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arXiv 2002.00060cs.DScs.DMmath.OC
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随机可扩展装箱问题

Stochastic Extensible Bin Packing

Guillaume Sagnol, Daniel Schmidt genannt Waldschmidt

摘要:

考虑随机可扩展装箱问题(SEBP),其中随机大小的$n$项被装入单位容量的$m$箱中.与经典的装箱问题不同,箱子的数量是固定的,并且可以以额外的成本进行扩展。这个问题在随机环境中起着重要的作用,例如在手术调度中:必须事先将患者分配到手术室,以便充分利用常规容量,同时加班量尽可能小。本文着重于不同类别的政策之间的基本比率:首先,我们考虑不可分割的价格,其中我们比较最优的非预期的政策对最优的分数分配政策。我们表明,这个比例有一个紧的上限$2$。此外,我们开发了一个分析的固定分配的LEPT规则产生一个紧密的近似比$(1+e^{-1}) \approx 1.368$的变体。此外,我们证明了固定分配的价格,相关的自适应性的好处,它描述了限制固定分配政策时的损失,是在同一个因素。这表明,在某种意义上,LEPT是我们所能期望的最佳固定分配策略。我们还提供了一个下界的性能,这种政策相比,最佳的固定分配政策。最后,我们得到了改进的边界的情况下,处理时间是从一个特定的家庭的分布,无论是有界的Pietra指数,或当familly是stochemical占主导地位的二阶。

英文摘要:

We consider the stochastic extensible bin packing problem (SEBP) in which $n$ items of stochastic size are packed into $m$ bins of unit capacity. In contrast to the classical bin packing problem, the number of bins is fixed and they can be extended at extra cost. This problem plays an important role in stochastic environments such as in surgery scheduling: Patients must be assigned to operating rooms beforehand, such that the regular capacity is fully utilized while the amount of overtime is as small as possible. This paper focuses on essential ratios between different classes of policies: First, we consider the price of non-splittability, in which we compare the optimal non-anticipatory policy against the optimal fractional assignment policy. We show that this ratio has a tight upper bound of $2$. Moreover, we develop an analysis of a fixed assignment variant of the LEPT rule yielding a tight approximation ratio of $(1+e^{-1}) \approx 1.368$. Furthermore, we prove that the price of fixed assignments, related to the benefit of adaptivity, which describes the loss when restricting to fixed assignment policies, is within the same factor. This shows that in some sense, LEPT is the best fixed assignment policy we can hope for. We also provide a lower bound on the performance of this policy comparing against an optimal fixed assignment policy. Finally, we obtain improved bounds for the case where the processing times are drawn from a particular family of distributions, with either a bounded Pietra index or when the familly is stochastically dominated at the second order.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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