Write a paper in which, a two-phase genetic algorithm (GA) model is proposed to solve the resource-constrained project scheduling problem. Both time-cost trade-off and resource scheduling are considered in the proposed model. In addition to ordinary resource constraints, the two-phase GA model also allows for interruption and overlap of activities. The model has a total of four subsystems: the input subsystem, the time-cost trade-off subsystem, the resource scheduling subsystem, and the output subsystem. The time-cost trade-off subsystem takes into account the direct cost, indirect cost, and interruption cost. The resource scheduling subsystem ensures that the precedence relationships, resource constraints, and interruption/overlap conditions are met.

An example project and a real project are presented to validate the model. To obtain an optimal solution, enumeration in GA processing with different combinations of GA parameters is necessary. The example project demonstrates how the two-phase GA model handles resource constraints and interruption/overlap of activities. The effectiveness of the two-phase GA model is proved through the generation of an optimal duration which is shorter than the planned construction duration.