The main advantage of the weighted sum approach is a straightforward implementation. Since a single objective is used in fitness assignment, a single objective GA can be used with minimum modifications. In addition, this approach is computationally efficient. The main disadvantage of this approach is that not all Pareto-optimal solutions can be investigated when the true Pareto front is non-convex. Therefore, multi-objective GA based on the weighed sum approach have difficulty in finding solutions uniformly distributed over a non-convex tradeoff surface [1].