Reference Architecture

The DE4A Reference Architecture is based on the Architecture Metamodel described in deliverable D2.1 Architecture Framework and applies the definitions and description language from ArchiMate and BPMN.

The first version of the Reference Architecture is developed with a clear focus on providing direction to the DE4A Pilots as part of the public deliverable D2.4 Project Start Architecture (PSA) - First iteration. Most important inputs to the PSA are the Architecture Framework, the detailed requirements of the DE4A Pilots as expressed in the public deliverables D4.1, D4.5 and D4.9 and an analysis of the legal requirements of Article 14 of the Regulation (EU) 2018/1724 establishing a single digital gateway to provide access to information, to procedures and to assistance and problem-solving service (SDGR).

The PSA - First iteration recognizes three distinct Reference Interaction Patterns: The design of the Intermediation Pattern took the Single Digital Gateway (SDG) Once-Only Technical System High Level Architecture (HLA) and insights gained from the TOOP Reference Architecture as starting point and was instrumental in uncovering implicit assumptions (i.e. working hypotheses) concerning the fundamental, Interdisciplinary Questions in context of cross-border exchange of evidence. The User-supported Intermediation Pattern can relax some of these hypotheses by introducing a direct interaction between the User and the Data Provider. These two patterns fall in the Time Horizon t=2 (~end 2023), whereas the third pattern, the Verifiable Credentials Pattern open a perspective to the potential future solution and investigates the transformative impact of new blockchain technologies.

The forthcoming Project Start Architecture - Second iteration introduces two additional Reference Interaction Pattern: the Subscription and Notification Pattern and the Lookup Pattern.

The development of the DE4A Reference Architecture started in the context of D2.4 Project Start Architecture (PSA) - First iteration and recognizes three distinct Reference Interaction Patterns:

• Intermediation Pattern
• User-supported Intermediation Pattern
• Verifiable Credentials Pattern

The forthcoming D2.5 Project Start Architecture (PSA) - Second iteration is introducing two additional Reference Interaction Pattern:

• Subscription and Notification Pattern
• Lookup Pattern

The Architecture Log keeps track of deviations from DE4A principles and the reference architecture in general and also records the implications.

The list of Interdisciplinary Questions deals with complex interdisciplenary topics and underlying working assumptions.

Reference Interaction Patterns

Reference Interaction Patterns:

• Intermediation Pattern
• User-supported Intermediation Pattern
• Verifiable Credentials Pattern
• Lookup Pattern
• Subscription and Notification Pattern