Christian Wartena studeerde Taal, Spraak en Informatica aan de Katholieke Universiteit Nijmegen. Van 1994 tot 2000 was hij wetenschappelijk medewerker aan het Institut für Linguistik aan de Universiteit van Potsdam (Duitsland) en werkzaam in het Innovationskolleg ‘Formale Modelle kognitiver Komplexität’. In 1999 promoveerde hij hier summa cum laude op het proefschrift ‘Storage structures and conditions on movement in natural languages’. Van 2000 tot 2005 werkte hij bij Lingenio (tot 2003 Linguatec Entwicklung und Services) in Heidelberg (Duitsland) aan de ontwikkeling van systemen voor automatisch vertalen en translation management.

Sinds 2005 maakt Christian Wartena deel uit van de Media Interaction-groep van Novay. Het zwaartepunt van zijn werk ligt hier vooral op projecten rond trefwoordextractie, (semantische) interoperabiliteit van metadata, social tagging en recommendation.

Publications

2010

• Christian Wartena.  Automatic classification of social tags.  In European Conference on Digital Libraries (ECDL),  2010a. to appear.
• Christian Wartena and Rogioer Brussee. Keyword extraction using co-occurrence. In DEXA Workshops, 2010. to appear.
• Luit Gazendam, Christian Wartena, and Rogioer Brussee. Thesaurus based term ranking for keyword extraction. In DEXA Workshops, 2010. to appear.
• Christian Wartena. Testing the distributional hypothesis for collaborative tagging systems.  In Thomas Hanneforth and Gisbert Fanselow, editors, Language and Logos. A Festschrift for Peter Staudacher, Studia Grammatica, pages 405 - 413. 2010b.
  

2009

• Luit Gazendam, Christian Wartena, Veronique Malaise, Guus Schreiber,  Annemiek de Jong, and Hennie Brugman. Automatic annotation suggestions for audiovisual archives:  Evaluation aspects. Interdisciplinary Science Reviews, 2  (3): 172-188, 2009. URL http://doi.ieeecomputersociety.org/10.1179/174327909X441090
• Christian Wartena, Rogier Brussee, and Martin Wibbels. Using tag co-occurrence for recommendation.  In ISDA, pages 273-278. IEEE Computer Society, 2009.  ISBN 978-0-7695-3872-3 http://doi.ieeecomputersociety.org/10.1109/ISDA.2009.130.
  

2008

• Christian Wartena and Rogier Brussee. Topic detection by clustering keywords. In DEXA Workshops, pages 54-58. IEEE Computer Society,  2008a. ISBN 978-0-7695-3299-8.
   URL http://doi.ieeecomputersociety.org/10.1109/DEXA.2008.120.
• Christian Wartena and Rogier Brussee. Instance-based mapping between thesauri and folksonomies. In Amit P. Sheth, Steffen Staab, Mike Dean, Massimo Paolucci, Diana  Maynard, Timothy W. Finin, and Krishnaprasad Thirunarayan, editors,  International Semantic Web Conference, volume 5318 of Lecture Notes in Computer Science, pages 356-370. Springer, 2008b. ISBN 978-3-540-88563-4. URL http://dx.doi.org/10.1007/978-3-540-88564-1_23.
• Christian Wartena. Storage products and linear control of derivations. Theory Comput. Syst., 42 (2): 157-186,  2008. URL http://dx.doi.org/10.1007/s00224-007-9053-2.
• Rogier Brussee and Christian Wartena. Automatic thesaurus generation using co-occurrence. In A. Nijholt, M. Pantic, M. Poel, and G.H.W. Hondorp, editors, Proceedings of the 20th Belgian Netherlands Conference on Artificial  Intelligence (BNAIC 2008, pages 41-48, University of Twente, Enschede, The  Netherlands, 2008. URL https://doc.novay.nl/dsweb/Get/Document-89762.
  

2007

• Henk Jonkers, Christian Wartena, and Hugo ter Doest.  A service-oriented architecture for a flexible digital public archive. Via Nova Architectura, September 2007. URL  http://www.via-nova-architectura.org/magazine/reviewed/a-service-oriented-architecture-for-a-flexible-digital-public-ar.html.
• Christian Wartena, Rogier Brussee, Luit Gazendam, and Willem-Olaf Huijsen. Apolda: A practical tool for semantic annotation. In DEXA Workshops, pages 288-292. IEEE Computer Society, 2007.
   ISBN 0-7695-2932-1. URL http://doi.ieeecomputersociety.org/10.1109/DEXA.2007.39.

