稀疏

This paper presents a fast algorithm based on the measured equation of invariance.Conformal meshes are made along the surface of two-dimensional scatterer.Renumbering of nodes changed the original sparse matrix into band one,and the consumption of computer memory and CPU time decrease from O(N2) to O.Via this new algorithm,electrically large problem can now be rapidly solved.

提要 本文基于不变性测试方程法提出一种快速算法，在二维散射体表面建立共形差分网格后，通过对节点的重新排序，将原问题中的稀疏矩阵变换为带状稀疏阵，从而使占用的计算机内存和计算时间均由O(N2)下降为O，可以解决原来无法计算的问题。

Its major feature is to reduce EMS memory allocation greatly by the help of two one dimensional arrays: one is used to deposite the elements within the band width of the matrix at input stage and latter store the elements within the band width of cholesky lower triangle matrix at output sta.

作者针对地球物理数值模拟中常碰到的大型稀疏变带宽方程组的求解问题，介绍了一种大型稀疏变带宽矩阵的存储方法及 Cholesky分解法。

To obtain a sparseness of support vector for least squares support vector regression, an algorithm called vector base learning is proposed in this paper.

使最小二乘支持向量机的解具有稀疏性，本文提出一种稀疏解算法——矢量基学习。

This approach not only inherits the advantages of absolute density based algorithms which can discover arbitrary shape clusters and are insensitive to noises , but also efficiently solves the following common problems: clustering results are very sensitive to the user-deflned parameters, reasonable parameters are hard to be determined, and high density clusters are contained fully in coterminous low density clusters. With this approach, incremental clustering can also be supported effectively by defining the affected sets and seed sets of the updating objects in this approach.

聚类算法的有效性问题主要表现在三个方面：其一，聚类算法大多要求用户输入一定的参数，例如希望产生的簇的数目，而这些参数通常难以确定，特别是针对高维空间中稀疏分布的实际应用数据集，用户几乎无法给出合适的算法参数，因此非专业用户需要与数据分析专家密切配合才能保证获得理想的聚类结果，导致算法的使用极为不便；其二，聚类结果对于输入的参数值过于敏感J，往往参数值的一些轻微变化却产生聚类结果的很大差异；其三，对于高维的实际应用数据集，其数据分布往往是稀疏的、杂乱的，很难为算法选择全局的参数进行准确的聚类分析，使得聚类的质量难以保证。

We propose a wave equation based migration scheme for imaging the steep dipping structures with 3D sparsely sampling dataset, especially sparsely sampled in the crossline direction.

针对稀疏采样，特别是crossline方向稀疏采样的三维地震数据，提出了一个基于波动方程方法的陡角度构造深度偏移成像方法。

Under this situation, sparse signal expansion theories, a kind of new multiscale analysis theory that has been developed in recent years, possess a better performance in detecting the singularities of the signal with straight line or curve in high dimensional space and can be used to express signals with sparse coefficients.

而稀疏信号表示理论是近几年发展起来的一类新的多尺度分析方法，它们对高维空间中具有直线或曲线奇异性信号具有良好的检测性能，可以用稀疏的系数来表示原信号。

Compared with the initial value problems of scalar conservation laws with smooth flux function, the global weak entropy solutions for the initial-boundary value problems of scalar conservation laws with weak discontinuous flux function include the following new interaction types: a rarefaction wave collides with the boundary and is absorbed compltetely or partially by the boundary; a rarefaction wave collides with the boundary and the boundary will reflect a contact or non-contact shock wave; a contact or non-contact shock wave collides with the boundary and is absorbed by the boundary; a contact or non-contact shock wave collides with the boundary and a new non-contact shock will rebound from the boundary simultaneously or later.

与具有光滑流函数的单个守恒律的初始值问题相比，具有弱间断流函数的单个守恒律初边值问题的整体弱熵解中包括下列新的相互作用类型：稀疏波碰到边界并被边界部分或全部吸收；稀疏波与边界相撞，边界反射出一个接触或非接触激波；接触或非接触激波碰到边界并被边界吸收；接触或非接触激波与边界相撞，边界同时或稍后反射出一个新的非接触激波。

In this algorithm scheme, the multiplication of inverse matrix and a matrix is executed by the matrix triangular factor decomposition and back-substitution for the solution.

该算法保留了原方程组系数矩阵的稀疏存储方式和稀疏矩阵的运算规则，减少了计算时间和运算过程所需要的存储空间。

In Chapter 5, a new method with direct partitioned column updates of cholesky factorization for solving large scale sparse unconstrained optimization problems is proposed, which depends on a consistent partition of the columns and cholesky factorization of the Hessian matrix.

第5章基于稀疏Hesse阵的列的相容分划，并在其Cholesky分解的基础上建立了求解大型稀疏无约束优化问题的直接校正Cholesky因子算法。

The forth algorithm is the same as the third one with an addition of finite termination criteria. Although the latter two algorithms have only linear rate of convergence, they are especially suitable for large-scale and sparse problems, with features of simple formula, small storage, sparsity preservation and easy implementation.

前者借助NCP函数把互补问题转化为等价的非光滑方程组，再用带参数的光滑方程组近似这些非光滑方程组，最后用牛顿型方法求解所得到的光滑方程组，希望通过光滑参数趋于零得到原来互补问题的解；后者基于等价不动点格式，构造了一个光滑迭代算法和一个具有有限终止性质的算法，虽然这种迭代算法仅有线性收敛速度，但由于其格式简单、存储量小、保稀疏性、非常易于计算机实现等特点，故较适用于求解大规模稀疏问题。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。