In my PhD thesis, I focus on the formal properties of k-partite k-uniform hypergraphs (tuples combining objects from k different sets) and their application on social annotations, e.g., social tagging datasets, where k=3 (documents, users, and tags/terms). The main goal is to generalize concepts from graph theory and complex network analysis to these structures. In particular, I'm trying to find out if processing them in their native representation can yield real advantages (if theoretical beauty doesn't count as "real") compared to approaches dealing with "flattened" versions of the data. Our work on generalized ("hyperincident") connected components and their application to social bookmarking spam was awarded the ACM SIGWEB's Douglas Engelbart Best Paper Award at HyperText 2009. Currently, I work on generalizations of modularity optimization for community detection.
N. Neubauer and K. Obermayer: Community Detection in Tagging-Induced Hypergraphs. Workshop on Information in Networks, 2010 [pdf]
D. Pannicke, M. Hahne, N. Neubauer, B. Ochab, R. Lieb, M. Meister, W. Rammert, K. Obermayer and R. Zarnekow: Akzeptanzfähigkeit von Tagging-Systemen in benutzergenerierten virtuellen Welten. Multikonferenz Wirtschaftsinformatik 2010
N. Neubauer and K. Obermayer: Towards Community Detection in k-Partite, k-Uniform Hypergraphs. Workshop on Analyzing Networks and Learning with Graphs at NIPS 2009 [pdf]
N. Neubauer and K. Obermayer: Connected Components of 3-Partite 3-Uniform Hypergraphs. Poster at The Learning Workshop 2009. [pdf abstract]
N. Neubauer, R. Wetzker and K. Obermayer: Tag Spam Creates Large Non-Giant Connected Components. Fifth International Workshop on Adversarial Information Retrieval on the Web (AIRWeb) at the World Wide Web Conference 2009. [pdf]
N. Neubauer and K. Obermayer: Hyperincident Connected Components in Tagging Networks. In Proceedings of the 20th ACM Conference on Hypertext and Hypermedia (Torino, Italy, June 29 - July 01, 2009). HT '09. ACM, New York, NY, 229-238. [pdf]
N. Neubauer and K. Obermayer: Predicting Tag Spam Examining Cooccurrences, Network Structures and URL Components. Wikis, Blogs, Bookmarking Tools - Mining the Web 2.0 Workshop at ECML/PKDD 2008 [pdf]
B. Ochab, N. Neubauer and K. Obermayer: Personalized Recommendations for the Web 3D. In: J. Kay, P. Pu, W. Nejdl and E. Herder (eds.): Adaptive Hypermedia and Adaptive Web-Based Systems - Fifth International Conference, AH 2008
N. Neubauer, C. Scheel, S. Albayrak, K. Obermayer: Distance Measures in Query Space: How Strongly to Use Feedback from Past Queries. Proceedings of the IEEE/WIC/ACM Web Intelligence 2007
C. Scheel, N. Neubauer, A. Lommatzsch, K. Obermayer, S. Albayrak: Efficient Query Delegation by Detecting Redundant Retrieval Strategies. SIGIR 2007 Workshop: Learning to Rank for Information Retrieval [pdf]
N. Neubauer: Recursive SOMs and Automata (Master's Thesis) Publications of the Institute of Cognitive Science, University of Osnabrück, Volume 11-2006 [pdf]
B. Hammer and N. Neubauer: On the capacity of unsupervised recursive neural networks for symbol processing , Second International Workshop on Neural-Symbolic Learning and Reasoning (NeSy '06) [slides]
S. Nagel and N. Neubauer: A Framework to Systematize Positions in Neuroethics, Essays in Philosophy, Vol 6, No 1, The Philosophy of Technology, edited by Peter Denton [html]
S. Nagel and N. Neubauer: A Framework to Systematize Positions in Neuroethics, presented at 'Neurophilosophy: The State of the Art', 05/2005
Friedrich Albert, Jaqueline Griego, Stanley James, Christiane Kabisch, Oleksandr Kolomiyets, Ute Kreitz, Jens Kunkemöller, Jiayong Liu, Christian Mühl, Saskia Nagel, Nicolas Neubauer and Frank Schumann: MINI: Mechanisms In Neuropsychological Issues. Publications of the Institute of Cognitive Science, University of Osnabrück, Volume 9-2005 [pdf]
L. Steels, J. De Beule and N. Neubauer: Linking in Fluid Construction Grammars. Proceedings of BNAIC. Transactions of the Belgian Royal Society of Arts and Sciences., pages 11-18, Brussels, 2005.
N. Neubauer: Emergence in a Multiagent Simulation of Communicative Behaviour. (Bachelor's Thesis), Publications of the Institute of Cognitive Science, University of Osnabrück, Volume 11-2004 [pdf]
L. Steels, J. De Beule, N. Neubauer and J. Van Looveren: Fluid Construction Grammars, Proceedings of the International Conference on Construction Grammars, 2004