蕴含权重的偏序集多准则决策法

针对偏序集方法不能解决含有权重的多准则决策问题,提出一种“隐式”赋权的偏序决策方法。首先将含有m个方案和n个准则的决策问题表示成偏序集,之后按权重由大到小的顺序,对准则进行逐步相加形成n个新的准则,得到一个新的偏序集。根据偏序集间的包含关系,证明了新偏序集不仅蕴含了权重信息,而且比初始偏序集有更强的排序能力。结果表明,该法在应用中仅需获取权重排序信息,无需精确权重,适用于权重难以确定的多准则决策问题。以三峡库区水质评价为例,例子表明新方法明显优于原有的偏序决策方法,能够对13个方案进行聚类和排序,而原有方法在该例中几乎难以应用。     

基于超序关系的风险决策方法

ELECTRE法是一种多目标属性决策方法.将该法中以一定风险程度建立超序关系的思想引入到风险决策中,提出了基于超序关系的风险决策方法并对求得的偏序结构进行了分析.最后给出的实例可表明该法是简单实用的.     

基于偏好关系的制造工艺资源评价与选择的模糊决策方法

制造工艺资源的评价和选择是实现资源优化配置的关键技术.本文分析了协同工艺设计中制造工艺资源选择决策研究状况,应用模糊数和模糊决策理论,建立基于偏好关系的制造工艺资源模糊评价模型,研究一种基于偏好关系的隶属度函数求解算法和基于偏序关系的多方案制造工艺资源排序决策方法,最后给出一个算例验证本文提出的资源评价方法的合理性和有效性.     

基于结构元最小二乘序的模糊线性回归

在具有模糊观测数据的线性回归问题中,通过定义模糊序指标实现模糊数的排序,借助经典最小二乘法原理,给出了使平方误差和在此排序方法下达到最小的模糊回归系数最小二乘序估计方法。三个例子的结果表明,文中的最小二乘方法能很好的对输入和输出为模糊数,回归系数为精确值的回归模型进行估计,更重要的是,此方法不仅对三角模糊数适用,对其他类型的模糊观测数据也适用。     

基于偏序集的模糊互补矩阵次序一致性检验与调整

针对模糊互补矩阵次序一致性检验和调整存在争议和繁杂问题,提出了模糊互补矩阵次序一致性检验与调整的偏序集表示方法。在定义了偏序集、模糊互补矩阵、截集矩阵等相关概念基础上,求出模糊互补矩阵B的0.5水平截集矩阵,证明了模糊互补判断矩阵次序一致性和0.5水平截集矩阵为偏序关系矩阵的等价性;模糊互补判断矩阵完全次序一致性的充要条件是任意截集均满足传递性;任意截集满足传递性和偏序关系矩阵的等价性。结果表明,利用0.5水平截集矩阵转换为矩阵来检验模糊互补矩阵的次序一致性;通过调整每个截集矩阵满足传递性并赋值,能够达到模糊互补矩阵完全次序一致性。最后,通过两个算例验证该检验和调整方法的合理性和可行性。     

基于结构元理论的模糊数综合排序指标

文章在分析了基于结构元理论的五个模糊数排序指标(自然序、加权序、左序、右序和组合序等)的基础上,定义了模糊数排序综合指标,使得前五个模糊数排序指标是其特殊情况。综合指标同时考虑了决策者对元素权重分配的主观态度和风险偏好。数据例子表明,模糊数的排序,对不同风险偏好的决策者将有不同的结论。     

基于结构元方法的模糊数互补判断矩阵排序法

利用模糊结构元方法,研究了决策信息以模糊数互补判断矩阵形式给出的有限方案决策问题。给出了模糊数互补判断矩阵的定义,介绍了模糊数排序的一种简捷方法——组合序。在该序的基础上,对模糊有序加权平均(FOWA)算子的若干性质进行证明。利用该算子能够将模糊数互补判断矩阵转换为实数矩阵,进而,对模糊数互补矩阵的排序问题转换成实数矩阵的排序问题。只要矩阵中的元为有界闭模糊数,就可以利用FOWA算子进行排序。最后通过算例对比分析,算例表明利用本文的方法进行排序更为简捷。     

L-模糊偏序集上的核算子与核系统

定义L-模糊偏序集上的L-核系统,给出了任一L-模糊偏序集上的L-核算子与L-核系统之间的一一对应关系,从而推广了有界完备L-模糊偏序集的情形,并使得模糊的情况与分明的情况更加协调。另外,也给出了L-闭包算子与L-闭包系统的相关结论。     

应用偏序集表示权重难以获知的TOPSIS模型

当权重难以获得时,应用TOPSIS模型会遇到困难.为此,提出应用偏序集表示TOPSIS模型,不仅实现TOPSIS模型的排序功能,还能提高排序的稳健性.首先,对偏序集决策方法进行简要介绍,之后根据权重大小排序信息,证明了偏序集排序与TOPSIS模型排序是保序的,可以应用偏序集方法表示TOPSIS模型.最后,通过例子可以看出,该方法易于操作、排序稳定,不需具体权重同样可以应用TOPSIS模型进行决策分析.     

基于级别优序关系和层次分析法的铝合金焊接方法决策

焊接工作者的经验总是有限的,凭经验选出的焊接方法不能保证最合适,因此开发出一种多属性决策专家系统是当前焊接工作者所急需的.在分析各种多属性决策方法的优缺点基础上,提出了基于级别优序关系和层次分析法的铝合金焊接方法决策算法.采用对数模糊优先规划方法从模糊判断矩阵中得出精确权重值,采用基于级别优序关系中的偏好顺序结构评估法(PROMETHEE)对可行方案进行排序,通过一个具体实例阐述了决策流程,结果表明方法具有一定的实用价值.最后指出研究中的不足和进一步研究方向.     

