Transforming Complex Sentences into a Semantic Hierarchy

Christina Niklaus, Matthias Cetto, André Freitas, Siegfried Handschuh


Abstract
We present an approach for recursively splitting and rephrasing complex English sentences into a novel semantic hierarchy of simplified sentences, with each of them presenting a more regular structure that may facilitate a wide variety of artificial intelligence tasks, such as machine translation (MT) or information extraction (IE). Using a set of hand-crafted transformation rules, input sentences are recursively transformed into a two-layered hierarchical representation in the form of core sentences and accompanying contexts that are linked via rhetorical relations. In this way, the semantic relationship of the decomposed constituents is preserved in the output, maintaining its interpretability for downstream applications. Both a thorough manual analysis and automatic evaluation across three datasets from two different domains demonstrate that the proposed syntactic simplification approach outperforms the state of the art in structural text simplification. Moreover, an extrinsic evaluation shows that when applying our framework as a preprocessing step the performance of state-of-the-art Open IE systems can be improved by up to 346% in precision and 52% in recall. To enable reproducible research, all code is provided online.
Anthology ID:
P19-1333
Volume:
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics
Month:
July
Year:
2019
Address:
Florence, Italy
Editors:
Anna Korhonen, David Traum, Lluís Màrquez
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3415–3427
Language:
URL:
https://aclanthology.org/P19-1333
DOI:
10.18653/v1/P19-1333
Bibkey:
Cite (ACL):
Christina Niklaus, Matthias Cetto, André Freitas, and Siegfried Handschuh. 2019. Transforming Complex Sentences into a Semantic Hierarchy. In Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics, pages 3415–3427, Florence, Italy. Association for Computational Linguistics.
Cite (Informal):
Transforming Complex Sentences into a Semantic Hierarchy (Niklaus et al., ACL 2019)
Copy Citation:
PDF:
https://aclanthology.org/P19-1333.pdf
Software:
 P19-1333.Software.zip
Video:
 https://aclanthology.org/P19-1333.mp4
Code
 Lambda-3/DiscourseSimplification
Data
NewselaWikiLargeWikiSplit