Author(s): Ding Hongling, DingWeiyong, AnGuobin
Pages: 63-66
Year: 2015 Issue:  1
Journal: Journal of Shandong Normal University(Natural Science)
Keyword:  coherent system; module; series; parallel; k-out-of-n structure;
Abstract: The signature is an important structural characteristic of a coherent system,which is defined as thevector whose ith element is the probability that the system fails concurrently with the ith component failure.However,its computation is often rather involved and complex.In this paper,we turns to the study of the agingproperties of signatures,which serves as a preliminary exploration of computation of signatures.There are the caseswhen a coherent system of large order is obtained as a series or parallel structure built from ”small”modules withknown signature.Two types of series structures of separate modules are provided under which the closure propertyof IFR signatures can be inherited.Meanwhile,a counterexample is presented to show that the closure property ofIFR signatures does not exist under the formation of parallel structure of separate modules.Finally,a conjecture israised for further study on this topic.