W3C home > Mailing lists > Public > public-prov-comments@w3.org > July 2012

Re: relations between activites

From: Paul Groth <p.t.groth@vu.nl>
Date: Fri, 6 Jul 2012 15:14:36 +0200
Message-ID: <CAJCyKRqtC47OWc_rDRhFcQGdJ-yy2toQBCguUywFGZpHO5Q8Jw@mail.gmail.com>
To: Satrajit Ghosh <satra@mit.edu>
Cc: "public-prov-comments@w3.org" <public-prov-comments@w3.org>
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?


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
Received on Friday, 6 July 2012 13:15:04 UTC

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