Johann Petrak


I am a researcher at the Austrian Research Institute for Artificial Intelligence and also a research fellow at the University of Sheffield and a member of the Natural Language Processing Group of the Computer Science Department.

I am working on a project that analyses the behaviour of visitors of a large Austrian news site and how the discourse in the online discussion forums influences the interaction with the site. I am also working on approaches for estimating semantic similarity between texts, machine learning approaches to tagging of text and large-scale multilingual entity recognition and disambiguation.
I am part of the core development team that develops the GATE NLP framework and have developed and contributed to a number of GATE plugins and other GATE related software as well as a number of other open-source projects.

I am interested in a wide range of research topics, including machine learning approaches for text tagging, learning to rank and metric learning, approaches to natural language processing based on imitation learning and cost-sensitive learning and the synergies between knowledge representation and ontologies on one hand and natural language processing on the other hand.



See also Google Scholar

Selected publications:

Selected Projects

A list of selected projects I participated in:


I am an enthusiastic developer and supporter of open source software and have contributed to the development of the GATE NLP framework, many GATE NLP plugins, and a number of other projects.

Some selected software projects: