离散问题

Robust filtering for the delta operator formulated linear uncertain discrete time systems with error variance constraints is considered.

研究基于Delta算子描述的线性不确定离散时间系统在稳态估计误差方差约束下的鲁棒滤波问题。

The mathematical programming formulation and related solution procedure are established by the traditional BEM. Through the discretization of space and time, the elastoplastic stress simulation method and reduce-basis technique are adopted to construct the self-equilibrium stress field. The numbers of variables and constraint equations in the resulting mathematical programming formulation are reduced greatly and then the dimension obstacle of computation in 3-D limit and shakedown analysis is overcome.

采用常规边界元方法建立了三维结构极限与安定分析的数学规划格式，通过对时间和空间的离散化，并采用弹塑性模拟法构造自平衡应力场和引入减缩基技术，大大减少了所形成的数学规划格式中的未知变量和约束方程的数目，有效地克服了三维结构极限与安定分析中的维数障碍问题。

In this article, aiming at a kind of elliptic problem, three types of preserving-symmetry finite volume schemes under quadrangle partition grids are firstly established . During the course of the establishing, the" vertex-centered" control volume are selected and the balance-equation is discretized by utilizing the finite volume element method.

本文首先对自共轭椭圆问题，在四边形剖分下，通过选取"vertex-centered"类型的控制体，并利用有限体积元方法对平衡方程进行离散，首次建立了四边形剖分下的三种保对称的有限体格式。

In this paper, the finite point method is used to obtain numerical solutions of one-dimensional and two-dimensional inverse heat conduction problems with a source parameter, and the corresponding discrete equations are obtained.

本文利用无网格有限点法求带有源参数的一维和二维热传导反问题，推导了相应的离散方程。

By employing the control Lyapunov function,a class of discrete-time nonlinear systems with multiple inputs was researched.

以控制Lyapunov函数为基础，研究了一类具有多个输入的非线性时间离散系统的反馈镇定问题。

Traditional authentication and access control technologies and means have been difficult to resolve heterogeneous collaborative environment Application System security issues, the fundamental reason is that identity can be forged, the environment and the dynamic changes of discrete control.

传统的身份认证及访问控制技术和手段已难以解决异构协同环境中应用系统的安全问题，根本原因在于身份的可伪造性、环境的动态变化以及控制的离散性。

Based on the element-free Galerkin method, the basic equations for steady thermal conductivity problem are deduced; and then the shaping of the coefficient matrices and load vectors in the discretization form of them are presented.

基于无单元伽辽金法基本理论，推导了稳态热传导问题的基本积分方程，并介绍了其离散形式中，包含刚度矩阵在内的各个系数矩阵和荷载向量的主要形成过程。

It introduced the calculation of stiffness matrix of wall and soil elements, Gauss elimination, the method of determining the minimum calculated decertization size and dynamic data team technology.

第四章 有限元求解方程计算的相关问题讨论了墙体和土体单元刚度矩阵的计算，介绍了高斯消去法，提出了离散区域尺寸的确定方法和动态数组技术的应用。

The GKS stability theorem for one-dimensional model of hyperbolic initial and boundary value problem, Trefethen's explanation and extension based on the concept of group velocity are generalized firstly. Another possible high-frequency instability mechanism in numerical realization of MTF is pointed out based on his explanation and extension, namely, coupling effect of outgoing harmonic wave along one direction and node motion in the other directions can reverse the energy propagation in multi-dimensional discrete grids.

本文概述了—维双曲型偏微分方程组初边值问题数值稳定性的GKS定理及Trefethen基于群速度概念对这一定理的解释和推广；并应用Trefethen的解释和推广指出了MTF在数值实现中可能出现的另一种高频失稳机制，即在多维离散网格中，沿某一空间方向的外行简谐波，由于与其他空间方向节点运动的耦合效应可以使能量传播方向反向。

Primitive root is a kernel parameter to implement Diffie- Hellman key exchange protocol and affects the security of the protocol directly.

它的基础是基于有限域中计算离散对数的困难性问题，其实现方法如下。

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。