Paper: Probabilistic Context-Free Grammar Induction Based On Structural Zeros

ACL ID N06-1040
Title Probabilistic Context-Free Grammar Induction Based On Structural Zeros
Venue Human Language Technologies
Session Main Conference
Year 2006
Authors

We present a method for induction of con- cise and accurate probabilistic context- free grammars for efficient use in early stages of a multi-stage parsing technique. The method is based on the use of statis- tical tests to determine if a non-terminal combination is unobserved due to sparse data or hard syntactic constraints. Ex- perimental results show that, using this method, high accuracies can be achieved with a non-terminal set that is orders of magnitude smaller than in typically induced probabilistic context-free gram- mars, leading to substantial speed-ups in parsing. The approach is further used in combination with an existing reranker to provide competitive WSJ parsing results.