多元积分方程自适应解法的优化

考虑核属于各向异性的Sobolev类的积分方程自适应直接方法的优化,得到误差阶的精确估计及相应的最优方法.     

多元积分方程自适应解法的最优化

In this paper it was considered that problem of optimization of adaptive direct algorithm of approximate solution of integral equations. For the Fredholm integral equations of second kind with kernels belonging to Besov classes there is determined the exact order of the error of an optimal adaptive direct algorithm and a algorithm for realizing it is indicated.     

多元Fredholm积分方程自适应直接方法的优化

考虑了以各向异性光滑函数为核及自由项的多元Fredholm积分方程类的自适应直接方法的优化,得到误差阶的精确估计及相应的最优算法。     

二阶奇异积分方程的直接解法

本文,我们讨论如下一类奇异积分方程的直接解法,这里假定,L为正向的Liapunouff封闭曲线,其内域为S;α_1(z),α_(?)(z)解析于S中,Holder连续于S上,K(z_1,z_2)在S×S上全纯。为简化计算,还假定α_1(z)-K(z,z)在S中无零点,α_1(z) K(z,z)仅有单零点z_1,…,z_μ,且zj∈S(j=,…,μ)、     

多元弱奇异积分方程近似解直接方法的优化

本文研究了多元弱奇异第二类Ｆｒｅｄｈｏｌｍ积分方程数ψ在适应直接方法意义下的最优近似解产 们推广了文献「１」中的相关结果。     

边界曲线积分方程的小波解法

The boundary measure method is applied to transfer the form of the integral equation in order to use the collocation method or Galerkin method. A simple way to computer the coefficients of the wavelet series is also introduced. The way presented in this paper can be used to solve PDE problem in the two dimension region with any form of boundary.     

奇异积分方程的数值解法

几乎在奇异积分方程的理论应用到实际工程问题的同时,它的数值解法就被提出来了。特别是近十多年来,奇异积分方程的数值解法的研究有了很大的发展。由于这种研究具极强的实用性,国外这方面的工作大多为一些大企业和军事研究机构所资助,因而研究十分活跃。从已有的成果来看,方法的应用先于理论分析,也就是说,不少方法已被提出或应用,但其数学原理的研究则不甚深入。随着应用的愈高要求,近年人们已把着眼点转向方法的数     

带Hilbert核的奇异积分方程的数值解法

作者在[1—4]中巳经系统讨论了带Cauchy核的奇异积分方程的数值解法.本文考虑带Hilbert核的奇异积分方程     

第二类Fredholm积分方程的泰勒展开解法

本进一步发展了用Taylor公式求解第二类Fredholm积分方程的方法，并给出了近似解的误差精度分析．     

基于自适应小波神经网络的第二类Fredholm积分方程数值解法

该文构造了一类三层前馈自适应小波神经网络,将小波分析中平移因子和伸缩因子的拟合设置为输入层到隐层的权值与阈值,采用小波基函数作为隐层激活函数,并根据梯度下降算法自适应地调整参数.应用自适应小波神经网络数值求解第二类Fredholm积分方程,通过数值算例验证了该方法的可行性和有效性.     

核属于H函数类的多维积分方程近似解直接方法的优化

本文我们确定了核属于 H函数类的多维第二类 Fredholm积分方程类在自适直接方法意义下的最优近似解的精确阶估计 ,并给出了最优算法 .     

Optimization of Approximate Solution of Integral Equations of Several Variables

In this paper, we consider the problem of optimization of adaptive direct methods of operator equations. Adaptivity of a direct method is understood in the sense that the subspace on the basis of which it is constructed is chosen depending on the operator of the concrete equation (otherwise, nonadaptive direct method is then concerned), which would essentially let us increase the precision. For some classes of the second kind of Fredhlom integral equations with anisotropic smooth kernels we determine the exact order of the error of adaptive direct methods, and we also give an optimal algorithm. Received April 13, 2001, Accepted September 13, 2001     

Adaptive Wavelet BEM for Boundary Integral Equations: Theory and Numerical Experiments

We are concerned with the numerical treatment of boundary integral equations by the adaptive wavelet boundary element method. In particular, we consider the second kind Fredholm integral equation for the double layer potential operator on patchwise smooth manifolds contained in ?³. The corresponding operator equations are treated by adaptive implementations that are in complete accordance with the underlying theory. The numerical experiments demonstrate that adaptive methods really pay off in this setting. The observed convergence rates fit together very well with the theoretical predictions based on the Besov regularity of the exact solution.     

算子方程近似解直接方法的优化和信息复杂性研究进展

算子方程近似解直接方法的优化和信息复杂性是80年代发展起来的连续复杂性理论的两个主要方面,是计算机科学和数学的交叉研究领域．本文拟就这两个方面的研究进展做一简要介绍．     

Error Analysis of Discrete Legendre Multi-Projection Methods for Nonlinear Fredholm Integral Equations

In this paper, polynomially-based discrete M-Galerkin and M-collocation methods are proposed to solve nonlinear Fredholm integral equation with a smooth kernel. Using su?ciently accurate numerical quadrature rule, we establish superconvergence results for the approximate and iterated approximate solutions of discrete Legendre M-Galerkin and M-collocation methods in both infinity and L²-norm. Numerical examples are presented to illustrate the theoretical results.     

非线性中立型延迟积分微分方程隐式Euler方法的收缩性

本文致力于研究非线性中立型延迟积分微分方程隐式Euler方法的收缩性。本文中的Lipschitz数是关于变量t的函数,而不是常数,最终能得到其数值解的结果是收缩的。     

On the Divergence of Collocation Solutions in Smooth Piecewise Polynomial Spaces for Volterra Integral Equations

In this paper we present a characterization of those smooth piecewise polynomial collocation spaces that lead to divergent collocation solutions for Volterra integral equations of the second kind. The key to these results is an equivalence result between such collocation solutions and collocation solutions in slightly smoother spaces for initial-value problems for ordinary differential equations. For the latter problems Mülthei (1979/1980) established a complete divergence (and convergence) theory. Our analysis can be extended to furnish divergence results for smooth collocation solutions to Volterra integral equations of the first kind. AMS subject classification (2000) 65R20, 65L20, 65L60.Received May 2004. Accepted September 2004. Communicated by Tom Lyche.Hermann Brunner: This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).     

Fractional Multistep Methods for Weakly Singular Volterra Integral Equations of the First Kind with Perturbed Data

ABSTRACT

Fractional multistep methods were introduced by C. Lubich for the quadrature of Abel integral operators and the solution of weakly singular Volterra integral equations of the first kind with exactly given right-hand sides. In the current paper, we consider the regularizing properties of these methods to solve the mentioned integral equations of the first kind for perturbed right-hand sides. Finally, numerical results are presented.     

L~1空间中直接离散法求解弱奇异积分方程特征值的探讨

在L~1空间中讨论弱奇异积分方程的特征值问题.利用弱奇异积分算子为紧算子,便可以对其直接进行离散化算法求出特征值.并将直接离散的方法与以往的迭代后离散的方法用实例通过Matlab作图进行对比,说明直接进行离散的方法更佳.