A finite population queueing system with a supporting inventory of spare parts-analysis and design

Abstract

In this thesis, a model is developed for a finite population queueing system deployed to meet a constant demand for the situation where failed units require a single spare part to initiate repair action. A supporting inventory of spare parts is included in the model operating under a one-for-one ordering policy. The system was modeled as a Markov process, and an algorithm is presented that numerically evaluates the steady state probabilities.

Cost was chosen as the measure of effectiveness of the system. Total system cost consists of shortage costs for not being able to meet the demand for units, population and repair facility annual equivalent costs, holding costs for keeping spare parts in inventory, and procurement and spare part costs related to procurement and purchase activities.

A computer program in BASIC, designed for a microcomputer, enables the decision maker to interactively find the design that optimizes the effectiveness measure of the system. The decision variables considered are the number of units in the population, the number of repair channels, and the maximum level of spare parts. One specific design problem is presented.