ABSTRACT
It is also possible to consider the non-periodic inspection scheme. In Grall et al., (2002) authors considered the ‘sequence’ inspection/remplacement policieswhere the inspection intervals depend on the information of the system deterioration (a function of the deterioration state). Failure is detected only by inspection and a cost of ‘inactivity of the system’ per unit time is calculated as soon as failure occurs. In order to deal with aperiodic inspections, they used the long-term expected average cost per unit time,which is based on of the semi-regenerative properties of the maintained systemconditionwith respect to the steady-state stationary probability distribution of the maintained system state. Grall et al., (2002) considered a maintenance policy using a multi-level control-limit rule, where failures are detected immediately.
