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Product Brief - Enterprise Architecture Specification

Services-Aware Enterprise Architecture Specification (SAEAF)

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Summary

The HL7 SOA-Aware Enterprise Architecture provides a framework for specification of standardized services that can be used by the HL7 community. It identifies artifacts and a constraint pattern that provides traceability from requirements. These specifications align with different levels of conformance that aid HL7 consumers in adopting standards in different contexts, and supports specific integration patterns between collaborators as they seek to achieve computable semantic interoperability.

Description

The ArB Jump Start project was convened in the spirit of the “Left Side of the RIM” meetings some years ago. That is, they were an attempt to simplify and clarify the problem of how services will be created in HL7, how services serve a strategic vision, and then to bring the results of those discussions back to the community in an open and transparent manner. The ArB, through its membership and in conjunction with the organizations that were represented at the meetings, has defined portions of an enterprise architecture that is services-aware, that can aid HL7 in crafting a strategic vision that supports services, and (somewhat surprisingly) seems to provide a number of extension points that allows the various artifacts from HL7 to be aligned. The members of the ArB termed this the “unified field theory.” While this was neither the goal nor the focus of the Jump Start Sessions, the ArB took this finding as an indicator that we are fundamentally on the right track.

The HL7 SOA-Aware Enterprise Architecture provides a framework for specification of standardized services that can be used by the HL7 community. It identifies artifacts and a constraint pattern that provides traceability from requirements. These specifications align with different levels of conformance that aid HL7 consumers in adopting standards in different contexts, and supports specific integration patterns between collaborators as they seek to achieve computable semantic interoperability. The HL7 SOA EA builds on the successes of the Healthcare Service Specification Project, taking many of its artifacts and its initial services as starting points. The lessons learned through the HSSP process as well as through the implementation of HSSP artifacts has provided a consistent touchstone for this effort.

The Enterprise Architecture provides things that HL7 supporters need to achieve working interoperability in any given context. It uses the RM-ODP standard as a framework within which to create and define artifacts and specifications. RM-ODP provides a 4 dimensional approach to specification via conformance assertions. This approach allows for complete system specifications to be built from the business, informational, computational, and engineering viewpoints, and for the technical realization of these things to verify and validate the conformance assertions arising from these viewpoints. The things that the EA provides are not limited to “services”, though SOA provides some focus and placeholders for talking about functional semantics in a way that has traditionally been difficult to breach.

The ArB feels that the combination of HL7, SOA, EA, RM-ODP, and MDA allows not only for a successful framework for the creation of services, but also most other HL7 artifacts. This “unified field theory” was not a goal of these ArB Jump Start sessions – on the contrary, the focus at first was very much on services to the exclusion of documents and messages. But in the process of creating a structure for specifying services, the ArB feels that they have provided a means of contextualizing other HL7 work, mixing it with a logical dynamic model, contract-based integration, functional specification, requirements traceability, and explicit expressions of policy and governance. Additionally, some clarity has been achieved in establishing the foundation of a governance model within HL7 as well as answering some existing questions around what it means to conform to HL7.

The ArB feels like it has provided a potent framework for specification of HL7 standards, including documents, services, and messages. This framework supports an explicit conformance model, and allows for extension of organizational governance models to incorporate these specifications. It has specified a meta-model for dynamic frameworks that aligns with two industry standards (SOA Pro and WS-CDL). It aligns with the recent work within several national organizations (DoD, Canada Infoway, NCI caBIG), and seems to align with the recent work from B.G.M.E. Blobel.

Resources

Work Groups

• ArB - Architecture Board