NataliaKwasnikowska and JanVanDenBussche, August 14, 2009
Refinement relation proposed in OPM V1.01.
The refinement relation introduced in OPM V1.01 allows the declaration of pairs of accounts, where one account provides a more detailed view of execution than the other one.
Current specification does not however provide a methodology for structuring accounts so that multiple refinements, about different parts of a past execution, can be independently included or excluded in a view. Such a methodology should also accommodate hierarchical refinement, in which a refinement can have itself certain parts that can be further refined.
Please see the attached document.
Hierarchical refinements are particularly useful for providing different levels of detail for execution of nested processes or generation of artifacts. Our methodology provides a solution for modeling multiple hierarchical refinements and an easy way of identifying which configurations of those refinement accounts can be simultaneously presented in a view.
Community is invited to provide comments on proposals.
I'm not sure I understand in a concrete way what is being proposed in terms of the OPM spec. Refines is already defined as is overlaps - seems like I could implement the hierachy proposed using just those constructs. Granted this is a useful use case that shows why one witness might want to provide multiple levels of refinement (we usually discuss refinement and overlap from the prspective of multiple who saw different parts or different granularities), but I'm not sure what has to change in OPM to accomodate this use.
No doubt that more work needs to be done on accounts, and their relationships (e.g. overlaps, refines). I think this proposal is interesting. For completeness, I would have liked to see the two examples spelled out in full, with the set RefAcc of accounts specified fully, and the various relations defined in full also.
I think that there may be some unnecessary restrictions:
This proposals was put under the heading "profile" though it does not mention the word "profile". I think this is currently not a profile since it does not offer a translation of OPM with hierarchical refinements into OPM without hierarchical refinements.
My main concern for this document is that I can't see under what circumstances someone would apply it. It needs to be clarified who is to read it and when. Is it clarifying the semantics of OPM or aiding a designer deciding what to record from their application?
Specific technical questions
Simon wrote "gives more detail about artifact A". What does this mean? Artifacts are constant in OPM, so what more detail is there to give? Paul and I in our translation of pasao to opm and versa came across this requierement. For instance, a given artifact seen at given level of abstraction is in fact a sent artifact and a received artifact in a refinement making communications explicit.
Can you illustrate how your approach deals with the following example:
The fully refined process P1 -> P2 -> P3 seems to have two ancestors here. Do you support it? Thanks,
This is interesting and I appreciate the effort out so far in this work. To address specifically the question on whether this should be further developed, I'd say certainly yes.
One the other hand, I am not expressing a vote as I am not sure what is there to approve at this stage: this reads more like a recommendation for a specific refinement pattern, than something that extends OPM, or should otherwise be prescribed. Is this meant to be a pattern whose adoption we encourage?
Comment by Jan & Natalia: We would appreciate indication of interest by people in further developing the notion of refinement in OPM.
Simon Miles - no, not yet, because I don't understand the circumstances for its use
-- NataliaKwasnikowska - 14 Aug 2009
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I | Attachment ![]() | Action | Size | Date | Who | Comment |
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![]() | refinement.pdf | manage | 60.9 K | 14 Aug 2009 - 16:09 | NataliaKwasnikowska | Proposal for modelling multiple and hierarchical refinements in OPM -- for review |