The Spectral Decomposition of Covariance Matrices for the Variance Components Models

The aim of this paper is to propose a simple method to determine the number of distinct eigenvalues and the spectral decomposition of covariance matrix for a variance components model. The method introduced in this paper is based on a partial ordering of symmetric matrix and relation matrix. A method is also given for checking straightforwardly whether these distinct eigenvalues are linear dependent as functions of variance components. Some examples and applications to illustrate the results are presented.     

NBU(2)性的偏序刻画

为刻画同一寿命分布类中两个不同分布的NBU(2)性的强弱,本文定义了一个新的偏序,即NBU(2)序,并证明NBU(2)序具有反身性,反对称性和传递性.另外,该偏序与超可加序、NBUE序,增凹序的关系也作了探讨.基于被比较分布是指数的情况,还建立了判定NBU(2)序的一个充要条件.     

三条路并的极值能量及一类图的能量排序

拟序是图能量排序中一种有效方法,基于该方法,已经得到了大量图类的极值能量排序的结果.Gutman给出了点数和为n的两条路的并的能量排序,而三条路的并的能量排序没有一个理想的结论.本文利用拟序法给出点数和为n的三条路的并的极值能量及一类图能量的排序.     

An inventory system with unit demand and varying ordering levels

An inventory system with unit demand, varying ordering levels and random lead times is considered in this paper. Ordering level is determined by the number of demands during last lead time. The ordering quantity will be such as to bring back the inventory level to S at the ordering epoch. No backlog is permitted. The time dependent probability distribution of the inventory level is obtained. Correlation between the number of demands during a lead time and the length of the next inventory dry period is obtained and it is illustrated by an example.     

Mean residual life and increasing convex comparison of shock models

Two devices are subjected to shocks arriving according to a general counting process. Let M₁ and M₂ be the random number of shocks that cause the failure of the first and the second device, respectively. We find conditions on the counting process such that the mean residual life ordering, the increasing convex ordering and the expectation ordering between M₁ and M₂ are preserved in the random lifetimes of the two devices.     

Estimating Stochastically Ordered Survival Functions via Geometric Programming

Many procedures have been proposed to compute nonparametric maximum likelihood estimators (NPMLEs) of survival functions under stochastic ordering constraints. However, each of them is only applicable to a specific type of stochastic ordering constraint and censoring, and is often hard to implement. In this article, we describe a general and flexible method based on geometric programming for computing the NPMLEs from right- or interval-censored data. To this end, we show that the monotonicity properties of the likelihood function and the stochastic ordering constraints considered in the literature allow us to reformulate the estimation problem as a geometric program (GP), a special type of mathematical optimization problem, which can be transformed to a convex optimization problem, and then solved globally and efficiently. We apply this GP-based method to real data examples to illustrate its generality in handling different types of ordering constraints and censoring. We also conduct simulation studies to examine its numerical performance for various sample sizes. Supplemental materials including technical details, computer code, and data files are available online.     

可换BCH-代数

引入了可换BCH-代数的概念,给出了可换BCH-代数的两个充要条件.对偏序可换BCH-代数进行了讨论,给出了偏序BCH-代数是可换的两个充要条件.证明了偏序可换BCH-代数的每个分支是一个下半格,局部有界偏序可换BCH-代数的每个分支是一个格.     

Weighted graph based ordering techniques for preconditioned conjugate gradient methods

We describe the basis of a matrix ordering heuristic for improving the incomplete factorization used in preconditioned conjugate gradient techniques applied to anisotropic PDE's. Several new matrix ordering techniques, derived from well-known algorithms in combinatorial graph theory, which attempt to implement this heuristic, are described. These ordering techniques are tested against a number of matrices arising from linear anisotropic PDE's, and compared with other matrix ordering techniques. A variation of RCM is shown to generally improve the quality of incomplete factorization preconditioners.This work was supported by by the Natural Sciences and Engineering Research Council of Canada, and by the Information Technology Research Center, which is funded by the Province of Ontario.     

A new heuristic algorithm solving the linear ordering problem

The linear ordering problem is an NP-hard combinatorial problem with a large number of applications. Contrary to another very popular problem from the same category, the traveling salesman problem, relatively little space in the literature has been devoted to the linear ordering problem so far. This is particularly true for the question of developing good heuristic algorithms solving this problem.In the paper we propose a new heuristic algorithm solving the linear ordering problem. In this algorithm we made use of the sorting through insertion pattern as well as of the operation of permutation reversal. The surprisingly positive effect of the reversal operation, justified in part theoretically and confirmed in computational examples, seems to be the result of a unique property of the problem, called in the paper the symmetry of the linear ordering problem. This property consists in the fact that if a given permutation is an optimal solution of the problem with the criterion function being maximized, then the reversed permutation is a solution of the problem with the same criterion function being minimized.     

ORDERING IN AUTOMATED THEOREMPROVING OF DIFFERENTIAL GEOMETRY

1.BackgroundMom1979,WuWentsunbeganthestudyofautomatedtheoremprovingindifferentialgeometry[1].Inhismethod,thehypotheses,representedbydifferentialpolynomials,aretriangulatedaccordingtoanorderofthevariablesinthepolynomials;theconclusionisprovedbythetriangulatedresultcalledcharacteristicset.Wuusedelement-basedorderingmethodwhichcanbeillustratedbythisexample'LettingxKybetwosmoothfunctionsofthesamevariable,thenxKX'KX"K'Ky'y,Ky"'.ThisorderisthefoundationofWu'seliminationprinciple.However,a…