Accession Number : ADA308475

Title :   Query Reformulation for Dynamic Information Integration.

Descriptive Note : Research rept.,

Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA MARINA DEL REY INFORMATION SCIENCES INST

Personal Author(s) : Arens, Yigal ; Knoblock, Craig A. ; Shen, Wei-Min

PDF Url : ADA308475

Report Date : JAN 1996

Pagination or Media Count : 38

Abstract : The standard approach to integrating heterogeneous information sources is to build a global schema that relates all of the information in the different sources, and to pose queries directly against it. The problem is that schema integration is usually difficult, and as soon as any of the information sources change or a new source is added, the process may have to be repeated. The SIMS system uses an alternative approach. A domain model of the application domain is created, establishing a fixed vocabulary for describing data sets in the domain. Using this language, each available information source is described. Queries to SIMS against the collection of available information sources are posed using terms from the domain model, and reformulation operators are employed to dynamically select an appropriate set of information sources and to determine how to integrate the available information to satisfy a query. This approach results in a system that is more flexible than existing ones, more easily scalable, and able to respond dynamically to newly available or unexpectedly missing information sources. This paper describes the very reformulation process in SIMS and the operators used in it. We provide precise definitions of the reformulation operators and explain the rationale behind choosing the specific ones SIMS uses. We have demonstrated the feasibility and effectiveness of this approach by applying SIMS in the domains of transportation planning and medical trauma care.

Descriptors :   *SOURCES, *INFORMATION SYSTEMS, *INTEGRATION, *SYSTEMS APPROACH, *INTERROGATION, DATA BASES, MODELS, DYNAMICS, HETEROGENEITY.

Subject Categories : Computer Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE