Exact and suboptimal reactive strategies for resource-constrained project scheduling with uncertain resource availabilities

In order to cope with the uncertainty inherent in practical project management, proactive and/or reactive strategies can be used. Proactive strategies try to anticipate future disruptions by incorporating slack time or excess resource availability into the schedule, whereas reactive strategies react after a disruption happened and try to revert to a feasible schedule. Traditionally, reactive approaches have focused on obtaining a good schedule with respect to the original objective function or a schedule that deviates as little as possible from the baseline schedule. In this paper, we present various approaches, exact as well as heuristic, for optimizing the latter objective and thus encouraging schedule stability. Furthermore, in contrast to traditional rescheduling algorithms, we present a new heuristic that also takes future uncertainty into account when repairing the schedule. We consider a variant of the resource-constrained project scheduling problem in which the uncertainty is modeled by means of unexpected re∗This research has been supported by project OT/03/14 of the Research Fund of K.U.Leuven, project G.0109.04 of the Research Programme of the Fund for Scientific Research Flanders (Belgium) (F.W.O.-Vlaanderen) and project NB/06/06 of the National Bank of Belgium. †Corresponding author. Tel: +32-16-326970; fax: +32-16-326732; e-mail: [email protected]