OwS Introduction: FHIR, CTS2, CTS2-LE and OwS

The OwS interpreter translates OwS defined vocabularies into HL7 FHIR ValueSet Resources. The generated resource definitions are rendered as XML and written to the file system. From there they can be loaded into any Terminology Server that implements a loader for FHIR resouces.

CTS2 and CTS2-LE

From the OwS perspective FHIR is only considered as an exchange format while the underlying OwS object model is based on the much more powerful CTS2 terminology services standard which allows for managing complex and extensible ontologies. E.g. while the recent FHIR version (DSTU-2) does not provide build-in mechanisms for semanticaly defined, poly-hierarchical ontologies and custom properties, such features are available with OwS. In order to make these features available to ontology developers, OwS is optimized for being used in conjunction with the Fraunhofer FOKUS CTS2-LE terminology server. CTS2-LE implements the CTS2 data model on top of RDF so that ontologies with semantically tagged edges and fully networked information models can be expressed. The CTS2-LE FHIR loader uses the extension mechanisms of FHIR and defines additional resources and elements for expressing custonm properties and arbitrary concept relationships. All ontologies defined with OwS can be loaded into CTS2-LE using the standard CTS2-LE FHIR loader.

Ready for FHIR STU-3

The above mentioned CTS2-LE features (custom properties and predicates) will be part of FHIR STU-3 which is recently balloted. As soon as this version of FHIR is released, OwS will allow for transforming OwS definitions into both FHIR STU-2 and STU-3. A system parameter will be provided that allows you to control whether OwS generated FHIR STU-2 or STU-3 compliant terminologies and value sets:

set FHIR.Version = STU-3

Placing this statement into your existing OwS document will automatically generate STU-3 code from an OwS definition that was originally written for DSTU-2.