A Multi-objective Scheduling Model for Solving the Resource-constrained Project Scheduling and Resource Leveling Problems

The project resource leveling problem was proposed to smooth resource usage and reduce resource fluctuation, while the resource-constrained project scheduling problem focuses on minimizing the project duration with limited resources. Solving the two interrelated problems separately is unlikely to result in a globally optimum schedule. The few integrated optimization methods that have been developed favor a predetermined resource profile that may be difficult to achieve. This paper proposes an integrated scheduling method to minimize the project duration and resource fluctuation by using the strength Pareto evolutionary approach II (SPEA II) which outperformed several other multi-objective optimization techniques in solving the resource-constrained project scheduling problem. An innovative chromosome representation scheme for SPEA II was proposed. A set of case studies were tested to compare the optimization performance of the proposed method with the best of the existing techniques. The results showed that the method yields better results than popular methods presented in the literature.