Abstract: The time-cost trade-off based on the strategic orientation is one of the most crucial aspects of enterprise project portfolio planning that plays a key role in enterprise resources benefit maximization, which in fact is a multi-objective optimization problem. A new evolutionary algorithm-ant colony optimization (ACO) algorithm is employed to solve the time-cost trade-off problem. According to the ant colony algorithm existing precocious, stagnation, local optimal shortcomings, adopting certainty and uncertainty search rules and combining with chaos, an improved ant colony algorithm is proposed. Experimental results indicate that join chaos and search rules, the developed ACO can effectively improve global optimization ability, can draw better results in solving time-cost trade-off of project portfolio.

Key words: time-cost trade-off, ant colony algorithm, project portfolio