MOSAIC: Masked Objective with Selective Adaptation for In-domain Contrastive Learning

Vera Pavlova, Mohammed Makhlouf


Abstract
We introduce MOSAIC (Masked Objective with Selective Adaptation for In-domain Contrastive learning), a multi-stage framework for domain adaptation of text embedding models that incorporates joint domain-specific masked supervision. Our approach addresses the challenges of adapting large-scale general-domain text embedding models to specialized domains. By jointly optimizing masked language modeling (MLM) and contrastive objectives within a unified training pipeline, our method enables effective learning of domain-relevant representations while preserving the robust semantic discrimination properties of the original model. We empirically validate our approach on both high-resource and low-resource domains, achieving improvements up to 13.4% in NDCG@10 (Normalized Discounted Cumulative Gain) over strong general-domain baselines. Comprehensive ablation studies further demonstrate the effectiveness of each component, highlighting the importance of balanced joint supervision and staged adaptation.
Anthology ID:
2026.findings-eacl.197
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
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Publisher:
Association for Computational Linguistics
Note:
Pages:
3792–3807
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.197/
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Cite (ACL):
Vera Pavlova and Mohammed Makhlouf. 2026. MOSAIC: Masked Objective with Selective Adaptation for In-domain Contrastive Learning. In Findings of the Association for Computational Linguistics: EACL 2026, pages 3792–3807, Rabat, Morocco. Association for Computational Linguistics.
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MOSAIC: Masked Objective with Selective Adaptation for In-domain Contrastive Learning (Pavlova & Makhlouf, Findings 2026)
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