Constraint based scheduling to deal with uncertain durations and self-timed execution

Abstract

In this paper we propose off-line and on-line extensions to the Resource Constrained Project Scheduling Problem. The off-line extension is a variant of RCPSP with time lags and uncertain, bounded activity durations. In this context we improve over our previous work presented in [12] by proposing an incremental flow computation for finding minimal conflict sets and a set of filtering rules for cumulative constraint propagation. The on-line extension is based instead on considering an on-line semantics such as the Self-Timed Execution and take it into account in the scheduling process. Adding the on-line aspect to the problem makes the CSP framework no longer suitable. We have extended the CSP framework to take into account general search decisions and auxiliary unbound variables. An extensive set of experimental results show an improvement of up to two orders of magnitude over our previous approach. © 2010 Springer-Verlag.