Knowledge and common knowledge in a distributed environment
Journal of the ACM (JACM)
Sound and efficient closed-world reasoning for planning
Artificial Intelligence
Query containment for data integration systems
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Tableau Techniques for Querying Information Sources through Global Schemas
ICDT '99 Proceedings of the 7th International Conference on Database Theory
Description Logics for Information Integration
Computational Logic: Logic Programming and Beyond, Essays in Honour of Robert A. Kowalski, Part II
Efficient Reasoning Using the Local Closed-World Assumption
AIMSA '00 Proceedings of the 9th International Conference on Artificial Intelligence: Methodology, Systems, and Applications
Knowledge representation for information integration
Information Systems - Special issue on web data integration
Completeness of integrated information sources
Information Systems - Special issue: Data quality in cooperative information systems
Approximate query answering in locally closed databases
AAAI'07 Proceedings of the 22nd national conference on Artificial intelligence - Volume 1
Towards a logical reconstruction of a theory for locally closed databases
ACM Transactions on Database Systems (TODS)
Logic in databases: report on the LID 2008 workshop
ACM SIGMOD Record
Representation of partial knowledge and query answering in locally complete databases
LPAR'06 Proceedings of the 13th international conference on Logic for Programming, Artificial Intelligence, and Reasoning
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The Closed-World Assumption (CWA) on a database expresses that an atom not in the database is false. The CWA is only applicable in domains where the database has complete knowledge. In many cases, for example in the context of distributed databases, a data source has only complete knowledge about part of the domain of discourse. In this paper, we introduce an expressive and intuitively appealing method of representing a local closed-world assumption (LCWA) of autonomous data-sources. This approach distinguishes between the data that is conveyed by a data-source and the meta-knowledge about the area in which these data is complete. The data is stored in a relational database that can be queried in the standard way, whereas the meta-knowledge about its completeness is expressed by a first order theory that can be processed by an independent reasoning system (for example a mediator). We consider different ways of representing our approach, relate it to other methods of representing local closed-word assumptions of data-sources, and show some useful properties of our framework which facilitate its application in real-life systems.