IHE PCC has been struggling all week with three different workflow profiles. One of the challenging pieces has been to identify the various systems involved. IHE uses the term Actor to identify the useful feature sets that could be specified for a system. We want organizations to be able to say: I want to obtain a system that implements the ABC actor of the XYZ profile and have it be meaningful to both the purchaser and the developer of such a system.
PCC already layered content specific actors on top of the IHE ITI XDS, XDM, XDR and XCA profiles. What we must now do is layer again, the workflow actors on top of XDW, and also associate these actors with content. All of this of course uses a common infrastructure (XDS) to support automation of ad-hoc workflow.
I think we have the right idea now, and will be moving forward. As with most design issues, it is fractal in nature, thus: Turtles all the way down.