Uncertain Resource Availabilities: Proactive and Reactive Procedures for Preemptive Resource Constrained project Scheduling Problem

Project scheduling is the part of project management that deals with determining when in time to start (and finish) which activities and with the allocation of scarce resources to the project activities. In practice, virtually all project managers are confronted with resource scarceness. In such cases, the Resource-Constrained Project Scheduling Problem (RCPSP) arises. This optimization problem has become popular over the last few decades because of its practical relevance to various industrial and research fields. Numerous procedures have been developed in the literature for finding either optimal or heuristic solutions for the RCPSP. Resource constrained project scheduling problem under stochastic circumstances have been considered in recent decades where uncertainty is modeled by means of activities’ duration. In this research we study an extension of basic stochastic RCPSP in which availability of resources is not predefined. Activities follow preempt-resume mode in case of any disruption due to resource infeasibility. A solution for this variant of RCPSP is defined in three steps by utilizing heuristic procedures for creating initial schedule, adding time and resource buffers in order to yield proactive schedule and applying reactive policies to encounter with unhandled breakdowns. Computational experiments depict that proposed combined procedure achieve significant performance gains over the use of each method separately.