Abalfazl Zareei - Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran
Farzad Zaerpour - Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran
Roya Ekrami - Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran

A new approach is presented to solve the project scheduling problem under fuzzy environment. Two LP models are used in order to calculate the earliest and latest events times. Utilizing fuzzy activity times in the project network will change the models to fuzzy forms which by utilizing Yager's ranking method, will be transformed to crisp ones. The transformed models can be solved by conventional solution methods. In this paper, we define the events’ criticality and the relative paths’ degree of criticality. The activity’s slack times help project manager to decide according to the practical applications and manage the project efficiently. In the other hand, the proposed approach is easy to use and simple to apply. Finally, through a numerical example, the validity of proposed method is confirmed.

Fuzzy CPM, Slack times, Ranking method