Improved multi-criteria fuzzy decision-making methods based on vague set

The characteristics and inadequateness of some main present score functions in the vague set theory are analyzed, and main factors of score functions are discussed. From the perspective of risk aversion and considering the effect of uncertainty degree, a new risk aversion type score function is constructed. The character of the new score function is discussed. Based on it, two methods handling multi-criteria fuzzy decision-making problem, score function method and weighted score function method, are introduced where the attributes weights are given to the form of real numbers. According to these methods, the outcome of the programs is given to the form of real numbers and thereby the optimal program is determined. An example of risk investment shows the effectiveness of these methods.