Olaf Hartig

Research Interests

1. Processing Queries over the Web of Linked Data
2. Data Quality and Trustworthiness of Linked Data
3. Web Data Provenance
4. Query Processing for RDF Knowledge Bases
5. Privacy Issues in the Semantic Web
6. Application of Semantic Technologies in Software Engineering

Current Projects

1. SQUIN (A Link Traversal Based Query System for the Web of Linked Data)
2. Web of Trusted Data
3. The Provenance Vocabulary

Closed Projects

1. DESWAP (Development Environment for Semantic Web APplications).

Publikationen

2012

• Query Prediction with Context Models for Populating Personal Linked Data Caches
  Olaf Hartig, Tom Heath
  Proceedings of the Poster Session at the 23rd ACM Conference on Hypertext and Social Media, Milwaukee, WI, USA, 2012/06 (pdf)

• Foundations of Traversal Based Query Execution over Linked Data
  Olaf Hartig, Johann-Christoph Freytag
  Proceedings of the 23rd ACM Conference on Hypertext and Social Media (HT), Semantic Data Track, Milwaukee, WI, USA, 2012/06 (pdf)

• SPARQL for a Web of Linked Data: Semantics and Computability
  Olaf Hartig
  Proceedings of the 9th Extended Semantic Web Conference (ESWC), Heraklion, Greece, 2012/05 (pdf)

• Populating Personal Linked Data Caches using Context Models
  Olaf Hartig, Tom Heath
  Proceedings of the Poster Session at the 21th International World Wide Web Conference (WWW), Lyon, France, 2012/04 (pdf)

• Towards Interoperable Provenance Publication on the Linked Data Web
  Jun Zhao, Olaf Hartig
  Proceedings of the 5th Linked Data on the Web (LDOW) Workshop at the World Wide Web Conference (WWW), Lyon, France, 2012/04 (pdf)

2011

• Zero-Knowledge Query Planning for an Iterator Implementation of Link Traversal Based Query Execution
  Olaf Hartig
  Proceedings of the 8th Extended Semantic Web Conference (ESWC), Heraklion, Greece, 2011/06 (pdf)

• A Main Memory Index Structure to Query Linked Data
  Olaf Hartig and Frank Huber
  Proceedings of the 4th Linked Data on the Web (LDOW) Workshop at the World Wide Web Conference (WWW), Hyderabad, India, 2011/03 (pdf)

• How Caching Improves Efficiency and Result Completeness for Querying Linked Data
  Olaf Hartig
  Proceedings of the 4th Linked Data on the Web (LDOW) Workshop at the World Wide Web Conference (WWW), Hyderabad, India, 2011/03 (pdf)

2010

• A Database Perspective on Consuming Linked Data on the Web
  Olaf Hartig, Andreas Langegger
  Datenbankspektrum, Semantic Web Special Issue, 2010/09 (link)

• Integrating Provenance into the Web of Data
  Olaf Hartig, Jun Zhao
  Proceedings of the Poster Session at the 7th Extended Semantic Web Conference (ESWC), Heraklion, Greece, 2010/06 (pdf)

• Towards a Data-Centric Notion of Trust in the Semantic Web (A Position Statement)
  Olaf Hartig
  Proceedings of the 2nd Workshop on Trust and Privacy on the Social and Semantic Web (SPOT) at the 7th Extended Semantic Web Conference (ESWC), Herakli, 2010/06 (pdf)

• Publishing and Consuming Provenance Metadata on the Web of Linked Data
  Olaf Hartig, Jun Zhao
  Proceedings of the 3rd International Provenance and Annotation Workshop (IPAW), Troy, New York, USA, 2010/06 (pdf)

2009

• Executing SPARQL Queries over the Web of Linked Data (Abstract)
  Olaf Hartig, Christian Bizer, Johann-Christoph Freytag
  Proceedings of the 8th International Semantic Web Conference (ISWC'09), Washington, DC, USA, 2009/10 (pdf)

