Fabio Furini The aim of this letter is to design and computationally test several improvements for the compact integer linear programming (ILP) formulations of the temporal bin packing problem with fire-ups (TBPP-FU). This problem is a challenging generalization of the classical bin packing problem in which the items, interpreted as jobs of given weight, are active only … Read more
A binary constraint satisfaction problem (BCSP) consist in determining an assignment of values to variables which is compatible with a set of constraints. The problem is called binary because the constraints involve only pairs of variables. The BCSP is a cornerstone problem in Constraint Programming (CP), appearing in a very wide range of real-world applications. … Read more
Given a graph G and an interdiction budget k, the Edge Interdiction Clique Problem (EICP) asks to find a subset of at most k edges to remove from G so that the size of the maximum clique, in the interdicted graph, is minimized. The EICP belongs to the family of interdiction problems with the aim … Read more
We investigate the problem of exactly separating cover inequalities of maximum depth and we develop a pseudo-polynomial-time algorithm for this purpose. Compared to the standard method based on the maximum violation, computational experiments carried out on knapsack and multi-dimensional knapsack instances show that, with a cutting-plane method based on the maximum-depth criterion, we can optimize … Read more
We study a family of discrete optimization problems asking for the maximization of the expected value of a concave, strictly increasing, and differentiable function composed with a set-union operator. The expected value is computed with respect to a set of coefficients taking values from a discrete set of scenarios. The function models the utility function … Read more
We study the Knapsack Problem with Conflict Graph (KPCG), a generalization of the Knapsack Problem in which a conflict graph specifies pairs of items (vertices of the graph) which cannot be simultaneously selected in a solution. The KPCG asks for determining a maximum-profit subset of items of total weight no larger than the knapsack capacity … Read more
A proper coloring of a given graph is an assignment of colors (integer numbers) to its vertices such that two adjacent vertices receives di different colors. This paper studies the Minimum Sum Coloring Problem (MSCP), which asks for fi nding a proper coloring while minimizing the sum of the colors assigned to the vertices. This paper presents … Read more
Given an undirected graph, we study the capacitated vertex separator problem which asks to find a subset of vertices of minimum cardinality, the removal of which induces a graph having a bounded number of pairwise disconnected shores (subsets of vertices) of limited cardinality. The problem is of great importance in the analysis and protection of … Read more
The family of Critical Node Detection Problems asks for finding a subset of vertices, deletion of which minimizes or maximizes a predefined connectivity measure on the remaining network. We study a problem of this family called the k-vertex cut problem. The problems asks for determining the minimum weight subset of nodes whose removal disconnects a … Read more
In spite of being an extremely successful method to tackle mathematical programs involving a very large number of variables, Column Generation (CG) is known to suffer from stabilization issues which can slow down its convergence significantly. In this article, we propose a new parameter-free stabilization technique for CG based on solving a lexicographic pricing problem. … Read more