en عمومى General پژوهشي Research <br> <div dir="ltr"></div> <span style="font-size:11pt"><span style="line-height:normal"><span style="unicode-bidi:embed"><span sans-serif="" style="font-family:Calibri,"><span style="font-size:12.0pt"><span new="" roman="" style="font-family:" times="">Nowadays, the project scheduling problem is one of the most common issues in project control and planning, especially the time-cost trade-off problem. In this paper, a bi-objective problem is presented to minimize the cost and makespan simultaneously. Besides the common constraints in literature, it is assumed some renewable resources are hired. Each of them has a specific access time and deadline; they cannot be used before the access time but can be used after the deadline due to the cost of delay penalty. The project costs consist of direct costs, indirect costs, and tardiness penalty cost of renewable resources. Because of the uncertainty, the project times are considered as fuzzy numbers. Due to the NP-Hard nature of these problems, the Tabu search algorithm is used to solve them. The results are also compared with the genetic algorithm to check the quality of answers.</span></span><span style="font-family:"Times New Roman","serif""></span></span></span></span></span> Project Scheduling, Time-Cost Trade-Off, Tardiness Penalty Cost of Renewable Resources, Genetic Algorithm (GA), Tabu Search (TS) Algorithm 21 32 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-491-3&slc_lang=en&sid=1 R. Sadeghian ramin_sadeghian@yahoo.com 10031947532846001736 10031947532846001736 Yes Associate Professor at Department of Industrial Engineering, Payame Noor University, PO BOX 19395-3697, Tehran, Iran