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INTEGRATION OF STEREO VISION AND OPTICAL-FLOW BY USING AN ENERGY-MINIMIZATION APPROACH

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 1989年第6期6卷 900-907页

作者： NASRABADI, NM CLIFFORD, SP LIU, Y []Computer Vision Research Group Department of Electrical Engineering Worcester Polytechnic Institute Worcester Massachusetts 01609

A cooperative method is proposed in which image intensity (brightness) and optical-flow information are integrated into a single stereo technique by modeling the input data as coupled Markov random fields (MRF’s). The Bayesian probabilistic estimation method and the MRF–Gibbs equivalence theory are used to integrate the optical flow and the gray-level intensity information to obtain an energy function that will explicitly represent the depth discontinuity and occlusion constraints on the solution. This energy function involves the similarity in intensity (or edge orientation) and the optical flow between corresponding sites of the left and right images as well as the smoothness constraint on the disparity solution. If a simple MRF is used to model the data, the energy function will yield a poor disparity by smoothing across object boundaries, particularly when occluding objects are present. We use optical-flow information to indicate object boundaries (depth discontinuities) and occluded regions, in order to improve the disparity solution in occluded regions. A stochastic relaxation algorithm (simulated annealing) is used to find a favorable disparity solution by minimization of the energy equation.

关键词： Brightness Medical imaging Motion estimation Optical flow Remote sensing Stereo matching

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A 3D Memristive Cubic Map with Dual Discrete Memristors: Design, Implementation, and Application in Image Encryption

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IEEE Transactions on Circuits and Systems for Video Technology 2025年

作者： Gao, Suo Iu, Herbert Ho-Ching Erkan, Ugur Simsek, Cemaleddin Toktas, Abdurrahim Cao, Yinghong Wu, Rui Mou, Jun Li, Qi Wang, Chunpeng Dalian Polytechnic University School of Information Science and Engineering Dalian116034 China The University of Western Australia School of Electrical Electronic and Computer Engineering Perth6009 Australia Faculty of Engineering Electrical and Electronics Engineering Respectively Karamanoglu Mehmetbey University Karaman70200 Turkey Ankara University Engineering Faculty Department of Artificial Intelligence and Data Engineering Ankara06830 Turkey Harbin Institute of Technology School of Computer Science and Technology Harbin150001 China Key Laboratory of Computing Power Network and Information Security Ministry of Education Shandong Computer Science Center National Supercomputer Center in Jinan Shandong Provincial Key Laboratory of Computer Networks Shandong Fundamental Research Center for Computer Science Jinan250000 China

Discrete chaotic systems based on memristors exhibit excellent dynamical properties and are more straightforward to implement in hardware, making them highly suitable for generating cryptographic keystreams. However, most existing memristor-based chaotic systems rely on a single memristor. This paper introduces a novel discrete chaotic system employing dual memristors, named the 3D memristive cubic map with dual discrete memristors (3D-MCM). The 3D-MCM system demonstrates richer and more intricate dynamical behaviors compared to its single-memristor counterparts, as verified through bifurcation diagrams, Lyapunov exponent spectra, and complexity analyses. Notably, the system exhibits coexisting attractors, substantially enhancing its dynamical complexity. Hardware implementation of the 3D-MCM attractors confirms its feasibility for industrial applications. To illustrate the system's potential in encryption tasks, this study integrates the quaternary-based permutation and dynamic emanating diffusion (QPDED-IE) scheme for image encryption with the *** results demonstrate that the QPDED-IE scheme based on the 3D-MCM exhibits strong diffusion and confusion properties, effectively resisting cryptanalytic attacks. © 1991-2012 IEEE.

关键词： Bifurcation (mathematics)

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Important considerations in the evaluation of absorbing boundary conditions

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ELECTROMAGNETICS 1996年第4期16卷 417-433页

作者： Lee, R Chen, Z Jevtic, JO Lee, JF [a] Department of Electrical Engineering ElectroScience Laboratory The Ohio State University Columbus OH USA [b] Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester MA USA

In this paper, we study the interaction of an absorbing boundary condition (ABC) with the discretization error. In many cases the major source of error is due to the discretization error and how it couples to the ABC. In order to study the ABC, we consider three methods to solve the problem. Two of these are finite element methods with either nodal elements or the recently proposed solenoidal elements. The third is based on analytical methods. The effect of electrical size of the geometry as well as the excitation on the error is studied within the context of the interaction between numerical dispersion and the ABC errors.

