arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.04925math.OC
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鲁棒设施定位问题静态分配策略的功效

On the Power of Static Assignment Policies for Robust Facility Location Problems

Omar El Housni, Vineet Goyal, David Shmoys

摘要:

考虑了需求不确定条件下的两阶段鲁棒设施定位问题。决策者需要决定在第一阶段的每个设施,以满足一个不确定的第二阶段的需求,使第一阶段的供应成本和最坏情况下的成本满足第二阶段的需求在所有情况下的总和最小化的供应(积分)单位。第二阶段决策只是指派决策,不可能增加追索供应能力。这使得我们的模型不同于现有的两阶段强大的设施定位和覆盖问题的工作。我们考虑一个隐含的模型的不确定性指数的需求情况下指定的上界$k$的第二阶段的客户端的数量。在一个最优解中,第二阶段的分配决定取决于场景,令人惊讶的是,我们表明,限制到一个固定的(静态)分数分配每个潜在的客户端,无论情况给我们一个$O(\log k/\log \log k)$近似的问题。此外,最好的静态分配可以有效地计算给我们所需的保证。

英文摘要:

We consider a two-stage robust facility location problem on a metric under an uncertain demand. The decision-maker needs to decide on the (integral) units of supply for each facility in the first stage to satisfy an uncertain second-stage demand, such that the sum of first stage supply cost and the worst-case cost of satisfying the second-stage demand over all scenarios is minimized. The second-stage decisions are only assignment decisions without the possibility of adding recourse supply capacity. This makes our model different from existing work on two-stage robust facility location and set covering problems. We consider an implicit model of uncertainty with an exponential number of demand scenarios specified by an upper bound $k$ on the number of second-stage clients. In an optimal solution, the second-stage assignment decisions depend on the scenario; surprisingly, we show that restricting to a fixed (static) fractional assignment for each potential client irrespective of the scenario gives us an $O(\log k/\log \log k)$-approximation for the problem. Moreover, the best such static assignment can be computed efficiently giving us the desired guarantee.

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