In a recent study (YAMASHITA; MORABITO, 2007a), it was proposed an exact algorithm to solve problems of resource-constrained project scheduling with resource availability costs under multiple modes of execution. That algorithm is an adaptation of another exact algorithm recorded in the literature for the particular case where there is only a single mode for executing the tasks. In the present study, we propose a new exact algorithm based on the branch and bound method to deal with multiple performing modes problem. Since the problem is NP-hard, the algorithm is computationally viable only for problems of moderate size. Numerous computational tests using the generator ProGen were run to compare the performance of the proposed algorithm with the former algorithm and with the CPLEX software. The results show that the proposed version of the algorithm is competitive with the other methods and encourage further research for the development of more elaborate versions of this algorithm.
Project scheduling; Multiple modes of execution; Resource availability cost; Branch and bound algorithm