关键词： Electromagnetic wave absorption

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Dual Three-Phase Four-Leg Multilevel Inverter with Backstepping Prediction for Unbalanced Low-Voltage Grids

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IEEE Transactions on Industry Applications 2025年

作者： Monteiro, Joaquim Pires, Fernao Cordeiro, Armando Silva, Jose Fernando Pinto, Sonia UnIRE ISEL Polytechnic University of Lisbon Lisbon1959-007 Portugal INESC-ID Lisbon1049-001 Portugal Polytechnic Institute of Setúbal Setúbal School of Technology Setúbal2914-508 Portugal ISEL Polytechnic University of Lisbon Lisbon1959-007 Portugal University of Lisbon Department of Electrical and Computer Engineering of Instituto Superior Técnico Lisbon1649-004 Portugal

Wind and solar renewable energy sources (RES) have been fundamental in reducing carbon emissions in electrical energy systems. However, when integrated into low voltage grids, some problems can arise due to the high number of single-phase loads. This situation often leads to unbalanced loads, which can result in increased losses or even under- or over-voltages in one of the phases. This issue is even more critical in the context of isolated microgrids. Therefore, this paper introduces a novel control system for a grid-connected photovoltaic (PV) generation setup based on a dual three-phase four-leg multilevel inverter. This power converter topology, comprising two four-leg two-level three-phase inverters, connects two PV arrays to a three-phase transformer with four wires which in turn connects to a grid. This arrangement is designed to inject PV-generated power into the low voltage (LV) grid, providing support for unbalanced loads. A backstepping method is derived to predict the optimum converter voltage and near optimum vector to control the load currents. As only one voltage prediction is needed a fast controller is obtained even if the converter has high number of voltage vectors. This backstepping prediction increases the speed of choosing the converter vector, allowing the control of the grid currents injected under both balanced and unbalanced conditions, while also maintaining balance of the capacitor DC voltages in RES. Experimental tests were conducted using a laboratory prototype to evaluate the backstepping prediction performance applied to the proposed PV generation system. © 2025 IEEE.

关键词： Solar power generation

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Evaluating cardiac function in ex vivo heart perfusion using lumped parameter models

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computers in Biology and Medicine 2025年 189卷 109922-109922页

作者： Roig, Raimon Casamitjana Li, Selena S. Asheghan, Mostafa Olverson, George Vincent, Doug Bolger-Chen, Maya Ajenu, Emmanuella Higuita, Manuela Lopera Tessier, Shannon N. Osho, Asishana D'Alessandro, David A. Rabi, S. Alireza Nezami, Farhad R. Division of Cardiac Surgery Department of Surgery Brigham and Women's Hospital Harvard Medical School BostonMA United States Division of Cardiac Surgery Department of Surgery Massachusetts General Hospital Harvard Medical School BostonMA United States Electrical Engineering Department Worcester Polytechnic Institute WorcesterMA United States Ventriflo Inc. PelhamNH United States Center for Engineering in Medicine and Surgery Massachusetts General Hospital Harvard Medical School and Shriners Children's Hospital BostonMA United States

Background: Heart transplant outcomes and survival depend on the ability to implant well-functioning organs, but there remain no reliable, objective measures of cardiac function prior to implantation. The lack of standardized protocols and advanced technologies results in inconsistencies and subjective assessments, increasing the risk for postoperative graft dysfunction, the leading cause of short-term morbidity and mortality after transplant. Ex-vivo heart perfusion (EVHP) provides a platform to evaluate donor hearts prior to implantation, using machine perfusion to reanimate the heart to a beating, physiologic state. The FDA-approved Organ Care System (OCS) is widely utilized for the evaluation and ex vivo preservation of hearts, particularly from donors after circulatory death (DCD). However, it does not permit a physiological assessment of heart function because, while the heart continues to beat, its chambers remain devoid of perfusate and thus are unable to perform any functional work. Method: In this study, we developed and validated a lumped parameter mathematical model to assess donor hearts during ex-vivo perfusion, using a customized, in-house EVHP setup that allows left ventricular loading. Results: We demonstrate the ability of our mathematical model to accurately predict hemodynamic parameters, enabling performance analysis of hearts during EVHP. Our model generates pressure-volume loops, allowing for the computation of ejection fraction, and was verified with experimental measurements taken via echocardiography. Conclusion: This promising tool demonstrates the unique opportunity to utilize mathematical modeling in the assessment of donor hearts, streamlining their performance evaluation. Ultimately, a more accurate assessment of donor hearts on EVHP may improve our utilization of available donor hearts, addressing the donor organ shortage that continues to limit transplant capabilities. © 2025

关键词： Heart

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NUMERICAL-SIMULATION OF ELECTROMAGNETIC ACOUSTIC TRANSDUCER IN THE TIME DOMAIN

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JOURNAL OF APPLIED PHYSICS 1991年第1期69卷 89-98页

作者： LUDWIG, R DAI, XW Department of Electrical Engineering Worcester Polytechnic Institute Worcester Massachusetts 01609

A novel multistage numerical modeling approach to simulate acoustic-wave generation and propagation of an electromagnetic acoustic transducer (EMAT) is presented. The model assumes a uniform static magnetic field in a conducting half-space. A meander coil winding situated above the half-space is driven by a transient high-frequency current pulse. The numerically computed eddy currents in the conducting specimen are combined with the static magnetic field to yield spatially and temporally diffusive Lorentz forces which in turn are coupled into the elastic-wave equation. This hyperbolic elastodynamic system is solved for the displacement field vector which gives rise to propagating elastic waves. Numerical transduction results are discussed for a generic two-wire transient EMAT configuration and for an isotropic half-space with electric and acoustic material parameters equivalent to those of aluminum.

