ECAI 2008

From the 20th to 25th of July, Johannes Liegl and Stefan Gindl attended the 18th European Conference for Artificial Intelligence (ECAI). This conference takes place every other year and brings together Europe's Artificial Intelligence research community. This year the conference was held in Patras (Greece) and it covered the following topics:

• Knowledge Representation and Reasoning
• Machine Learning
• Model-Based Diagnosis and Reasoning
• Cognitive Modeling and Interaction
• Natural Language Processing
• Uncertainty in AI
• Distributed and Multi-Agent Systems
• Constraints and Search
• Planning and Scheduling
• Perception, Sensing and Cognitive Robotics

Johannes Liegl gave a talk in the Computational Aspects of Affectual and Emotional Interaction Workshop (CAFFEi) where he presented the results of an evaluation of different sentiment detection methods on web-based reviews. The evaluation covered a broad range of different methods for sentiment detection. The performance of rather simple methods that rely on a manually created dictionary containing words and their associated sentiment values was compared to more complex machine-learning based methods. The overall finding was that, though the simple methods delivered acceptable results, they were outperformed by the more sophisticated ones like the Maximum Entropy model.

Sentiment analysis was an obvious trend at the workshop, as a significant amount of attention was drawn to it. About half the accepted papers covered this topic. One paper, for example, investigated the idea of applying the PageRank algorithm on WordNet's Synonym/Antonym relations to automatically extract a sentiment dictionary from a small set of seed words. Another one empirically proved that words that are not used in their literal sense are strong indicators for subjectivity and express strong polarity.
Meeting some of the members of the European sentiment analysis research community was really motivating, it also helped to align our future work and possible collaborations. It was also very helpful to talk about and exchange language resources like dictionaries and corpora.

Further Reading
Gindl, S., Liegl, J. (2008): "Evaluation of Different Sentiment Detection Methods for Polarity Classification on Web-Based Reviews", 18th European Conference on Artificial Intelligence (ECAI-2008), ECAI Workshop on Computational Aspects of Affectual and Emotional Interaction, Patras, Greece. (Link)

Relevant Links
ECAI 2008
ECAI 2008 Program

Contact
Dipl.-Ing. Johannes Liegl, Dipl.-Ing. Stefan Gindl
MODUL University Vienna
Department of New Media Technology
Am Kahlenberg 1, 1190 Vienna, Austria
johannes.liegl@modul.ac.at, stefan.gindl@modul.ac.at | www.modul.ac.at