Note:  This work has been done when the authors were visiting the Department of Statistics, University of California, Davis, USA as Visiting Professors.
Abstract: Finding an optimal way to compare the systems of different orders and to order them according to their lives, which are random in nature, is a problem of great concern to the reliability engineers. A direct method of comparing system lives or an indirect method using dominance of the signature vectors of the systems are often used. But these methods have their own limitations. In particular, it has been observed that these methods work under a restrictive setup and for a group of simple systems only. The problem becomes complicated for large and complex systems. In this paper a technique based on stochastic ordering has been proposed to resolve the issue. The method discussed here works under a more general and less restrictive framework. It has been shown to work well for different coherent systems with different component life distributions. Simulation studies have been done to prove the worthiness of the proposed method.
Keywords: Coherent system, minimal cut set, stochastic ordering, system life