查询词典 numerical function

The Frechet derivative of the cost function is determined via the solution of an adjoint partial differential equation, and the boundary shape is then modified in a direction of descent. This process is repeated until an optimum solution is approached. The advantage is that the cost function variation is independent of the flow field variation, with the result that the gradient of cost function with respect to arbitrary number of design variables can be determined without the need for additional flow-field evaluations. So each design cycle requires the numerical solution of both the flow and the adjoint equations leading to a computational cost roughly equal to the cost of two flow solutions.

虽然他们的研究成果大多数都可以在公开性文献上看到，但是其中一些具体的细节问题的处理方法却没有透露，比如：伴随方程如何离散求解才能减小最终梯度计算中的误差，使得设计过程有效地进行；伴随方程与流动方程的边界条件是不同的，如何合理地处理伴随方程的边界条件，才能推动设计过程朝着设计目标而发展；在减阻问题中目标函数如何定义，求解梯度的具体数学公式如何推导，如何通过数值方法来实现它们等。

The characteristic function of the probability density function of response variable is obtained by the high efficient multidimensional numerical integration method or convolution integral based on response surface method. Then the discrete probability density function of response variable is calculated using the fast Fourier inverse transform technique, at last the cumulative distribution function of the response variable can be quantitatively determined.

首先利用高效多维数值积分方法或基于响应面法的卷积积分求解功能函数的分布函数的特征函数，也就是进行Fourier正变换；然后利用快速Fourier逆变换数值求解功能函数的概率密度函数，进而求得失效概率。

The authors studied carefully two numerical differential methods, finite difference method and rational polynomial technique, and pointed that FDM is the special ease of RPT when the limit state function is linear. Accordingly, FDM3 can be used for the continuous linear limit state function and RPT5 for the continuous nonlinear limit state function. For the discontinuous limit state function, RPT should be used because of the large error of FDM.

对于可靠度分析中常用的有限差分法及有理多项式法这两种数值微分方法，本文详细研究了二者间的异同及其求导结果与步长的关系，指出了对于相同的步长控制系数及取样方式，FDM是RPT在线性情况下的特例；对于连续的线性功能函数，可直接用3点FDM求导；对于连续的非线性功能函数，可用5点RPT求导；对于非连续的功能函数，应采用RPT求导。

In the homogeneous model, the function of tendons is assumed to be uniform in some approximated way in order to form an equivalent homogeneous material within concrete. The formulation of the homogeneous model is same with that of general FEM for common continuum, let alone the elastic matrix being resultant of that of tendon and concrete. The computation is simple, but the approximate assumption makes this method cannot be generalized, because it only represents the constitution and function of tendons in such a rough way, that the numerical results are inaccurate. In the combined model, the function of tendon is considered by the stiffness matrix with rod element, then add it into the stiffness matrix of concrete by a rational way.

均匀类单元是设想将钢筋均匀弥散于整个单元中，使其成为一种连续均匀材料单元，这种单元的与一般有限元的单元刚度矩阵推导过程一样，只不过其弹性矩阵由混凝土和钢筋两部迭加而成的，此类单元刚阵计算简明而又不会扩大计算规模，但均匀弥散只是为计算简单而作一种假想，不贴近单元构造实际，也不符合实际作用效果。

This book reviews the many areas of numerical analysis, including the configuration polynomial, finite difference, factorial polynomials, summation, Newton formula, operator and configuration polynomial, Cheung section, close polynomials, TaylM more item type, interpolation, numerical differentiation, numerical integration, and with the series, differential equations, differential equations, least squares polynomial approximation, minimax polynomial approximation, rational function approximation, triangular approximation, non-linear algebra, linear equations, linear programming, boundary value problems, MonteCarIo methods and so on.

