Generalized local branching heuristics and the capacitated ring tree problem

Generalized local branching heuristics and the capacitated ring tree problem

In this paper we present a heuristic framework that is based on mathematical programming to solve network design problems. Our techniques combine local branching with locally exact refinements. In an iterative strategy an existing solution is refined by solving restricted mixed integer programs (MIPs) to optimality. These are obtained from the master problem MIP by limiting the number of variab...

Approximating the Generalized Capacitated Tree-Routing Problem

In this paper, we introduce the generalized capacitated tree-routing problem (GCTR), which is described as follows. Given a connected graph G = (V, E) with a sink s ∈ V and a set M ⊆ V − {s} of terminals with a nonnegative demand q(v), v ∈ M , we wish to find a collection T = {T1, T2, . . . , T`} of trees rooted at s to send all the demands to s, where the total demand collected by each tree Ti...

On the approximation of the generalized capacitated tree-routing problem

Let G=(V,E) be a connected graph such that each edge e in E is weighted by a nonnegative real w(e). Let s be a vertex designated as a sink, M subset of V be a set of terminals with a demand function q:MR +, k>0 be a routing capacity, and λ≥1 be an integer edge capacity. The capacitated tree-routing problem (CTR) asks to find a partition M={Z 1,Z 2,...,Z l } of M and a set T={T1,T2,...,Tl} of tr...

Randomized heuristics for the Capacitated Clustering Problem

A Local Branching Approach for the Set Covering Problem

The set covering problem (SCP) is a well-known combinatorial optimization problem. This paper investigates development of a local branching approach for the SCP. This solution strategy is exact in nature, though it is designed to improve the heuristic behavior of the mixed integer programming solver. The algorithm parameters are tuned by design of experiments approach. The proposed method is te...