收敛区域

The result shows that the improved Snake Model can quickly converge the concavity region and the more complex region,and has decreased the dependence of the result of segmentation to the initial value and the influence of noise point to the boundary.

结果表明，改进的Snake模型能迅速地收敛到深凹陷区域和更复杂区域，且减弱了分割结果对初值的依赖性和噪声点对边界的影响。

According to this understanding, this thesis tries to modify PSO algorithm in order to improve its quality of solutions. The main approches include: using uniform design to ensure the uniform distribution of initial particles in the design space; adding mutation operation to increase the diversity of particles; decreasing the maximum velocity limitation and the velocity inertia automatically to balance the local and the global search efforts; developing a new approach to treat the design variables exceeding the bounds; using extensive local searches to escape local minimum. The overall effect of these approaches can yield better results for most test problems.

有鉴於此，本文针对粒子群演化法之流程参考相关文献并稍作改变，使得粒子群演算法在结果的收敛上更具优势，本文的主要改进的方法包括：应用均匀设计的概念使得初始的粒子可以更均匀地分布在空间上；利用突变增加粒子之间的差异性与多样性；利用适当控制的最大速度限制及惯性权重控制，达到区域搜寻与全域搜寻的效果；应用新的边界处理机制处理设计变数超过上、下限的问题；利用区域强化搜寻针对粒子附近地区，再作进一步的搜索以得到更佳之结果；将各种方法综合后配合粒子群演算法使用，可以得到不错的结果。

This paper presents a multigrid parallel algorithm of one dimensional virtual boundary ransack forecast, and discusses its convergence.

对网格方程组作多重网格区域分裂并行计算，虚拟边界预报提出一维搜索算法，并讨论相应的收敛性；通过 GS迭代的性质，构造区间压缩算法，证明了其收敛性。

Numerical results illustrate the effectiveness of the optimized domain decomposition methods we proposed compared with the classical Schwarz methods.

在此基础上考察了古典Schwarz算法和各种优化区域分解算法的收敛性质，验证了优化区域分解算法。

However, the classical Schwarz waveform relaxation method has a disadvantage, namely its convergence rate is slow.

但一般的Schwarz波形松弛算法同时也有收敛速度慢的缺点，本文就是通过将传统Schwarz区域分解算法进行改进，以加快它的收敛速度。

After summarizing the waveform relaxation methods and domain decomposition, we finish some research on optimal Schwarz waveform relaxation algorithm as follows: In the first part, we apply Schwarz waveform relaxation methods on telegraph equation system to get optimal transmission conditions to speed up the algorithm.

在对波形松弛算法以及区域分解进行了综述性介绍后，本文对Schwarz波形松弛迭代算法具体进行了以下研究：首先，本文将在电报方程系统上应用Schwarz波形松弛迭代算法，通过强制加入新的局部传输条件分别给出了两种加速算法并通过定理保证了其优化后的收敛性，进而得到优化Schwarz波形松弛算法，然后通过数值试验对传统Schwarz波形松弛算法与优化Schwarz波形松弛算法进行了比较，研究了收敛率与优化系数的关系，找到了使算法最优的系数取值；最后得出优化后的Schwarz波形松弛算法优于常规Schwarz波形松弛算法的结论。

The overlapping domain decomposition method and nonoverlapping domain decomposition method is introduced for the Laplace problems.

介绍了求解Laplace方程的重叠和不重叠区域分解法，研究了重叠域大小与迭代收敛性的关系，比较了重叠和不重叠区域分解法的迭代次数。

In chapter 2 and chapter 3,the nonoverlapping DDMand overlapping DDM based on natural boundary reduction for 2-D exteriorHelmholtz problem are studied respectively,the convergence and the conver-gence rate of these algorithm are discussed,some numerical results are given.

其次，分别研究二维Helmholtz方程外问题的基于自然边界归化的非重叠型和重叠型区域分解算法，分析了这些算法的收敛性和收敛速度，并给出了数值算例。

Key words:Spectral and pseudospectral approximation,incompressible fluid flow,un-bounded domain,nonlinear partial differential equations.

本文的主要方法与技巧对无界区域中的其它偏微分方程同样适用。关键词：方法谱与拟谱逼近，无界区域，不可压缩流，非线形偏微分方程。收敛性和稳定性

Under the given project scheduling specified by the upper-level algorithm, combined with a critical chain-based heuristic, the lower-level genetic algorithm reallocates the resources to shorten the project duration so that the rate of converging to the global optimum district is improved, and a variable mutation probability is developed to avoid premature convergence.

在由上层算法确定的调度顺序下，下层遗传算法结合基于关键链的启发式算法，对系统资源重新优化配置，使算法加速向最优解区域收敛，并在下层设计了随迭代代数增加的可变变异概率，以避免早熟收敛。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。