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Max-Margin Incremental CCG Parsing

Miloš Stanojević, Mark Steedman


Abstract
Incremental syntactic parsing has been an active research area both for cognitive scientists trying to model human sentence processing and for NLP researchers attempting to combine incremental parsing with language modelling for ASR and MT. Most effort has been directed at designing the right transition mechanism, but less has been done to answer the question of what a probabilistic model for those transition parsers should look like. A very incremental transition mechanism of a recently proposed CCG parser when trained in straightforward locally normalised discriminative fashion produces very bad results on English CCGbank. We identify three biases as the causes of this problem: label bias, exposure bias and imbalanced probabilities bias. While known techniques for tackling these biases improve results, they still do not make the parser state of the art. Instead, we tackle all of these three biases at the same time using an improved version of beam search optimisation that minimises all beam search violations instead of minimising only the biggest violation. The new incremental parser gives better results than all previously published incremental CCG parsers, and outperforms even some widely used non-incremental CCG parsers.
Anthology ID:
2020.acl-main.378
Original:
2020.acl-main.378v1
Version 2:
2020.acl-main.378v2
Volume:
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics
Month:
July
Year:
2020
Address:
Online
Editors:
Dan Jurafsky, Joyce Chai, Natalie Schluter, Joel Tetreault
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4111–4122
Language:
URL:
https://aclanthology.org/2020.acl-main.378
DOI:
10.18653/v1/2020.acl-main.378
Bibkey:
Cite (ACL):
Miloš Stanojević and Mark Steedman. 2020. Max-Margin Incremental CCG Parsing. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 4111–4122, Online. Association for Computational Linguistics.
Cite (Informal):
Max-Margin Incremental CCG Parsing (Stanojević & Steedman, ACL 2020)
Copy Citation:
PDF:
https://aclanthology.org/2020.acl-main.378.pdf
Video:
 http://slideslive.com/38928795