Download presentation
Presentation is loading. Please wait.
1
Infomaster: An information Integration Tool O. M. Duschka and M. R. Genesereth Presentation by Cui Tao
2
Introduction Huge amount of information online: – Distribution: Not every query can be answered by the data in a single database Fragmentation: horizontal, vertical – Heterogeneity Notational heterogeneity: –Different access language and protocol: Parsing HTML, SQL, OQL, Z39.50 Conceptual heterogeneity: –Semantic mismatches – Instability
3
Introduction Intelligent agents – Search and find desired information – Convert formats – Translate different context – Etc… – Not feasible yet – Considerable research in ontologies and natural language understanding is required
4
Introduction Infomaster: an information integration tool – Provide integrated access – Manage evolving information sources – Add new information sources – Remove outdated information sources
5
Architecture
6
Tested Application Areas Newspaper classifieds – Provide a uniform search interface – Gather corresponding classifieds from all relevant newspapers Product catalogs – Provide terminology translation Campus databases
7
Abstraction Hierarchy
8
Descriptions of Relationships Interface relation & Site relation: in the terms of Base relation Interface relation v.s. Base relation: Interface Base
9
Descriptions of Relationships Site relation v.s. Base relation: Base Site
10
Descriptions of Relationships Site relation v.s. Base relation: Base Site
11
Query Processing Example: BMWs built in 1996 that are for sale for a Price below their average market value.
12
Reduction: Interface relations Base relations Simple: User’s query --- Interface relation --- Base relation Example rewritten query:
13
Abduction Base relations Site relations Site relations are expressed in terms of base relations, but not vice versa Query rewritten problem: answer queries using views Abduction: use a standard model elimination theorem prover
14
Abduction Base relations Site relations : The set of all descriptions of the site relations : A set of site relations : The rewritten user query after the reduction step
15
Abduction Base relations Site relations The example query plans:
16
Optimization Assume: All ads in sjmn are in sfc
17
Conclusions The first integration system: – Arbitrary positive relational algebra user queries – DB description Efficient optimization by use: – Integrity constraints – Local completeness information Flexible Use of query planning: – Expressive description language – Constraint – Background theories
18
Related Works Information Manifold project and SIMS project: – Explore the use of descriptions logics for describing information sources Occam project – Use general AI planning techniques to generate information gathering plans TSIMMIS project – Use pattern matching techniques to match user queries and predefined queries.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.