A New MBS Representation for Resource-Constrained Project Scheduling Problems

In this paper, a new moving block sequence (MBS) representation for resource-constrained project scheduling problems (RCPSPs) is proposed, which is different from the classical activity list that has been widely used for RCPSPs. An activity in a project of RCPSPs has fixed duration and resource demands, thus, it can be modeled as a rectangle block whose height represents the resource demands and width the duration. Therefore, by modeling every activity in a project as a block, a project that consists of N activities can be represented as a permutation of N blocks that satisfy the precedence constraints. Then, for every activity in the project, four initial positions and corresponding move modes are designed, by using which activities can be moved from their initial positions to the appropriate locations that minimize the makespan of the project without violating the precedence and resource constraints. Based on this newly designed MBS representation, the multi-agent evolutionary algorithm (MAEA) is used for solving RCPSPs. The comparison with 16 existing state-of-the-art algorithms on benchmark J30 test set, which contains 480 instances in total, shows that the proposed algorithm is competitive in solving RCPSPs.