DOS Seminar

Wednesday, April 18, 2012 - 4:00pm to 5:00pm

ISyE Executive Classroom

TITLE:  Storing Fresh Produce for Fast Retrieval in an Automated Compact Cross-dock System

SPEAKER: Nima Zaerpour, Visiting Scholar from Rotterdam School of Management, Erasmus University


We study temporary storage of fresh produce in a cross-dock center. In order to minimize cooling cost, compact storage systems are used. A major disadvantage of such compact systems is additional retrieval time needed, caused by necessary reshuffles due to the improper storage sequence of unit loads. In practice therefore, a dedicated-storage policy is used in which every storage lane in the system accommodates only one product. However, this policy does not use the planned arrival time information of the products. To make use of this information, this paper proposes a mathematical model considering a shared-storage policy minimizing the total retrieval time. The policy allows different products to share the same lane. In order to solve real-sized problems an effective and efficient heuristic is proposed, based on a greedy construction and an improvement part, which provides near optimal solutions, and which is robust against disturbances in arrival or departure times. The gaps between the results of the heuristic and the lower bound are often zero and mostly less than 1%. Our results, tested for a major distributor of fresh produce, show that the shared-storage policy can reduce the retrieval time by 16% on average as compared to the dedicated-storage policy.

This is a joint work with Dr. John Bartholdi.

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Qie He