different preferable one with passive elements, and the attenuation is to be as low as possible. To give a visible way to design better circuits in such situations, we propose a graphical representation to understand the attenuation from the viewpoint of hyperbolic geometry. We reveal that the attenuation in logarithmic scale (typically decibels or nepers) is proportionate to the hyperbolic length of the path representing the movement of the reflection coefficient, and the constant of proportionality is determined by the unloaded Q-factor of the connected elements. Exploiting the result, we can find preferable topologies by using the Smith chart with an intuition. In addition to this graphical representation, we also reveal the lower bound of the attenuation in terms of the hyperbolic distance between the two reflection coefficients that we want to match. A new usage of the Smith chart to estimate the loss and its lower bound is given in this brief.
Auteurs: Kyohei Yamada;Takashi Ohira;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 485 - 489
Editeur: IEEE
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» Gravity-Capillary Wave Spectral Modulation by Gravity Waves
Résumé:
In order to more fully understand the specific hydrodynamic relationship between young wind-generated gravity-capillary waves and longer gravity waves, a laboratory experiment was devised to observe changes in short wave spectral behavior over the phase of a long wave. This paper endeavors to expand on the body of laboratory wave modulation data and extend the investigation in support of the radar remote sensing of ocean surface waves. Measurements were made in the University of Miami's surge-structure-atmosphere interaction facility in the air-sea interaction saltwater tank wind-wave tank, with 10 m referenced wind speeds ranging between 5 and 23 m/s and paddle-generated wave steepnesses “ak” varying between 0.05 <; ak <; 0.3. A polarimetric camera was used to capture high sampling frequency maps of wave slope, yielding spatiotemporal information about short wind-wave behavior [provided as temporal variations in the wavenumber spectrum, where k ≈ 15(100-1000) rad/m]. The simultaneous and colocated long wave phase was measured via a side-looking camera. Hydrodynamic modulation transfer function (MTF) phases are found to be in general agreement with established values (between 2 and 10 radians) at the given wind speeds. The positive phase of the modulation places it immediately downwind of the long wave crest, with MTF magnitudes strongest for high wavenumbers at the lowest wind speeds. The results are also presented to show the modulation of gravity-capillary and pure capillary waves as variations in mean square slope over the long wave phase, with peak roughness enhancement found to move upwind of the long wave crest with increasing wind forcing.
Auteurs: Nathan J. M. Laxague;Milan Curcic;Jan-Victor Björkqvist;Brian K. Haus;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2477 - 2485
Editeur: IEEE
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» Ground Moving Target Indication for High-Resolution Wide-Swath Synthetic Aperture Radar Systems
Résumé:
This letter presents a new scheme for ground moving target indication in high-resolution wide-swath (HRWS)-synthetic aperture radar (SAR) systems. The asymmetry of the Doppler spectra is measured to extract the range bins with moving targets. To improve the computational efficiency, only the extracted range bins are used to restore the unambiguous Doppler spectra. The two-look processing technique is then applied to generate two looks and moving targets are indicated by comparing the difference between the two looks. In this detection scheme, the configuration of the conventional HRWS-SAR system remains unchanged and no additional receiving channels are needed. The experimental results show the effectiveness of this detection scheme.
Auteurs: Hongchao Zheng;Junfeng Wang;Xingzhao Liu;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 749 - 753
Editeur: IEEE
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» Ground-Based Cloud Detection Using Graph Model Built Upon Superpixels
Résumé:
Cloud detection plays an important role in climate models, climate predictions, and meteorological services. Although researchers have given increasing efforts on cloud detection, the performance is still unsatisfactory due to the diverse nature of clouds. Considering the fact that one source of information (color or texture) is not enough to segment cloud from clear sky, in this letter, we propose a novel ground-based cloud detection method using graph model (GM) built upon superpixels to integrate multiple sources of information. First, we use the superpixel segmentation to divide the image into a series of subregions according to the color similarity and spatial continuity. Next, adjacent superpixels are merged according to their similarity of extracted features. Finally, we build a GM on the merged superpixels by considering each superpixel as a node and adding edges between neighboring ones. The unary cost is set according to the classification score of Random Forests, while pairwise cost reflects the penalties for color and texture discontinuity between neighboring components. The final segmentation could be acquired by minimizing the cost function. Moreover, the algorithm is computationally efficient as we use the superpixels rather than raw pixels as computation units. Experimental results demonstrate the effectiveness and efficiency of the proposed method for cloud detection.
Auteurs: Cunzhao Shi;Yu Wang;Chunheng Wang;Baihua Xiao;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 719 - 723
Editeur: IEEE
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» Guest Editor's Introduction to the Special Section on the ACM Symposium on Interactive 3D Graphics and Games (I3D)
Résumé:
Auteurs: Kartic Subr;Li-Yi Wei;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1427 - 1427
Editeur: IEEE
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» Guest Editorial Special Section on the 2016 IEEE Latin American Symposium on Circuits and Systems (LASCAS 2016)
Résumé:
Welcome to this Special Section, a collection of selected papers presented at the 2016 IEEE Latin American Symposium on Circuits and Systems (LASCAS 2016), held in Florianópolis, Brazil, from February 28 to March 2, 2016. Over 250 delegates attended the conference, where 100 papers were presented, selected from 203 papers submitted across 20 tracks.
