Computers and Operations Research
Reservation storage policy for AS/RS at air cargo terminals
WSC '05 Proceedings of the 37th conference on Winter simulation
Optimization of storage location assignment for fixed rack systems
WISM'10 Proceedings of the 2010 international conference on Web information systems and mining
Robust Storage Assignment in Unit-Load Warehouses
Management Science
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In existing AS/RS research, storage assignment policies are evaluated based on the probability that item type j will be stored (and subsequently retrieved). This note applies the turnover-based and class-based assignment policies of Hausman et al. (1976) to a stochastic environment by identifying the kth pallet of item type j: Frequently demanded pallets are stored close to the input/output point and rarely demanded pallets are stored at the end of the storage rack. We consider a discrete storage rack and a continuous storage rack. For the continuous rack case, we develop an expression for expected one-way travel time given uniform and exponentially distributed demand. We show that the turnover-based policy applied to the stochastic environment is optimal (it minimizes one-way travel time) and that both the turnover-based and class-based assignment policies applied in the stochastic environment reduce expected storage/retrieval time compared with random assignment. These savings can be directly translated into increased throughput capacity for existing systems and can be used to improve the design of proposed systems.