基于非对称相似关系的粗集改进模型

改进了基于非对称相似关系的粗集的上、下近似的定义,并从理论上证明了新定义的上、下近似比原来的更合理,并进一步用一个算例来验证。     

Simultaneous perturbation stochastic approximation algorithm combined with neural network and fuzzy simulation

In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochastic approximation algorithm is proposed by integrating neural network with fuzzy simulation. At first, fuzzy simulation is used to generate a set of input-output data. Then a neural network is trained according to the set. Finally, the trained neural network is embedded in simultaneous perturbation stochastic approximation algorithm. Simultaneous perturbation stochastic approximation algorithm is used to search the optimal solution. Two numerical examples are presented to illustrate the effectiveness of the proposed algorithm.     

Hilbert空间内单调的李普希茨算子的一种逼近方法

证明了Chiduime定理对于Ishikawa迭代也成立。     

一类修正的Bernstein算子的点态逼近估计

利用经典的Bojanic-Cheng分解方法,结合分析技术,研究了修正的Bernstein算子对一类绝对连续函数的逼近,得到比较精确的收敛阶和渐近展开式.     

Hermite插值算子在加权Lp范数下的导数逼近

讨论以第二类Chebyshev多项式的零点为插值结点组的Hermite插值算子在加权Lp范数下的导数逼近问题的一种特殊情况,得到利用最佳逼近的精确阶估计.     

Converse result on Szász-type operators

Szasz-type operators can be constructed by a Poisson process. The purpose of this paper is to derive the converse result in connection with Szasz-type operators by Steckin-Marchaud-type inequalities and new Ditzian modulus of continuity. The degree of approximation on deterministic signals is also given.     

线性约束下广义中心对称矩阵扩充及其最佳逼近

文章讨论子矩阵约束下‖AX-Z‖2＋‖YHA-WH‖2=min的广义中心对称解及其最佳逼近,给出了解存在的充要条件及通解的表达式,并且给出了解集合中与给定矩阵的最佳逼近。     

Forward displacement analysis of a redundant parallel manipulator by approximation algorithms

This paper presents the forward displacement analysis of an 8-PSS （prismatic-spherical-spherical） redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting of a PSS joint and a strut with fixed length. A general approximation algorithm is used to solve the problem. To avoid the extraction of root in the approximation process, the forward displacement analysis of the 8-PSS redundant parallel manipulator is transformed into another equivalent problem on the assumption that the strut is extensible while the slider is fixed. The problem is solved by a modified approximation algorithm which predicates that the manipulator will move along a pose vector to reduce the difference between the desired configuration and an instantaneous one, and the best movement should be with minimum norm and least quadratic sum. The characteristic of this modified algorithm is that its convergence domain is larger than that of the general approximation algorithm. Simulation results show that the modelified algorithm is general and can be used for the forward displacement analysis of the redundant parallel manipulator actuated by a revolute joint.     

粗糙模糊集的截集性质及其应用

本文研究了粗糙模糊集的截集性质,粗糙模糊集的上、下近似算子具有保截集性质.在此基础上给出了粗糙模糊集的分解定理,证明了模糊上、下近似算子是其限制在经典集合上算子的典范扩张.最后,利用截集性质简化了模糊集的粗糙度和精度的计算,并给出一个应用实例.     

矩阵方程AXB＋CYD=E的中心对称解的递推算法

讨论了矩阵方程AXB＋CYD=E中心对称解的迭代算法,该算法能够判断矩阵方程是否有中心对称解,在有解的条件下,能得到它的中心对称解,而且在选取特殊的初始矩阵时,该算法能够求出矩阵方程的极小范数中心对称解,以及对给定的矩阵进行最佳逼近的中心对称解．