Auteurs: Pedro M. Julián;Lisandro Lovisolo;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1017 - 1018
Editeur: IEEE
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» Guided Wave Tomography of Pipe Bends
Résumé:
Detection and monitoring of corrosion and erosion damage in pipe bends are open challenges due to the curvature of the elbow, the complex morphology of these defects, and their unpredictable location. Combining model-based inversion with guided ultrasonic waves propagating along the elbow and inside its walls offers the possibility of mapping wall-thickness losses over the entire bend and from a few permanently installed transducers under the realm of guided wave tomography (GWT). This paper provides the experimental demonstration of GWT of pipe bends based on a novel curved ray tomography algorithm and an optimal transducer configuration consisting of two ring arrays mounted at the ends of the elbow and a line of transducers fixed to the outer side of the elbow (extrados). Using realistic, localized corrosion defects, it is shown that detection of both the presence and progression of damage can be achieved with 100% sensitivity regardless of damage position around the bend. Importantly, this is possible for defects as shallow as 0.50% of wall thickness (WT) and for maximum depth increments of just 0.25% WT. However, due to the highly irregular profile of corrosion defects, GWT generally underestimates maximum depth relative to the values obtained from 3-D laser scans of the same defects, leading in many cases to errors between 3% WT and 8% WT.
Auteurs: Alex J. Brath;Francesco Simonetti;Peter B. Nagy;Geir Instanes;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 847 - 858
Editeur: IEEE
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» Handoff Performance Improvements in an Integrated Train-Ground Communication System Based on Wireless Network Virtualization
Résumé:
In existing urban rail transit systems, the train-ground communication system for different subsystems is deployed independently. Investing and constructing the communication infrastructures repeatedly not only wastes substantial social resources, but it also is difficult to maintain all these infrastructures. In this paper, we propose an integrated train-ground communication system based on wireless network virtualization for urban rail transit systems. In order to improve the communication-based train control (CBTC) subsystem performance during handoff, we propose a novel handoff scheme to support handoff between virtual networks. The application-layer quality-of-service (QoS) parameters of the CBTC, passenger information system, and closed circuit television subsystems are used as the performance measures in the handoff design. We then formulate the QoS optimization problem in the proposed integrated train-ground communication system as an approximate dynamic programming (ADP) problem. The extensive simulation results show that the proposed integrated train-ground communication system QoS can be improved substantially with our ADP-based optimization model.
Auteurs: Li Zhu;Fei Richard Yu;Tao Tang;Bin Ning;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1165 - 1178
Editeur: IEEE
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» Hardness of Firewall Analysis
Résumé:
We identify 13 problems whose solutions can significantly enhance our ability to design and analyze firewalls and other packet classifiers. These problems include the firewall equivalence problem, the firewall redundancy problem, the firewall verification problem, and the firewall completeness problem. The main result of this paper is to prove that every one of these problems is NP-hard. Our proof of this result is interesting in the following way. Only one of the 13 problems, the so called slice probing problem, is shown to be NP-hard by a reduction from the well-known 3-SAT problem. Then, the remaining 12 problems are shown to be NP-hard by reductions from the slice probing problem. This proof suggests that the slice probing problem plays an important role in the design and analysis of firewalls. The negative results of this paper suggest that firewalls designers may need to rely on SAT solvers to solve instances of these 13 problems or may be content with probabilistic solutions of these problems. On the positive side, we show that each of the 13 firewall analysis problems presented in this paper is polynomially reducible to the slice probing problem. Thus any algorithm, that can effectively solve the slice probing problem, can also be employed to effectively solve any of these 13 problems.
Auteurs: Ehab S. Elmallah;Mohamed G. Gouda;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 339 - 349
Editeur: IEEE
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» Hardware Architecture Based on Parallel Tiled QRD Algorithm for Future MIMO Systems
Résumé:
QR decomposition (QRD) has been a vital component in the transceiver processor of future multiple-input multiple-output (MIMO) systems, in which antenna configuration will be more and more flexible. Therefore, the QRD hardware architecture in the future MIMO systems should be more flexible to meet various antenna configurations. Unfortunately, the existing QRD hardware architectures mainly focus on the matrix of one or several fixed sizes. This paper presents a new triangular systolic array QRD hardware architecture based on parallel tiled QRD algorithm to decompose an $ {8}times {8}$ real matrix. The designed hardware architecture is flexible and can be used in various MIMO systems, in which the number of antennas is smaller than 4. This paper also proposes a modified algorithm for the bottleneck operations of parallel tiled QRD algorithm to reduce the hardware overhead. To further reduce the hardware overhead, the Newton–Raphson algorithm is adopted in the proposed algorithm. The implementation results show that the normalized processing latency performance and the normalized processing efficiency performance of the designed QRD hardware architecture both are better than most of the existing QRD hardware architectures. To the best of our knowledge, the hardware architecture presented in this paper achieves the superior normalized QRD rate performance to the existing QRD hardware architectures.
Auteurs: Cang Liu;Chuan Tang;Zuocheng Xing;Luechao Yuan;Yang Zhang;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1714 - 1724
Editeur: IEEE
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» Hardware Implementation Overhead of Switchable Matching Networks
Résumé:
Nowadays, more and more RF systems include switchable matching networks to decrease the impact of the environment-dependent antenna impedance on the RF front end performance. This paper reviews the theoretical lower limit on the required number of matching states to match VSWR ranges and then presents an analysis of hardware implementations to actually implement a suitable switchable matching network. A number of matching network topologies are analyzed: PI networks, loaded transmission lines, branch line coupler based circuits, single circulators and cascaded circulators. In our investigation only narrow-band applications are targeted. For the various circuit implementations the required number of matching states for each hardware implementation is compared to the theoretical minimum number of states required for the same matching in order to benchmark their hardware implementation overhead. It appears that a matching network using cascaded circulators is the closest to the theoretical optimum for networks with a relatively low number of states: this type of matching network was implemented and analyzed in more detail.
