Adversarial Sample Generation for Aspect based Sentiment Classification

Mamta, Asif Ekbal


Abstract
Deep learning models have been proven vulnerable towards small imperceptible perturbed input, known as adversarial samples, which are indiscernible by humans. Initial attacks in Natural Language Processing perturb characters or words in sentences using heuristics and synonyms-based strategies, resulting in grammatical incorrect or out-of-context sentences. Recent works attempt to generate contextual adversarial samples using a masked language model, capturing word relevance using leave-one-out (LOO). However, they lack the design to maintain the semantic coherency for aspect based sentiment analysis (ABSA) tasks. Moreover, they focused on resource-rich languages like English. We present an attack algorithm for the ABSA task by exploiting model explainability techniques to address these limitations. It does not require access to the training data, raw access to the model, or calibrating a new model. Our proposed method generates adversarial samples for a given aspect, maintaining more semantic coherency. In addition, it can be generalized to low-resource languages, which are at high risk due to resource scarcity. We show the effectiveness of the proposed attack using automatic and human evaluation. Our method outperforms the state-of-art methods in perturbation ratio, success rate, and semantic coherence.
Anthology ID:
2022.findings-aacl.44
Volume:
Findings of the Association for Computational Linguistics: AACL-IJCNLP 2022
Month:
November
Year:
2022
Address:
Online only
Editors:
Yulan He, Heng Ji, Sujian Li, Yang Liu, Chua-Hui Chang
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
478–492
Language:
URL:
https://aclanthology.org/2022.findings-aacl.44
DOI:
Bibkey:
Cite (ACL):
Mamta and Asif Ekbal. 2022. Adversarial Sample Generation for Aspect based Sentiment Classification. In Findings of the Association for Computational Linguistics: AACL-IJCNLP 2022, pages 478–492, Online only. Association for Computational Linguistics.
Cite (Informal):
Adversarial Sample Generation for Aspect based Sentiment Classification (Mamta & Ekbal, Findings 2022)
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PDF:
https://aclanthology.org/2022.findings-aacl.44.pdf