Recent work have exhibited specific structure among combinatorial problem instances that could be used to speed up search or to help users understand the dynamic and static intimate structure of the problem being solved. Several Operations Research approaches apply decomposition or relaxation strategies upon such a structure identified within a given problem. This paper presents how Benders dec...

In this paper, a new mixed integer mathematical programme is proposed for the application of Hub Location Problems (HLP) in public transport planning. This model is among the few existing ones for this application. Some classes of valid inequalities are proposed yielding a very tight model. To solve instances of this problem where existing standard solvers fail, two approaches are proposed. The...

This paper presents a tutorial on the state-of-the-art software for solution of two-stage (mixed-integer) linear stochastic programs and provides list designed this purpose. The methodologies are classified according to decomposition alternatives types variables in problem. We review fundamentals Benders decomposition, dual progressive hedging, as well possible improvements variants. also prese...

The classical assembly line balancing problem consists of assigning assembly work to workstations. In the presence of setup times that depend on the sequence of tasks assigned to each workstation, the problem becomes more complicated given that two interdependent problems, namely assignment and sequencing, must be solved simultaneously. The hierarchical nature of these two problems also suggest...

Motivated by an industrial application, we study a specific employee timetabling problem. Several investigations are being conducted: a lower bound by Lagrangian relaxation, a heuristic based on a cut generation process and an exact method by Benders decomposition. Experimental results on real and generated instances are reported.

We develop algorithmic innovations for the dual decomposition method to address two-stage stochastic programs with mixed-integer recourse and provide a parallel software implementation that we call DSP. Our innovations include the derivation of valid inequalities that tighten Lagrangian subproblems and that allow the guaranteed recovery of feasible solutions for problems without (relative) comp...

The author regrets that some terms are missing or misspecified in the Karush–Kuhn–Tucker conditions in Sections 3.7–3.10 on page 346. Corrections are given below. add multiplier p m c m (discount rate in tree node m multiplied by the probability of its occurrence) to d d (number of days in demand season d).

Network Design problems concern the selection of arcs in a graph in order to satisfy, at minimum cost, some flow requirements, usually expressed in the form of origin-destination pair demands. Benders decomposition methods, based on the idea of partition and delayed constraint generation, have been successfully applied to many of these problems. This article presents a review of these applicati...

The problem of maximal hub covering as a challenging problem in operation research. Transportation programming seeks to find an optimal location of a set of hubs to reach maximum flow in a network. Since the main structure's parameters of the problem such as origin-destination flows, costs and travel time, change periodically in the real world applications, new issues arise in handling it. In t...