1. Introduction
Decision Support System (DSS) [1] is an information system that participates and supports the decision-making process of human beings. Through a series of human-machine conversations, it can provide a variety of dependable programs and check the decision-makers' requirements and assumptions, thus achieving the aim of supporting decision-making. Until now, people have not reached an agreement upon the definition of DSS. Generally speaking, it is an interactive computer information system that can help decision-makers make use of data and models and solve the problem of non-structures. It makes full use of suitable computer techniques and through the interactive human-machine model, helps and enhances the effectiveness of decision-making about semi-structures and non-structures.