Auteurs: Ettore Lorenzo Firrao;Anne-Johan Annema;Frank E. van Vliet;Bram Nauta;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1152 - 1163
Editeur: IEEE
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» Hardware/Software Approach to Designing Low-Power RNS-Enhanced Arithmetic Units
Résumé:
In this paper, we propose a new approach to use a residue number system (RNS) to design an arithmetic unit to parallelize execution of addition and multiplication. The chosen RNS is defined by a moduli set composed of one larger even modulus ${2^{k}}$ and all remaining moduli of the type ${2^{n}-1}$ , selected to fit into the word size of a typical general-purpose processor, e.g., 32 or 64 b. The RNS operations are implemented in hardware, except for the reverse conversion, which is implemented in software, allowing not only to save hardware area but also offering the ease of run-time changing of the dynamic range, which in turn can result in reducing both power consumption and execution time. Simulation experiments were performed on synthesized seven-operation arithmetic units with varying dynamic range for three applications: constant-coefficient filtering, matrix multiplication, and large Montgomery multiplication. The results show that thanks to smaller modular multipliers, RNS arithmetic units have smaller both area and delay, and, consequently, they allow to achieve up to over 20% energy saving for a constant-coefficient filter application, up to over 28% for the matrix multiplication, and up to 27% for Montgomery multiplication, compared with executions using a positional arithmetic unit.
Auteurs: Piotr Patronik;Stanisław J. Piestrak;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1031 - 1039
Editeur: IEEE
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» Harnessing Encrypted Data in Cloud for Secure and Efficient Mobile Image Sharing
Résumé:
Nowadays, large volumes of multimedia data are outsourced to the cloud to better serve mobile applications. Along with this trend, highly correlated datasets can occur commonly, where the rich information buried in correlated data is useful for many cloud data generation/dissemination services. In light of this, we propose to enable a secure and efficient cloud-assisted image sharing architecture for mobile devices, by leveraging outsourced encrypted image datasets with privacy assurance. Different from traditional image sharing, we aim to provide a mobile-friendly design that saves the transmission cost for mobile clients, by directly utilizing outsourced correlated images to reproduce the image of interest inside the cloud for immediate dissemination. First, we propose a secure and efficient index design that allows the mobile client to securely find from encrypted image datasets the candidate selection pertaining to the image of interest for sharing. We then design two specialized encryption mechanisms that support secure image reproduction from encrypted candidate selection. We formally analyze the security strength of the design. Our experiments explicitly show that both the bandwidth and energy consumptions at the mobile client can be saved, while achieving all service requirements and security guarantees.
Auteurs: Helei Cui;Xingliang Yuan;Cong Wang;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1315 - 1329
Editeur: IEEE
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» Has Intel created a universal memory technology? [News]
Résumé:
Today's computers shuttle data around a byzantine system of several different kinds of short- and long-term memory. No wonder, then, that engineers have long dreamed of one memory technology to rule them all, a universal memory that would simplify computing and streamline the path of data.
Auteurs: Katherine Bourzac;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 9 - 10
Editeur: IEEE
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» Hazelnut Oil Classification by NMR Techniques
Résumé:
Nuclear magnetic resonance (NMR) has been widely used in chemical analysis and medical diagnosis. In recent years, thanks to the development of the NMR instrumentation and the software for data analysis, it is becoming a useful tool for quality control in the food industry. In this field, several applications have been developed related to the compositional and structural analysis, authentication, packaging, and on-line monitoring. This paper highlights the capability of NMR to discern between the oil extracted from healthy and unhealthy hazelnuts, as a preliminary step toward the automatic detection of the hidden defects in full hazelnuts. Different processing techniques are analyzed on the CPMG response in order to set up the final measurement system.
Auteurs: Domenico Di Caro;Consolatina Liguori;Antonio Pietrosanto;Paolo Sommella;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 928 - 934
Editeur: IEEE
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» Heterogeneous Networked Cooperative Scheduling With Anarchic Particle Swarm Optimization
Résumé:
This paper proposes a mathematical model and new solving algorithm for scheduling of a distributed production network with heterogeneous parallel factories distributed in the different geographical places. In this problem, two subproblems must be solved, i.e., 1) assigning jobs to appropriate factory and 2) scheduling jobs on parallel machines in each factory. We also assume that after initial assignment, for better balancing in machines’ loading in the different factories, each job can be shifted among factories. After modeling the problem as mixed integer linear programming, with proposing a new method for solution representation, we propose a novel solving algorithm namely anarchic particle swarm optimization to minimize makespan of jobs. This algorithm is inspired by an anarchic society whose members behave anarchically to improve their situations. By such anarchic particles, the algorithm can prevent falling in local optimum traps. The obtained results of mixed integer linear programming solved by CPLEX are compared with the proposed algorithm, a genetic algorithm and a noncooperative local scheduling for small-sized instances. At the end, the effectiveness of anarchic particle swarm optimization, standard particle swarm optimization, and genetic algorithm are examined on the test problems which contained up to 500 jobs.
