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IONIZATION COEFFICIENT FOR HOLES IN POLYCRYSTALLINE SELENIUM

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE 1971年第2期7卷 421-+页

作者： LANYON, HPD RICHARDSON, RE Electrical Engineering Department Worcester Polytechnic Institute Worcester Massachusetts

AbstractTheionization coefficient for holes in polycrystalline selenium has been measured as a function of temperature through the field dependence of photocurrent. At 250 °K the breakdown field strength is approximately 2×105V/cm decreasing to 1.5×105V/cm at 156 °K. The phonon creation length is 100 Å at 300 °K becoming larger as the temperature is decreased. The magnitudes of the breakdown fields and the phonon creation length indicate that the breakdown process can be described in terms of the Wolff model of brea

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IMAGE-RECONSTRUCTION TECHNIQUES IN TOMOGRAPHIC IMAGING-SYSTEMS

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL PROCESSING 1986年第4期34卷 952-962页

作者： SOUMEKH, M Department of Electrical Engineering Worcester Polytechnic Institute Worcester MA USA

This paper addresses the problems of image reconstruction in fan beam straight-path tomography and image reconstruction from incomplete object projections data. A method for restoring the parallel beam projections of a test object from its fan beam projections in straight-path tomography is introduced. The scheme utilizes FFT routines to accomplish the restoration task. It is shown that the approach reduces the required amount of the collected fan beam data by one-half. Moreover, a noniterative method of image reconstruction, when arbitrary segments of the object projections cannot be detected, is presented. The technique exploits the functional properties of the object projections, in conjunction with a priori information available about the test object, to restore the unknown data. The method's applications in straight-path and diffraction tomography systems are shown.

关键词： Image reconstruction Tomography Structural beams Diffraction Image restoration Ultrasonic variables measurement Fourier transforms System testing Ultrasonic imaging Optical scattering

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CONNECTED REORIENTATIONS OF MIXED MULTIGRAPHS

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NETWORKS 1989年第2期19卷 235-246页

作者： SHI, WG JUELS, RJ Department of Electrical Engineering Worcester Polytechnic Institute Worcester Massachusetts 01609

We study here the problem of reorienting the directed edges of mixed multigraphs so as to establish or preserve reachability, which may be destroyed by edge removal. We develop a linear time/space algorithm which tests whether reorienting designated directed edges can reestablish reachability, and which constructs such a reorientation whenever possible. We also develop a linear time/space algorithm which, when reachability has been destroyed by the removal of a single edge, optimally restores reachability through the reversal of selected edges. Finally, we show the reliability of a graph allowing reversals to be twice that of a graph for which reversals are not permitted.

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A fully-informed search scheme-based particle swarm optimisation for parameter estimation of proton exchange membrane fuel cell

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International Journal of Ambient Energy 2025年第1期46卷

作者： Jangir, Pradeep Arpita Premkumar, Manoharan Agrawal, Sunilkumar P. Pandya, Sundaram B. Parmar, Anil Abualigah, Laith University Centre for Research and Development Chandigarh University Mohali India Department of CSE Graphic Era Hill University Dehradun India Department of CSE Graphic Era Deemed To Be University Dehradun India Applied Science Research Center Applied Science Private University Amman Jordan Centre for Research Impact & Outcome Chitkara University Institute of Engineering and Technology Chitkara University Punjab Rajpura India Department of Biosciences Saveetha School of Engineering Saveetha Institute of Medical and Technical Sciences Chennai India Department of Electrical and Electronics Engineering Dayananda Sagar College of Engineering Bengaluru India Department of Electrical Engineering Government Engineering College Gandhinagar India Department of Electrical Engineering Shri K.J. Polytechnic Bharuch India Computer Science Department Al al-Bayt University Mafraq Jordan

