The Quadratic Assignment Problem (QAP) has remained one of the great challenges in combinatorial optimization. It is still considered a computationally nontrivial task to solve modest size problems,â€¦ (More)

Semideenite programming (SDP) relaxations for the quadratic assignment problem (QAP) are derived using the dual of the (homogenized) Lagrangian dual of appropriate equivalent representations of QAP.â€¦ (More)

An exact solution method for the graph bisection problem is presented. We describe a branch-and-bound algorithm which is based on a cutting plane approach combining semideenite programming andâ€¦ (More)

Airline crew rostering is an important part of airline operations and an interesting problem for the application of operations research. The objective is to assign anonymous crew pairings either toâ€¦ (More)

We consider transformations of the (metric) Quadratic Assignment Problem (QAP), that exploit the metric structure of a given instance. We show in particular, how the structural properties ofâ€¦ (More)

Column generation is a state of the art method for optimally solving di cult large scale optimization problems such as airline crew as signment We show how to apply column generation even if thoseâ€¦ (More)

The quadratic assignment problem (QAP) belongs to the hard core of N P-hard optimization problems. After almost forty years of research only relatively small instances can be solved to optimality.â€¦ (More)

The paper argues that modelling provides a convenient and cost eeective means of characterizing and predicting the behaviour of environmental systems disturbed by man. A series of modelling criteriaâ€¦ (More)