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Teaser, summary, work performed and final results

Periodic Reporting for period 1 - FREYA (Connected Open Identifiers for Discovery, Access and Use of Research Resources)


Persistent identifiers (PIDs) are an essential element in how research is conducted. They identify and link to digital objects such as online publications and datasets, or real-world entities such as individual researchers and organisations. They provide a convenient and...


Persistent identifiers (PIDs) are an essential element in how research is conducted. They identify and link to digital objects such as online publications and datasets, or real-world entities such as individual researchers and organisations. They provide a convenient and reliable way to refer to these entities and find and access them online.

The FREYA project is developing persistent identifiers into a core component of European and global research e-infrastructures. Although PIDs are already well established in most areas of research, there is still great potential (and necessity) for extending their scope and use within e-infrastructures, and particularly the European Open Science Cloud (EOSC). The movement towards FAIR data places PIDs at centre stage: every aspect of FAIR needs a good PID infrastructure.

The vision of FREYA is built on three key ideas: the PID Graph, PID Forum and PID Commons. The PID Graph is the vision of linking together a wide range of entities with PIDs to allow complex queries going beyond link-following, for example about the impact of particular scientific facilities through the outputs of experiments conducted on them. The Graph is a vision, but consists also in the tools for making that vision a reality—interfaces, standards, practices. In FREYA it is also embodied in the development of pilot applications, embedded in their fields of research and responding to real user needs. The PID Forum is the assembly of stakeholders brought together by FREYA to oversee the project’s developments and provide input and feedback. The PID Commons refers to the structures and mechanisms for achieving sustainability of the PID infrastructure: not only services provided by FREYA partners, but governance more widely, especially within the context of the EOSC.

Work performed

In the first half of the project (18 months), FREYA has worked to define and implement the bases of the PID Graph implementation, to develop PIDs for entities that do not yet have them, and to create and enhance discipline-focussed PID services that will contribute to the overall PID Graph. Important progress has been made, reflected in the corresponding project deliverables, on:
1. identifying and prioritising a comprehensive range of PID Graph use cases;
2. work on backend architecture supporting the PID Graph;
3. a standardized approach to work with the PID Graph both as consumer and contributor;
4. prototype client implementations addressing PID Graph use cases.

FREYA has established an excellent track record in communication with stakeholders and communities in the world of PIDs. At an early stage the project’s initial online communication channels were set up in the form of a Twitter channel and website. FREYA has been represented at many high-profile events including RDA Plenary Meetings, PIDapalooza (a major annual event dedicated to PIDs) and many conferences. An active group of FREYA Ambassadors has been established. A major development was the launch of, a website for all kinds of information exchange about PIDs, under the aegis of FREYA.

Regarding the PID Commons, the landscape has changed rapidly as the FREYA project ahs progressed, and especially as the EOSC juggernaut has gathered momentum and its structures and procedures have become more clearly defined. The plan calls for three cycles of engagement, review, analysis and recommendations. The first cycle has been completed. The work began with a comprehensive review of relevant existing material to inform the planning. Three facets of sustainability are identified: maintainability, adaptability and desirability. The FREYA outputs have been analysed from the perspective of sustainability and in terms of different types of services. The roles in sustainability were considered, and how FREYA’s stakeholder groups relate to them. The ‘how’ of sustainability was analysed, taking account of the context, most importantly the existing PID infrastructure and the EOSC.

Fruitful collaboration is under way with other EOSC-building projects, EOSC-hub and OpenAIRE Advance.

Final results

In the remainder of the project, the vision of the PID Graph will be consolidated in a set of approaches, standards and services whose value will have been demonstrated within the FREYA project itself, and are ready to take their place in the EOSC. An important technical direction is the use of GraphQL as a means of connecting the PID Graph, which will lead to a more uniform implementation, as well as making the PID Graph easier to consume and to extend by others outside of FREYA. Another iimportant result in the context of the EOSC will be FREYA’s PID Services Registry.

The individual PID Graphs of FREYA partners will be enrich and extended, either with new PID types or through advancement in already-established connections. Work on prototypes for new PID services will lead to advanced demonstrators. There is also exploratory work scheduled, looking into the feasibility of extending the use of existing PIDs for entities such as scientific equipment, as well as a focus on metadata—can PID metadata incorporate extended provenance information, and on the other hand, can metadata that is currently being captured but not being utilised, be used in new workflows for PID registration?

There will be further development of the PID Forum and the activities around it, as well as developing PID-related training materials and the Ambassador Programme. Engagement activities will continue via interactive events and There will be expansion of cooperation and integration with the EOSC and RDA, and extending the geographical and disciplinary reach to connect to stakeholders who are currently underrepresented.

The nature of the PID Commons will be clarified through internal workshops and external consultation, especially in the context of EOSC. FREYA will help to deliver two milestones from the European Commission Staff Working Document ‘Implementation Roadmap for the European Open Science Cloud’: ‘Develop initial EOSC federating core including the EOSC shared resources’, and ‘FAIR persistent unique identifier policy defined’.

The impacts of all this work will be felt in the areas of research supported by the European Open Science Cloud and beyond, by providing a firm foundation for exploiting PIDs to develop innovative applications, and establishing effective and resilient governance mechanisms to ensure that PIDs continue to develop in ways that benefit and are open to the communities they serve.

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