Jeff Heflin

Contact Info:

Courses:

Here are the courses I am currently teaching or have taught recently. For a complete list of the courses I have taught, click here

• Fall 2009
  • CSE 431: Intelligent Agents, TTh 1:10-2:25pm, room TBD
  • CSE 262: Programming Languages, MWF 10:10-11am, Christmas-Saucon 303
• Spring 2009
  • CSE 327: Artificial Intelligence Theory and Practice, MWF 10:10-11am, Maginnes 111
• Fall 2008
  • CSE 262: Programming Languages
  • CSE 428: Semantic Web Topics
• Spring 2008
  • CSE 327: Artificial Intelligence Theory and Practice
• Fall 2007
  • CSE 431: Intelligent Agents
  • CSE 262: Programming Languages

Research:

The Semantic Web and Agent Technologies (SWAT) Lab

The Semantic Web is a vision for extending the Web so that machines can more intelligently integrate and process the wealth of information that is available. Unlike HTML and ordinary XML, Semantic Web languages such as SHOE, DAML+OIL, and OWL (a W3C Recommendation), allow semantics (i.e., meaning) to be explicitly associated with the content. The semantics are formally specified in ontologies, which can be shared via the Internet and extended for local needs. The SWAT lab is at the forefront of Semantic Web research by studying issues such as interoperability of distributed ontologies, ontology evolution, and system architectures and tools for the Semantic Web. See the group's homepage for details.

Selected Publications:

Y. Guo and J. Heflin. Document-Centric Query Answering for the Semantic Web. 2007 IEEE/WIC/ACM International Conference on Web Intelligence (WI '07), pp. 409-415, 2007.

This paper presents an approach to querying the Semantic Web that considers the document-oriented nature of Semantic Web data. It defines queries in which one can ask what is entailed by a given subset of the documents in the knowledge base as well as queries in which one asks for which documents entail specificanswers. It provides algorithms for solving theses problems and describes an experiment in which many of the queries can be answered in miliseconds.

Z. Pan, A. Qasem, J. Heflin. An Investigation into the Feasibility of the Semantic Web. In Proc. of the Twenty First National Conference on Artificial Intelligence (AAAI 2006), Boston, USA, 2006. pp. 1394-1399.

This is the first paper to discuss our attempts to realize the vision of the Semantic Web as a Web-scale query-answering system. We loaded nearly 350,000 real-world semantic web documents that committed to 41,000 ontologies into our DLDB system and then used additional "mapping ontologies" to integrate them. This experiment yielded promising results in that query times ranged from a few milliseconds to 5 seconds.

Y. Guo, Z. Pan, and J. Heflin. LUBM: A Benchmark for OWL Knowledge Base Systems. Journal of Web Semantics 3(2), 2005, pp158-182.

This is the definitive reference on the Lehigh University Benchmark (LUBM) and on empirical evaluation of Semantic Web knowledge base systems in general. This journal article coalesces the results from the ISWC 2003 and ISWC 2004 papers. In addition, it includes a discussion of preliminary tests on Jena and SPARQL versions of the benchmark queries.

Y. Guo, Z. Pan, and J. Heflin. An Evaluation of Knowledge Base Systems for Large OWL Datasets. Third International Semantic Web Conference, Hiroshima, Japan, LNCS 3298, Springer, 2004, pp. 274-288.

This paper, which won the Best Paper Award at ISWC 2004, is the first comprehensive experiment to compare different Semantic Web reasoners. Using our Lehigh University Benchmark (LUBM), we analyze the performance of Sesame (both a memory-based and data-based versions), OWL Jess KB and DLDB on different sizes of OWL datasets.

J. Heflin and Z. Pan. A Model Theoretic Semantics for Ontology Versioning. Third International Semantic Web Conference, Hiroshima, Japan, LNCS 3298 Springer, 2004, pp. 62-76.

This paper discusses the crucial problems that occur when distributed ontologies evolve over time. It provides a formal semantics for ontology perspective theory, which is our recommended solution to the problem.

Recent Service Activities:

• Journal of Web Semantics, Editorial board.
• International Journal on Semantic Web and Information Systems, Special Issue on Scalability and Performance of Semantic Web Systems, Guest Editor.
• Eighteenth International World Wide Web Conference (WWW 2009), Semantic Data/Web track, Program committee.
• Twenty-First International Conference on Artificial Intelligence (IJCAI-09), Program committee
• The 4th International Workshop on Scalable Semantic Web Knowledge Base Systems (SSWS2008), Organizing committee.
• Eighth International Semantic Web Conference (ISWC 2009), Workshop Co-Chair, Program committee
• Third IEEE International Conference on Semantic Computing (ICSC 2009), Technical Program Co-Chair
• 2009 Japan-America Frontiers of Engineering, State-of-the-art Technologies for Knowledge Management Session, Co-chair.

Education:

• Ph.D. in Computer Science, University of Maryland, 2001.
• M.S. in Computer Science, University of Maryland, 1999.
• B.S. in Computer Science, The College of William and Mary, 1992.

Memberships:

• American Association for Artificial Intelligence (1998 - present)
• Phi Beta Kappa, Alpha of Virginia Chapter (inducted 1992)
• Sigma Xi, The Scientific Research Society (inducted 2007)
• Web-Ontology Working Group (2001 - 2004)

Information for Prospective Graduate Students:

• Please do not send me e-mail asking me to evaluate your chances of admission to the department. I typically do not respond to such requests.
• If you are interested in joining my research group, then send me an e-mail that specifically describes what you would like to do and what prior qualifications you have. However, I recommend that you read some of my publications and explore our current research first. If I think your interests match our research, then I will contact you for further information.

Semantic Web Resources:

• Semantic Web Activity at W3C
  The World Wide Web Consortium's collection of specifications, working groups, and resources related to the Semantic Web.
• SemanticWeb.org
  A Semantic Wiki for the Semantic Web community. Includes information on tools, ontologies, people, and events.
• SemWebCentral
  A web site for non-developers to learn about the Semantic Web and for developers to share Semantic Web tools.
• The Semantic Web by Tim Berners-Lee, James Hendler, and Ora Lassila
  The Scientific American article that presents the vision of the Semantic Web.