Inspection policies: Comparisons and modifications

This paper discusses: (1) Comparisons between optimum and nearly optimum inspection policies: (2) Inspection policies for modified inspection models. In Section 2, it numerically compares the optimum inspection policy by Barlow et al. with the nearly optimum ones by Kaio and Osaki, Munford and Shahani, and Nakagawa and Yasui, assuming a gamma lifetime distribution. In Section 3, the paper treats a modified inspection model taking account of two kinds of imperfect inspection probabilities, obtains the structure of the optimum inspection policy, and discusses the optimum policy minimizing the total expected cost up to the detection of the failure. The numerical examples are presented. In Section 4, the paper considers another modified inspection model with imperfect inspection probability and checking time. It obtains the nearly optimum inspection policy which minimizes the nearly total expected cost up to the detection of the failure.