I. Introduction
As we know, numerous optimization problems in scientific research and engineering are multi-objective optimization problems. It has been proved that the Evolutionary Algorithm (EA) is a powerful solution to this kind of problems. The underlying reasons are, firstly, the EA uses chromosome-based populations, and allows the generation of several members of the Pareto optimal set in a single run. Secondly, the EA is less susceptible to the shape or continuity of the Pareto front. Schaffer applied the EA to deal with multi-objective optimization problems in 1984[1]. During the past decade, a lot of similar methods have also been proposed, and the Multi-Objective Evolutionary Algorithm (MOEA) becomes a typical approach.