Importance analysis for reconfigurable systems

Importance measures are used in reliability engineering to rank the system components according to their contributions to proper functioning of the entire system and to find the most effective ways of reliability enhancement. Traditionally, the importance measures do not consider the possible change of system structure with the improvement of specific component reliability. However, if a component's reliability changes, the optimal system structure/configuration may also change and the importance of the corresponding component will depend on the chosen structure. When the most promising component reliability improvement is determined, the component importance should be taken into account with respect to the possible structure changes. This paper studies the component reliability importance indices with respect to the changes of the optimal component sequencing. This importance measure indicates the critical components in providing the system reliability enhancement by both enhancing the component's reliability and reconfiguring the system. Examples of linear consecutive-k-out-of-n: F and G systems are considered to demonstrate the change of the component Birnbaum importance with the optimal system reconfiguration. The results show that the change of the importance index corresponds to the change of the system optimal configuration and the importance index can change not monotonically with the variation of the component reliability.