2006

• Christian Wartena, Peter Fennema, and Rogier Brussee. Exchanging personal information. In Proceedings of the Workshop on Ubiquitous User Modelling  (UbiqUM2006) in conjunction with The 17th European Conference on Artificial  Intelligence (ECAI2006), Riva del Garda, 2006a.
• Christian Wartena, Anjo Anjewierden, and William van Dieten. Using patterns over ontology terms to detect inconsistencies in large text collections (extended abstract). In Ontologies in Text Technology: Approaches to Extract Semantic Knowledge from Syntactic Information (OTT 2006), pages 107 - 112,  Osnabrueck, 2006b.
   URL http://www.cogsci.uni-osnabrueck.de/ott06/ott06-abstracts/wartena_anjewierden_vandieten.pdf.

2000

• Christian Wartena. Extending linear indexed grammars. In roceedings of the TAG+5 Workshop, pages 207 - 214, Paris,  2000a. URL  http://tagplus.linguist.jussieu.fr/PS/21.ps.gz.
• Christian Wartena. A note on the complexity of optimality systems. In Oliver Boldt and Helmut Juergensen, editors, Pre-Proceedings of DCAGRS 2000 Descriptional Complexity of Automata, Grammars and Related Structures, Report 555. Department of Computer Science  of the University of Western Ontario, 2000b. URL http://roa.rutgers.edu/view.php3?id=400>http://roa.rutgers.edu/view.php3?id=400.
• Christian Wartena. Operations on storage types. In Oliver Boldt and Helmut Juergensen, editors, Pre-Proceedings of DCAGRS 2000 Descriptional Complexity of Automata, Grammars and Related Structures, Report 555. Department of Computer Science of the University of Western Ontario, 2000c.
• Christian Wartena. A note on the generative capacity of optimality systems. In Reinhard Blutner and Gerhard Jaeger, editors, Studies in Optimality Theory, Linguistics in Potsdam 8, pages 64 - 72. University of  Potsdam, 2000d.

1999

• Christian Wartena. On the concatenation of one-turn pushdowns. Grammars, 2 (3): 259-269, December 1999. http://www.springerlink.com/content/q867665284777470.
  
• Jens Michaelis and Christian Wartena.  LIGs with reduced derivation sets.  In Gosse Bouma, Geert-Jan M. Kruijff, Erhard Hinrichs, and Richard T. Oehrle, editors, Constraints and Resources in Natural Language Syntax and Semantics, volume II of Studies in Constrained  Based Lexicalism, pages 263-279. CSLI Publications, Stanford, CA, 1999.

1998

• Jens Michaelis and Christian Wartena. Unidirectional inheritance of indices. A weakly context-free facet  of LIGs. In Proceedings of the Joint Conference on Formal Grammar,  Head-Driven Phrase Structure Grammar and Categorial Grammar (FHCG '98),  pages 258-267, Saarbruecken, 1998.
• Christian Wartena. Grammars with composite storages. In Michael Moortgat, editor, LACL, volume 2014 of Lecture Notes in Computer Science, pages 266-286. Springer, 1998. ISBN 3-540-42251-X. URL http://link.springer.de/link/service/series/0558/bibs/2014/20140266.htm
    

1997

• Jens Michaelis and Christian Wartena. How linguistic constraints on movement conspire to yield languages  analyzable with a restricted form of LIGs.  In Proceedings of the Conference on Formal Grammar (FG '97),  pages 158-168, Aix en Provence, 1997.

Other Publications

• Rogier Brussee, Harry van Vliet, and Christian Wartena. Een ontologie van openbare vermakelijkheden. InformatieProfessional, 2008 (12): 20-23,  2008.
   URL http://www.informatieprofessional.nl/magazines/artikelen.html?view=article&article_id=18.
• Christian Wartena. Zoeken met tags: Tagvarianten semantisch getemd. InformatieProfessional, 2010 (3): 20-23,  2010c.