Many complex real world objects can be easily modeled using set-valued attributes. Such attributes appear in several application domains, e.g., in retail databases they can represent the set of products purchased by a customer, in multimedia databases they can be used to represent the set of objects contained in an image, in web server logs they correspond to web pages and links visited by a user. Finally, in data mining applications set-valued attributes are commonly used to store time-series and market basket data. Contemporary database systems allow storing set-valued attributes in the database (e.g., as nested tables or user-defined types), but they don't provide either language primitives or indexes to process and query such attributes. On the other hand, the ability to efficiently perform set-oriented queries in large data volumes could greatly enhance many above mentioned applications and is impatiently anticipated by many potential users. The talk will present the concept of a new index structure, called hierarchical bitmap index, supporting different classes of set-oriented queries, including subset, superset and similarity queries. First, set retrieval problem will be stated and different classes of set-oriented queries will be presented. Then, the talk will present the logical structure of the index and algorithms for performing set-oriented queries using the index. Finally, the talk will present an example of applying the index to support multilevel association rules discovery.
Tadeusz Morzy received his M. Sc., Ph. D. and Polish Habilitation from the Technical University of Poznań, Poland. Currently, he is professor of computer science at the Institute of Computing Science of the Technical University of Poznań. He has held visiting positions at the Loyola University, New Orleans in USA, Klagenfurt University in Austria, University La Sapienza in Italy, Free University Amsterdam, and the Polish-Japanese Institute of Information Technology, Warsaw, Poland. He has authored and coauthored over 90 papers on databases, data mining, and data warehousing. He is co-author of a book on "Concurrency Control in Distributed Database Systems" by North-Holland, and editor and coauthor of “Handbook on Data Management” by Springer. He served as General Chair of the 2nd ADBIS Conference (1998), and has served/serves has on numerous program committees of international conferences and workshops. His research interests include data mining, data warehousing, transaction processing in database and data warehouse systems, access methods and query processing for databases, database optimization and performance evaluation.
Sprecher: Prof. Tadeusz Morzy Wann: Montag, 4. Juli 2005, 14:00 Uhr (s.t.) Wo: E.2.69, Universität Klagenfurt