| Article ID: | iaor201111443 |
| Volume: | 39 |
| Issue: | 7 |
| Start Page Number: | 1402 |
| End Page Number: | 1410 |
| Publication Date: | Jul 2012 |
| Journal: | Computers and Operations Research |
| Authors: | Venkateshan Prahalad, Szmerekovsky Joseph G |
| Keywords: | programming: integer, combinatorial optimization, networks, project management |
Four integer programming formulations are studied for the irregular costs project scheduling problem with time/cost trade‐offs (PSIC). Three formulations using standard assignment type variables are tested against a more novel integer programming formulation. Empirical tests show that in many instances the new formulation performs best and can solve problems with up to 90 activities in a reasonable amount of time. This is explained by a reduced number of binary variables, a tighter linear programming (LP) relaxation, and the sparsity and embedded network structure of the constraint matrix of the new formulation.