Ustnlp16 at SemEval-2025 Task 9: Improving Model Performance through Imbalance Handling and Focal Loss
Zhuoang Cai, Zhenghao Li, Yang Liu, Liyuan Guo, Yangqiu Song
Abstract
Classification tasks often suffer from imbal- anced data distribution, which presents chal- lenges in food hazard detection due to severe class imbalances, short and unstructured text, and overlapping semantic categories. In this paper, we present our system for SemEval- 2025 Task 9: Food Hazard Detection, which ad- dresses these issues by applying data augmenta- tion techniques to improve classification perfor- mance. We utilize transformer-based models, BERT and RoBERTa, as backbone classifiers and explore various data balancing strategies, including random oversampling, Easy Data Augmentation (EDA), and focal loss. Our ex- periments show that EDA effectively mitigates class imbalance, leading to significant improve- ments in accuracy and F1 scores. Furthermore, combining focal loss with oversampling and EDA further enhances model robustness, par- ticularly for hard-to-classify examples. These findings contribute to the development of more effective NLP-based classification models for food hazard detection.- Anthology ID:
- 2025.semeval-1.200
- Volume:
- Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025)
- Month:
- July
- Year:
- 2025
- Address:
- Vienna, Austria
- Editors:
- Sara Rosenthal, Aiala Rosá, Debanjan Ghosh, Marcos Zampieri
- Venues:
- SemEval | WS
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 1522–1527
- Language:
- URL:
- https://preview.aclanthology.org/corrections-2025-08/2025.semeval-1.200/
- DOI:
- Cite (ACL):
- Zhuoang Cai, Zhenghao Li, Yang Liu, Liyuan Guo, and Yangqiu Song. 2025. Ustnlp16 at SemEval-2025 Task 9: Improving Model Performance through Imbalance Handling and Focal Loss. In Proceedings of the 19th International Workshop on Semantic Evaluation (SemEval-2025), pages 1522–1527, Vienna, Austria. Association for Computational Linguistics.
- Cite (Informal):
- Ustnlp16 at SemEval-2025 Task 9: Improving Model Performance through Imbalance Handling and Focal Loss (Cai et al., SemEval 2025)
- PDF:
- https://preview.aclanthology.org/corrections-2025-08/2025.semeval-1.200.pdf