Vague ALC(D):a Fuzzy Description Logic Based on Vague Sets

The ordinary fuzzy description logic with a single membership degree is unable to represent imprecise knowledge but describes knowledge at an abstract level,thus lacking powerful means to express the numerical information on physical substances.A fuzzy description logic based on vague sets and combined with concrete domain,named vague ALC(D),is therefore proposed,where the vague sets are employed to represent fuzzy knowledge by membership degree intervals.The syntax,semantics and inference rules of vague ALC(D) are given,as well as the relevant tableaux algorithm that is developed for reasoning in the vague ALC(D).The vague ALC(D) enables the representation and inference of fuzzy knowledge including numerical information to be more accurate,thus enhancing its expressability and reasonability in fuzzy description logic.