A two-phase method for a multi-skilled project scheduling problem with discounted cash flows

This paper considers a multi-skilled project scheduling problem that is a newly developed extension of the Resource-Constrained Project Scheduling Problem (RCPSP). The main difference in such problems, compared with classic scheduling problems, is associated with the given resources, which are only dependent on human type. Additionally, the net present value of a given project is considered by its cash in and out flow to guarantee project success. To solve the given problem, an enhanced two-phase method is proposed using genetic and path relinking algorithms, whose parameters are tuned by the Taguchi method to provide robust comparisons. Furthermore, the potential changes in the project execution method are considered for some of the mostly used payment methods. Finally, some different-sized instances are tested to check the performance and efficiency of the proposed method.