关键词： ACOUSTIC TRANSDUCERS SIMULATION NUMERICAL ANALYSIS DESIGN MAGNETIC FIELDS MAGNET COILS WAVE PROPAGATION ULTRASONIC WAVES

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COHERENT PULSE PROPAGATION IN A 2-PHOTON AMPLIFIER

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LETTERE AL NUOVO CIMENTO 1971年第19期1卷 775-+页

作者： ESTES, LE NARDUCCI, LM SHAMMAS, B Electrical Engineering Department Worcester Polytechnic Institute Worcester Physics Department Worcester Polytechnic Institute Worcester

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COHERENT ABSORPTION IN A HOMOGENEOUSLY BROADENED MEDIUM

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IEEE JOURNAL OF QUANTUM ELECTRONICS 1970年第9期QE 6卷 546-+页

作者： ESTES, LE ETESON, DC NARDUCCI, LM Department of Electrical Engineering Worcester Polytechnic Institute Worcester MA USA Department of Physics Worcester Polytechnic Institute Worcester MA USA

An investigation of the propagation properties of a short pulse in a resonant absorber with a homogeneously broadened transition is presented with two main questions in mind: 1) the influence of the input pulse area on the transitory regime and on the steady-state propagation; 2) the effects of atomic coherence on the pulse shaping and the time delay of the leading edge of the pulse. The transitory regime of a propagating pulse is investigated and the stability of some asymptotic wave form confirmed. As expected, the transversal relaxation mechanism affects critically the major features of the coherent interaction. A detailed analysis of this problem is also presented.

关键词： Absorption Pulse shaping methods Optical propagation Space vector pulse width modulation Nonlinear optics Resonance light scattering Steady-state Coherence Delay effects Asymptotic stability

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TELEX: Two-Level Learned Index for Rich Queries on Enclave-based Blockchain Systems

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IEEE Transactions on Knowledge and Data engineering 2025年

作者： Wu, Haotian Tang, Yuzhe Shen, Zhaoyan Tao, Jun Lin, Chenhao Peng, Zhe The Hong Kong Polytechnic University Department of Industrial and Systems Engineering Hong Kong Syracuse University Department of Electrical Engineering and Computer Science United States Shandong University School of Computer Science and Technology China Southeast University School of Cyber Science and Engineering China Xi'an Jiaotong University Faculty of Electronic and Information Engineering China The Hong Kong Polytechnic University Shenzhen Research Institute Hong Kong

Blockchain has become a popular paradigm for secure and immutable data storage. Despite its numerous applications across various fields, concerns regarding the user privacy and result integrity during data queries persist. Additionally, the need for rich query functionalities to harness the full potential of blockchain data remains an area ripe for exploration. In order to address these challenges, our paper first utilizes a framework based on the Trusted Execution Environment (TEE) and oblivious RAM technique to achieve both privacy and data integrity. To enhance the query efficiency over the entire blockchain, we then devise a two-level learned indexing methodology named TELEX within the TEE for both integer and string keys. We also propose different query processing algorithms for versatile query types, including exact queries, aggregate queries, Boolean queries, and range queries. By implementing the prototype and conducting extensive evaluation, we demonstrate the feasibility and remarkable improvement in efficiency compared to existing solutions. © 1989-2012 IEEE.

关键词： Query languages

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AN INFORMATION-THEORETIC ANALYSIS OF CUTANEOUS RECEPTOR RESPONSES

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IEEE TRANSACTIONS ON BIOMEDICAL engineering 1984年第4期31卷 377-383页

作者： FULLER, MS LOOFT, FJ Department of Electrical Engineering Worcester Polytechnic Institute Worcester MA USA

Two prevalent underlying assumptions related to cutaneous receptor research are that receptor responses are conditionally independent given the stimulus, and that stimulus information is encoded through a mean rate code. In this paper, an information-theoretic technique that can be used to test these assumptions is developed and presented. Results are presented from experiments designed to evaluate the efficiency of mean rate codes and the independence of receptor discharges recorded from cutaneous receptor afferent neurons.

关键词： Information analysis Testing Neurons Biomedical measurements Data analysis Channel capacity Random processes Pattern analysis Transfer functions Public healthcare

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