本书综述了数值分析领域的诸多内容，包括配置多项式、有限差分、阶乘多项式、求和法、Newton公式、算子与配置多项式、祥条、密切多项式、TaylM多项式、插值、数值微分、数值积分、和与级数、差分方程、微分方程、最小二乘多项式逼近、极小化极大多项式逼近、有理函数逼近、三角逼近、非线性代数、线性方程组、线性规划、边值问题、MonteCarIo方法等内容。本书的特色主要表现在利用例题及大量详细的题解来透彻地阐明所述内容的内涵，同时附有大量的补充题以便读者进一步巩固和深化从书中获得的数值分析知识。

In this dissertation, many works have been done on the basis of the summarization of the merits of all kinds of meshless methods after a large number of relevant references are read and studied. The basic ideas, principles of meshless methods and their development in the recent years are introduced synoptically. Applications of Element-free Galerkin method in elastic foundation plate are studied deeply and some useful conclusions are obtained as follows:(1) Comparisons between numerical solutions and analytical solutions for several different styles of weight functions, including Gaussian weight function, spline weight function and singular weight function etc, are performed. The results show that Gaussian weight function is the best one.(2) Ranges of relevant parameters for Gaussian weight function are given.(3) Influences of nodal distribution schemes and the number of Gaussian integrated dots on computational results are discussed.

在本文中，作者在认真阅读和研究所搜集到的大量参考文献、综合各种无网格法优点的基础上，首先，对无网格法的基本思想、基本原理、发展现状作了概括性的介绍；其次，对无单元Galerkin法在弹性地基板计算中的应用进行了较为深入的探讨：(1)分别对高斯型、样条型、奇异型等不同形式的权函数进行比较分析，数值计算结果与级数解析解的比较表明，高斯型权函数效果较好：(2)对高斯型权函数进行参数研究，得到地基板计算中相关参数的选取范围；(3)对不同节点分布方案和不同高斯积分对计算结果的影响等作了有益的讨论。

In chapter 2, we firstly introduce the model of a discrete-time neural network with generalized input-output function. The model generalizes the input-output function in transiently chaotic neural network to a class of continuous, differentiable and monotone increasing functions. Secondly we study the uniformly asymptotical stability of equilibrium in the non-autonomous model. Finally, several examples and numerical simulations are given to illustrate and reinforce our theories. In chapter 3, we firstly introduce a specific class of discrete-time neural network models with sinusoidal activation function.

在本文的第二章中，首先介绍了一类具有广义输入输出函数的非自治离散神经网络模型，该模型把瞬时混沌神经网络模型中的输入输出函数推广到了一般的单调递增且连续可微的函数；其次，利用Schauder不动点原理和利用Lyapunov函数逆定理依次证明了模型平衡点的存在性和该模型在时变权值下的一致渐近稳定性；最后，对几个具体的例子进行数值模拟，数值模拟的结果更好地说明了我们的结论。

In the second chapter the theory of weighted residual technique is illustrated and the boundary integral function of the potential problem is deduced by it. Method of obtaining Greens function fundamental solution is presented. It also illustrates how to deal with inhomogeneous regions and the third boundary condition. At last the numerical solution of boundary integral function is presented.

第二章首先说明了加权余量法的原理，并由此推出了势问题的边界元积分方程，还介绍了无限域中格林函数的基本解的求法，以及多介质域和第三类边界条件的处理方法，最后说明了边界积分方程的数值解法。

The purpose of this dissertation is to study a principle or method to describe and analyze the complex problems with high gradients arising from practical engineering. The main contents cover:1. The Bezier function was introduced to approximate high gradient functions, and a suitable coupled function was derived. Some detail numerical results show that the Bezier-based function is dominant over other combination function such as polynominal and trigonometric series, when to describe a high gradient function.

针对工程中大量存在的高梯度问题进行函数逼近的研究，引入Bezier函数对高梯度问题进行函数逼近，构成以Bezier函数为主的复合逼近函数，数值考证表明：与常规多项式插值函数的逼近及"幂／三角"复合函数的逼近相比，基于Bezier函数的逼近函数对高梯度问题的描述具有明显优势。

The presentnumerical control engine bed main engine factory primary mission isaccording to product design request production foundation rack and soon manufacture lathe bed, column and the function part which needswith it collection fits out the integrity the numerical control enginebed product, does not have the function part, does not have presenteach numerical control engine bed.

现在的数控机床主机厂的主要任务就是按产品设计要求生产制造床身、立柱等基础机架件并把所需的功能部件与之集装成完整的数控机床产品，没有功能部件，就没有现在的各种数控机床。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。