Beyond Known Event Types: Open-Domain Event Detection via Ontology-Guided Grounding–Discovery Resolution

Yuhan Hu, Yupeng Qi, Yongxi Luo, Chen Su, Shan Huang, Ziyu Lyu


Abstract
Open-domain event detection aims to identify known event types while discovering previously unseen ones from unstructured documents. In practice, event detection systems often operate with an evolving event set rather than a complete type inventory. Under this setting, existing zero-shot event detection methods can fail in two ways when the event type is absent from the predefined set: the model may either miss the event or assign it to a plausible but wrong known type, hiding the need for discovery. To address this problem, we propose OGED, an  ̲Ontology- ̲Guided open-domain  ̲Event  ̲Detection framework for grounding–discovery resolution, i.e., deciding whether an event mention should be assigned to an existing type or should induce a new type. OGED organizes the available event types into a hierarchical search structure, uses cluster-level scheduler and adaptive planning to keep known-type assignment and new-type discovery jointly active, and applies retrieval-gated verification together with conflict selection to resolve competing assignments before output. Experiments on a unified benchmark with 564 event types show that OGED outperforms strong baselines on both known-type detection and unknown-type discovery. Code is available at https://github.com/chenzhouli/OGED.
Anthology ID:
2026.findings-emnlp.2001
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
42649–42667
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2001/
DOI:
Bibkey:
Cite (ACL):
Yuhan Hu, Yupeng Qi, Yongxi Luo, Chen Su, Shan Huang, and Ziyu Lyu. 2026. Beyond Known Event Types: Open-Domain Event Detection via Ontology-Guided Grounding–Discovery Resolution. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 42649–42667, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Beyond Known Event Types: Open-Domain Event Detection via Ontology-Guided Grounding–Discovery Resolution (Hu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2001.pdf