Strategic Options in Logistic Systems

摘要

This thesis develops a model of a multi-echelon inventory system that is comprised of three bases and a centralized repair facility. Each base has a specific level of aircraft. An aircraft is grounded if part A or part B fails and there is no immediate replacement. Part A may be repaired at base level; part B, however, can only be repaired at the depot. Both parts are repaired in the same labor constrained depot shop. The model provides a tool to analyze alternative logistics strategies. The issues that we investigate include increasing spare levels of parts A and B, increasing repair capability at depot and base level, redesigning part A to reduce mean time between failures, and decreasing transportation time between bases and depot. From the base manager's point of view, the strategies that offer the greatest impact at base level are (1) reducing transportation pipeline time and (2) alternating spare levels. These strategies would be extremely expensive and would undergo close scrutiny during Air Force planning and budgeting processes. From the viewpoint of the depot manager, the strategies that offer the greatest impact at depot level are (1) altering repair capacity at depot or base and (2) redesigning part A. The redesign of a part is a very time consuming and expensive strategy that results in minimal changes at base and depot. The strategy that increases the depot worker resource is the only one that positively affects the performance measures at both depot and base.