查询词典 discrete problem

Discrete calculus , discrete probability distribution s, discrete Fourier transform s, discrete geometry , discrete logarithm s, discrete differential geometry , discrete exterior calculus , discrete Morse theory , difference equation s, and discrete dynamical system s.

在应用数学中，离散模型连续模型的离散近似。在离散模型中，离散方程are fit to 数据。使用递推关系是这种建模方式的一般方法。时标微积分是差分方程理论与微分方程理论的统一，应用在需要建立离散和连续同步数据模型的领域。

Thirdly, on the base of the existent error estimate of elliptical Galerkin projection operator, obtain semi-discrete and complete-discrete error estimates betwent EFG solution and exact solution of parabolic partial differential equation. Semi-discrete error estimate show that the rank of r is accordance with the approximation rank of subspace S_h. Complete-discrete error estimates show that it not only have relation with radius r of domain of influence, but also have relation with the step length of time variable and the way of discrete.Lastly, give typical examples and draw up procedures of MATLAB.

再次，在"椭圆Galerkin投影"算子的误差估计的基础上，对用EFG法解抛物型偏微分方程的EFG解与精确解之间作了半离散和全离散的误差估计，半离散的误差估计表明所给出的误差界限关于r的阶是与子空间S_h的逼近阶相一致的，全离散的误差估计表明所产生的误差不但与影响域半径r有关，而且与离散时间变量的步长τ及其离散方式有关。

Using the mathematical tool"DifferenceGeometry",it is possible to define the discrete geometric metrics such as discretefirst fundamental form,discrete second fundamental form,discrete unit mainnormal vector,discrete Gauss curvature,discrete mean curvature and discreteLaplacian.

首先，运用"差分几何"这一工具，可以构造离散第一、第二基本形式，离散单位主法向，离散高斯曲率，离散中曲率等离散几何量和离散Laplace算子。

The basic idea is to set a continuous solution of the region with a finite number of discrete points instead of a grid consisting of, these discrete points called grid nodes the solution of a continuous area on a given function of continuous variables used in the definition of discrete grid variable function approximation the original equation and boundary conditions in the micro-business operators to approximate differential, integral with the points and to approximate, so the original differential equations and boundary conditions are replaced by algebraic equations near Side, that is, finite difference equations , solve this equation group can get the original problem in discrete points on the approximate solution.

基本思想是把连续的定解区域用有限个离散点构成的网格来代替，这些离散点称作网格的节点；把连续定解区域上的连续变量的函数用在网格上定义的离散变量函数来近似；把原方程和定解条件中的微商用差商来近似，积分用积分和来近似，于是原微分方程和定解条件就近似地代之以代数方程组，即有限差分方程组，解此方程组就可以得到原问题在离散点上的近似解。

A novel hybrid algorithm, which combines predictor-corrector primal-dual interior point method and genetic algorithm, is presented for dynamic and static reactive optimization in this dissertation. The algorithm fully make use of the advantage of interior point method in solving successive optimization problem and the advantage of genetic algorithm in solving discrete optimization problem. The original problem is divided into three parts: total successive problem, discrete problem and successive problem.

结合内点法和遗传算法，本文提出了一种新颖的混合算法用于求解动、静态无功优化问题，算法充分利用了内点法易于求解连续优化问题和遗传算法易于求解离散优化问题的优势，将原优化问题分解为初步的连续优化问题、离散变量优化问题、连续变量优化问题这三个子问题分别求解。

The underlying uniformity on a discrete metric space is the discrete uniformity, and the underlying topology on a discrete uniform space is the discrete topology.

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The combinatorial and delimitative algorithm can be used to solve the problem. A software called "Power Discrete" to implement this algorithm is developed by using Microsoft Visual6.0. It is a useful tool for linear programming problem with discrete variables and for discrete optimum design of structures, and in addition, the software also includes other algorithms such as genetic algorithm.

在国际上， 20世纪 60年代末期和 70年代初期，研究人员已开始对工程离散变量优化设计问题进行研究，但由于当时对于连续变量的非线性规划问题的研究还不够深入，所以在 70年代和80年代，研究的重点集中于连续变量的非线性规划问题。

For reducing boundary distortion area, the elevations of grid DEM are viewed as a discrete sequence under a generalized coordinate, so that the boundary problem of two-dimensional discrete wavelet transform is turned into the boundary problem of one-dimensional discrete wavelet transform, which not only greatly reduces the boundary distortion area, improves the precision of reconstructed DEM data near the boundary, but also decreases the number of zeros adding on the boundary for wavelet transform, and boosts the compression ratio. On the basis of analyzing the distribution characteristics of coefficients in low and high frequency bands, a mixed entropy coding plan is applied, and a high efficient quantizator called"self-adaptive hard threshold"is established, which is helpful for improving the precision of the reconstructed DEM data and for enhancing compression ratio.

为了减小小波变换山区格网DEM数据压缩中边界失真区域，将山区格网DEM高程值视为广义坐标下的离散随机序列，把二维离散小波变换中的边界问题转换为一维离散小波变换中的边界问题，不仅大大减少了小波变换边界失真区域，提高了重构DEM数据边界点的精度，而且减少了边界补零个数，提高了压缩比；通过对山区格网DEM数据小波变换低频区和高频区变换系数分布特点的分析，采取了霍夫曼—游程混合熵编码方案，设计了高效、低失真的"自适应硬阈值"量化器，即对低频区变换系数不进行量化，直接进行霍夫曼编码；对高频区变换系数则先用"自适应硬阈值"方法量化处理，再进行游程编码。

A numerical calculation program is written up for the various solution methods in this paper and the program is being used in various aspects of inverse problem of environmental hydraulics, including inverse problem in reverse process of one-dimensional unstable diffusion, inverse problem in reverse process of convection-diffusion, inverse problem for the dispersion coefficient in water quality model, The inverse problem of coefficient identification for nonlinear Boussinesq equation, parameter identification inverse problem for water quality model, the inversion of parameter of BOD-DO water model, the inverse problem of the source of convection-diffusion, identification of the steady-state permeability for two dimensional isotropic medium, two-dimensional steady inverse problem of convection-diffusion and parameter identification inverse problem for two-dimensional parabolic equation, etc.

对本文提出的各种算法，编制了数值计算程序，并把它应用于环境水力学反问题诸多领域，包括污染物一维非恒定扩散逆过程反问题，对流扩散方程逆过程反问题，河流水质纵向弥散系数反问题，非线性Boussinesq方程反问题，河流水质多参数识别反问题，BOD-DO水质模型参数反演问题，对流—扩散方程源项反问题及二维恒定各向同性介质渗透系数反问题，二维定常对流——扩散方程及二维抛物型方程参数控制反问题等。

In reliability-based optimization problems of a ship's longitudinal structural design, there are lots of discrete variables and continuous variables. This kind of mixed-discrete non-linear optimization problem containing discrete and continuous variables has long been payed attention to, which is more difficult to solve when a number of reliability constraints are taken into account.

在船舶纵向结构的可靠性优化设计中，含有许多离散型设计变量和连续型设计变量，这种含有两种不同性质设计变量的大型结构物的混和优化问题，一直是人们瞩目的难题，尤其是考虑了多个可靠性约束条件之后，求解这种非线性优化问题就更为困难。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。