Approximations of Concept Based on Multielement Bounds

• Published in: Database and Expert Systems Applications pp. 676 - 685
• Main Authors: Lu, Jianjiang, Xu, Baowen, Kang, Dazhou, Li, Yanhui, Wang, Peng
• Format: Book Chapter Conference Proceeding
• Language: English
• Published: Berlin, Heidelberg Springer Berlin Heidelberg 2005; Springer
• Series: Lecture Notes in Computer Science
• Subjects: Applied sciences; Artificial intelligence; Computer science; control theory; systems; Concept Query; Exact sciences and technology; Information Item; Information Retrieval; Information Source; Information systems. Data bases; Lower Approximation; Memory organisation. Data processing; Software; Lower bound; Filtering; Database query; Ontology; Information system; Information retrieval; Information extraction; Heterogeneity; Upper bound; Disjunction; Information source; World wide web; Database; Internet; Artificial intelligence
• ISBN: 3540285660; 9783540285663
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/11546924_66

Ontology-based information system can increase the precise and recall of information retrieval and filtering on the Web but faces the problem of Ontology heterogeneity. The approximate information filtering approach rewrites queries with their approximations to suit specific ontology-based information sources. The core of the approach is to find approximations of concepts. The current methods find least upper bounds and greatest lower bounds of a concept and then use them to get upper and lower approximations of the concept. However, they consider the bounds only containing separate concepts, so the quality of approximations is not very acceptable. This paper defines multielement least upper bounds and multielement greatest lower bounds that contain not only separate concepts but also disjunctions or conjunctions of concepts. It can be proved that the approximations based on them can be better approximations of concepts than the current methods.