A hybrid Lagrangean metaheuristic for single machine scheduling problem with sequence-dependent setup times and due dates

In this article, a hybrid Lagrangean metaheuristic is proposed for single machine scheduling problems with sequence-dependent setup times and due dates. The objective function considered throughout this work, is to minimize the total tardiness. Related works and taxonomies for hybrid metaheuristics are analyzed, through a thorough historical overview. The proposed hybrid Lagrangean metaheuristic is a … Read more

A hybrid Lagrangean heuristic with GRASP and path-relinking for set K-covering

The set multicovering or set K-covering problem is an extension of the classical set covering problem, in which each object is required to be covered at least K times. The problem finds applications in the design of communication networks and in computational biology. We describe a GRASP with path-relinking heuristic for the set K-covering problem, … Read more

An Improved Algorithm for the Generalized Quadratic Assignment Problem

In the Generalized Quadratic Assignment Problem (GQAP), given M facilities and N locations, one must assign each facility to one location so as to satisfy the given facility space requirements, minimizing the sum of installation and facility interaction costs. In this paper, we propose a new Lagrangean relaxation and a lower bounding procedure for the … Read more

A Lagrangean Relaxation and Decomposition Algorithm for the Video Placement and Routing Problem

Video on Demand (VoD) is a technology used to provide a number of programs to a number of users on request. In developing a VoD system, a fundamental problem is load balancing, which is further characterized by optimally placing videos to a number of predefined servers and routing the user program requests to available resources. … Read more

The Integration of an Interior-Point Cutting-Plane Method within a Branch-and-Price Algorithm

This paper presents a novel integration of interior point cutting plane methods within branch-and-price algorithms. Unlike the classical method, columns are generated at a “central” dual solution by applying the analytic centre cutting plane method (ACCPM) on the dual of the full master problem. First, we introduce improvements to ACCPM. We propose a new procedure … Read more