Auteurs: Javad Behnamian;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 166 - 178
Editeur: IEEE
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» Hierarchical MK Splines: Algorithm and Applications to Data Fitting
Résumé:
In the era of big data, it is very important to study large-scale data fitting methods. In order to ensure the calculation speed and accuracy, we propose a new kind of hierarchical many-knot splines (hereinafter called “hierarchical MK splines,” generally abbreviated as HMK splines) in this paper. The HMK splines method produces a sequence of MK spline functions. These MK spline functions are constructed into one ideal interpolation function by the MK spline refinement. In the case of regular sampling data, HMK splines can achieve the purpose of accurate approximation for the given data points without solving systems of equations. Further, in order to deal with the issues of scattered data fitting, the use of least-squares method will lead to the necessary of solving a linear system of equations. Since the ill-conditioned systems of equations often lead to unacceptable deviation of calculation results, one tries to avoid it as much as possible. The HMK splines algorithm can meet this requirement; it can avoid the intolerable deviation caused by solving systems of equations. Experimental results show that large-scale scattered data fitting can be easily achieved by the HMK splines algorithm and the reconstruction of nonuniform samples has a high accuracy.
Auteurs: Zhanchuan Cai;Ting Lan;Caimu Zheng;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 921 - 934
Editeur: IEEE
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» High Performance Ge pMOSFETs With HfO2/Hf-Cap/GeOx Gate Stack and Suitable Post Metal Annealing Treatments
Résumé:
An equivalent oxide thickness of ~0.53 nm, gate leakage current density of $sim 10^{-4}text{A}$ /cm2 at V FB + 1 V, ION/ IOFF ratio of $10^{text {4}}$ , subthreshold swing of 136 mV/dec, and peak hole mobility of 375 cm2/V-s at N $_{text {inv}} = 1.6 times 10^{12}$ cm−2 in Ge p-type metal–oxide–semiconductor-field-effect transistors (pMOSFETs) are achieved by HfO2/Hf-cap/GeOx gate stack with suitable post-metal-annealing (PMA) treatments. Such a high mobility in Ge pMOSFETs can be attributed to an ultrathin GeOx layer at the surface of Ge substrate. Ge+ and Ge+2 in GeOx layer are re-oxidized to higher oxidation state by gettered oxygen, which is captured by Hf-cap from GeOx and HfO2 during PMA. The minimized contents of Ge+1 and Ge+2 in GeOx are crucial to achieve excellent electrical characteristics.
Auteurs: Shih-Han Yi;Kuei-Shu Chang-Liao;Tzung-Yu Wu;Chia-Wei Hsu;Jiayi Huang;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 544 - 547
Editeur: IEEE
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» High Quality Factor Coaxial Cable Fabry-Perot Resonator for Sensing Applications
Résumé:
This paper describes a novel coaxial cable Fabry–Perot resonator for sensing applications. The sensor is fabricated by creating two highly reflective mirrors in a coaxial cable. The device physics was discussed. The temperature response of the sensor was tested. The temperature measurement is achieved by monitoring the frequency shift of the reflection and transmission spectra as the temperature is increased linearly in steps of 5 °C from 35 °C to 80 °C. This sensor exhibited high temperature sensitivity and measurement resolution. The high quality factor of this sensor leads to high measurement resolution. Highest $Q$ factor of 133 was recorded. It has been derived that the $Q$ factor decreases as the frequency increases.
Auteurs: Mohammed Farhan Ahmed;Ting Xue;Bin Wu;Jie Huang;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3052 - 3057
Editeur: IEEE
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» High Resolution Digital Imager Based on Time Multiplexing Algorithm
Résumé:
In this paper, a new high-resolution digital imager based on a time multiplexing scheme is proposed. The imager produces a 256-grayscale image through capturing 256 successive frames that each belongs to a specific luminance range. Each pixel includes a 1-b analog-to-digital converter (ADC) and a single bit static memory to improve the fill factor. The in-pixel ADC is designed as a compact and fast converter to achieve a high-resolution and video-rate image sensor. The proposed sensor is designed and implemented in a standard 180-nm CMOS technology. The imager achieves an overall dynamic range of over 140 dB at video rate imaging. The pixel pitch is $18.3~mu text{m}$ and the fill factor is about 48%. The circuit operates at a supply voltage as low as 800 mV. At this supply voltage and at video rate imaging, its power consumption is about 4.33 nW. The proposed imager can directly perform some pre-processing algorithms, such as image segmentation and binarization. Additionally, the proposed method transfers the memory and process units of the pixels to the external of the sensor array so it provides a suitable structure for designing high-resolution, wide dynamic range, and fast general-purpose image sensors.
Auteurs: Kourosh Hassanli;Sayed Masoud Sayedi;J. Jacob Wikner;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2831 - 2840
Editeur: IEEE
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» High Responsivity Fire Detectors Based on PbS Colloidal Quantum Dot Photoconductors
Résumé:
In this letter, we report on high responsivity fire detectors based on PbS colloidal quantum dots photoconductors. The devices operate in the near infrared and are equipped with a visible light silicon filter for wavelength selectivity. Devices are fabricated by a simple, low cost, and silicon compatible process based on drop casting of a ligand exchanged solution of PbS nanoparticles. The photodetectors exhibit responsivity as high as 20 A/W at 1-V bias. We exploit the combination of their high responsivity and spectral response for the development of a novel fire detector able to detect a small flame at a distance exceeding 15 m in ambient illumination.
