Joint Optimization of Manufacturing Quantities and Maintenance for a Deteriorating Production System

The aim of this thesis is to jointly optimize manufacturing quantities and maintenance policies for deteriorating production systems under the age-based and the condition-based maintenance. In the age-based maintenance model, the time to component failure, the preventive maintenance time and the corrective maintenance time are all assumed to be random variables. Lost sales due to repair delay are permitted and shortage costs are also considered. Preventive maintenance is performed after M production runs to restore the production facility to the 'good as new' condition. Corrective maintenance is performed upon failure. In the condition-based maintenance model, deterioration of the production facility is caused by ageing and environmental factors. The proportional hazards model is employed to evaluate the production facility's hazard rate and the condition-based control limit policy is used to minimize the average cost and guarantee the system's reliability. The deterioration is modeled as a semi-Markov decision process.