Long-run Cost Criterion Research Articles

Optimal block replacement based on expert judgement method

Applying the theory of uncertainty is a good approach to study the reliability of a system when there is a little frequency of suitable data. Based on this theory, the policy of block replacement with minimal repair is considered assuming the system lifetime follows a power law process. The unknown parameters are estimated according to evidence theory that affects the epistemic uncertainty. The Dempster-Shafer as well as Yager rules are applied to aggregate the judgements and mental estimates of two or more experts. After determining the unknown parameters, a judgement interval is derived for the optimal replacement time using the long-run cost criterion.

Maintenance policies for an heterogeneous two-component system with stochastic and economic dependencies

This paper deals with the problem of maintenance optimization of a two-component system with stochastic dependence when components are heterogeneous regarding their degradation model. The system is composed of a gradually deteriorating component and another component subject to sudden failures e.g. due to shocks. Components are dependent in such a way that the lifetime parameters of component subject to shocks depend on the degradation level of the gradually deteriorating component. In addition, economic dependence is also considered allowing a reduction of maintenance costs by grouping maintenance tasks. Several maintenance policies are proposed and their performances regarding a long-run cost criterion are analyzed through numerical experiments. The advantages and weaknesses of the considered policies are discussed.