查询词典 approximation method

The application of the lattice Boltzmann method in unsteady open channel flows was studied in detail in the paper. An existing lattice BGK model was mended; For the problem of negative local equilibrium and evolutionary distribution, we proposed a lattice Boltzmann model based on cell-population equilibrium, which is a direct non-negative approximation to the continuous Maxwell distribution. The model reduces the transport and collision, two basic evolution steps in the LB model, to transport of the non-equilibrium distribution.

本文系统的研究了格子Boltzmann 方法在明渠非恒定流中的应用问题，改进了一个现有的LB 模型，数值实验表明此改进是有效的；在平衡态分布函数及分布函数的非负性问题上，作者提出了一个基于单元均衡的格子Boltzmann 模型，通过直接对Maxwell 分布函数的离散化实现对速度分布函数的非负离散，这种方法将传统模型演化过程中的碰撞和输运两个步骤直接表现为粒子的输运。

Keywords Closed convex cone;gradient projection method;Least-squares solution;Inverse matrix problem;Inverse eigenvalue problem;Matrix completion problem;Optimal approximation

Article From 湖南大学；应用数学博士论文 2005年度闭凸锥；投影梯度法；最小二乘解；矩阵反问题；矩阵逆特征值问题；矩阵完全化；最佳逼近

Digital holography ; Microscopic digital holography ; Wave front reconstruction ; Fresnel approximation ; Convolution method ; Angular spectrum theorem

数字全息；显微数字全息；波前重建；菲涅耳近似；卷积法；角谱方法

In order to apply virtual reality technique into medical image processing, make convenient for surgeons to access virtual and mini invasive surgery, this paper, presents a full interactive virtual endoscopy system framework, analyzing and discussing system architecture and algorithm models. We explain some key procedures in virtual endoscopy system such as definition of world coordinate, virtual camera, surface detection, normal approximation, volume rendering and surface rendering, and also some interactive control method.

在综合利用各种计算机图形、图象技术的基础上，提出了完整的交互式虚拟内窥镜系统的框架，同时对系统结构和各种模型进行了分析和讨论，还针对系统的实时性和绘制结果的逼真性要求，提出了基于 Object Cache和扩展的区域增长方法，并将其应用到医学图象处理当中，得到了较好的效果。

A projection method is used to smooth out start and end points of the ruling line sets. With predefined Euclidean 6 space distances, the problem of ruled surface approximation from line sets in Euclidean 3 space can be converted into a least square B-spline curve fitting issue in Euclidean 6 space.

利用"投影"光顺法对齐直母线段族首末端点，再通过定义欧氏6空间下的距离函数，将欧氏3空间下的直线族逼近直纹面问题转换成欧氏6空间下B样条曲线最小二乘拟合问题。

Then,the arrangement method for pressure monitoring points was proposed according to the approximation degree of nodes'pressure changes.

最后，根据各节点压力变化的近似程度和特征，提出供水管网压力监测点的布置方案。

Taking the process of grooving as an example, the optimal solution is worked out with objective simplex method. The degree of approximation between every objective function and given corresponding target value is observed.

以切槽车刀的车削为实例，采用目标单纯形法求得其最优解，确定了每一个目标函数与事先给定的对应目标值的逼近程度。

This paper presents an improved variable stepsize BP learning algorithm by making use of the concept of model approximation degree and by taking advantages of the merits of simulated annealing method.

基于模型逼近度和接受概率的一个变步长快速BP学习算法叶东毅（福州大学计算机科学系福州350002）摘要本文给出模型逼近度的概念。

Fourier transform method can be directly derived from symbol function＇s separable approximation.

Fourier变换方法则直接用象征函数的可分表示求出。

In this paper, the theoretical model of CQI is described in an atom-diatom system in the condition of the molecular beam, based on the first-Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials. The method of observing and measuring correctly the differential interference angle is presented. The relation between differential and parameter, velocity is obtained. The relation of the integral interference angle and temperature is discussed.

文中利用一阶含时波恩近似和L-J相互作用势，建立了原子-双原子分子碰撞系统转动传能的量子干涉模型，描述了观察和测量微分干涉角的方法，得到了微分干涉角与碰撞半径和碰撞速度间的关系，同时也得到了积分干涉角和实验温度的关系。

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。