Towards a type-2 fuzzy description logic for semantic search engine

Classical description logics are limited in dealing with the crisp concepts and relationships, which makes it difficult to represent and process imprecise information in real applications. In this paper we present a type-2 fuzzy version of ALC and describe its syntax, semantics and reasoning algorithms, as well as the implementation of the logic with type-2 fuzzy OWL. Comparing with type-1 fuzzy ALC, system based on type-2 fuzzy ALC can define imprecise knowledge more exactly by using membership degree interval. To evaluate the ability of type-2 fuzzy ALC for handling vague information, we apply it to semantic search engine for building the fuzzy ontology and carry out the experiments through comparing with other search schemes. The experimental results show that the type-2 fuzzy ALC based system can increase the number of relevant hits and improve the precision of semantic search engine.