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Quadrature-free spline method for two-dimensional Navier-Stokes equation

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Applied Mathematics(A Journal of Chinese Universities) 2008年第1期23卷 31-42页

作者： HU Xian-liang han dan-fu Dept. of Math. Zhejiang Univ. Hangzhou 310027 China.

In this paper, a quadrature-free scheme of spline method for two-dimensional Navier- Stokes equation is derived, which can dramatically improve the efficiency of spline method for fluid problems proposed by Lai and Wenston（2004）. Additionally, the explicit formulation for boundary condition with up to second order derivatives is presented. The numerical simulations on several benchmark problems show that the scheme is very efficient.

关键词： quadrature-free spline method Navier-Stokes equation.

The shape optimization of the arterial graft design by level set methods

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Applied Mathematics(A Journal of Chinese Universities) 2016年第2期31卷 205-218页

作者： JIANG Dong han dan-fu HU Xian-liang School of Mathematical Sciences Zhejiang University Department of Mathematics Hangzhou Normal University

The goal of the arterial graft design problem is to find an optimal graft built on an occluded artery, which can be mathematically modeled by a fluid based shape optimization problem. The smoothness of the graft is one of the important aspects in the arterial graft design problem since it affects the flow of the blood significantly. As an attractive design tool for this problem, level set methods are quite efficient for obtaining better shape of the graft. In this paper, a cubic spline level set method and a radial basis function level set method are designed to solve the arterial graft design problem. In both approaches, the shape of the arterial graft is implicitly tracked by the zero-level contour of a level set function and a high level of smoothness of the graft is achieved. Numerical results show the efficiency of the algorithms in the arterial graft design.

关键词： Arterial graft Shape optimization Level set method Adjoint variable method.

A second order isoparametric finite element method for elliptic interface problems

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Applied Mathematics(A Journal of Chinese Universities) 2013年第1期28卷 57-74页

作者： FANG Xu-fa han dan-fu HU Xian-liang Department of Mathematics Zhejiang University

A second order isoparametric finite element method （IPFEM） is proposed for elliptic interface problems. It yields better accuracy than some existing second-order methods, when the coefficients or the flux across the immersed curved interface is discontinuous. Based on an initial Cartesian mesh, a mesh optimization strategy is presented by employing curved boundary elements at the interface, and an incomplete quadratic finite element space is constructed on the optimized mesh. It turns out that the number of curved boundary elements is far less than that of the straight one, and the total degree of freedom is almost the same as the uniform Cartesian mesh. Numerical examples with simple and complicated geometrical interfaces demonstrate the efficiency of the proposed method.

关键词： Isoparametric element elliptic problem curved boundary element interface element immersed interface problem.

Modified two-grid method for solving coupled Navier-Stokes/Darcy model based on Newton iteration

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Applied Mathematics(A Journal of Chinese Universities) 2015年第2期30卷 127-140页

作者： SHEN Yu-jing han dan-fu SHAO Xin-ping Department of Mathematics Zhejiang University Department of Mathematics Hangzhou Normal University School of Science Hangzhou Dianzi University

A new decoupled two-gird algorithm with the Newton iteration is proposed for solving the coupled Navier-Stokes/Darcy model which describes a fluid flow filtrating through porous media. Moreover the error estimate is given, which shows that the same order of accuracy can be achieved as solving the system directly in the fine mesh when h = H2. Both theoretical analysis and numerical experiments illustrate the efficiency of the algorithm for solving the coupled problem.

关键词： Navier-Stokes equation Darcy's law interface coupling two-grid algorithm Newton iteration

A weak condition for secant method to solve systems of nonlinear equations

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Applied Mathematics(A Journal of Chinese Universities) 2009年第1期24卷 90-96页

作者： LIANG Ke-wei han dan-fu ZhanG Hong ZHU Cheng-yan Dept. of Math. Zhejiang Univ. Hangzhou 310027 China Dept. of Information Technology Zhejiang Economic & Trade Polytechnic Hangzhou 310018 China

In this paper, a new weak condition for the convergence of secant method to solve the systems of nonlinear equations is proposed. A convergence ball with the center x0 is replaced by that with xl, the first approximation generated by the secant method with the initial data x-1 and x0. Under the bounded conditions of the divided difference, a convergence theorem is obtained and two examples to illustrate the weakness of convergence conditions are provided. Moreover, the secant method is applied to a system of nonlinear equations to demonstrate the viability and effectiveness of the results in the paper.

关键词： secant method Banach space radius of convergence systems of nonlinear equations complexity

A Survey on Distributed Network Localization from a Graph Laplacian Perspective

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Journal of Systems Science & Complexity 2024年第1期37卷 273-293页

作者： han Zhimin LIN Zhiyun fu Minyue Artificial Intelligence Institute School of AutomationHangzhou Dianzi UniversityHangzhou 310018China Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent ManufacturingSouthern University of Science and TechnologyShenzhen 518055China Peng Cheng Laboratory Shenzhen 518000China

Network localization serves as a fundamental component for enabling various position based operations in multi-agent systems,facilitating tasks like target searching and formation control by providing accurate position information for all nodes in the *** localization focuses on the challenge of determining the positions of nodes within a network,relying on the known positions of anchor nodes and internode relative *** the past few decades,distributed network localization has garnered significant attention from *** paper aims to provide a review of main results and advancements in the field of distributed network localization,with a particular focus on the perspective of graph *** to its favorable characteristics,graph Laplacian unifies various network localization,even when dealing with diverse types of internode relative measurements,into a unified protocol framework,which can be constructed by a linear method and ensure the global convergence.