• Using Web Data Provenance for Quality Assessment
  Olaf Hartig, Jun Zhao
  Proceedings of the 1st International Workshop on the Role of Semantic Web in Provenance Management (SWPM) at the International Semantic Web Conference, 2009/10 (pdf)

• Querying Trust in RDF Data with tSPARQL (Abstract)
  Olaf Hartig
  Proceedings of the 6th European Semantic Web Conference (ESWC), Heraklion, Greece; (Best Paper Award), 2009/06 (pdf)

• Linked Data for Building a Map of Researchers (Scripting Challenge Submission)
  Olaf Hartig, Hannes Mühleisen, Johann-Christoph Freytag
  Proceedings of the 5th Workshop on Scripting for the Semantic Web (SFSW) at the European Semantic Web Conference (ESWC), Heraklion, Greece, 2009/06 (pdf)

• Provenance Information in the Web of Data
  Olaf Hartig
  Proceedings of the Linked Data on the Web (LDOW'09) Workshop at the World Wide Web Conference (WWW), Madrid, Spain, 2009/04 (pdf)

2008

• Designing Component-Based Semantic Web Applications with DESWAP
  Olaf Hartig, Martin Kost, Johann-Christoph Freytag
  Proceedings of the Poster and Demonstration Session at the 7th International Semantic Web Conference (ISWC'08), Karlsruhe, Germany, 2008/10 (pdf)

• Automatic Component Selection with Semantic Technologies
  Olaf Hartig, Martin Kost, Johann-Christoph Freytag
  Proceedings of the 4th International Workshop on Semantic Web Enabled Software Engineering (SWESE) at ISWC, Karlsruhe, Germany, 2008/10 (pdf)

• Trustworthiness of Data on the Web
  Olaf Hartig
  Proceedings of the STI Berlin & CSW PhD Workshop, Berlin, Germany, 2008/09 (pdf)

2007

• The SPARQL Query Graph Model for Query Optimization (Abstract)
  Olaf Hartig, Ralf Heese
  Proceedings of the 4th European Semantic Web Conference, Autria, 2007/06

Student Advisor

1. "Quality Characteristics of Linked Data Publishing Datasources" (Diploma Thesis) Annika Flemming, completed
2. "Provenance-Based Trust Assessment of Web Data" (Diploma Thesis) Thomas Riegmann, completed
3. "Caching for Link Traversal Based Query Execution in the Web of Linked Data" (Diploma Thesis) Jan Wehrs, completed
4. "Efficient Management of Trust Ratings for Web Data" (Semester Thesis) Robert Nagel, completed
5. "Trustworthiness of Collaboratively Created Statements in Semantic Web Applications" (Diploma Thesis) Heiko Müller, completed
6. "Visualization of OWL-S Process Models" (Semester Thesis) Hermann Schwarz, completed
7. "Intelligent Search for Software and Supported Functionalities in DESWAP" (Master Thesis) Carmen Garcia Valero, completed

