A new approach to solve time–cost trade-off problem with fuzzy decision variables

Time–cost trade-off problem is one of the main aspects of project scheduling. Due to variations in the real world, usually, risks in estimation of project parameters are considerably high. Therefore, use of uncertain models, which is capable of formulating vagueness in the real world, to solve time–cost trade-off problems, gives a scheduling with more stability against environmental variations. On the other hand, crisp decision making in uncertain environment causes loss of some parts of information. This paper presents a new optimal model for time–cost trade-off problem in a fuzzy environment. In order to solve this problem, a new solution method for possibility goal programming problems is developed. The significant feature of this model is the determination of optimal duration for each activity in the form of triangular fuzzy numbers. To validate the algorithm developed here, a case study will be presented.