iMak AI Lab at ArGuard Shared Tasks: Heterogeneous LoRA Ensembles of Vision-Language Models for Arabic Hateful Meme Detection

Artiom Lipinski, Ilya Makarov


Abstract
We describe our submissions to Task A of the ArGuard 2026 shared task on harmful-content detection in Arabic memes: binary hateful-meme detection (Subtask A1) and fine-grained multilabel categorization (Subtask A2). Our A1 system is a probability-averaging ensemble of 22 fine-tuned models: 18 Qwen3-VL vision-language members (8B and 32B) trained with LoRA and scored via first-token logits, and 4 Arabic text-encoder members (MARBERTv2, AraBERTv02-twitter), combined at a fixed 0.85/0.15 modality mix. The system ranked first on Subtask A1 with 0.8234 macro F1, 2.2 points above our best single member. For A2, six LoRA-tuned VLMs with sigmoid multilabel heads, an A1-consistency mask, and flat 0.5 thresholds scored 0.3900 macro F1. Post-hoc analysis on the released gold labels shows that our single global threshold survived an unannounced 8-point drop in the share of hateful memes in the test set, and that most remaining errors in both subtasks separate benign sarcasm or humor from mockery aimed at a protected target.
Anthology ID:
2026.arabicnlp-sharedtasks.57
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Muhammad Abdul-Mageed, Tamer Elsayed, Houda Bouamor, Samhaa El-Beltagy, Hend Al-Khalifa, Ahmed Abdelali, AbdelRahim Elmadany, Abdellah El Mekki, Kareem Darwish, Sakhar Alkhereyf, Hamzah Luqman, Salam Khalifa, Samar Magdy, Zaid Alyafeai, Injy Hamed, Wajdi Zaghouani, Imed Zitouni
Venue:
ArabicNLP
SIG:
SIGARAB
Publisher:
Association for Computational Linguistics
Note:
Pages:
443–447
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.57/
DOI:
Bibkey:
Cite (ACL):
Artiom Lipinski and Ilya Makarov. 2026. iMak AI Lab at ArGuard Shared Tasks: Heterogeneous LoRA Ensembles of Vision-Language Models for Arabic Hateful Meme Detection. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 443–447, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
iMak AI Lab at ArGuard Shared Tasks: Heterogeneous LoRA Ensembles of Vision-Language Models for Arabic Hateful Meme Detection (Lipinski & Makarov, ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.57.pdf