A novel importance measure for external factors based on system performance

Importance measures and analysis have been used to identify weak components to prioritize system upgrading activities, maintenance activities, etc. Traditionally, importance measures do not consider the possible effect due to external environment and phenomena, which however can be causes of system failures and therefore should be taken into consideration. This paper proposes a novel importance measure for multi-state systems with the consideration of external factors. And the proposed importance analysis can effectively quantify the effect of the state of the external factor on the component and system performance.