In this study, we employ a recent variant of Particle Swarm Optimisation specifically for single objective numerical optimisation (PSO-sono) to pinpoint the optimal parameters of proton exchange membrane fuel cells (PEMFC) across certain operational scenarios. This research focuses on optimising seven parameters–(Formula presented.) and B–to replicate polarisation curves that align closely with those provided in manufacturers’ datasheets. The PSO-sono algorithm incorporates hybrid paradigms and adaptive parameter schemes, enhancing the traditional PSO algorithm's performance. The efficacy of PSO-sono was evaluated using six commercial PEMFC stacks: BCS 500-W PEM, BCS 250-W PEM, Nedstack PS6 PEM, 500W SR-12PEM, H-12 PEM and HORIZON 500W PEM, under varied operational conditions. The objective function for optimisation was the sum of squared errors (SSE) between the parameter-derived results and the actual experimental data from these fuel cell stacks. To establish the robustness of PSO-sono, its outcomes were benchmarked against results from other PSO variants, including PSO, CLPSO, DNLPSO, SLPSO, EPSO, PSO-DE, HFPSO, MPSO and HPSO. The I/V and P/V curves derived from PSO-sono showed a precise alignment with the datasheet specifications for all PEMFC models tested. Conclusively, the PEMFC model utilising the PSO-sono approach outperformed all other algorithms in terms of accuracy and convergence speed. © 2025 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Particle swarm optimization (PSO)

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A UNIFIED BOUNDARY-ELEMENT FINITE-ELEMENT PACKAGE

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IEEE TRANSACTIONS ON electrical INSULATION 1993年第2期28卷 161-167页

作者： LEVIN, PL HANSEN, AJ BEATOVIC, D GAN, H PETRANGELO, JH Computational Fields Laboratory Department of Electrical Engineering Worcester Polytechnic Institute

In this paper we describe a set of computer programs designed for research and educational objectives in the analysis of low frequency electric and magnetic field phenomena. These programs are developed around a standard and easily extensible user interface, run on both PC compatible and X window platforms, and offer the user a wide range of analysis tools. They are capable of solving Poisson's equation for arbitrarily shaped axi-symmetric and two dimensional geometries.

关键词： boundary-elements methods electric fields electrical engineering computing finite element analysis graphical user interfaces magnetic fields mesh generation microcomputer applications physics computing Delaunay mesh generator Laplace equation PC compatibility Poisson equation X window platforms axisymmetric geometry boundary-element finite-element package computer programs educational objectives extensible user interface low frequency electric fields low frequency magnetic fields research objectives two-dimensional geometries Finite element methods Gallium nitride Geometry Graphics Laboratories Magnetic analysis Packaging Poisson equations Standards development User interfaces

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A Sensorless Method based on Zero-sequence Back-EMF for Five-phase Open-end Winding PMSM with Deadtime Compensation

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IEEE Transactions on Energy Conversion 2025年

作者： Jiang, Chunyang Wang, Yingjie Liu, Hongchen Wheeler, Pat Bao, Danyang Northeast Forestry University College of Computer and Control Engineering Harbin 150001 China Harbin Institute of Technology School of Electrical Engineering and Automation Harbin 150001 China University of Nottingham Department of Electrical and Electronics Engineering Nottingham NG7 2RD United Kingdom Shenzhen Polytechnic University School of Mechanical and Electrical Engineering Shenzhen 518000 China

This paper proposes a sensorless method using the zero-sequence back electromotive force (ZSB-EMF) for five-phase open-end winding permanent magnet synchronous machine (OEW-PMSM) with common dc bus. The output of the zero-sequence controller, which is applied to suppress the zero-sequence current (ZSC), is used to reconstruct the ZSB-EMF. Then the position of the rotor is extracted from the output signal of the zero-sequence controller by single phase locked loop. A compensation of the deadtime is proposed to eliminate the negative effect for the position estimation and increase the effective modulation index. The proposed method needs no parameters of the motor, like the resistance, d-q inductance, which are vulnerable and might affect the accuracy of the estimation for the conventional sensorless methods based on the ZSB-EMF. It is easy to implement and the resistance network and complex calculation of conventional methods are also avoided. Experimental results on the five-phase open-end winding PMSM drive system are shown to validate the proposed sensorless method. © 1986-2012 IEEE.

关键词： Common dc Bus Deadtime Compensation Five-phase Open-end Winding Permanent Magnet Synchronous Machine Sensorless method

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STEREO VISION CORRESPONDENCE USING A MULTICHANNEL GRAPH MATCHING TECHNIQUE

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IMAGE AND VISION COMPUTING 1989年第4期7卷 237-245页

作者： NASRABADI, NM LIU, Y Computer Vision Research Group Department of Electrical Engineering Atwater Kent Laboratories Worcester Polytechnic Institute Worcester MA 01609 USA