关键词： Distributed network localization graph Laplaian sensor network

A semantic segmentation-based underwater acoustic image transmission framework for cooperative SLAM

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Defence Technology（防务技术） 2024年第3期33卷 339-351页

作者： Jiaxu Li Guangyao han Shuai Chang Xiaomei fu School of Marine Science and Technology Tianjin UniversityTianjin 300072China

With the development of underwater sonar detection technology,simultaneous localization and mapping(SLAM)approach has attracted much attention in underwater navigation field in recent *** the weak detection ability of a single vehicle limits the SLAM performance in wide ***,cooperative SLAM using multiple vehicles has become an important research *** key factor of cooperative SLAM is timely and efficient sonar image transmission among underwater ***,the limited bandwidth of underwater acoustic channels contradicts a large amount of sonar image *** is essential to compress the images before ***,deep neural networks have great value in image compression by virtue of the powerful learning ability of neural networks,but the existing sonar image compression methods based on neural network usually focus on the pixel-level information without the semantic-level *** this paper,we propose a novel underwater acoustic transmission scheme called UAT-SSIC that includes semantic segmentation-based sonar image compression(SSIC)framework and the joint source-channel codec,to improve the accuracy of the semantic information of the reconstructed sonar image at the *** SSIC framework consists of Auto-Encoder structure-based sonar image compression network,which is measured by a semantic segmentation network's *** that sonar images have the characteristics of blurred target edges,the semantic segmentation network used a special dilated convolution neural network(DiCNN)to enhance segmentation accuracy by expanding the range of receptive *** joint source-channel codec with unequal error protection is proposed that adjusts the power level of the transmitted data,which deal with sonar image transmission error caused by the serious underwater acoustic *** results demonstrate that our method preserves more semantic information,with advantages over existing methods at the sa

关键词： Semantic segmentation Sonar image transmission Learning-based compression

Temperature field characteristics of CF/PEEK thermoplastic composites formed by automated fiber placement using hot gas torch with slit structure nozzle

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Chinese Journal of Aeronautics 2024年第6期37卷 392-409页

作者： Ziang JIN Shouzheng SUN Sunil Chandrakant JOSHI Zhenyu han Hongya fu State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

In-situ consolidation forming of high-performance thermoplastic composites by Automated Fiber Placement(AFP)is of significant interest in *** the laying process,the heating temperature has a great influence on the quality of the formed components.A threedimensional heat transfer finite element model of Carbon Fiber(CF)/Polyether Ether Ketone(PEEK)heated by Slit Structure Nozzle Hot Gas Torch(SSNHGT)assisted AFP is *** influence of gas flow rate,heat transfer distance,and laying speed on heating temperature is *** results show that the overall temperature increases and then decreases as the gas flow rate *** the increase in heat transfer distance and laying speed,the overall temperature ***,the gas flow rate has the greatest influence on the temperature of CF/PEEK being heated,followed by the laying speed and finally the heat transfer ***,the model can also be extended to other fiber-reinforced polymer composites formed by hot gas torch assisted AFP,which can guide the optimization of process parameters for subsequent heating temperature control.

关键词： Fiber reinforced plastics Thermoplastics Heating temperature Automated fiber placement CF/PEEK

Fermented Lentinus edodes extract containingα-glucan ameliorates concanavalin A-induced autoimmune hepatitis in mice

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Food Science and Human Wellness 2024年第4期13卷 2102-2115页

作者： Xin Hu dan Cheng Yingxia Zhang Po Li Xiaoping Wu Junsheng fu College of Life Sciences Fujian Agriculture and Forestry UniversityFuzhou 350002China Mycological Research Center Fujian Agriculture and Forestry UniversityFuzhou 350002China Shanghai Lithy One-Health Group Technology Co. Ltd.Shanghai 200235China

Autoimmune hepatitis(AIH)is a chronic inflammatory liver disease that threatens human health *** aim of this study was to detect the protective effect of a fermented Lentinus edodes extract containingα-glucan(FLA),in a concanavalin A(Con A)-induced AIH mouse model and to determine the underlying liver-protective *** results showed that compared with the model group,the level of proinflammatory cytokines in serum of FLA pretreated mice was significantly decreased,and the degree of inflammatory cell infiltration in liver,thymus and spleen was significantly *** polymerase chain reaction,immunohistochemistry,and Western blotting showed that FLA pre-treatment inhibited the Con A-induced apoptosis of hepatocytes by down-regulating the expression of BAX and up-regulating the expression of *** research found that FLA may improve liver injury in mice by activating NRF2 signaling pathway and inhibiting TRAF6/NF-κB signaling ***,FLA may improve liver injury in mice by shifting gut microbial composition to reduce the release of inflammatory cytokines in the serum and prevent the necrosis of ***-regulation of NRF2 signaling pathway,down-regulation of TRAF6/NF-κB signaling pathway,and an increase in the relative abundance of Lactobacillus_johnsonii and Ligilactobacillus_murinus play a protective role in liver.

关键词： Autoimmune hepatitis Concanavalin A Lentinus edodes TRAF6/NF-κB NRF2