查询词典 finite difference approximation

By using the spectrum approximation theory of compact operator, the approximation of anisotropic nonconforming ?nite element method for Stokes eigenvalue pronlem are presented and the optimal error estimates are obtained, which are as same as those of traditional ?nite element methods.

利用紧算子谱逼近理论，给出了 Stokes 特征值问题的各向异性非协调有限元逼近方法及最优误差估计，得到了与剖分网格满足正则性或拟一致性关键假设下相同的收敛效果。

By academic analyzing, it is concluded that two order discrete paraxial approximation formula of the paper, multiple transmitting formula and polynomial extrapolation formula are the different forms of continuous paraxial approximation formula, so they are with nearly equivalent precision and stability and with equivalent applicability and limitation.

据此文献[3]将傍轴近似公式归结为一类从特定的无限域模型导出的人工边界条件，并且提出了新的从一般无限域模型导出的具有普适性的、称为"多次透射公式"的局部人工边界条件。那么，是否也可以从一般无限域模型导出具有普适性的傍轴近似公式呢？

Both continuous paraxial approximation formula and two order discrete paraxial approximation formula are developed for one way wave motion transmitting apparently along normal direction based on kinematics model and local polynomial interpolation function.

引言 Clayton和Engquist在1977年和1980年提出的傍轴近似公式[1，2]是迄今为止最具代表性的局部人工边界条件之一。但是上述傍轴近似公式是从特定的波动微分方程出发推导建立的，因此其普适性受到限制。

In the third chapter, we study the approximation and weighted approximation for a kind of generalized Baskakov operators of two-variable. Using different weight functions, we discuss the convergence on weighted space of polynomials and rate of convergence with Jacobi weight for this kind of two-dimensional product-type operators, which extends the results of one-dimensional operators.

第三章研究一类二元广义Baskakov算子的逼近及其加权逼近，主要针对于不同的权函数讨论了这类乘积型的二元算子及其导数在多项式权空间上的收敛性和加Jacobi权的收敛阶，把一元的结果推广到多元的情形。

In the last section ,according to the basis theory of rough set ,we propose the definition of an approximation space which is basing on the convex cone that contain the origin ,and define the upper and the lower approximation of convex cone ,then discuss some operation properties.

文章的最后是基于粗糙集的基本理论，提出了可利用含原点的凸锥构造一个近似空间，定义了此空间的上、下近似，总结了一些运算性质。

In chapter three, we prove that there exist solutions to the Ky Fan variation inequality, as the set-valued mappings are defined on spheres in infinite dimensional Banach spaces or odd dimensional Euclidean spaces, following from these theorems, we obtain some fixed point theorems for set-valued mappings defined on a sphere. When G is an approximate compact convex subset of E, or G is a almost quasi-convex set-valued mapping, we prove that there exist solutions to and type generalized Ky Fan variation inequality, following these theorems, we prove several best approximation theorems and coincidence theorems involving two set-valued mappings and two different spaces. In chapter four, we first present a new Simplicial algorithm for computing the Leray - Schauder fixed points, the algorithm can solve the set-valued nonlinear complementarily problem. We give a condition to guarantee the computation proceeding in a bounded region. We present integer-labeling algorithms for computing fixed points of some set-valued mappings, the best approximation points and solutions to a kind of set-valued variation inequalities.

第四章给出了计算定义在非凸集上的非自映射的Leray-Schauder不动点的算法，而现有的不动点算法都是计算凸集的上半连续集值自映射的不动点；给出了保证计算有界的一个充分条件，我们的条件大大弱于Mdrrill条件，我们的算法也可用来计算Eaves不动点；给出了集值非线性互补问题存在解的一个充分条件，此时可利用Leray-Schauder不动点算法来求解；向量标号算法以往是计算集值映射不动点的唯一有效算法，我们给出用整数标号算法计算一类集值映射的Kakutani 不动点的算法；定义在紧凸集上的连续映射不一定有不动点，但一定有最近点，最近点是不动点概念的推广，我们给出了计算最近点的算法；集值映射变分不等式尚无有效的求解算法，我们给出求解一类集值映射变分不等式的算法。

After summarizing the existing research results, this article proposes new methods on moving force identification based on radial basis function approximation method and cubic spline function approximation method, and discusses the influence which some parameters to the precision of identification through calculating an example.

文章首先在第一章中介绍了已有的移动荷载识别方法及国内外的研究状况，在此基础上提出了研究目标和意义，即提出新的移动荷载识别方法，并通过数字模拟来讨论新方法的精度，以便评估桥梁的动力特性，为桥梁的设计和汽车性能的改进提供依据。

The properties of the λ-cut sets of the lower and upper approximation are discussed,and then the F-Union Decomposition theorem of the lower and upper approximation of rough fuzzy sets is given.

基于此，本文在逐一增加属性形式下的等价类F-分解的基础上，讨论了粗模糊集的F-分解形式，并给出了粗模糊上、下近似集合的F-分解定理及相关推论。

Thus, there is no way to demonstrate that sufficient data has been collected to form a mathematically valid approximation (or known degree of approximation) of the complete data set.

因此， 没有方法示范充份的数据已经被收集形成完全数据组的一个算术有效近似值。

Two-dimensional Bernstein type operators on simplex are constructed, and a necessary and sufficient condition of uniform approximation by mem is obtained, at the same time, the degree of approximation is characterized by two-order moduli of smoothness.

并且构造出单纯形上推广的二元Bernstein型算子，给出其一致收敛的一个充要条件，同时用二阶连续模刻划了它们的逼近度性质。

A strange and mysterious deep sea creature.

一种奇异、神秘的深海生物。

It's a yellow rectangle .

这是黄色的长方形。