MOSAIC at GENAI Detection Task 3 : Zero-Shot Detection Using an Ensemble of Models

Matthieu Dubois, François Yvon, Pablo Piantanida


Abstract
MOSAIC introduces a new ensemble approach that combines several detector models to spot AI-generated texts. The method enhances the reliability of detection by integrating insights from multiple models, thus addressing the limitations of using a single detector model which often results in performance brittleness. This approach also involves using a theoretically grounded algorithm to minimize the worst-case expected encoding size across models, thereby optimizing the detection process. In this submission, we report evaluation results on the RAID benchmark, a comprehensive English-centric testbed for machine-generated texts. These results were obtained in the context of the “Cross-domain Machine-Generated Text Detection” shared task. We show that our model can be competitive for a variety of domains and generator models, but that it can be challenged by adversarial attacks and by changes in the text generation strategy.
Anthology ID:
2025.genaidetect-1.44
Volume:
Proceedings of the 1stWorkshop on GenAI Content Detection (GenAIDetect)
Month:
January
Year:
2025
Address:
Abu Dhabi, UAE
Editors:
Firoj Alam, Preslav Nakov, Nizar Habash, Iryna Gurevych, Shammur Chowdhury, Artem Shelmanov, Yuxia Wang, Ekaterina Artemova, Mucahid Kutlu, George Mikros
Venues:
GenAIDetect | WS
SIG:
Publisher:
International Conference on Computational Linguistics
Note:
Pages:
371–376
Language:
URL:
https://aclanthology.org/2025.genaidetect-1.44/
DOI:
Bibkey:
Cite (ACL):
Matthieu Dubois, François Yvon, and Pablo Piantanida. 2025. MOSAIC at GENAI Detection Task 3 : Zero-Shot Detection Using an Ensemble of Models. In Proceedings of the 1stWorkshop on GenAI Content Detection (GenAIDetect), pages 371–376, Abu Dhabi, UAE. International Conference on Computational Linguistics.
Cite (Informal):
MOSAIC at GENAI Detection Task 3 : Zero-Shot Detection Using an Ensemble of Models (Dubois et al., GenAIDetect 2025)
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PDF:
https://aclanthology.org/2025.genaidetect-1.44.pdf