A Scatter Search Algorithm for the Slab Stack Shuffling Problem

摘要

Slab Stack Shuffling (SSS) problem is a kind of warehousing operations management problem abstracted from steel industry. SSS problem is to choose appropriate slabs for hot rolling schedule with the objective of minimizing shuffles during the retrieval process. Different from previous literatures, the substitute of slabs is a set of slabs which satisfy the given order demand. The problem in this paper considers balancing the shuffles between two sub-yards and the measurement of one shuffle is also different. The problem is formulated as an integer programming model by considering above practical requirements. The complexity of the model motivated us to develop a scatter search algorithm to solve the problem approximately. Problem-oriented coding scheme and solution combination method are proposed in scatter search. The computational results tested on real data show that the shuffles are decreased by 36.9% in average compared with the manual schedule.