研究源自煤炭港口料场管理的堆取料机调度问题.该问题中,堆取料机从长为L的料场作业区最左端开始空机或载料运行,两者的速度之比为s:1(s ≥ 1).决策者需确定储料堆在作业区的分布以及堆取料机处理它们的先后次序,目的是极小化一批煤料运输船的在港服务时间.考虑堆取料机处理完毕需要回到料场终端的作业模型,证明了存在最坏情况界不超过1+1/4s的近似算法.
This paper studies the reclaimer scheduling problem that arises in the management of a stockyard at a coal terminal. In this problem, we are given a single reclaimer initially located at the left end of a stock pad of length L. The reclaimer can either travel across or reclaim stockpiles on the stock pad, with a speed ratio of s ≥ 1. The scheduler has to decide the placement positions of the stockpiles on the stock pad and sequence the reclaiming of the stockpiles so as to minimize the total time serving the arrived vessels. We show that there exists an approximation algorithm with a worst case ratio no larger than 1 + 1/4s, provided that the reclaimer has to return to the endpoints of the stock pad.
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