- Program Co-Chair of TIR '07 , 4th International Workshop on Text-based Information Retrieval, in conjunction with DEXA 2007, 3-7 September 2007, Regensburg, Germany.
- Program Co-Chair of the Track 'Emerging Web Technologies' at 33rd Conference on
Current Trends in Theory and Practice of Computer Science,
(SOFSEM 2007), January 20 - 26, 2007, Hotel Sklar, Harrachov, Czech Republic.
- Organising Chair at 6th
Int. Symposium on Representations and Methodology of Future Computing Technologies (RM2003), Trier (Germany) March 10-11, 2003.
- Organising Chair at Trierer
Symposium für Elektronisches Publizieren, Institut für
Telematik / Zentrum für Wissenschaftliches Elektronisches Publizieren
(WEP), Trier (Germany), March 25-26, 1999.
- SAAKM 2008, Semantic Authoring, Annotation, and Knowledge Markup Workshop, co-located with the EKAW 2008 - 16th International Conference on Knowledge Engineering and Knowledge Management Knowledge Patterns, September 28th, 2008, Acitrezza, Catania, Italy.
- ESOE 2007, Int. Workshop on Emergent Semantics and Ontology Evolution, co-located with Int. Conference on Semantic Web (ISWC 2007), November 12th, 2007, Busan, Korea.
- SAAKM 2007, Semantic Authoring, Annotation, and Knowledge Markup Workshop, co-located with the 4th. Int. Conference on Knowledge Capture 2007 (KCap-2007), October 28-31th, 2007, Whistler, British Columbia, Canada.
- CSSW 2007, Conference on Social Semantic Web, in conjunction with SABRE 2007 Conference on Software, Agents and Services for Business, Research, and E-Science, September 26-28th, Leipzig (Germany).
- I-Semantics 2007, International Technology Conference, September 5-7, 2007, Graz, Austria.
- Semantic Desktop Design, workshop colocated with ESCW2007, June 6-7, Innsbruck, Austria.
- Bridging the Gap between Semantic Web and Web2.0, workshop colocated with ESCW2007, June 6-7, 2007, Innsbruck, Austria.