a hybrid method based on fuzzy ahp and vikor for the discrete time-cost-quality trade-off problem

time, cost and quality are considered as the main components in managing each project. previous researches have mainly focused on the time-cost trade-off problems. recently quality is considered as the most important factor in project�s success, which is influenced by time acceleration that is the less time is spent the more success is gained. in time-cost-quality trade-off problems, each activity can be done in various execution modes and determination of these execution modes is seen as to minimize the project time and cost and maximize its quality .in this paper, three integer programming models are provided and one of the main objectives is optimized in each model by assigning the proper bound to other objectives. following the non-dominated solutions obtained by solving models, and by means of hybrid approach of fuzzy ahp strategy and vikor method regarded as multi-criteria decision making methods, the best possible alternative (from among non-dominated solutions) has been suggested.fuzzy ahp method has been used to determine the importance rate of each objective. in this method linguistic variables were used which take us closer to reality. at the end, with applying these weights in vikor method, the best possible alternatives (among non-dominated solutions) were found. using this hybrid approach can help managers, to a great extent, in selecting the appropriate solution so that maximum desirability is obtained due to the importance rate of the objective functions from the viewpoint of decision maker.