en Optimal design Optimal design پژوهشي Research <font size="2">In this paper, an efficient multi-objective model is proposed to solve time-cost trade off problem considering cash flows. The proposed multi-objective meta-heuristic is based on Ant colony optimization and is called Non Dominated Archiving Ant Colony Optimization (NAACO). The significant feature of this work is consideration of uncertainties in time, cost and more importantly interest rate. A fuzzy approach is adopted to account for uncertainties. Mathematics of cash-flow analysis in a fuzzy environment is described. A case study is done using the proposed approach </font> Multi-objective optimization; time-cost trade off; cash-flow analysis; naaco; uncertainty; fuzzy sets theory 557 570 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-1-38&slc_lang=en&sid=1 A. Afshar 18003194753284600334 18003194753284600334 Yes E. Kalhor 18003194753284600335 18003194753284600335 No