Auteurs: Andrea De Iacovo;Carlo Venettacci;Lorenzo Colace;Leonardo Scopa;Sabrina Foglia;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 703 - 706
Editeur: IEEE
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» High Speed Band-Limited 850-nm VCSEL Link Based on Time-Domain Interference Elimination
Résumé:
Short-distance optical interconnection among servers in data centers has attracted the attentions of a multitude of researchers. The method to make the optical link with high transmission capacity and low cost becomes increasingly crucial. Considering these requirements, we propose a new equalization method for time-domain interference elimination in this letter, employed in a band-limited 850-nm vertical cavity surface-emitting laser (VCSEL) link. The method is named simplified maximum likelihood sequence estimation (MLSE), which reduces about 87.8% computational complexity in digital signal processing compared with the conventional MLSE. Based on the proposed simplified-MLSE and combined with the feed-forward equalizer (FFE), a 60-Gb/s non-return-to-zero (NRZ)-modulated VCSEL link could transmit via 56-m OM4 multimode fiber (MMF), and the bit error rate (BER) is still lower than the 7% hard-decision forward error correction (FEC) threshold. The 3-dB bandwidth of the employed 850-nm VCSEL in this transmission system is only 18 GHz, fulfilling the principle of cost-efficient optical interconnects and showing the enormous potential of our proposal in data centers.
Auteurs: Zhongwei Tan;Chuanchuan Yang;Yixiao Zhu;Zhaopeng Xu;Kaiheng Zou;Fan Zhang;Ziyu Wang;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 751 - 754
Editeur: IEEE
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» High Speed Electro-Absorption Modulator for Long Range Retroreflective Free Space Optics
Résumé:
In this letter, we present the design and implementation of a pixelated electro-absorption modulator-based modulating retroreflector (MRR) for high-speed optical wireless communications. The modulator is based on a multiple quantum well structure embedded in an asymmetric Fabry–Perot cavity. This MRR was used in an outdoor link, operating at 150 Mb/s with a bit error rate (BER) of $1.22times 10^{-6}$ at a range of 200 m. The system was also tested in laboratory-controlled conditions achieving a data rate of 200 Mb/s with a BER of $2times 10^{-4}$ . To the best of our knowledge, this is the fastest retroreflective free-space optics demonstration in both the indoor and outdoor environments.
Auteurs: C. Quintana;Q. Wang;D. Jakonis;X. Piao;G. Erry;D. Platt;Y. Thueux;A. Gomez;G. Faulkner;H. Chun;M. Salter;D. O’Brien;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 707 - 710
Editeur: IEEE
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» High Step-Up DC–DC Converter With Minimum Output Voltage Ripple
Résumé:
In this paper, a new structure for high step-up dc–dc converters is proposed. In the proposed structure, it is possible to extend the topology by increasing the number of active–passive inductor cells. High voltage gain with lower duty cycle, low-current and -voltage stresses on switches, small inductors, and small size of filter are the main advantages of the proposed structure. The proposed converter is analyzed in different operating modes. In order to design the components’ values of the proposed converter, the equations of output voltage ripple are calculated in each operating mode and a design procedure is proposed based on the aforementioned equations. Moreover, the losses and efficiency of the converter are calculated. In order to validate the correctness of calculations and analyses, the experimental results are given.
Auteurs: Hamed Mashinchi Maheri;Ebrahim Babaei;Mehran Sabahi;Seyed Hossein Hosseini;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3568 - 3575
Editeur: IEEE
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» High Voltage Diodes in Diamond Using (100)- and (111)- Substrates
Résumé:
We present a comparative study of PIN structures in diamond on type IIa (100)- and type IIb (111)- oriented bulk diamond substrates. An 8.5- $mu text{m}$ thick i-layer demonstrated a blocking voltage>1kV for the (100)-oriented diamond sample without any mesa isolation, passivation, or edge termination structures. PIN diodes with a 530nm thick drift region, on the (111)- sample, demonstrated a blocking voltage of 207V at a current level of 1A/cm2 with a corresponding blocking electric field of 3.9MV/cm. A deep ultraviolet light emission was observed only in (111)-diodes under forward bias, confirming well-behaved p-n junction characteristics in (111) as compared to (100).
Auteurs: Maitreya Dutta;Franz A. M. Koeck;Wenwen Li;Robert J. Nemanich;Srabanti Chowdhury;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 600 - 603
Editeur: IEEE
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» High Voltage Stress Induced in Transparent Polycrystalline Diamond Field-Effect Transistor and Enhanced Endurance Using Thick Al2O3 Passivation Layer
Résumé:
A transparent polycrystalline diamond field-effect transistor (FET) was fabricated and measured in room temperature measurements, which reveals comparatively high maximum current density and high breakdown voltage of more than 1000 V. A harsh stress environment is proposed for simple and time-effective reliability stress measurement of the FET using a method of 50 continuous cycles of 500-V voltage stress. A 400-nm-thick Al2O3 counter-destructive passivation layer was implemented on the FET for the stress measurements. Devices with wide gate–drain length ( ${L}_text {GD}$ ) retain their FET characteristics after the harsh stress measurements by only 50% reductions maximum current density.
Auteurs: Mohd Syamsul;Yuya Kitabayashi;Takuya Kudo;Daisuke Matsumura;Hiroshi Kawarada;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 607 - 610
Editeur: IEEE
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» High-Breakdown, High- $f_{mathrm{ max}}$ Multiport Stacked-Transistor Topologies for the ${W}$ -Band Power Amplifiers
Résumé:
Effect of silicon technology limitations, including transistor nonidealities, layout parasitics, and low-quality factor on-chip passive components on millimeter wave stacked switching power amplifiers operating at the ${W}$ -band frequencies (75–110 GHz), is presented in this paper. To mitigate the performance degradation in output power and PAE arising from such causes, high-breakdown voltage, high- $f_{mathrm{ max}}$ multiport stacked-transistor topologies are proposed for realizing power amplifiers with high output power and high efficiency at 75–110 GHz. A 90-nm silicon germanium (SiGe) BiCMOS process is used to propose active structures comprising of two and three stacked transistors with integrated layout parasitics that achieve $f_{mathrm{ max}}$ and breakdown voltage of 295 GHz and 8 V and 260 GHz and 11 V, respectively. Functionality of such multiport transistor topologies is demonstrated in proof-of-concept implementations, including a five-stage two-stacked switching power amplifier (PA) that achieves peak output power and PAE of 22 dBm and 19% at 85 GHz, and a six-stage three-stacked PA that achieves peak output power and PAE of 23.3 dBm and 17% at 83 GHz, respectively. For comparison with conventional switching PA designs using native transistor footprints, a five-stage ${W}$ -band nonstacked Class-E amplifiers is also fabricated in the same 90-nm SiGe BiCMOS process with output power and PAE of 19.5 dBm and 16% at 88 GHz. The superior performance of output power and PAE in designs using the multiport transistor topologies highlights the benefit of the proposed approach.
