- From: Paul Groth <p.t.groth@vu.nl>
- Date: Fri, 6 Jul 2012 17:09:10 +0200
- To: Timothy Lebo <lebot@rpi.edu>
- Cc: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>, Provenance Working Group <public-prov-wg@w3.org>
My suggestion would be to put this as an issue to be considered with all the issues arising from last call. I think as a process, we should try to collect these issues and then see what we do about each. cheers Paul On Fri, Jul 6, 2012 at 5:04 PM, Timothy Lebo <lebot@rpi.edu> wrote: > Stian, > > (cc'ing our working group list instead of the comments list) > > On Jul 6, 2012, at 10:09 AM, Stian Soiland-Reyes wrote: > >> I would at least be very interested in defining activity composition >> as part of PROV. >> >> I think as Tim points out there are many existing ways to model >> composition, but I don't think that means that PROV should ignore >> composition of activities and entities - it would be important to >> understand that for the outcome of the ex:Project there were many >> ex:MRIScannings - if we leave these to custom attributes, then those >> are separate islands in PROV. > > As Paul mentions, heading down the path of composition leads to an abundance of details that would need to be considered, and is beyond the scope of our charter. > For example, I imagine we'd want temporal constraints imposing that the start of a child must not precede the start of the parent, etc. > That's a whole new area of the material that we have not addressed as a WG during its lifetime, and deserves more time than we can give it as things are finishing up. > > Regarding your "islands" comment, that is the nature of defining any model with any coherent scope. > We've had the "island" argument for Dictionaries, and they ended up in a Note (with only Collection and hadMember surviving as a Rec). > So, perhaps we respond to Satra's comment with a bare-bones activity composition? > I'd like to point out that specialization already provides an orthogonal dimension similar to activity composition, but specialization is only among entities. > Also, is there adequate prior art on activity composition and granularity management? From what I've seen, the community has only stabbed at different parts of the elephant. > >> >> We did get rid of wasStartedByActivity for simplicity. Perhaps for >> wasInformedBy we can suggest some subtypes like prov:WasPartOf ? > > Although wasPartOf may be a subtype of wasInformedBy from a workflow perspective, I think communication and part hood are orthogonal in general. > So tucking it under there doesn't seem appropriate. > > Regards, > Tim > > >> >> >> >> On Fri, Jul 6, 2012 at 2:14 PM, Paul Groth <p.t.groth@vu.nl> wrote: >>> Hi Satra, >>> >>> Thanks for the question. We actually have had several people ask a >>> similar question. So I'm also curious what the group will answer :-) >>> >>> For wasFollowedBy, we actually have the relation wasInformedBy which >>> you can use for activity ordering. >>> >>> I think we were reticent to start defining the composition of >>> activities because that could lead down the path of defining an entire >>> workflow or programming language, which is not in our charter or >>> something we would want to do. I guess the answer was that we were >>> worried about feature creep. Do we stop at just composition or would >>> other constructs be necessary? >>> >>> thanks >>> Paul >>> >>> On Fri, Jul 6, 2012 at 2:45 PM, Satrajit Ghosh <satra@mit.edu> wrote: >>>> hello, >>>> >>>> i was discussing this with luc and based on his feedback thought it might be >>>> useful to bring this up on the list. >>>> >>>> ---- >>>> question: >>>> how do you encode that a certain activity "emailing a letter" happened >>>> during another activity "a meeting"? >>>> >>>> for example we conduct research studies/projects. >>>> >>>> activity(p1, [prov:type='ex:Project']) >>>> activity(p2, [prov:type='ex:MRIScanning', ex:session=1]) >>>> activity(p3, [prov:type='ex:MRIScanning', ex:session=2]) >>>> >>>> how would i encode that this activity p2 and p3 were conducted during p1? >>>> how would i encode p3 followed p2? >>>> >>>> >>>> luc's response: >>>> Regarding your question, there may be a few options: >>>> you could add time information to your activities. This will help you >>>> understand their ordering. >>>> >>>> Alternatively, if you want an explicit dependency in your graph, then p2 may >>>> generate something >>>> that starts p3, and/or is consumed by p3 >>>> >>>> Finally, prov doesn't have relations between activities, to express their >>>> nesting, etc. It's important >>>> but we felt this is not specific to provenance, but to process executions. >>>> ---- >>>> >>>> it's the last point on this response that i was not completely sure about. >>>> why "relations between activities" is "not specific to provenance, but to >>>> process executions." >>>> >>>> in the above example, one could say: >>>> >>>> wasSubtaskOf(p2, p1) >>>> wasSubtaskOf(p3, p1) >>>> wasFollowedBy(p2, p3) >>>> >>>> any clarification as to why such relations would be outside the realm of >>>> provenance would be much appreciated. >>>> >>>> cheers, >>>> >>>> satra >>> >> >> >> >> -- >> Stian Soiland-Reyes, myGrid team >> School of Computer Science >> The University of Manchester >> >> > -- -- Dr. Paul Groth (p.t.groth@vu.nl) http://www.few.vu.nl/~pgroth/ Assistant Professor Knowledge Representation & Reasoning Group Artificial Intelligence Section Department of Computer Science VU University Amsterdam
Received on Friday, 6 July 2012 15:09:38 UTC