Incorporating Generalized Quantifiers into Description Logic to Improve Source Selection
35 Pages Posted: 2 Oct 2001
Date Written: June 2001
Source selection allows the users to express what they want while the system automatically performs the identification and selection of relevant sources to answer the query request. To automate that process, the system must be able to represent the contents of data sources in a description language. Descriptions of source contents can be characterized by the two concepts of scope and size. This paper builds upon and extends the concept language, description logic (DL), to propose a novel representation system to achieve that goal. We point out that there are technical barriers within description logic limiting the types of data sources that can be represented. Specifically, we show that (1) DL is awkward in representing sufficient conditions, and (2) DL can describe properties of a concept itself only in the case of existential quantification. These barriers limit expressions of size information in source descriptions and thus cause us to extend DL with the notion of generalized quantifiers to make them inter-operable with traditional logic. The proposed formalism integrates the nice features of generalized quantifiers into description logic, and hence achieves more expressive power than previous representation systems based purely on description logic. It is also shown that the proposed language preserves those mathematical properties that traditional logic-based formalisms are known to hold.
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