查询词典 uniform approximation

It is proved that the upper approximation of such fuzzy rough set in a fuzzy approximation space is just its image derived according to generalized extension principle and binary fuzzy similar relation.

通过对偶方式定义了模糊集的上、下近似算子，给出了模糊粗糙集在相应的模糊关系及模糊集的截集下的表示定理，证明了这种模糊粗糙集关于模糊近似空间的上近似恰为其在二元模糊相似关系下导出的广义扩张原理之下的像。

The general form of solution for the non symmetric matrix A is given, the expression of optimal approximation solution is presented, and an algorithm for solving the problem is described. The total least squares problem with symmetric and bisymmetry constraints is discussed respectively. A sufficient condition for existence of solution is derived by use of the theory of matrix Ricaati equation. The general form of solution is given if the problem has a solution, and the expression of optimal approximation solution is presented. Some numerical examples are given.

对矩阵A是非对称情形，给出了解的一般表达式，证明了最佳逼近问题解的存在唯一性，并给出了其解的表达式，描述了求解问题的算法；讨论了带对称和双对称约束的总体最小二乘问题，利用Ricaati矩阵方程的理论得到了解存在的一个充分条件，分别对对称矩阵和双对称矩阵两种情形，给出了解的一般表达式，证明了最佳逼近问题解的存在唯一性，给出了其解的表达式，提出了求解这些问题的算法，并给出了数值例子。

In the fourth chapter, firstly it introduces the Boolean functions algebraic expressions of the 2-value clock-controlled stop-and-go generator and Gunther generator. It reveals the balanced property of the two kinds of Boolean functions, and studies the Walsh cycle spectrum and the autocorrelation function. It also obtains the coincidence rate of their output sequences with affine sum of some bits of input sequences, and analyzes their ability of resisting the best affine approximation cryptanalysis and differential cryptanalysis. Secondly, we properly present a new definition of the Best Affine Approximation, namely BAA on the Boolean vector functions, followed by the spectral characteristic of such defined BAA attacks through using the decomposition formula of the union distribution for random variables. A lower bound of such BAA attacks is proposed. Finally, we also study the spectral characteristic of the second kind of nonlinearity of Boolean vector functions, followed by a higher bound of such nonlinearity. Furthermore, the limited relationship between the second kind of nonlinearity of Boolean vector functions and the linear structure of the linear combination of every component is analyzed.

在第四章中，首先给出了2值密钥流"停走生成器"和"衮特生成器"中实际存在的布尔函数的代数表示，揭示了这两类布尔函数的平衡性，随后研究了它们的Walsh循环谱和自相关函数等，得到了它们的输出序列与输入序列中的某些bit的仿射项的符合率，分析了它们抵抗最佳仿射逼近攻击和差分攻击的能力；其次，我们合理地给出了布尔向量函数最佳仿射逼近的新定义，利用布尔随机变量联合分布的分解式考察了相应的谱特征，并给出了布尔向量函数与其最佳仿射逼近的符合率的一个下界；最后，我们还考察了布尔向量函数第二类非线性度的谱特征，给出了布尔向量函数第二类非线性度的一个上界，并揭示了布尔向量函数第二类非线性度与其各个分量的线性和的线性结构之间存在的制约关系。

It solves the imaging problem in great contrast. In chapter 2, the author deeply studies and analyzes the arithmetic of the method of Born approximation inversion and points out the limitations and disadvantage of the method. The good inverse results can be obtained in little disturbance by Born approximation.

本文提出的反演理论，考虑到散射序列中高阶项对成像结果的影响，在反演时利用逆散射序列中的高阶项以弥补散射场数据的丢失，使得在大扰动量的情况下同样能够实现界面位置和形态的精确成像，解决了大对比度情况下的成像问题。

It enlarges the range of quasi-linear Born approximation, and makes the prestack depth migration method based on quasi-linear Born approximation to be able to adapt strong lateral velocity variation.

在散射波场计算中，使用了一个更稳定的散射波场计算公式，扩大了拟线性Born近似的应用范围，使基于拟线性Born近似的叠前深度偏移方法能够适应更强的横向速度变化。

The calculations have shown that the second Born approximation can give better results,as compared with experiments.The prediction of K-W formula is only equivalent to the first Born approximation.

结果表明第二玻恩近似结果与实验结果符合得比较好，K-W公式的预言只相当于第一玻恩近似。

A one-sided difference approximation is used for convection terms and a second-order central difference approximation for diffusion term.

二阶一边差分逼近用于对流项的离散，二阶中心差分逼近用于扩散项的离散。

The design of low pass FIR filter applying in electric system by using both window function and chebyshev approximation methods in MATLAB software were introduced,and the conclusion was gotten that the filter design based chebyshev approximation methods was best.

1概述在数字滤波器家族中，FIR滤波器与IIR滤波器相比，由于具有严格的线性相位和因果稳定性等一系列优点，因而得到了广泛应用。

By using the spectrum approximation theory of compact operator, the approximation of anisotropic nonconforming ?nite element method for Stokes eigenvalue pronlem are presented and the optimal error estimates are obtained, which are as same as those of traditional ?nite element methods.

利用紧算子谱逼近理论，给出了 Stokes 特征值问题的各向异性非协调有限元逼近方法及最优误差估计，得到了与剖分网格满足正则性或拟一致性关键假设下相同的收敛效果。

By academic analyzing, it is concluded that two order discrete paraxial approximation formula of the paper, multiple transmitting formula and polynomial extrapolation formula are the different forms of continuous paraxial approximation formula, so they are with nearly equivalent precision and stability and with equivalent applicability and limitation.

据此文献[3]将傍轴近似公式归结为一类从特定的无限域模型导出的人工边界条件，并且提出了新的从一般无限域模型导出的具有普适性的、称为"多次透射公式"的局部人工边界条件。那么，是否也可以从一般无限域模型导出具有普适性的傍轴近似公式呢？

According to our present broadcasting situation,the thesis proposes using new technology to update and reform the present HFC. It also suggests broadcasting using self-advantage and arranging EPON in order to win the supermarket.

论文从我国广电的现状出发，结合实际，积极倡导采用新技术更新、改造我国现有的HFC网络；倡导广电现阶段利用自身优势，部署EPON网络来赢取市场。

A new general kinetic equation was derived in which the effect of the removal of condensation water was taken into account completely, and was applied to the polyesterification kinetic study of AA/HPHP and AA/NPG. It was found that the reaction order of self-catalyzed polyesterification was not constant. For these polyesterifications, the reaction order was 2.5 at a low temperature, while 3.0 at a high temperature.

考虑缩合水的排除对反应体系的影响，用体积浓度单位推导出一个新的聚酯反应总包动力学方程，并应用到AA/HPHP和AA/NPG两个聚酯化反应的动力学研究中，研究发现，自催化聚酯反应的反应级数并不是固定值，对于AA/HPHP和AA/NPG两个聚酯化反应而言，低温时反应级数为2.5，高温时反应级数为3.0。