OSTrails Metadata Model for SKGs

The RDA Scholarly Knowledge Graph Interoperability Framework (SKG-IF) Core Data Model defines a minimal, interoperable metadata model for representing SKG data in a machine-actionable way.

The model is used to describe the main SKG-IF entities, their attributes, and their relations, using Semantic Web technologies. It reuses and aligns existing ontologies that address specific scholarly communication scenarios, ensuring compatibility with the overall aims of SKG-IF while avoiding reinvention of established models.

The SKG-IF Core Data Model, summarised in Graffoo diagrams, supports the representation of the following key entities:

  • Agent: individuals or organisations (or other acting entities) involved in the creation, publication, dissemination, curation, or assessment of research products.

  • Data source: services or platforms where research products (metadata and, where applicable, files) are stored, preserved, made discoverable, and accessed.

  • Grant: funding awarded by a funding body to one or more agents.

  • Research product: research outputs of different types, such as research literature, research data, research software, or other categories.

  • Topic: scientific disciplines, subjects, or keywords relevant to a research product and its context.

  • Venue: publishing or dissemination channels through which research products are made available (e.g., journals, conferences, platforms).

The SKG-IF Core Data Model is implemented as an OWL ontology, the SKG-IF Ontology (SKG-O). Rather than introducing yet another standalone bibliographic ontology, SKG-O aggregates and organises complementary ontological entities from several existing vocabularies used within SKG-IF, providing a coherent space for descriptive metadata compliant with the SKG-IF Data Model.

SKG-O is structured into six ontological modules, one for each SKG-IF entity type, all formally imported into the main ontology:

Version and usage

Within the SKG Commons, the SKG-IF Core Data Model and SKG-O serve as the foundational layer on which higher-level specifications are built: SKG-IF Extensions, application profiles, and the SKG Commons API specifications. All additional constraints and specialisations are defined on top of this core model, ensuring alignment with the RDA SKG-IF framework.

SKG-IF data produced under the Interoperability Framework align with SKG-O via the SKG-IF JSON-LD context, which binds JSON structures to ontology terms. Furthermore, a dedicated SHACL shapes document is provided for semantic validation of data against the Core Data Model, ensuring conformance and consistency across implementations.

Scope and role within the SKG Commons

Within the SKG Commons, the SKG-IF Core Data Model:

  • Defines the minimum set of concepts required to describe SKGs in a machine-actionable, semantically rich way

  • Establishes a shared semantic baseline across tools and services

  • Enables interoperability without dictating internal data models or architectures in individual systems

Domain- or policy-specific requirements are intentionally handled at higher layers (e.g., SKG-IF Extensions and application profiles). This separation keeps the core model stable, reusable, and broadly applicable across communities and infrastructures.

Community governance and maintenance

The SKG-IF Core Data Model and SKG-O are developed and maintained by the community within the Research Data Alliance (RDA) SKG-IF activities. Issues, discussions, and change proposals concerning the model and ontology are managed via the established RDA community processes.

Typical resources include:

These venues are the authoritative channels for proposing changes, reporting issues, and discussing the ongoing evolution of the SKG-IF Core Data Model and its ontology.