ABSTRACT
Reliability importance measures providing information about the importance of components on the system performance (reliability, maintainability, safety, or any performance metrics of interest) have been widely used in reliability studies and risk analysis. They are useful tools to identify design weaknesses or operation bottlenecks and to suggest optimal modifications for system upgrade. Recently, a new importance measure, called Differential Importance Measure (DIM), has been introduced for use in risk-informed decisionmaking (Borgonovo andApostolakis 2001; Borgonovo et al. 2003; Vinod et al. 2003; Marseguerra and Zio 2004). The DIM is defined as a first-order sensitivity measure that ranks the parameters of the risk model according to the fraction of the total change in the risk metric that is due to a small change in the parameters’ values, taken one at a time. However, this importance measure is often only applicable on a limited class of system with independent components.
