AI4PC-Howard University at SemEval-2026 Task 5: Calibrated Hybrid Ensembling and Retrieval-Augmented LLM Reasoning for Narrative Word-Sense Plausibility

Kwaku Asare, Saurav Aryal


Abstract
We present two complementary approaches for rating word-sense plausibility in SemEval-2026 Task 5 (literary homonyms in five-sentence stories). Approach 1 is a retrieve-then-generate pipeline using an open-weight Llama 3.1 70B Instruct model with structured reasoning and a self-correction pass. Approach 2 is a hybrid ensemble that combines API-based LLM prompting with transformer representations and a learned calibration layer trained on the development set. On the development set, Approach 2 achieves Spearman ρ = 0.7393 (p 10-102) with accuracy 0.8010 (471/588). Approach 1 achieves ρ = 0.5187 (p 10-65) with accuracy 0.6032 (561/930). We emphasize that Approach 1 does not exceed RoBERTabase in accuracy (0.6032 vs. 0.6410), but provides stronger rank correlation.
Anthology ID:
2026.semeval-1.326
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
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Publisher:
Association for Computational Linguistics
Note:
Pages:
2592–2596
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URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.326/
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Cite (ACL):
Kwaku Asare and Saurav Aryal. 2026. AI4PC-Howard University at SemEval-2026 Task 5: Calibrated Hybrid Ensembling and Retrieval-Augmented LLM Reasoning for Narrative Word-Sense Plausibility. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2592–2596, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
AI4PC-Howard University at SemEval-2026 Task 5: Calibrated Hybrid Ensembling and Retrieval-Augmented LLM Reasoning for Narrative Word-Sense Plausibility (Asare & Aryal, SemEval 2026)
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https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.326.pdf