寿命变量的序关系及其封闭性质

Four comparisions of life variances and their properties

基于寿命变量在随机序、凸序、凹序及均值下的比较 ,较详细地研究了这几种比较间的关系以及它们对串。

Based on the comparision of life variances under stochastic order?convex order?concave order and expectation ,this paper studies the relatoins among these four comparisions in detail and their confinment ability on serial and parallel systems and convolution calculation.