A multichannel feature-based stereo vision technique is described in this paper where curve segments are used as the feature primitives in the matching process. Curve segments are extracted by tracking the zero-crossings of the left and right images. The generalized Hough transform of each curve and the curve length are used as a local feature vector in representing the distinctive characteristics of the curve segment. The feature vector of each curve segment in the left image is used as a constraint to find an instance of the same curve segment in the right image. The epipolar constraint on the centroids of the curve segment is used to limit the searching space in the right image. A relational graph is formed from the left image by treating the centroids of the curve segments as the nodes of the graph. The local features of the curve segments are used to represent the local properties of the nodes, and the relationship between the nodes represents the structural properties of the objects in the scene. A similar graph is also formed from the right image curve segments. A graph isomorphism is then formed between the two graphs by using the epipolar constraint on the centroids, the local properties of the nodes, node assignment and the structural relationship (compatibility) between the nodes.

关键词： stereo vision graph matching

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PHASE DETECTION OF R-WAVES IN NOISY ELECTROCARDIOGRAMS

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IEEE TRANSACTIONS ON BIOMEDICAL engineering 1972年第1期BM19卷 63-&页

作者： AMAZEEN, PG FELDMAN, CL MORUZZI, RL Electrical Engineering Department Worcester Polytechnic Institute Worcester MA USA Mechanical Engineering Department Worcester Polytechnic Institute Worcester MA USA

Ventricular fibrillation, a form of electrical instability of the myocardium, is strongly suspected to be a significant contributor to ``sudden'' coronary fatalities. Present evidence indicates that ventricular fibrillation is often preceded by other forms of abnormal electrical activity of the heart, especially ventricular premature beats (VPBs). Early detection of the presence of VPBs in the electrocardiogram may be important in making medical decisions to avert a later coronary attack.

关键词： Phase detection Phase noise Muscles Timing Heart rate variability Frequency Fibrillation Cardiology Morphology Low-frequency noise

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RESTRICTIONS ON SEMICLASSICAL APPROXIMATION

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PHYSICS LETTERS A 1968年第6期A 27卷 388-&页

作者： ESTES, LE KEIL, TH NARDUCCI, LM Electrical Engineering Department Worcester Polytechnic Institute UK Physics Department Worcester Polytechnic Institute UK

The semiclassical approximation for two coupled harmonic oscillators is discussed. The range of validity of the approximation is obtained.

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The impact of indoor environmental quality on tourist accommodation ratings using guest reviews

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Building and Environment 2025年 280卷

作者： Zhang, Fan Seshadri, Karthick Liu, Shichao Santamouris, Matthaios School of Engineering and Built Environment Griffith University SouthportQLD Australia Department of Computer Science and Engineering National Institute of Technology Andhra Pradesh Tadepalligudem India Department of Civil Environmental Architectural Engineering Worcester Polytechnic Institute MA United States High Performance Architecture School of Built Environment University of New South Wales SydneyNSW Australia

Guest satisfaction is pivotal for the hospitality industry, yet the role of Indoor Environmental Quality (IEQ) in shaping guest ratings remains inadequately explored. This study addresses this gap by leveraging web-mining, natural language processing and the Three-Factor Theory to analyse guest reviews of Australian hotels and serviced apartments listed on ***. Findings indicate that most IEQ factors—thermal comfort, indoor air quality, luminous environment, acoustics, space, facilities, cleanliness, and layout—function as Basic Factors. While deficiencies in these areas drive dissatisfaction, their adequacy alone does not significantly enhance satisfaction. Notably, exterior view serves as an Excitement Factor in budget accommodations (three stars or below) but transitions to a Basic Factor in luxury settings. Among all IEQ factors, cleanliness, indoor air quality, and acoustics had the strongest negative impacts when underperforming, whereas satisfactory exterior views, cleanliness, and available space positively influenced guest ratings. The COVID-19 pandemic intensified these effects, heightening guest sensitivity to IEQ deficiencies (e.g., poor air quality) while elevating expectations for high-performing attributes like exterior views and available space. Overall, IEQ factors accounted for 32.8 % of customer ratings in budget hotels and 23.9 % in luxury accommodations. The findings underscore the necessity of ensuring satisfactory performance across all IEQ factors, particularly cleanliness and indoor air quality, while strategically enhancing exterior views and spatial configuration to optimize guest satisfaction. These insights provide hospitality managers and policymakers with data-driven guidance for enhancing guest satisfaction and operational resilience in post-pandemic hospitality settings. © 2025 The Author(s)

关键词： Indoor air pollution

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