(An) optimal boundary shape for class-based storage-assignment policy in automated storage/retrieval systems

Abstract

This thesis studies class-based storage assignment policy, under dual command, in terms of the expected travel time of Storage/Retrieval machine (S/R machine) in Automated Storage/Retrieval Systems (AS/RS). for 2-class-based storage assignment policy, the expected round-trip time of S/R machine is determined when the center of a squared shaped region for class-one items is located on the line connecting the origin and the center of the rack. Relaxing the requirement of square-Lboundary, a heuristic procedure is proposed which determines an optimal partition of descrete rack. An application of the procedure confirms that the L-shape partition is not optimal as suggested by the other previous works.