Auteurs: Kunal Datta;Hossein Hashemi;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1305 - 1319
Editeur: IEEE
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» High-Density Reconfigurable Devices With Programmable Bottom-Gate Array
Résumé:
A novel poly-Si reconfigurable device with a programmable bottom-gate (BG) array is demonstrated for the first time. The BG has non-volatile memory functionality. This device is very efficient in terms of device size and functionality. By changing the bias or program/erase state of the BGs, a device can be transformed to a certain device type among ${n}$ -/ ${p}$ -MOSFETs, and ${n}$ - ${p}$ and ${p}$ - $ {n}$ diodes. The threshold voltage ( $ {V}_{mathsf {th}}$ ) and contact resistance ( ${R}_{mathsf {c}}$ ) of MOSFETs can be controlled independently by the BGs. The subthreshold swings for ${n}$ -/ ${p}$ -MOSFETs are 200 and 230 mV/decade, respectively. The $ {I}_{ mathrm{scriptscriptstyle ON}}/ {I}_{ mathrm{scriptscriptstyle OFF}}$ s of the ${n}$ -/ ${p}$ -MOSFETs measured from a single reconfigurable device are more than $10^{6}$ , which are comparable to those of conventional poly-Si devices.
Auteurs: Jun-Mo Park;Jong-Ho Bae;Jai-Ho Eum;Sung Hun Jin;Byung-Gook Park;Jong-Ho Lee;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 564 - 567
Editeur: IEEE
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» High-Gain and Wide-Bandwidth Filtering Planar Antenna Array-Based Solely on Resonators
Résumé:
This paper presents a new approach for the design of high-gain and wide-bandwidth planar antenna arrays. It is based on the coupling matrix theory which allows the design of the arrays using all-resonator structures. The parameters of the matrix offer the flexibility of achieving a controllable bandwidth. They also introduce a frequency filtering functionality into the arrays which can remove the need to place a bandpass filter after the arrays at the very front end of a communication system. The new approach has been applied to using novel topologies to form two wideband $4 times 4$ planar antenna arrays utilizing rectangular waveguide cavity resonators operated at X-band frequencies. The first topology is seventh order and based on 39 resonators configured in two waveguide-layers; that is one layer for the feed resonators and one layer for the radiating resonators. The second topology is fourth order based on 25 resonators configured only in a single waveguide-layer. Fabrication and measurements have been performed, showing very good agreement with the simulations.
Auteurs: Rashad H. Mahmud;Michael J. Lancaster;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2367 - 2375
Editeur: IEEE
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» High-Linearity AlGaN/GaN FinFETs for Microwave Power Applications
Résumé:
In this letter, we have proposed a novel AlGaN/GaN FinFET featuring T-shaped gate and extremely linearity of transconductance characteristics ( $text{G}_{mathrm {m}})$ . The formation of AlGaN/GaN nano-fins only in the gate opening region is enabled by a developed fabrication process, which is simple and well compatible with the conventional one. When normalized to effective channel width, the fabricated FinFET delivers a 1.45 times higher current density and a 1.66 times higher output power density as high as 11.3 W/mm at 8 GHz compared with the planar HEMTs, along with clearly improved linearity characteristics thanks to a flatter $text{G}_{mathrm {m}}$ response afforded by much lower source access resistance. To the best of our knowledge, this is the first demonstration of superior power performance of high-linearity GaN FinFETs, indicating significant advantages of tri-gate configuration over planar HEMTs for microwave power applications.
Auteurs: Kai Zhang;Yuechan Kong;Guangrun Zhu;Jianjun Zhou;Xinxin Yu;Cen Kong;Zhonghui Li;Tangsheng Chen;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 615 - 618
Editeur: IEEE
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» High-Performance Black Phosphorus MOSFETs Using Crystal Orientation Control and Contact Engineering
Résumé:
We report high performance, orientation-controlled, and locally back-gated black phosphorus (BP) n-MOSFETs and p-MOSFETs with titanium and permalloy contacts, respectively. Devices with channel length ranging from 0.3 to $0.7~mu text{m}$ are analyzed. Armchair-oriented BP p-MOSFETs (n-MOSFETs) display 3.5 times (1.5 times) higher maximum current compared with zigzag devices. Saturated transconductance values up to 4.8 times (1.6 times) higher for BP p-MOSFETs (n-MOSFETs) oriented along the armchair direction compared with the zigzag direction are observed. Using this orientation control and contact engineering, n-MOSFETs with transconductance of $110~mu text{S}/mu text{m}$ and p-MOSFETs with contact resistance as low as 0.31 $text{k}Omega cdot mu text{m}$ are demonstrated.
