A Transition-Based Directed Acyclic Graph Parser for UCCA

Daniel Hershcovich, Omri Abend, Ari Rappoport


Abstract
We present the first parser for UCCA, a cross-linguistically applicable framework for semantic representation, which builds on extensive typological work and supports rapid annotation. UCCA poses a challenge for existing parsing techniques, as it exhibits reentrancy (resulting in DAG structures), discontinuous structures and non-terminal nodes corresponding to complex semantic units. To our knowledge, the conjunction of these formal properties is not supported by any existing parser. Our transition-based parser, which uses a novel transition set and features based on bidirectional LSTMs, has value not just for UCCA parsing: its ability to handle more general graph structures can inform the development of parsers for other semantic DAG structures, and in languages that frequently use discontinuous structures.
Anthology ID:
P17-1104
Volume:
Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2017
Address:
Vancouver, Canada
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1127–1138
Language:
URL:
https://aclanthology.org/P17-1104
DOI:
10.18653/v1/P17-1104
Bibkey:
Cite (ACL):
Daniel Hershcovich, Omri Abend, and Ari Rappoport. 2017. A Transition-Based Directed Acyclic Graph Parser for UCCA. In Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 1127–1138, Vancouver, Canada. Association for Computational Linguistics.
Cite (Informal):
A Transition-Based Directed Acyclic Graph Parser for UCCA (Hershcovich et al., ACL 2017)
Copy Citation:
PDF:
https://aclanthology.org/P17-1104.pdf
Note:
 P17-1104.Notes.pdf
Presentation:
 P17-1104.Presentation.pdf
Software:
 P17-1104.Software.zip
Video:
 https://vimeo.com/234958945
Code
 danielhers/tupa