Data Integration & Semantic Alignment Across Disciplines with NFDIcore

Presented at the HMC Conference 2026 "Metadata in Action", 28–30 April 2026, DKFZ, Heidelberg, Germany. This poster presents NFDIcore, a mid-level ontology providing a shared, minimal, and stable semantic backbone for the National Research Data Infrastructure (NFDI). NFDIcore represents metadata about research data, agents, projects, services, and guidelines, and serves as a unified framework for data management, organisation, and integration across scientific disciplines. The poster introduces the modular architecture of NFDIcore, which enables it to act as the basis for domain-specific ontological extensions. Four such extensions are presented: CTO (NFDI4Culture): decentralised access to cultural heritage resources MEMO (NFDI4Memory): metadata harmonisation and provenance representation in historical sciences DSAI (NFDI4DataScience): annotation of the AI research lifecycle from datasets to models to publications MWO (NFDI-MatWerk): lifecycle annotation and integration for materials science data The poster further describes the ongoing mapping of NFDIcore to DCAT-AP+ (Data Catalog Vocabulary with a provenance layer), enabling broader interoperability, interdisciplinary data reuse, and knowledge transfer across NFDI consortia.