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Integrated Photonics Research, Silicon and Nanophotonics, IPRSN 2011

作者： Wang, Chih-Yu Chung, Shih-Yung Teng, Chun-Hao Chen, Chung-Ping Chang, Hung-Chun Graduate Institute of Electronics Engineering National Taiwan University Taipei 10617 Taiwan Department of Applied Mathematics Center of Mathematical Modeling and Scientific Computing National Chiao Tung University Hsinchu 30010 Taiwan Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan Graduate Institute of Photonics and Optoelectronics National Taiwan University Taipei 10617 Taiwan Graduate Institute of Communication Engineering National Taiwan University Taipei 10617 Taiwan

A high-order accurate pseudospectral frequency-domain (PSFD) method is used to analyze light scattering by plasmonic cylinders. Field coupling and enhancement within the gap of close spaced cylinders are examined. Die... 详细信息

ISBN: (纸本)9781557529138

关键词： Light scattering

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Anisotropic spectral manifold wavelet descriptor for deformable shape analysis and matching 26

Anisotropic spectral manifold wavelet descriptor for deforma...

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26th Pacific Conference on Computer Graphics and Applications, Pacific Graphics 2018

作者： Li, Qinsong Liu, Shengjun Hu, Ling Liu, Xinru Institute of Engineering Modeling and Scientific Computing Central South University Hunan Changsha410083 China School of Mathematics and Computational Science Hunan First Normal University Hunan Changsha410205 China State Key Laboratory of High Performance Manufacturing Complex Central South University Hunan Changsha410083 China

ISBN: (纸本)9783038680734

In this paper, we present a novel framework termed Anisotropic Spectral Manifold Wavelet Transform (ASMWT) for shape analysis. ASMWT comprehensively analyzes the signals from multiple directions on local manifold regions of the shape with a series of low-pass and band-pass frequency filters in each direction. Using the ASMWT coefficients of a very simple function, we efficiently construct a localizable and discriminative multiscale point descriptor, named as the Anisotropic Spectral Manifold Wavelet Descriptor (ASMWD). Since the filters used in our descriptor are direction-sensitive and able to robustly reconstruct the signals with a finite number of scales, it makes our descriptor be intrinsic-symmetry unambiguous, compact as well as efficient. The extensive experimental results demonstrate that our method achieves significant performance than several state-of-the-art methods when applied in vertex-wise shape matching. © 2018 The Author(s).

关键词： Wavelet transforms

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Experimental and kinetic modeling study of oxidation of acetonitrile 38th

Experimental and kinetic modeling study of oxidation of acet...

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38th International Symposium on Combustion, 2021

作者： Alzueta, María U. Guerrero, Marta Millera, Ángela Marshall, Paul Glarborg, Peter Aragón Institute of Engineering Research I3A Department of Chemical and Environmental Engineering University of Zaragoza Zaragoza 50018 Spain Department of Chemistry Center for Advanced Scientific Computing and Modeling University of North Texas 1155 Union Circle 305070 Denton TX 76203-5017 United States Dtu Chemical Engineering Technical University of Denmark Lyngby DK-2800 Denmark

Oxidation of acetonitrile was studied in a flow reactor in the absence and presence of nitric oxide. The experiments were conducted at atmospheric pressure in the temperature range 1150 K–1450 K, varying the excess air ratio from slightly fuel-lean to very lean. Oxidation of acetonitrile was slow below 1300 K. NO, hydrogen cyanide, and nitrous oxide were detected as important products. A detailed chemical kinetic model for oxidation of acetonitrile was developed, based on a critical evaluation of data from literature. The rate coefficients for the reactions of acetonitrile and CH₂CN with O₂ were calculated from ab initio theory. modeling predictions were in satisfactory agreement with experiments. Calculations were sensitive to thermal dissociation of acrolein and to the branching fraction for CH₃CN + OH to CH₂CN + H₂O and HOCN +CH₃ , respectively.

关键词： Kinetic theory

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Towards distributed multiscale simulation of biological processes

Towards distributed multiscale simulation of biological proc...

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7th IEEE International Conference on e-Science Workshops, eScienceW 201

作者： Bernsdorf, Jörg Berti, Guntram Chopard, Bastien Hegewald, Jan Krafczyk, Manfred Wang, Dinan Lorenz, Eric Hoekstra, Alfons German Research School for Simulation Sciences RWTH Aachen University Aachen Germany Berti CMM Consulting Mathematical Methods Bonn Germany Scientific and Parallel Computing Group University of Geneva Geneva Switzerland Institute for Computational Modeling in Civil Engineering Technische Universität Braunschweig Brunswick Germany Meteorological Institute University of Bonn Bonn Germany Section Computational Science University of Amsterdam Amsterdam Netherlands

ISBN: (纸本)9780769545981

The understanding of biological processes, e.g. related to cardio-vascular disease and treatment, can significantly be improved by numerical simulation. In this paper, we present an approach for a multiscale simulation environment, applied for the prediction of in-stent re-stenos is. Our focus is on the coupling of distributed, heterogeneous hardware to take into account the different requirements of the coupled sub-systems concerning computing power. For such a concept, which is an extension of the standard multiscale computing approach, we want to apply the term Distributed Multiscale computing. © 2011 IEEE.