Program Committees

• 12th International Conference on Web Engineering (ICWE), July 2012, Berlin, Germany
• 1st Workshop on Methods for Establishing Trust with Open Data (METHOD), July 2012, Izmir, Turkey
• 4th International Provenance and Annotation Workshop (IPAW), June 2012, Santa Barbara, California, USA
• 9th Extended Semantic Web Conference (ESWC), May 2012, Heraklion, Griechenland
• 3rd International Workshop on the Role of Semantic Web in Provenance Management (SWPM), May 2012, Heraklion, Griechenland
• 5th Linked Data on the Web Workshop (LDOW), April 2012, Lyon, France
• 21th International World Wide Web Conference (WWW), April 2012, Lyon, France
• 16th International Conference on Information Quality (ICIQ), November 2011, Adelaide, Australia
• 4th Social Data on the Web Workshop (SDoW), October 2011, Bonn, Germany
• 7th International Conference on Semantic Systems (I-Semantics), September 2011, Graz, Austria
• 2nd International Workshop on Traceability and Compliance of Semi-Structured Processes (TC4SP), August 2011, Clermont-Ferrand, France
• 22nd International Joint Conference on Artificial Intelligence (IJCAI), July 2011, Barcelona, Spain
• 11h International Conference on Web Engineering (ICWE), June 2011, Paphos, Cyprus   (Best Review Award winner)
• 8th Extended Semantic Web Conference (ESWC), Linked Open Data Track, Juni 2011, Heraklion, Griechenland
• 4th Linked Data on the Web Workshop (LDOW), March 2011, Hyderabad, India
• IUI Workshop on Context-aware Retrieval and Recommendation (CaRR), February 2011, Palo Alto, USA
• 9th International Semantic Web Conference (ISWC), Poster and Demo track, November 2010, Shanghai, China
• 3rd Social Data on the Web Workshop (SDoW), November 2010, Shanghai, China
• 2nd International Workshop on the Role of Semantic Web in Provenance Management (SWPM), November 2010, Shanghai, China
• 15th International Conference on Information Quality (ICIQ), November 2010, Little Rock, Arkansas, USA
• 1st International Workshop on Traceability and Compliance of Semi-Structured Processes (TC4SP), September 2010, Hoboken, NJ, USA
• Triplification Challenge 2010 at I-Semantics, September 2010, Graz, Austria
• 6th International Conference on Semantic Systems (I-Semantics), September 2010, Graz, Austria
• 2nd Conference on Semantic Technology and Knowledge Engineering (STAKE), July 2010, Kuching, Sarawak, Malaysia
• 3rd International Provenance and Annotation Workshop (IPAW), June 2010, Troy, New York, USA
• 7th Extended Semantic Web Conference (ESWC), In Use Track, June 2010, Heraklion, Greece
• 2nd Workshop on Trust and Privacy on the Social and Semantic Web (SPOT), June 2010, Heraklion, Greece
• 3rd Linked Data on the Web Workshop (LDOW), April 2010, Raleigh, North Carolina, USA
• 2nd Social Data on the Web Workshop (SDoW), October 2009, Washington DC, USA
• 5th International Conference on Semantic Systems (i-Semantics), September 2009, Graz, Austria
• 2nd Linked Data on the Web Workshop (LDOW), April 2009, Madrid, Spain

Additional Activities

• Invited Expert in the W3C Provenance Working Group
• Invited Expert in the W3C Provenance Incubator Group
• Organizer of the "3rd International Workshop on Consuming Linked Data (COLD)" at the 11th International Semantic Web Conference (ISWC), November 2012, Boston, USA
• Organizer of the "2nd Linked Data-a-thon" at the 10th International Semantic Web Conference (ISWC), October 2011, Bonn, Germany
• Organizer of the "2nd International Workshop on Consuming Linked Data (COLD)" at the 10th International Semantic Web Conference (ISWC), October 2011, Bonn, Germany
• Organizer of the "1st International Workshop on Consuming Linked Data (COLD)" at the 9th International Semantic Web Conference (ISWC), November 2010, Shanghai, China
• Lecturer at the Indian-Summer School on Linked Data, September 2011, Leipzig, Germany
• Presenter of the tutorial "An Introduction to SPARQL and Queries over Linked Data" at the 12th International Conference on Web Engineering (ICWE), July 2012, Berlin, Germany
• Presenter of the tutorial "How to Consume Linked Data on the Web" at the 19th International World Wide Web Conference (WWW), April 2010, Raleigh, NC, USA
• Presenter of the tutorial "How to Consume Linked Data on the Web" at the 8th International Semantic Web Conference (ISWC), October 2009, Washington DC, USA
• Presenter of the tutorial "How to Publish Linked Data on the Web" at the 7th International Semantic Web Conference (ISWC), October 2008, Karlsruhe, Germany
• Semantic Technologies Coordinator of the "9th Extended Semantic Web Conference (ESWC)", May 2012, Heraklion, Greece
• Research Intern with Talis in Birmingham, UK, Summer 2010
• Particpant in the Dagstuhl seminar on "Principles of Provenance", February 2012, Schloss Dagstuhl, Germany
• Particpant in the Dagstuhl seminar on "Semantic Data Management", April 2012, Schloss Dagstuhl, Germany