Boundary Smoothing for Named Entity Recognition

Enwei Zhu, Jinpeng Li


Abstract
Neural named entity recognition (NER) models may easily encounter the over-confidence issue, which degrades the performance and calibration. Inspired by label smoothing and driven by the ambiguity of boundary annotation in NER engineering, we propose boundary smoothing as a regularization technique for span-based neural NER models. It re-assigns entity probabilities from annotated spans to the surrounding ones. Built on a simple but strong baseline, our model achieves results better than or competitive with previous state-of-the-art systems on eight well-known NER benchmarks. Further empirical analysis suggests that boundary smoothing effectively mitigates over-confidence, improves model calibration, and brings flatter neural minima and more smoothed loss landscapes.
Anthology ID:
2022.acl-long.490
Volume:
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
May
Year:
2022
Address:
Dublin, Ireland
Editors:
Smaranda Muresan, Preslav Nakov, Aline Villavicencio
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7096–7108
Language:
URL:
https://aclanthology.org/2022.acl-long.490
DOI:
10.18653/v1/2022.acl-long.490
Bibkey:
Cite (ACL):
Enwei Zhu and Jinpeng Li. 2022. Boundary Smoothing for Named Entity Recognition. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 7096–7108, Dublin, Ireland. Association for Computational Linguistics.
Cite (Informal):
Boundary Smoothing for Named Entity Recognition (Zhu & Li, ACL 2022)
Copy Citation:
PDF:
https://aclanthology.org/2022.acl-long.490.pdf
Software:
 2022.acl-long.490.software.zip
Code
 syuoni/eznlp
Data
ACE 2004ACE 2005CoNLLCoNLL 2003CoNLL++MSRA CN NEROntoNotes 4.0OntoNotes 5.0Resume NERWeibo NER