Abstract
We deal with the extension of division operation for flexible queries in relational databases where several graded notions are involved, such as the levels of certainty, of importance, or of fulfillment of a graded property, as well as fuzzy quantifiers. We address the case where both levels of fulfillment and levels of importance are present in the specification of a requirement. Furthermore, we consider the case where a level of fulfillment may be ill-known in the available data, which is expressed by a fuzzy-valued degree. We also show that quantifiers like most can be handled by a suitable weakening of the min operation in our extension.
This paper is a revised and extended version of a paper entitled “Find the items which certainly have (most of the) important characteristics to a sufficient degree” by the same authors, prepared for the 7th World Congress of the International Fuzzy Systems Associations (IFSA’97), Prague, June 25–29, 1997 (Proceedings published by Academia, Praha, Vol. 2, pp. 243–248).
Visiting scholar at IRIT, on leave from Information Science Department, Chiba-Keizai College, Japan.
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Dubois, D., Nakata, M., Prade, H. (2000). Extended Divisions for Flexible Queries in Relational Databases. In: Pons, O., Vila, M.A., Kacprzyk, J. (eds) Knowledge Management in Fuzzy Databases. Studies in Fuzziness and Soft Computing, vol 39. Physica, Heidelberg. https://doi.org/10.1007/978-3-7908-1865-9_6
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DOI: https://doi.org/10.1007/978-3-7908-1865-9_6
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