The PI has developed several maintenance-center inventory models; in each she has considered the problem of determining how many repairable spare parts to stock at a maintenance center. Complex machines receive scheduled overhauls at the maintenance center, at which time all failed parts are removed and replaced by spares. The failed parts are repaired and returned for use as spares. If a part is needed for an overhaul while all spares are in the repair shop, the resulting shortage is remedied by emergency repair at premium cost. Objectives have included: (1) maximizing job-completion rate subject to a constraining on total inventory investment; (2) minimizing expected shortage costs, under a similar constraint; (3) determining the optimal number of spares and repair strategy when there is a choice of repair rates, using a Markov decision model; and (4) determining the optimal replenishment policy when failed spares are sometimes condemned as irreparable. In the proposed research, PI will study (1) multi-echelon inventory models and (2) cyclic queuing networks, in order to incorporate these ideas into more realistic models. This research has been reviewed and recommended for funding under the program for Research Opportunities for Women, which incorporates considerations of professional development, in this case through participation in the operations research program at Stanford University.
