Lehigh University

SWAT abstracts 2003

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Guo, Y.; Heflin, J; and Pan, Z. Benchmarking DAML+OIL Repositories. Second International Semantic Web Conference, ISWC 2003, LNCS 2870. Springer, 2003, pp. 613-627

We present a benchmark that facilitates the evaluation of DAML+OIL repositories in a standard and systematic way. This benchmark is intended to evaluate the performance of DAML+OIL repositories with respect to extensional queries over a large data set that commits to a single realistic ontology. It consists of the ontology, customizable synthetic data, a set of test queries, and several performance metrics. Main features of the benchmark include simulated data for the university domain, a repeatable data set that can be scaled to an arbitrary size, and an approach for measuring the degree to which a repository returns complete query answers. We also show a benchmark experiment for the evaluation of DLDB, a DAML+OIL repository that extends a relational database management system with description logic inference capabilities.

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Pan, Z and Heflin, J. DLDB: Extending Relational Databases to Support Semantic Web Queries. In Workshop on Practical and Scaleable Semantic Web Systems, ISWC 2003, pp. 109-113.

We present DLDB, a knowledge base system that extends a relational database management system with additional capabilities for DAML+OIL inference. We discuss a number of database schemas that can be used to store RDF data and discuss the tradeoffs of each. Then we describe how we extend our design to support DAML+OIL entailments. The most significant aspect of our approach is the use of a description logic reasoner to precompute the subsumption hierarchy. We describe a lightweight implementation that makes use of a common RDBMS (MS Access) and the FaCT description logic reasoner. Surprisingly, this simple approach provides good results for extensional queries over a large set of DAML+OIL data that commits to a representa-tive ontology of moderate complexity. As such, we expect such systems to be adequate for personal or small-business usage.



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Kogut, P. and Heflin, J. Semantic Web Technologies for Aerospace. IEEE Aerospace Conference, March 2003, Big Sky, MT.

Emerging Semantic Web technology such as the DARPA Agent Markup Language (DAML) will support advanced semantic interoperability in the next generation of aerospace architectures. The basic idea of DAML is to mark up artifacts (e.g., documents, sensors, databases, legacy software) so that software agents can interpret and reason with the information. DAML will support the representation of ontologies (which include taxonomies of terms and semantic relations) via extensions to XML. XML alone is not sufficient for agents because it provides only syntactic interoperability that depends on implicit semantic agreements. DAML is the official starting point for the Web Ontology Language, an emerging standard from the World Wide Web Consortium. This paper will cover promising aerospace applications and significant challenges for Semantic Web technologies. Potential applications include higher-level information fusion, collaboration in both operational and engineering environments and rapid systems integration. The challenges that will be discussed include the complexity of ontology development, automation of markup, semantic mismatch between current object-oriented models and Semantic Web ontologies, scalability issues related to reasoning with large knowledge bases and technology transition issues. The paper will explain ongoing research that is focused on addressing these challenges.
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Heflin, J., Hendler, J., and Luke, S. SHOE: A Blueprint for the Semantic Web. In Fensel, D., Hendler, J., Lieberman, H., and Wahlster, W. (Eds.), Spinning the Semantic Web. MIT Press, Cambridge, MA, 2003.

The term Semantic Web was coined by Tim Berners-Lee to describe his proposal for "a web of meaning," as opposed to the "web of links" that currently exists on the Internet. To achieve this vision, we need to develop languages and tools that enable machine understandable web pages. The SHOE project, begun in 1995, was one of the first efforts to explore these issues. In this paper, we describe our experiences developing and using the SHOE language. We begin by describing the unique features of the World Wide Web and how they must influence potential Semantic Web languages. Then we present SHOE, a language which allows web pages to be annotated with semantics, describe its syntax and semantics, and discuss our approaches to handling the problems of interoperability in distributed environments and ontology evolution. Finally, we provide an overview of a suite of tools for the Semantic Web, and discuss the application of the language and tools to two different domains.




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