Paper: Non-Local Modeling With A Mixture Of PCFGs

ACL ID W06-2903
Title Non-Local Modeling With A Mixture Of PCFGs
Venue International Conference on Computational Natural Language Learning
Session Main Conference
Year 2006

While most work on parsing with PCFGs has focused on local correlations between tree configurations, we attempt to model non-local correlations using a finite mix- ture of PCFGs. A mixture grammar fit with the EM algorithm shows improve- ment over a single PCFG, both in parsing accuracy and in test data likelihood. We argue that this improvement comes from the learning of specialized grammars that capture non-local correlations.