Reliability Analysis of Phased-Mission System in Irrelevancy Coverage Model

Abstract

In a phased-mission system (PMS), an uncovered component fault may lead to a mission failure regardless of the status of other components, and the reliability can be analyzed with traditional imperfect fault coverage model (IFCM). The IFCM, however, only considers the coverage of faulty components. Recently, an irrelevancy coverage model (ICM) is proposed to cover both faulty components and irrelevant components, but the analysis is limited to normal non-phased mission systems. This paper first demonstrates that, the coverage of irrelevant components is also important in PMSs, as an initially relevant component could also become irrelevant later due to the failures of other components, and an uncovered fault of irrelevant component may threaten the whole mission as well. A method to analyze the reliability of PMS in ICM is proposed using sum of disjoint products (SDP) technique. Experimental results demonstrate not only the effectiveness of the proposed reliability analysis method, but also that the ICM can achieve higher reliability than the IFCM for PMSs in general.