Auteurs: Nazila Haratipour;Seon Namgung;Roberto Grassi;Tony Low;Sang-Hyun Oh;Steven J. Koester;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 685 - 688
Editeur: IEEE
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» High-Performance Uniaxial Tensile Strained n-Channel JL SOI FETs and Triangular JL Bulk FinFETs for Nanoscaled Applications
Résumé:
In this paper, one proposed an effective method to enhance current drivability of junctionless FETs (JL-FETs) by utilizing uniaxial tensile strain effects. The strained layers were deposited on JL-FETs on silicon-on-insulator (SOI) and bulk Si wafers, respectively. Strained JL SOI FETs show an extremely low subthreshold swing (S.S.) of 65 mV/decade with $I_{ mathrm{scriptscriptstyle ON}}/I_{ mathrm{scriptscriptstyle OFF}} >10^{9}$ ; strained JL bulk FinFETs show an S.S. of 75 mV/decade with $I_{ mathrm{scriptscriptstyle ON}}/I_{ mathrm{scriptscriptstyle OFF}}>10^{7}$ . For strained JL bulk FinFETs, a triangular fin shape could suppress leakage current effectively. Regardless of substrates, JL FETs showed excellent performance owing to uniaxial tensile strain technology. Analysis of leakage current in strained JL FETs included effects on Gate-induced drain leakage trap-assisted tunneling effects were discussed by ${I}_{D}$ ${V}_{G}$ curves under various temperatures and activation energy. Compared with JL SOI gate-all-around structures, JL bulk FinFET possesses higher ${I}_{D}$ and offer the promise of higher integration flexibility for Si CMOS compatible process for the future applications.
Auteurs: Po-Jung Sung;Ta-Chun Cho;Fu-Ju Hou;Fu-Kuo Hsueh;Sheng-Ti Chung;Yao-Jen Lee;Michael I. Current;Tien-Sheng Chao;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2054 - 2060
Editeur: IEEE
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» High-Power Photodiode-Integrated-Connected Array Antenna
Résumé:
We present a novel optical feeding technique to achieve efficient excitation of an ultrawideband-connected array (CA) antenna. The passive fiber optic feed allows for preservation of the theoretical bandwidth and low profile of elementary connected dipole elements. In order to improve effective radiated power, high-power charge compensated modified unitravelling carrier photodiodes are integrated into an antenna array for the first time. Circuit and full-wave simulations, which include all required antenna and feed components, are conducted for the optimization of the array's performance. A 9 × 12 element CA is populated with a 1-D array of four photodiode-integrated active elements to demonstrate the concept. The optically fed array is confirmed experimentally to have a 3-dB bandwidth of approximately 7–17 GHz, in good agreement with simulations.
Auteurs: Matthew R. Konkol;Dylan D. Ross;Shouyuan Shi;Charles E. Harrity;Andrew A. Wright;Christopher A. Schuetz;Dennis W. Prather;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 2010 - 2016
Editeur: IEEE
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» High-Power Terahertz Wave Generation by Optical Rectification of a Gaussian Laser Pulse Propagating in Magnetoplasma
Résumé:
This paper presents an investigation of terahertz (THz) wave generation by optical rectification of a Gaussian laser pulse propagating in plasma having periodic density perturbation in the presence of an externally applied static magnetic field in the axial direction. The nonuniform intensity of laser pulse leads to the generation of quasi-static ponderomotive force. The electrons acquire nonlinear oscillatory velocity under the influence of the force. This velocity, on coupling with the density perturbation, induces a nonlinear current density in the radial direction. This nonlinear current density drives a wave, the frequency of which depends on the pulse duration of the laser. The frequency falls in the THz range if the pulse duration of the laser is chosen thoughtfully. For the resonant excitation of the radiation, phase matching is required, which is provided by the periodic density perturbation. Axially applied external magnetic field can be utilized as a controlling parameter to enhance the nonlinear coupling and the yield of the generated wave. The effect of the axial magnetic field on the generated THz intensity is investigated. Variations in THz radiation intensity as functions of the density ripple amplitude and background plasma density have also been studied.
Auteurs: Ram K. Singh;Subodh Kumar;Ram P. Sharma;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 786 - 790
Editeur: IEEE
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» High-Q Sensor Based on Symmetrical Split Ring Resonator With Spurlines for Solids Material Detection
Résumé:
This paper presents novel structures of planar microwave sensors for detecting and characterizing the dielectric properties in common solid materials which produce high Q-factors with capability to suppress undesired harmonic spurious. These sensors are based on novel planar symmetrical split ring resonator with spurlines filters by employing the perturbation theory, in which the dielectric properties of the resonator affect the Q-factor and resonance frequency. The proposed sensors achieve narrow resonance with low insertion loss and high-Q and sensitivity which peaked up to 652 at 2.22 GHz operating frequency. By using a specific experimental methodology, practical materials are applied as standards (Roger 5880, Roger 4350, FR4) to validate the sensitivity of the sensors for permitting potentially material characterization and detection. Accordingly, the mathematical equation is derived to extract the materials with unknown properties. The average accuracy percentage of the measured results for all cases of the designed sensors is found within 97%–98% compared with those in the literature for the same tested standard materials. It is believed that these sensors would lead for a promising solution of characterizing material particularly in determining material properties and quality, such as in food industry, bio-sensing medicine applications, and therapeutics goods detections.
