Modality-Conditioned Ensembles and Zero-Shot Cross-Encoder Reranking for Relation Classification Between Astronomy-Paper Objects

M. Tahsan Zahid, Most. Atkia Farzana, Tonmoy Sarker Sourav


Abstract
The WASP 2026 (AstroCLIMB) task requires classifying the relation between a pair of objects drawn from astronomy papers — same_figure, same_paper, related_papers, or unrelated_papers — where each pair combines text (captions) and/or images (figures) in one of three disjoint modality configurations: image+text, text+text, and image+image. Since same_figure cannot occur outside the image+text subset, a single unified classifier is structurally sub-optimal; we instead adopt three independent per-modality classifiers whose predictions are pooled for the competition metric (pooled macro-F1). Starting from a hand-engineered baseline (CLIP, SciNCL and DINOv2 embeddings with lexical/OCR features and a LightGBM ensemble), we find that replacing the encoder with a joint vision-language embedding model (Qwen3-VL-Embedding-2B) produces the largest single improvement among the experiments we tested (public leaderboard 0.4808 → 0.62319), exceeding the combined effect of six feature-engineering ideas that were implemented and measured but produced less than 0.01 macro-F1 each. We further show that zero-shot cross-encoder rerankers (Qwen3-VL-Reranker-2B, Qwen3-Reranker-4B), applied with no task-specific fine-tuning, add a second large improvement on top of the engineered ensemble (leaderboard 0.64210 → 0.66299), and that an untrained text+text reranker alone already outperforms the fully engineered pipeline on that subset (macro-F1 0.7111 vs. 0.6704). We report a parallel distant-supervision branch that trains on 120,000 externally-labeled pairs mined from the competition’s source corpus and reaches a comparable but lower leaderboard score (0.57713) through a different mechanism; under our tested data and modeling regimes, this suggests that representation quality was a stronger bottleneck than either additional hand-engineered features or additional distant supervision. All reported numbers are traced to raw out-of-fold prediction arrays or literal notebook output under a shared leak-free StratifiedKFold(5) protocol, and we document two negative results (a broken nested-honest validation split, and several feature-engineering ideas that measurably hurt) as concrete engineering findings.
Anthology ID:
2026.wasp-1.13
Volume:
Proceedings of the 4th Workshop on Artificial Intelligence for Scientific Publications
Month:
November
Year:
2026
Address:
Hengqin, Zhuhai, China
Editors:
Alberto Accomazzi, Tirthankar Ghosal, Felix Grezes, Kelly Lockhart, Atilla Kaan Alkan
Venues:
WASP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
112–121
Language:
URL:
https://aclanthology.org/2026.wasp-1.13/
DOI:
Bibkey:
Cite (ACL):
M. Tahsan Zahid, Most. Atkia Farzana, and Tonmoy Sarker Sourav. 2026. Modality-Conditioned Ensembles and Zero-Shot Cross-Encoder Reranking for Relation Classification Between Astronomy-Paper Objects. In Proceedings of the 4th Workshop on Artificial Intelligence for Scientific Publications, pages 112–121, Hengqin, Zhuhai, China. Association for Computational Linguistics.
Cite (Informal):
Modality-Conditioned Ensembles and Zero-Shot Cross-Encoder Reranking for Relation Classification Between Astronomy-Paper Objects (Zahid et al., WASP 2026)
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PDF:
https://aclanthology.org/2026.wasp-1.13.pdf