ANLP_UniSo at KnowledgeGraphEval 2026: Domain-Adaptive Nested Named Entity Recognition for Arabic via GlobalPointer Ensembling

Eya Bouzaiene, Omar Trigui, Lamia Belguith


Abstract
The ANLP_UniSo team submitted a system to Subtask 1 (Named Entity Recognition) of KnowledgeGraphEval 2026, which focuses on nested NER in Arabic and evaluates crossdomain and cross-dialect generalization from the Wojood corpus to the multi-domain Konooz benchmark. The system is a combination of an Efficient GlobalPointer decoder with rotary position embeddings and a MARBERT backbone. To reduce the domain gap, first domainadaptive pretraining (DAPT) is performed on unlabeled Konooz text, and then a pseudolabeling self-training stage is applied. A second model based on AraBERT is trained and combined to the other model using a stacking ensemble to improve prediction diversity. As for the Wojood test set, the best ensemble achieves a micro F1 of 0.9288, increasing to 0.9292 when entity-type-specific decision thresholds are used, compared with 0.9211 for the single MARBERT model. On the official blind Konooz test set, however, the submitted system obtains a micro F1 of 0.7106 (macro F1 = 0.6101, weighted F1 = 0.7013, P = 0.8143, R = 0.6304, accuracy = 0.9948). The lower recall suggests that the decoding threshold chosen based on the Wojood validation data was too strict for the domain-shifted Konooz data. the system study the difference and propose a threshold-recalibration strategy to improve the performance under the target-domain distribution.
Anthology ID:
2026.arabicnlp-sharedtasks.157
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:
1250–1254
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.157/
DOI:
Bibkey:
Cite (ACL):
Eya Bouzaiene, Omar Trigui, and Lamia Belguith. 2026. ANLP_UniSo at KnowledgeGraphEval 2026: Domain-Adaptive Nested Named Entity Recognition for Arabic via GlobalPointer Ensembling. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 1250–1254, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ANLP_UniSo at KnowledgeGraphEval 2026: Domain-Adaptive Nested Named Entity Recognition for Arabic via GlobalPointer Ensembling (Bouzaiene et al., ArabicNLP 2026)
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PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.157.pdf