Uncertainty-Aware Contrastive Sentence Embedding With Local Context Representation for Text Classification

Han Liu, Jiaqing Zhan, Zhichao Chen, Qin Zhang


Abstract
In real-world applications of natural language processing, it is essential to effectively adapt a pre-trained model to a downstream task. While text classification is undertaken as a downstream task, it is crucial to produce meaningful sentence embedding that is adaptive to the task. In this paper, we explore how to effectively adapt a pre-trained model for extracting meaningful context representations from sentences, and propose an uncertainty-aware contrastive sentence embedding approach that involves addressing language ambiguity and inter-class separability for a text classification task. Specifically, we design an end-to-end strategy for driving the process of learning to transform a word embedding matrix into a contextualized sentence vector and to quantify the representation uncertainty of the sentence, while the word embedding matrix is produced by a pre-trained model without fine-tuning, and a label-wise contrastive learning strategy is designed to enhance intra-class compactness and inter-class separability. The results on public data sets show that a considerable improvement of text classification accuracy is achieved by adopting the proposed approach in comparison with using those state-of-the-art methods.
Anthology ID:
2026.findings-acl.1927
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
38702–38716
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1927/
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Cite (ACL):
Han Liu, Jiaqing Zhan, Zhichao Chen, and Qin Zhang. 2026. Uncertainty-Aware Contrastive Sentence Embedding With Local Context Representation for Text Classification. In Findings of the Association for Computational Linguistics: ACL 2026, pages 38702–38716, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Uncertainty-Aware Contrastive Sentence Embedding With Local Context Representation for Text Classification (Liu et al., Findings 2026)
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