INSPECTION TIMES FOR STANDBY UNITS

This paper studies optimal timing of inspections for units in cold sta nd-by. The problem is approached in continuous time. The policies deve loped adapt optimally to information provided by failures of the main unit and by ageing of both the standby and the main unit. Results incl ude a general form for the optimal policy, consisting of a recursive r elation between successive inspection times, and of a renewal-type int egral equation to determine the value of the objective function for a given policy. Further results are derived for the case in which the fa ilure densities describing the process are log-concave. Then the stopp ing rule is easily characterized. It is also shown that the interval b etween inspections decreases with time, and that the optimal schedule is unique. A binary search algorithm for finding the solution is outli ned.