Article ID: | iaor2000917 |
Country: | Netherlands |
Volume: | 111 |
Issue: | 3 |
Start Page Number: | 448 |
End Page Number: | 460 |
Publication Date: | Dec 1998 |
Journal: | European Journal of Operational Research |
Authors: | Guignard Monique, Ryul Choonho, Spielberg Kurt |
Keywords: | programming: branch and bound, programming: integer |
Integrated timber harvest and transportation planning problems can be modeled as 0-1 mixed integer programming problems, but initial computations led to large integrality gaps which cannot be overcome easily. In this paper we show how this situation can be substantially improved by a combination of techniques, such as: addition of logical inequalities, lifting of inequalities and careful selection of Branch-and-Bound branching priorities based on a consideration of double-contraction. We compare various combinations of tightening techniques in terms of (integer) variables and constraints, LP bound, number of nodes in the Branch-and-Bound tree and CPU time.