McMasterNLP at KnowledgeGraphEval-2026: Heterogeneous Expert Systems for Arabic Knowledge Graph Construction

Abdelaziz Essam Abdalla Serour, Suhaila Mohammed, Sruthi Rajnikhanth, Saeed Abuzannad, Daniel Hu, Milad Alshomary, Allison Lahnala


Abstract
Automated knowledge graph (KG) construction involves two core components: nested named entity recognition (NER) and relation extraction (RE). In this work, we address cross-domain nested NER alongside RE. We integrate domain adaptation methods within a mixture-of-experts ensemble system for nested NER from Arabic text, evaluated in a cross-domain setting. The system combines multiple Arabic pretrained encoders for token- and span-level classification with domain data augmentation, and integrates their predictions using a vote-based ensemble routing with a complementary XLM-R expert. For RE, we employ an adversarially trained relation classifier backed by auxiliary entity types, NLI reranking, and structural schema rules, treating no_relation as a standard relation label. We additionally study a positive-relation setting that excludes no_relation from both training and inference. Our NER system reaches 0.7438 micro F1 on the hidden test set. For RE, the positive-relation setting achieves 0.9608 micro F1, while the no_relation-aware system achieves 0.9295.
Anthology ID:
2026.arabicnlp-sharedtasks.154
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:
1227–1237
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.154/
DOI:
Bibkey:
Cite (ACL):
Abdelaziz Essam Abdalla Serour, Suhaila Mohammed, Sruthi Rajnikhanth, Saeed Abuzannad, Daniel Hu, Milad Alshomary, and Allison Lahnala. 2026. McMasterNLP at KnowledgeGraphEval-2026: Heterogeneous Expert Systems for Arabic Knowledge Graph Construction. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1227–1237, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
McMasterNLP at KnowledgeGraphEval-2026: Heterogeneous Expert Systems for Arabic Knowledge Graph Construction (Serour et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.154.pdf