Interlinking Research Data and Services in the Historical Sciences: MemO and the NFDI4Memory Knowledge Graph
Abstract
The German National Research Data Infrastructure (NFDI) aims to harmonize the flow of data from science and research. Consequently, the NFDI4Memory consortium, responsible for data from historically oriented sciences, also pursues this bigger objective. The goal is to realize a FAIR digital research environment in which users can discover content through shared semantic structures on previously unconnected materials. Essential to this effort is the development of the NFDI4Memory Ontology (MemO) and the NFDI4Memory Knowledge Graph (MemO KG). In combination, they build the ground for the NFDI4Memory Data Space, supporting federated searches and semantic interoperability. As a modular extension of the interconsortial mid-level ontologies NFDIcore and the Culture Ontology, MemO incorporates domain-specific concepts from the historical sciences, among others, including the harmonization of metadata and the detailed representation of provenance. The MemO KG serves as a central index, harmonizing metadata for research data, institutions, researchers, and services. This infrastructure lays the groundwork for a unified point of access to research data across disciplines and consortia. Thereby, it fosters new modes of exploration and research data acquisition in historical research.
Full text
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 November 2, 2025 – Sci-K 2025 @ ISWC 2025, Nara, Japan Interlinking Research Data and Services in the Historical Sciences: MemO and the NFDI4Memory Knowledge Graph Sarah Rebecca Ondraszek, Tabea Tietz, Jörg Waitelonis, and Harald Sack FIZ Karlsruhe – Leibniz Institute for Information Infrastructure, Germany Institute of Applied Informatics and Formal Description Methods (AIFB) of KIT, Karlsruhe, Germany
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 2 The German National Research Data Infrastructure
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 3 NFDI4Memory is a part of the National Research Data Infrastructure (NFDI). NFDI is a German Research Foundation (DFG)-funded initiative for FAIR, interoperable data infrastructures across research domains. NFDI4Memory and associated challenges
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 NFDI4Memory is a consortium with a focus on the historically oriented humanities. NFDI4Memory and associated challenges NFDI4Memory task areas: https://opus4.kobv.de/opus4-h-da/frontdoor/deliver/index/docId /352/file/nfdi4memory_proposal_public.pdf 4
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 5 Challenges
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 6 ●Highly diverse disciplines, data formats, etc. (OAI-PMH, RDF/XML, …). ●Fragmented, heterogeneous historical research data (EHRI, DDB, FactGrid, …). ●Multiple, unconnected access points (also data aggregators). ●As always… limited resources – workforce, time, infrastructures, etc. NFDI4Memory and associated challenges
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 7 Motivation
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 8 ●Connect distributed, heterogeneous data and enable FAIR data sharing. ●NFDI4Memory knowledge graph (KG) as central index connecting decentralized sources without duplicating data. ○Unified access via the NFDI4Memory Data Space. ●Linking via shared concepts (people, places, events). ○A corresponding formalization through the NFDI4Memory ontology = MemO, based on NFDIcore. Motivation
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 9 Related work
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 MemO and the NFDI4Memory Knowledge Graph Two conceptual subgraphs: ●Research Data Graph (RDG) focuses on ‘primary’ research data. ●This includes, among other things: ○archival materials, ○hierarchical relationships between documents, ○provenance descriptions, ○document-content-relationships (such as mentioned persons, events, …). 16
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 17 A modeling example
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 Modeling example: cross-linking with FactGrid ●FactGrid: a collaborative Wikibase graph database for researchers with a historical research interest. ●Central aspects: Provenance information (for claims, for provided information, etc.). ●Challenges: Entity vs. metadata about an entity (see following example). 18
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 19 Example: Provenance about claims in FactGrid https://database.factgrid.de/wiki/Item:Q595
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 A data story about cross-connections ●Traditional challenge: Researcher needs to search multiple unconnected repositories separately. ●MemO solution: Single entry point for querying across disparate collections using … ○… keywords, ○… facets, ○… or SPARQL queries. 20
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 21 Example: cross-linking with FactGrid
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 22 Conclusion
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 Conclusion and future work ●Integrated system of the MemO ontology (as modular extensions of NFDIcore and CTO) and MemO KG. ●Next steps include: ○expanding with additional domain modules (archival structures, DataSpace requirements), ○and continuing KG population. ●Full release: End of November. ●Evaluation planned especially through collaboration with domain experts. 23
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 24 THANK YOU! Visual graphics generated with AI. Sarah Rebecca Ondraszek, Tabea Tietz, Jörg Waitelonis, and Harald Sack FIZ Karlsruhe – Leibniz Institute for Information Infrastructure Karlsruhe Institute for Technology (KIT) Private Mastodon: @sourisnumerique FIZ ISE Mastodon: @fizise Mail: sarah-rebecca.ondraszek@fiz-karlsruhe.de Check out the MemOverse in the latest prototype!
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 25 Resources ●NFDIcore: https://ise-fizkarlsruhe.github.io/nfdicore/ ●NFDI4Culture ontology: https://nfdi.fiz-karlsruhe.de/4culture/ontology/ ●Culture Portal: https://nfdi4culture.de/de/dienste/details/culture-information-portal.html ●NFDI4Memory knowledge graph: https://nfdi.fiz-karlsruhe.de/4memory/ ●NFDI4Memory ontology (MemO): https://nfdi.fiz-karlsruhe.de/4memory/ontology/ ●EHRI: https://ehri-kg.ehri-project.eu/ ●DDB: https://www.deutsche-digitale-bibliothek.de ●FactGrid: https://database.factgrid.de/
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 32 Example: Classifiers and interconnections. *Schematic example of an archival document. Item: Documents from the Department of Personal Information on World War I and World War II. https://www.bundesarchiv.de/das-bundesarchiv/aus-unserer-archivarbeit/unterlagen-der-abteilung-personenbezogene-auskuenfte-zum-ersten-u nd-zweiten-weltkrieg/ *
Sarah Ondraszek et al., Interlinking Historical Research Data, Sci-K 2025 @ ISWC 2025, November 2, 2025 33 Example: Classifiers and interconnections. http://www.deutsche-digitale-bibliothek.de/item/GQWQTBVFT4ALGUD4V3KJQ7HZ3HWW3RMR