We study the generalizedk-median version of the warehouse-retailer network design problem(kWRND).We formulate the k-WRND as a binary integer program and propose a 6-approximation randomized algorithm based on Lagrangian relaxation.
In this paper,we study a stochastic version of the fault-tolerant facility location problem.By exploiting the stochastic structure,we propose a 5-approximation algorithm which uses the LP-rounding technique based on the revised optimal solution to the linear programming relaxation of the stochastic fault-tolerant facility location problem.
研究带惩罚和软容量约束的下界设施选址问题.扩展Guha等(Guha S,Meyerson A,Munagala K.Hierarchical placement and network design problems[C]//Proceedings of Foundations of Computer Science,2000:892328,DOI:10.1109/SFCS.2000.892328)和Karger等(Karger D R,Minkoff M.Building steiner trees with incomplete global knowledge[C]//Proceedings of Foundations of Computer Science,2000:892329,DOI:10.1109/SFCS.2000.892329)的工作到带有惩罚的下界约束设施选址问题,提出了一个新的双标准近似算法,得到了同样的近似比(1+α)/(1-α)ρ.进一步考虑带惩罚和软容量约束的下界设施选址问题,得到了近似比为2(1+α)/(1-α)ρ的双标准近似算法.
In this paper, we consider the fault-tolerant concave facility location problem （FTCFL） with uniform requirements. By investigating the structure of the FTCFL, we obtain a modified dual-fitting bifactor approximation algorithm. Combining the scaling and greedy argumentation technique, the approximation factor is proved to be 1.52.