关键词： Stents

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The Exploration of Neural Collapse under Imbalanced Data

arXiv

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arXiv 2024年

作者： Liu, Haixia School of Mathematics and Statistics Institute of Interdisciplinary Research for Mathematics and Applied Science Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Hubei Wuhan China

Neural collapse, a newly identified characteristic, describes a property of solutions during model training. In this paper, we explore neural collapse in the context of imbalanced data. We consider the L-extended unconstrained feature model with a bias term and provide a theoretical analysis of global minimizer. Our findings include: (1) Features within the same class converge to their class mean, similar to both the balanced case and the imbalanced case without bias. (2) The geometric structure is mainly on the left orthonormal transformation of the product of L linear classifiers and the right transformation of the class-mean matrix. (3) Some rows of the left orthonormal transformation of the product of L linear classifiers collapse to zeros and others are orthogonal, which relies on the singular values of Ŷ = (IK − 1/Nn1TK)D, where K is class size, n is the vector of sample size for each class, D is the diagonal matrix whose diagonal entries are given by √n. Similar results are for the columns of the right orthonormal transformation of the product of class-mean matrix and D. (4) The i-th row of the left orthonormal transformation of the product of L linear classifiers aligns with the i-th column of the right orthonormal transformation of the product of class-mean matrix and D. (5) We provide the estimation of singular values about Ŷ . Our numerical experiments support these theoretical *** Codes ***, *** Copyright © 2024, The Authors. All rights reserved.

关键词： Linear transformations

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A Diffuse-Interface Lattice Boltzmann Method for the Dendritic Growth with Thermosolutal Convection

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Communications in Computational Physics 2023年第4期33卷 1164-1188页

作者： Chengjie Zhan Zhenhua Chai Baochang Shi Ping Jiang Shaoning Geng Dongke Sun School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan430074P.R.China Institute of Interdisciplinary Research for Mathematics and Applied Science Huazhong University of Science and TechnologyWuhan 430074P.R.China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan430074P.R.China The State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074P.R.China School of Mechanical Engineering Southeast UniversityNanjing 211189P.R.China

In this work,we proposed a diffuse-interface model for the dendritic growth with thermosolutal *** this model,the sharp boundary between the fluid and solid dendrite is firstly replaced by a thin but nonzero thickness diffuse interface,which is described by the order parameter,and the diffuse-interface based governing equations for the dendritic growth are *** solve the model for the dendritic growth with thermosolutal convection,we also developed a diffuse-interface multirelaxation-time lattice Boltzmann(LB)*** this method,the order parameter in the phase-field equation is combined into the force caused by the fluid-solid interaction,and the treatment on the complex fluid-solid interface can be *** addition,four LB models are designed for the phase-field equation,concentration equation,temperature equation and the Navier-Stokes equations in a unified ***,we performed some simulations of the dendritic growth to test the present diffuse-interface LB method,and found that the numerical results are in good agreements with some previous works.

关键词： Dendritic growth diffuse interface lattice Boltzmann method phase-field method.

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Shape correspondence using anisotropic Chebyshev spectral CNNs

Shape correspondence using anisotropic Chebyshev spectral CN...

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Conference on Computer Vision and Pattern Recognition (CVPR)

作者： Qinsong Li Shengjun Liu Ling Hu Xinru Liu Institute of Engineering Modeling and Scientific Computing Central South University State Key Laboratory of High Performance Manufacturing Complex Central South University School of Mathematics and Computational Science Hunan First Normal University

ISBN: (数字)9781728171685

ISBN: (纸本)9781728171692

Establishing correspondence between shapes is a very important and active research topic in many domains. Due to the powerful ability of deep learning on geometric data, lots of attractive results have been achieved by convolutional neural networks (CNNs). In this paper, we propose a novel architecture for shape correspondence, termed Anisotropic Chebyshev spectral CNNs (ACSCNNs), based on a new extension of the manifold convolution operator. The extended convolution operators aggregate the local features of signals by a set of oriented kernels around each point, which allows to much more comprehensively capture the intrinsic signal information. Rather than using fixed oriented kernels in the spatial domain in previous CNNs, in our framework, the kernels are learned by spectral filtering, based on the eigen-decompositions of multiple Anisotropic Laplace-Beltrami Operators. To reduce the computational complexity, we employ an explicit expansion of the Chebyshev polynomial basis to represent the spectral filters whose expansion coefficients are trainable. Through the benchmark experiments of shape correspondence, our architecture is demonstrated to be efficient and be able to provide better than the state-of-the-art results in several datasets even if using constant functions as inputs.

