Learn More
We present a new Lagrangian-based heuristic for solving large-scale set-covering problems arising from crew-scheduling at the Italian Railways (Fer-rovie dello Stato). Our heuristic obtained impressive results when compared to state of the art codes on a test-bed provided by the company, which includes instances with sizes ranging from 50,000 variables and(More)
In this paper we deal with the Minimum Power Multicasting problem (MPM) in wireless ad-hoc networks. By using an appropriate choice of the decision variables and by exploiting the topological properties of the problem, we are able to define an original formulation based on a Set Covering model. Moreover, we propose for its solution two exact procedures that(More)
1 Abstract A (0; 1) matrix A is said to be ideal if all the vertices of the polytope Q(A) = fx : Ax 1; 0 x 1g are integral. The issue of nding a satisfactory characterization of those matrices which are minimally non-ideal is a well known open problem. An outstanding result toward the solution of this problem, due to Alfred Lehman, is the description of(More)