DFKI-LT - Validation and Evaluation of Automatically Acquired Multiword Expressions for Grammar Engineering

Aline Villavicencio, Valia Kordoni, Yi Zhang, Marco Idiart, Carlos Ramisch
Validation and Evaluation of Automatically Acquired Multiword Expressions for Grammar Engineering
2 Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL), Pages 1034-1043, Prague, Czech Republic, 6/2007
 
This paper focuses on the evaluation of methods for the automatic acquisition of Multiword Expressions (MWEs) for robust grammar engineering. First we investigate the hypothesis that MWEs can be detected by the distinct statistical properties of their component words, regardless of their type, comparing 3 statistical measures: mutual information (MI), Chi^2 and permutation entropy (PE). Our overall conclusion is that at least two measures, MI and PE, seem to differentiate MWEs from non-MWEs. We then investigate the influence of the size and quality of different corpora, using the BNC and the Web search engines Google and Yahoo. We conclude that, in terms of language usage, web generated corpora are fairly similar to more carefully built corpora, like the BNC, indicating that the lack of control and balance of these corpora are probably compensated by their size. Finally, we show a qualitative evaluation of the results of automatically adding extracted MWEs to existing linguistic resources. We argue that such a process improves qualitatively, if a more compositional approach to grammar/lexicon automated extension is adopted.
 
Files: BibTeX, D07-1110.pdf