Modeling Time-Cost Trade-Off Problem with Fuzzy Activity Duration Times

The time-cost trade-off problem is a type of the project scheduling problem which studies how to modify project activities so as to achieve the trade-off between the project cost and the completion time. In real projects, the trade-off between project cost and project completion time, and the uncertainty of the environment are both considerable aspects for decision-makers. In this paper, an expected value model for the fuzzy time-cost trade-off problem is proposed, in which credibility theory is applied to describe the uncertainty of activity duration times. A searching method as a hybrid intelligent algorithm integrating fuzzy simulation and genetic algorithm is produced to search the optimal schedules.