Age Replacement Overtime

We consider a unit operating for a job with random working cycles, in which case, it would be impossible or impractical to replace the unit in a strict or deterministic fashion [1, p. 72], [2, p. 245]. From such a viewpoint, we have already proposed replacement overtime in which the unit is replaced at the first completion of working cycles over a planned time T [3, p. 34, 8].