Ant Colony Algorithm for Scheduling Resource Constrained Projects with Discounted Cash Flows

For long-term projects with considerable cash flows, the project managers aim to maximize the net present values instead of to minimize project durations. An ant colony algorithm is proposed to coordinate the allocation of scarce resources to improve the net present values. The algorithm adaptively adjusts resource allocation according to the pheromone generated by artificial ants employed to search for suitable schedules. The crossover operation, inverse mutation and elitist strategy are applied to accelerate the searching, and a backward scheduling technique is adopted to postpone cash outflows. An experimental testing indicates that the proposed algorithm helps to improve the net present values of resource constrained projects