Paper: An Empirical Study On Rule Granularity And Unification Interleaving Toward An Efficient Unification-Based Parsing System

ACL ID C92-1030
Title An Empirical Study On Rule Granularity And Unification Interleaving Toward An Efficient Unification-Based Parsing System
Venue International Conference on Computational Linguistics
Session Main Conference
Year 1992
Authors
  • Masaaki Nagata (ATR Interpreting Telephony Research Laboratories, Osaka Japan)

This paper describes an empirical study on the op- timal granularity of the phrase structure rules and the optimal strategy for interleaving CFG parsing with unification in order to implement an eltlcient unification-based parsing system. We claim that us- ing "medium-grained" CFG phrase structure rules, which balance tile computational cost of CI?G parsing and unification, are a cost-effective solution for mak- ing unification-based grammar both efficicnt and easy to maintain. We also claim that "late unification", which delays unification until a complete CI"G parse is found, saves unnecessary copies of DAGs for ir- relevant subparses and improves performance signifi- cantly. The effectiveness of these methods was proved in an extensive experiment. The results show that, on average, the ...