Improving Named Entity Recognition by External Context Retrieving and Cooperative Learning

Xinyu Wang, Yong Jiang, Nguyen Bach, Tao Wang, Zhongqiang Huang, Fei Huang, Kewei Tu


Abstract
Recent advances in Named Entity Recognition (NER) show that document-level contexts can significantly improve model performance. In many application scenarios, however, such contexts are not available. In this paper, we propose to find external contexts of a sentence by retrieving and selecting a set of semantically relevant texts through a search engine, with the original sentence as the query. We find empirically that the contextual representations computed on the retrieval-based input view, constructed through the concatenation of a sentence and its external contexts, can achieve significantly improved performance compared to the original input view based only on the sentence. Furthermore, we can improve the model performance of both input views by Cooperative Learning, a training method that encourages the two input views to produce similar contextual representations or output label distributions. Experiments show that our approach can achieve new state-of-the-art performance on 8 NER data sets across 5 domains.
Anthology ID:
2021.acl-long.142
Volume:
Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)
Month:
August
Year:
2021
Address:
Online
Editors:
Chengqing Zong, Fei Xia, Wenjie Li, Roberto Navigli
Venues:
ACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1800–1812
Language:
URL:
https://aclanthology.org/2021.acl-long.142
DOI:
10.18653/v1/2021.acl-long.142
Bibkey:
Cite (ACL):
Xinyu Wang, Yong Jiang, Nguyen Bach, Tao Wang, Zhongqiang Huang, Fei Huang, and Kewei Tu. 2021. Improving Named Entity Recognition by External Context Retrieving and Cooperative Learning. In Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers), pages 1800–1812, Online. Association for Computational Linguistics.
Cite (Informal):
Improving Named Entity Recognition by External Context Retrieving and Cooperative Learning (Wang et al., ACL-IJCNLP 2021)
Copy Citation:
PDF:
https://preview.aclanthology.org/nschneid-patch-4/2021.acl-long.142.pdf
Video:
 https://preview.aclanthology.org/nschneid-patch-4/2021.acl-long.142.mp4
Code
 modelscope/adaseq +  additional community code
Data
BC5CDRCMeEECoNLLCoNLL 2003CoNLL++CoNLL-2000MSRA CN NERNCBI DiseaseResume NERWNUT 2016 NERWNUT 2017Weibo NER