A multi-mode resource-constrained discrete time–cost tradeoff problem and its genetic algorithm based solution

The discrete time–cost tradeoff problem (DTCTP) is an important subject in the project scheduling theory and applications. Due to the fact that the resources used in projects in modern enterprises mainly belong to renewable resources, e.g. manpower resources, the general DTCTP is extended to a new multi-mode resource-constrained DTCTP model (MRC-DTCTP). The multi-mode resource-constrained project scheduling problem (MRCPSP) was referred and the renewable resource constraints were added to the general DTCTP. By predefining the resource price, the renewable resources are related to the project costs, including direct cost and indirect cost. Every activity can be executed in the crashing way in which the project direct costs are used to shorten the activity duration. According to the characteristics of the MRC-DTCTP, an improved genetic algorithm for solving it was developed and its effectiveness was verified by compared with the exact algorithm. Finally an entire time–cost tradeoff curve for a project network was drawn through computing project deadline problem, and the advantages of the MRC-DTCTP were investigated based on computation results.