Date of Award
Doctor of Philosophy
Industrial and Manufacturing Systems Engineering
Pius J. Egbelu
Cross docking is a warehouse management concept in which items delivered to a warehouse by delivery trucks are immediately sorted out and reorganized based on customer demands and are routed and loaded into shipping trucks for delivery to customers without actually being held in inventory in the warehouse. Because accuracy in material management is required in such operations, a cross docking operation is heavily dependent on accurate flow of information. In this research, three out of thirty-two different models identified were studied. All three models assume there is one receiving dock and one shipping dock at the warehouse.;The first model studied assumes there is temporary storage at the shipping dock. In this model, both the receiving and the shipping trucks must stay at the docks until they finish their unloading or loading tasks once they come into docks. The second model assumes there is no temporary storage. However, both the receiving truck and the shipping truck can move in and out of the dock during their tasks. Therefore, it is possible for a truck to execute part of its task at the dock, moves out, waits and goes into the dock again to execute its remaining loading or unloading tasks. The third model assumes there is temporary storage and trucks can move in and out of the dock as in the second model.;In all the models studied, the objective is to find the best truck spotting sequence for both receiving and shipping trucks to minimize total operation time or maximize the system throughput. The product routing and the spotting sequences of the receiving and shipping trucks are all determined simultaneously. Mixed integer programming, branch and bound, search algorithm, complete enumeration, and heuristics were used in modeling the problems. Based on test results, the heuristics and the search algorithms produced very good solutions when compared with the optimal solutions. The solution approaches developed will provide a basis for operating more efficient cross docking warehouses. When designed and analyzed in the way undertaken in this research, warehouse operators can expect to save millions of dollars annually in their operations.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu
Yu, Wooyeon, "Operational strategies for cross docking systems " (2002). Retrospective Theses and Dissertations. 413.