Systems used in the production of goods and
delivery of services constitute the vast majority of
most industry’s capital. These systems are subject
to deterioration with usage and age (Valdez-Flores
and Feldman, 1989). Most of them are maintained
or repairable systems. For some systems, such as
aircrafts, submarines, military systems, and nuclear
systems, it is extremely important to avoid
failure during actual operation because it can be