HiTRANS: A Hierarchical Transformer Network for Nested Named Entity Recognition

Zhiwei YANG, Jing MA, Hechang Chen*, Yunke Zhang, Yi Chuang*

*Corresponding author for this work

Research output: Chapter in book/report/conference proceedingConference contribution

Abstract

Nested Named Entity Recognition (NNER) has been extensively studied, aiming to identify all nested entities from potential spans (i.e., one or more continuous tokens). However, recent studies for NNER either focus on tedious tagging schemas or utilize complex structures, which fail to learn effective span representations from the input sentence with highly nested entities. Intuitively, explicit span representations will contribute to NNER due to the rich context information they contain. In this study, we propose a Hierarchical Transformer (HiTRANS) network for the NNER task, which decomposes the input sentence into multi-grained spans and enhances the representation learning in a hierarchical manner. Specifically, we first utilize a two-phase module to generate span representations by aggregating context information based on a bottom-up and top-down transformer network. Then a label prediction layer is designed to recognize nested entities hierarchically, which naturally explores semantic dependencies among different spans. Experiments on GENIA, ACE-2004, ACE-2005 and NNE datasets demonstrate that our proposed method achieves much better performance than the state-of-the-art approaches.
Original languageEnglish
Title of host publicationFindings of the Association for Computational Linguistics
Subtitle of host publicationEMNLP 2021
PublisherAssociation for Computational Linguistics (ACL)
Pages124-132
Number of pages9
DOIs
Publication statusPublished - Nov 2021
EventThe 2021 Conference on Empirical Methods in Natural Language Processing - Barceló Bávaro Convention Centre, and also Virtually, Punta Cana, Dominican Republic
Duration: 7 Nov 202111 Nov 2021
https://2021.emnlp.org/
https://aclanthology.org/volumes/2021.emnlp-main/

Conference

ConferenceThe 2021 Conference on Empirical Methods in Natural Language Processing
Abbreviated titleEMNLP 2021
Country/TerritoryDominican Republic
CityPunta Cana
Period7/11/2111/11/21
Internet address

Fingerprint

Dive into the research topics of 'HiTRANS: A Hierarchical Transformer Network for Nested Named Entity Recognition'. Together they form a unique fingerprint.

Cite this