Proceedings IJCAI-99, Stockholm, August, 1999

An Iterative Sampling Procedure for Resource Constrained Project Scheduling with Time Windows

Amedeo Cesta (1), Angelo Oddi(1) and Stephen F. Smith(2)

(1) IP-CNR
National Research Council
Viale Marx 15
I-00137 Rome, Italy

(2)The Robotics Institute
Carnegie Mellon University
Pittsburgh, PA 15213, USA


In this paper, we extend and integrate previously reported techniques for resource constrained scheduling to develop a CSP procedure for solving RCPSP/max, the resource constrained project scheduling problem with time windows (generalized precedence relations between start time of activities). RCPSP/max is a well-studied problem within the Operations Research community and the presence of a large set of benchmark problems provides a good opportunity for comparative performance analysis. Our base CSP scheduling model generalizes previous profile-based approaches to cumulative scheduling by focusing on global analysis of minimal conflicting sets rather than pairwise conflict analysis. This generalization increases the tendency for more effective conflict resolution. Since RCPSP/max is an optimization problem, other ideas from prior work are adapted to embed this base CSP model within a multi-pass, iterative sampling procedure. The overall procedure, called ISES (Iterative Sampling Earliest Solutions), is applied to the above mentioned set of benchmark problems. ISES is shown to perform quite well in comparison to current state-of-the-art procedures for RCPSP/max, particularly as search space size becomes limiting for systematic procedures.
Amedeo Cesta and Angelo Oddi's work is supported by Italian Space Agency, by CNR Committee 12 on Information Technology (Project SCI*SIA), and CNR Committee 4 on Biology and Medicine. Stephen F. Smith's work has been sponsored in part by the National Aeronautics and Space Administration under contract NCC 2-976, by the US Department of Defense Advanced Research Projects Agency under contract F30602-97-20227, and by the CMU Robotics Institute.
Copyright 1999, Cesta, Oddi and Smith. All rights reserved.
Full paper in Postscript