基于分散型和扩散型随机序对几种寿命分布类的刻画

本文基于分散型和(或)扩散型随机序，利用随机变量的剩余寿命给出了寿命分布类ILR，IFR，DMRL和IFR(2)及其对偶类的刻画．作为主要结果的一个应用，用k／n-系统的剩余寿命对IFR和DMRLS及其对偶类进行了刻画．这些结果拓宽和加强了文献中已有的结果．     

几类随机序关系关于随机最大与随机最小的反向封闭性质

研究了右扩展序、TTT序、单调增凸序和单调增凹序分别关于随机最大与随机最小的反向封闭性质, 并讨论了相关年龄概念关于随机最大与随机最小的反向封闭性质.     

关于DMRL序的若干结论（英文）

设X,Y为非负绝对连续随机变量,X,Y分别具有各自的分布函数F_X,G_Y,使得F_X(0)=G_Y(0)=0,右连续的反函数F_X~(-1),G_Y~(-1),与生存函数F_X,G_Y.记X≤_(dmrl)Y,称X在DMRL(递减的平均剩余寿命)序下比Y小,如果函数∫_G_Y~(-1)(p)~∞G_Y(x)dx/∫_F_X~(-1)(p)~∞F_X(x)dx关于p∈(0,1)递增.考察了DMRL序的特征性质,获得了若干封闭与逆封闭性质.同时,给出了满足DMRL序的若干说明性实例.     

关于矩阵的Sharp序、*序和减序

给出短阵sharp序的一个新的刻画，由此得到(半)正定短阵sharp序与其平方矩阵sharp序之间的关系．我们还讨论正规矩阵的*序与减序之间的关系，推广了关于Hermmite矩阵的相应结果．     

更新过程中的几个随机比较结果

本文研究了更新过程中的几个随机比较结果.通过对不同时刻之前的最后一次更新发生时刻变量在失效率序、反向失效率序和似然比序意义下的随机比较,获得了若底分布F是IFR,则t之前最后一次更新的发生时刻变量SN(t)在失效率序和反向失效率序意义下关于t单调递增;若底分布F是IFR且绝对连续,则SN(t)在似然比序意义下关于t单调递增.     

完备稠序线性序拓扑空间上的奇周期轨序关系

研究完备稠序线性序拓扑空间上连续自映射的周期轨,指出当连续自映射有（2n＋1）-周期轨而没有（2n-1）-周期轨时,该（2n＋1）-周期轨上各点的序关系.利用这个关系将Sharkovskii定理从实直线推广到完备稠序线性序拓扑空间上。     

态族带序结构的范畴

范畴的态族可以赋予一些结构,如Ab范畴,但在自然界中我们大量接触的是连续现象,作为现代分析的基础,连续是用序关系处理的.因此,本文赋予范畴的态族一个序结构,引进了带序范畴和正序函子,以此作为连续性的一种范畴描述.如范畴C带T_0拓扑,若(?)U_fg,(?)U_f,U_g,使得U_fg=U_f.U_g.则按开集的一种包含关系即构造出带拓扑的范畴上的序结构,从而在拓     

诱导的I-fuzzy拓扑生成序空间

本文研究了模糊拓扑生成序空间与其诱导的I-fuzzy拓扑生成序空间之间的关系.利用三种Lowen映射内在关联的方法,引入了三种I-fuzzy拓扑生成序空间,建立了诱导的I-fuzzy拓扑生成序空间理论.获得了诱导的I-fuzzy拓扑与诱导的I-fuzzy拓扑生成序之间的从属关系.     

风险的变异序在保险中的应用

利用风险的变异序,对保险中两类问题——保费计算和破产概率进行了研究.首先通过建立一种变异序原理,从精算数学的角度给出常用的三种保费计算法的合理性,其次研究了破产风险与变异序的关系,得出结论:较变异的风险将导致高风险的破产.     

方案集团序方法的进一步研究

从集团序方法出发,探讨了该方法在实际应用中面临的新问题,并将基于相对位置排队的思想引入到集团序中.借助优先关系0-1矩阵,有效地集结了各个不同集团排序方案之间的差异,通过阈值的设定,定义了方案之间的优先关系,进而得到方案间新的排序结果.不仅丰富了集团序的研究成果,也为集团序的进一步研究提供了新的研究空间和研究内容.     

����DMRL������ɽ���

Let and be two nonnegative absolutely continuous random variables with respective distribution functions and such that, right-continuous inverse functions and, and survival functions and, respectively. We write, and say is smaller than in the DMRL (decreasing mean residual life) order, if the function is increasing in. Some characterization properties of the DMRL order are investigated. The closure and reversed closure properties of the DMRL order are obtained. Meanwhile, some illustrative examples that meet the DMRL order are shown as well.     

Two suggestions of how to define a stochastic stress-strength system

In this paper we suggest how to generalize a stress-strength system treated in Ebrahimi (1984) at a fixed point of time to a dynamic situation in two ways. In the first approach we assume that a stress factor starts and stops to influence the system and different stress factors add up to total system stress at any time. In the second approach we assume that a stress factors starts and stops to influence the system and stress factors do not accumulate additively.     

SOME MULTIVARIATE DMRL AND NBUE DEFINITIONS BASED ON CONDITIONAL STOCHASTIC ORDER

ＳＯＭＥＭＵＬＴＩＶＡＲＩＡＴＥＤＭＲＬＡＮＤＮＢＵＥＤＥＦＩＮＩＴＩＯＮＳＢＡＳＥＤＯＮＣＯＮＤＩＴＩＯＮＡＬＳＴＯＣＨＡＳＴＩＣＯＲＤＥＲＷＡＮＧＹＵＥＤＯＮＧ（王跃东）ＣＡＯＪＩＮＨＵＡ（曹晋华）（ＤｅｐａｒｔｍｅｎｔｏｆＳｔａｔｉｓｔｉｃｓ，...     

Proximity between life distributions and exponential distributions (I)

Many classes of life distributions have been introduced into reliability theory. Because of the importance of exponential distributions in reliability theory, it is interesting to study the difference between life distributions and exponential distributions. In this paper, we study the proximity between the life distribution in various classes and the exponential distribution. We shall give some simple upper bounds.This research was partially supported by the National Natural Science Foundation of China.     

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.     

独立元件组成的n中取k系统剩余寿命的年龄性质

研究了独立元件组成的n中取k系统的剩余寿命长度的年龄性质,该系统在时刻t＜0有n-k个元件失效.对于几类寿命分布元件,讨论了元件仅仅独立的情形下,n中取k个系统剩余寿命的特征.     

Aging properties of the residual life length of k‐out‐of‐n systems with independent but non‐identical components

The k‐out‐of‐n structure is a very popular type of redundancy in fault‐tolerant systems, it has founded wide applications in industrial and military systems during the past several decades. This paper will investigate the residual life length of a k‐out‐of‐n system with independent (not necessarily identical) components, given that the (n?k)th failure has occurred at time t?0. Behaviour of PF₂, IFR, DRHR, DMRL, NBU(2) and NBUC classes of life distributions are derived in terms of the monotonicity of the residual life given the time of the (n?k)th failure. Copyright © 2004 John Wiley & Sons, Ltd.     

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.     

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.