The general framework for the research activities is based on
statistical decision theory and problem specific modelling. The
prototypical area where this approach has been pushed forward is
speech recognition. The approach is expressed by the equation:
The characteristic advantages of the probabilistic framework and statistical decision theory are:
From speech recognition, we have extended and are still extending this approach to other areas, in particular the translation of spoken and written language and other tasks in natural language processing.
For language translation, the approach is expressed by the equation:
This approach has been pursued in projects like VERBMOBIL (German) and EUTRANS (European). The experimental comparisons with traditional rule-based and other competing approaches show that the statistical approach is competitive in terms of performance or even superior. In addition, it offers a couple of advantages like increased robustness and easy adaptation to a new task. In the final large-scale end-to-end evaluation of the VERBMOBIL translation project, the RWTH Aachen translation approach achieved a sentence error rate which was lower by a factor of two in comparison with three competing translation approaches.
In summary, the research activities of the Lehrstuhl für Informatik 6 cover the following applications:
Most of these research activities have been or are carried out in the framework of national or European projects, such as the national German project VERBMOBIL and European projects like ARISE, EUTRANS, CORETEX, and ADVISOR. In addition, there are bilateral research projects with companies.