Abstract:

This thesis exposes the ranking limitation of score functions by exploring the connotation of score functions of Vague sets and appraising the strength and weakness of various existing score functions. Through an exhaustive enquiry into the connotation of the undefined and unascertained information of Vague value as well as an expected definition of Vague value, a new category of score function is to be contrived, which correlates various Vague value with a certain value of the Fuzzy set. When there is an equal score function value, a second ranking is to be executed with definite information. It has been confirmed by examples that this approach renders it feasible to produce an outcome which matches reality cognition and the Vague value which corresponds various score function values can present a reasonable evaluation.