Density-Aware Prototypical Network for Few-Shot Relation Classification

Jianfeng Wu, Mengting Hu, Yike Wu, Bingzhe Wu, Yalan Xie, Mingming Liu, Renhong Cheng


Abstract
In recent years, few-shot relation classification has evoked many research interests. Yet a more challenging problem, i.e. none-of-the-above (NOTA), is under-explored. Existing works mainly regard NOTA as an extra class and treat it the same as known relations. However, such a solution ignores the overall instance distribution, where NOTA instances are actually outliers and distributed unnaturally compared with known ones. In this paper, we propose a density-aware prototypical network (D-Proto) to treat various instances distinctly. Specifically, we design unique training objectives to separate known instances and isolate NOTA instances, respectively. This produces an ideal instance distribution, where known instances are dense yet NOTAs have a small density. Moreover, we propose a NOTA detection module to further enlarge the density of known samples, and discriminate NOTA and known samples accurately. Experimental results demonstrate that the proposed method outperforms strong baselines with robustness towards various NOTA rates. The code will be made public after the paper is accepted.
Anthology ID:
2023.findings-emnlp.162
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2023
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2477–2489
Language:
URL:
https://aclanthology.org/2023.findings-emnlp.162
DOI:
10.18653/v1/2023.findings-emnlp.162
Bibkey:
Cite (ACL):
Jianfeng Wu, Mengting Hu, Yike Wu, Bingzhe Wu, Yalan Xie, Mingming Liu, and Renhong Cheng. 2023. Density-Aware Prototypical Network for Few-Shot Relation Classification. In Findings of the Association for Computational Linguistics: EMNLP 2023, pages 2477–2489, Singapore. Association for Computational Linguistics.
Cite (Informal):
Density-Aware Prototypical Network for Few-Shot Relation Classification (Wu et al., Findings 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.findings-emnlp.162.pdf