A Recent Mathematical Development in Maintenance Theory

This paper introduces the mathematics of delay-time analysisand places it in context. Both the nature of and the scope fordelay-time models are indicated, and example prototype modelsdeveloped in the context of inspection policies. The essentialrole of subjective estimation is indicated, and the need toconsider revisions of both the prior delay-time distributionand the delay-time model highlighted. An unavoidable bias thatarises when estimating delay-time is discussed and the appropriatedistribution of biased estimates derived. A mechanism for correctingthis bias when estimating a delay-time distribution is proposed,based upon maximum-likelihood considerations. Finally, generalcomments are made concerning other developments and applicationsof the technique.