Paper: A Comparison of Loopy Belief Propagation and Dual Decomposition for Integrated CCG Supertagging and Parsing

ACL ID P11-1048
Title A Comparison of Loopy Belief Propagation and Dual Decomposition for Integrated CCG Supertagging and Parsing
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 2011
Authors

Via an oracle experiment, we show that the upper bound on accuracy of a CCG parser is significantly lowered when its search space is pruned using a supertagger, though the su- pertagger also prunes many bad parses. In- spired by this analysis, we design a single model with both supertagging and parsing fea- tures, rather than separating them into dis- tinct models chained together in a pipeline. To overcome the resulting increase in com- plexity, we experiment with both belief prop- agation and dual decomposition approaches to inference, the first empirical comparison of these algorithms that we are aware of on a structured natural language processing prob- lem. On CCGbank we achieve a labelled de- pendency F-measure of 88.8% on gold POS tags, and 86.7% on automatic part-of-speeoch tags, t...