Auteurs: Rammah Ali Alahnomi;Zahriladha Zakaria;Eliyana Ruslan;Siti Rosmaniza Ab Rashid;Amyrul Azuan Mohd Bahar;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2766 - 2775
Editeur: IEEE
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» High-Quality and Stable Electron Emission Device With Sub-30-nm Aligned Nanogap Arrays
Résumé:
A high-quality and stable electron device of aligned gold nanogap arrays is demonstrated by using a well-controlled method with electron beam lithography and focused ion beam. Sub-30-nm nanogap arrays could be precisely fabricated with reproducibility. Field emission (FE) properties of the nanogaps are directly measured in the vacuum chamber of scanning electron microscopy with a nanomanipulator. Experimental investigation and calculations are carried out to reveal the transition process from the leakage current to the FE. Importantly, the controllable method could allow us to readily construct varying nanospacings. Besides, we also illustrate the independence of emission current on the vacuum degree over a large range, widening the applied range of the devices. These studies clearly demonstrate that electronic devices with sub-30-nm vacuum channel can be readily achieved by coupling varying nanogaps into nanostructures. It may pave the way for exploring the physics in tunneling transport devices, and therefore enable a new generation of high-performance, high-speed and low-cost electronic devices.
Auteurs: Ji Xu;Qilong Wang;Zhi Tao;Yusheng Zhai;Chen Guangdian;Zhiyang Qi;Xiaobing Zhang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2364 - 2368
Editeur: IEEE
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» High-Speed Resonant Surface Acoustic Wave Instrumentation Based on Instantaneous Frequency Measurement
Résumé:
Surface acoustic wave (SAW) resonators are used for a broad range of wireless sensing applications, some of them having high demands on the resolution as well as the measurement update rate. This paper presents a new interrogation method for precise and fast frequency determination of passive SAW resonators based on instantaneous frequency measurement by a low-cost six-port interferometer. Using a delay line, the frequency measurement is reduced to a phase measurement that can be instantaneously evaluated by the six-port network. No complex signal processing is necessary providing high update rates and low hardware costs. An in-depth analysis of the system concept and its building blocks is presented, and the advantages as well as the limitations are discussed and compared with the current state of the art. Finally, a demonstrator in the 2.4-GHz frequency band shows the feasibility and the precision of the concept with measurement times of only a few microseconds.
Auteurs: Fabian Lurz;Stefan Lindner;Sarah Linz;Sebastian Mann;Robert Weigel;Alexander Koelpin;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 974 - 984
Editeur: IEEE
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» Higher Order Asymptotic Approximations of Eigenmodes for a Circular Waveguide Terminated by a Perfectly Matched Layer
Résumé:
In this paper, the improved asymptotic solutions of eigenmodes (leaky and Berenger modes) are provided for a circular waveguide terminated by a perfectly matched layer. Furthermore, a systematic asymptotic approach is developed by the inverse power series. Numerical simulations demonstrate that the high-precision asymptotic eigenmodes can be obtained.
Auteurs: Jianxin Zhu;Chaofeng Dong;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1980 - 1987
Editeur: IEEE
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» Higher Order Linear Dynamical Systems for Smoke Detection in Video Surveillance Applications
Résumé:
In this paper, we consider the problem of multi-dimensional dynamic texture analysis, and we introduce a new higher order linear dynamical system (h-LDS) descriptor. The proposed h-LDS descriptor is based on the higher order decomposition of the multidimensional image data and enables the analysis of dynamic textures by using information from various image elements. In addition, we propose a methodology for its application to video-based early warning systems that focus on smoke identification. More specifically, the proposed methodology enables the representation of video subsequences as histograms of h-LDS descriptors produced by the smoke candidate image patches in each subsequence. Finally, to further improve the classification accuracy, we propose the combination of multidimensional dynamic texture analysis with the spatiotemporal modeling of smoke by using a particle swarm optimization approach. The ability of the h-LDS to analyze the dynamic texture information is evaluated through a multivariate comparison against the standard LDS descriptor. The experimental results that use two video datasets have shown the great potential of the proposed smoke detection method.
Auteurs: Kosmas Dimitropoulos;Panagiotis Barmpoutis;Nikos Grammalidis;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1143 - 1154
Editeur: IEEE
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» Highly Sensitive D-Shaped Photonic Crystal Fiber-Based Plasmonic Biosensor in Visible to Near-IR
Résumé:
A simple D-shaped photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) biosensor is proposed for refractive index sensing in visible to near infrared (IR) region. A thin Titanium di-oxide (TiO2) layer is used as an adhesive layer to strongly attach the plasmonic gold (Au) layer with silica fiber surface. TiO2 also helps to tune the operating sensor wavelength from visible to near IR (550–1770-nm wavelength). Finite-element method has been used to investigate the guiding properties. The proposed sensor shows the maximum wavelength interrogation sensitivity of 46 000 nm/RIU and the average sensitivity of 9,800 nm/RIU in the sensing range of 1.33–1.43. It also shows the maximum amplitude sensitivity of 1,086 RIU $^{-1}$ . Using the wavelength and amplitude interrogation methods, proposed sensor gives the theoretical maximum resolution of 2.2 $times 10^{-6}$ and 9.2 $times 10^{-6}$ RIU, respectively. To the best of our knowledge, it has the highest sensitivity and sensor resolution among the reported PCF SPR sensors. The proposed D-shaped PCF has been fabricated following the standard stack-and-draw method to show the feasibility of the proposed sensor. Due to the promising results over the broad range of analyte RI, it would be an excellent candidate for the detection of biomolecules, organic chemicals, chemical, and other analytes.
Auteurs: Ahmmed A. Rifat;Rajib Ahmed;G. Amouzad Mahdiraji;F. R. Mahamd Adikan;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2776 - 2783
Editeur: IEEE
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