Graph Ensemble Learning over Multiple Dependency Trees for Aspect-level Sentiment Classification

Xiaochen Hou, Peng Qi, Guangtao Wang, Rex Ying, Jing Huang, Xiaodong He, Bowen Zhou


Abstract
Recent work on aspect-level sentiment classification has demonstrated the efficacy of incorporating syntactic structures such as dependency trees with graph neural networks (GNN), but these approaches are usually vulnerable to parsing errors. To better leverage syntactic information in the face of unavoidable errors, we propose a simple yet effective graph ensemble technique, GraphMerge, to make use of the predictions from different parsers. Instead of assigning one set of model parameters to each dependency tree, we first combine the dependency relations from different parses before applying GNNs over the resulting graph. This allows GNN models to be robust to parse errors at no additional computational cost, and helps avoid overparameterization and overfitting from GNN layer stacking by introducing more connectivity into the ensemble graph. Our experiments on the SemEval 2014 Task 4 and ACL 14 Twitter datasets show that our GraphMerge model not only outperforms models with single dependency tree, but also beats other ensemble models without adding model parameters.
Anthology ID:
2021.naacl-main.229
Volume:
Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies
Month:
June
Year:
2021
Address:
Online
Editors:
Kristina Toutanova, Anna Rumshisky, Luke Zettlemoyer, Dilek Hakkani-Tur, Iz Beltagy, Steven Bethard, Ryan Cotterell, Tanmoy Chakraborty, Yichao Zhou
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2884–2894
Language:
URL:
https://aclanthology.org/2021.naacl-main.229
DOI:
10.18653/v1/2021.naacl-main.229
Bibkey:
Cite (ACL):
Xiaochen Hou, Peng Qi, Guangtao Wang, Rex Ying, Jing Huang, Xiaodong He, and Bowen Zhou. 2021. Graph Ensemble Learning over Multiple Dependency Trees for Aspect-level Sentiment Classification. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 2884–2894, Online. Association for Computational Linguistics.
Cite (Informal):
Graph Ensemble Learning over Multiple Dependency Trees for Aspect-level Sentiment Classification (Hou et al., NAACL 2021)
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PDF:
https://aclanthology.org/2021.naacl-main.229.pdf
Video:
 https://aclanthology.org/2021.naacl-main.229.mp4