Fatemeh Fathallahi - M.Sc. Student, Department of Industrial Engineering, K.N. Toosi University of Technology, Tehran, Iran
Amir Abbas Najafi - Assistant Professor, Department of Industrial Engineering, K.N. Toosi University of Technology,Tehran, Iran
Amirhossein vaeztehrani - M.Sc. Student, Department of Industrial Engineering, Sharif University of Technology, Tehran, Iran

Project scheduling is one of the most important aspects of project planning and management. In real world project scheduling is confronted with a lot of uncertainties and imprecise. To cope with these uncertainties and lack of information, implementing fuzzy sets can be sufficient. In this paper we consider fully fuzzy project scheduling problem with discounted cash flows. The duration of activity, the cash flows of each activity and the interest rate are assumed to be triangular fuzzy numbers. Two objective functions which are to maximize the net present value (NPV) of the project and to minimize the project duration are considered. The method of LP-Metric as a technique of multi objective decision making (MODM) and fuzzy mathematical programming are used to transform the fully fuzzy multi objective model to a crisp model. Finally Taylor expansion is used to transform the nonlinear objective function to linear one for solving the problem and an example is considered for better explanation.

Fuzzy project scheduling- Fuzzy discounted cash flow- Net present value- Makespan