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Re: relations between activites

From: Timothy Lebo <lebot@rpi.edu>
Date: Fri, 6 Jul 2012 13:13:16 -0400
Cc: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>, Provenance Working Group <public-prov-wg@w3.org>
Message-Id: <F5016583-1ED7-436E-A125-FB4EC66E3EEE@rpi.edu>
To: Paul Groth <p.t.groth@vu.nl>

On Jul 6, 2012, at 11:09 AM, Paul Groth wrote:

> My suggestion would be to put this as an issue to be considered with
> all the issues arising from last call.
> 

I made ISSUE-447 for this thread.

-Tim


> 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 17:13:55 UTC

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