关键词： Shape Manifolds Convolution Kernel Machine learning Eigenvalues and eigenfunctions Chebyshev approximation

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SCIRun/BioPSE: integrated problem solving environment for bioelectric field problems and visualization

SCIRun/BioPSE: integrated problem solving environment for bi...

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IEEE International Symposium on Biomedical Imaging

作者： R.S. MacLeod O.M. Weinstein J. Davison de St Germain D.H. Brooks C.R. Johnson S.G. Parker Scientific Computing and Imaging Institute University of Utah Salt Lake UT USA Department of Electrical and Computer Engineering Northeastern University Boston MA USA Center for Bioelectric Field Modeling Simulation and Visualization NIH/NCRR

SCIRun is a general purpose problem solving environment that seeks to integrate the steps of preparing, executing, and visualizing simulations of physical and biological systems. The implementation of SCIRun is by means of an interactive dataflow network consisting of modules and data pipes exposed as a visual programming language. SCIRun also contains specific modules for bioelectric field simulations and visualizations and the combination of SCIRun with this package is known as BioPSE (***/software/biopse). This software has been in the public domain since 2000 and in that time we have developed strategies for software development, engineering, testing, documentation, and training. We have also continued to expand the scope of the SCIRun/BioPSE package not only through our own codes but by constructing bridges to other systems, both open source and proprietary. We have also created a repository for relevant sample networks and datasets with the aim of allowing diverse groups to test and evaluate algorithms using identical data and to share their results with the community for comparison of performance and accuracy. We present here a summary of the software system and describe specific experiences and conclusions with regard to creating and managing a large open source software project carried out within a university setting.

关键词： Biopsy Problem-solving Bioelectric phenomena Data visualization Biological system modeling Packaging Biological systems Computer languages Software packages Programming

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Consistent and conservative phase-field-based lattice Boltzmann method for incompressible two-phase flows

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Physical Review E 2022年第2期106卷 025319-025319页

作者： Chengjie Zhan Zhenhua Chai Baochang Shi School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 China Institute of Interdisciplinary Research for Mathematics and Applied Science Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan 430074 China

In this work, we consider a general consistent and conservative phase-field model for the incompressible two-phase flows. In this model, not only the Cahn-Hilliard or Allen-Cahn equation can be adopted, but also the mass and the momentum fluxes in the Navier-Stokes equations are reformulated such that the consistency of reduction, consistency of mass and momentum transport, and the consistency of mass conservation are satisfied. We further develop a lattice Boltzmann (LB) method, and show that through the direct Taylor expansion, the present LB method can correctly recover the consistent and conservative phase-field model. Additionally, if the divergence of the extra momentum flux is seen as a force term, the extra force in the present LB method would include another term which has not been considered in the previous LB methods. To quantitatively evaluate the incompressibility and the consistency of the mass conservation, two statistical variables are introduced in the study of the deformation of a square droplet, and the results show that the present LB method is more accurate. The layered Poiseuille flow and a droplet spreading on an ideal wall are further investigated, and the numerical results are in good agreement with the analytical solutions. Finally, the problems of the Rayleigh-Taylor instability, a single rising bubble, and the dam break with the high Reynolds numbers and/or large density ratios are studied, and it is found that the present consistent and conservative LB method is robust for such complex two-phase flows.

关键词： Contact line dynamics Multiphase flows Rayleigh-Taylor instability

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Macroscopic finite-difference scheme based on the mesoscopic regularized lattice-Boltzmann method

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Physical Review E 2024年第2期109卷 025301-025301页

作者： Xi Liu Ying Chen Zhenhua Chai Baochang Shi School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 China Institute of Interdisciplinary Research for Mathematics and Applied Science Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan 430074 China

In this paper, we develop a macroscopic finite-difference scheme from the mesoscopic regularized lattice Boltzmann (RLB) method to solve the Navier-Stokes equations (NSEs) and convection-diffusion equation (CDE). Unlike the commonly used RLB method based on the evolution of a set of distribution functions, this macroscopic finite-difference scheme is constructed based on the hydrodynamic variables of NSEs (density, momentum, and strain rate tensor) or macroscopic variables of CDE (concentration and flux), and thus shares low memory requirement and high computational efficiency. Based on an accuracy analysis, it is shown that, the same as the mesoscopic RLB method, the macroscopic finite-difference scheme also has a second-order accuracy in space. In addition, we would like to point out that compared with the RLB method and its equivalent macroscopic numerical scheme, the present macroscopic finite-difference scheme is much simpler and more efficient since it is only a two-level system with macroscopic variables. Finally, we perform some simulations of several benchmark problems, and find that the numerical results are not only in agreement with analytical solutions, but also consistent with the theoretical analysis.

关键词： Complex fluids Lattice-Boltzmann methods Navier-Stokes equation

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