j∈Si d(j, F )    , where for any F ⊆ V , d(j, F ) = minf∈F d(j, f). This is a “min-max” or “robust” version of the k-median problem. Note that in contrast to the recent papers on robust and stochastic problems, we have only one stage of decisionmaking where we select a set of k facilities to open. Once a set of open facilities is fixed, each client in the uncertain client-set connects to the...

in this paper we study finding the $(k,l)$-core problem on a tree which the vertices have positive or negative weights. let $t=(v,e)$ be a tree. the $(k,l)$-core of $t$ is a subtree with at most $k$ leaves and with a diameter of at most $l$ which the sum of the weighted distances from all vertices to this subtree is minimized. we show that, when the sum of the weights of vertices is negative, t...

The Multiple Capacitated Facility Location Problem (MCFLP) is a well-known and studied in the international literature optimization problem. A web-based Decision Support System (DSS) for this problem is being implemented. The geographical information data of the enterprises' locations are usually either ignored by the modeler or entered manually in these systems. In this paper, we integrate geo...

Network location models comprise one of the main categories of location models. These models have various applications in regional and urban planning as well as in transportation, distribution, and energy management. In a network location problem, nodes represent demand points and candidate locations to locate the facilities. If the links network is unchangeably determined, the problem will be ...

In rapidly growing urban areas, it is deemed vital to expand (or contract) an existing network of public facilities to meet anticipated changes in the level of demand. We present a multi-period capacitated median model for school network facility location planning that minimizes transportation costs, while functional costs are subject to a budget constraint. The proposed Vintage Flexible Capaci...

This paper presents a simple and effective Genetic Algorithm (GA) for the two-stage capacitated facility location problem (TSCFLP). The TSCFLP is a typical location problem which arises in freight transportation. In this problem, a single product must be transported from a set of plants to meet customers demands, passing out by intermediate depots. The objective is to minimize the operation cos...

In this paper we present a three-phase heuristic for the Capacitated LocationRouting Problem. In the first stage, we apply a GRASP followed by local search procedures to construct a bundle of solutions. In the second stage, an integer-linear program (ILP) is solved taking as input the different routes belonging to the solutions of the bundle, with the objective of constructing a new solution as...