Optimal Replacement Policy for Stepdown Warrantied System with Minimal Repair

응급수리(應急修理)가 가능(可能)한 단계별(段階別) 사후보증제품(事後保證製品)의 최적교체정책(最適交替正策)

An age replacement policy is considered for a system under a stepdown warranty. It is assumed that only minimal repairs are performed for failures occurred before age T.A unique optimal value of T which minimiges the expected cost rate is obtained. The cases of the free replacement warranty, prorata warranty and hybrid warranty are also considered and some numerical examples are given.