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Re: Activity composition

From: Jim McCusker <mccusj@rpi.edu>
Date: Wed, 9 May 2012 17:56:01 -0400
Message-ID: <CAAtgn=TowzPTZ6tUo=+JLV+0KT27D5UzESiR1twxDwAsL5xyAw@mail.gmail.com>
To: Paolo Ncl <Paolo.Missier@ncl.ac.uk>
Cc: Davide Ceolin <davide.ceolin@gmail.com>, "public-prov-comments@w3.org" <public-prov-comments@w3.org>
There are some problems here with composition though, specifically when you
try to say something like this:

:a1 a prov:Activity.
:a2 a prov:Activity; dc:partOf :a1.

:e1 a prov:Entity; prov:wasGeneratedBy :a1, :a2.

Basically, since :a2 is part of :a1, and :a2 served as a "final activity"
(there aren't any further activities that used :e1), :e1, by virtue of
being generated by :a2 was also generated by :a1. But since wasGeneratedBy
is functional, we cannot assert that without :a1 and :a2 becoming identical


On Wed, May 9, 2012 at 5:47 PM, Paolo Ncl <Paolo.Missier@ncl.ac.uk> wrote:

> Davide
> I guess it depends on how you define "part of" in this setting. You can
> specify that an activity has started another, which makes, informally, the
> former a "parent" of the latter. You can use this to model forking, for
> example. This is about the observed behavior of a process and is within
> scope. But there is no way to express structural containment, or
> composition, because describing process models and structure (for instance,
> the structure of a program, a workflow, a script etc.) is not within the
> PROV scope.
> I hope others in the group concur with this interpretation
> Regards,
> P.Missier - paolo.missier@ncl.ac.uk
> On 7 May 2012, at 21:44, Davide Ceolin <davide.ceolin@gmail.com> wrote:
> > Hello,
> >
> > I am a PhD student of the VU University Amsterdam, and I would have a
> question about the composition of activities in PROV. I noticed that it is
> not possible to explicitly state that an activity is actually part of
> another one.
> >
> > Suppose that a given entity is the result of an activity and, in turn,
> this activity is part of a larger one.
> >
> > I can represent this scenario with two separate graphs stating that each
> of the two activities generated the entity, and from them (and their
> execution times, etc.) I may infer that one is part of the other one, but I
> can't explicitly state that.
> >
> > Is there a specific reason for such a limitation?
> >
> > Thanks,
> >
> > Davide
> >
> > Davide Ceolin MSc.
> > PhD student
> > The Network Institute
> > VU University Amsterdam
> > d.ceolin@vu.nl
> > http://www.few.vu.nl/~dceolin/
> >
> >
> >

Jim McCusker
Programmer Analyst
Krauthammer Lab, Pathology Informatics
Yale School of Medicine
james.mccusker@yale.edu | (203) 785-6330

PhD Student
Tetherless World Constellation
Rensselaer Polytechnic Institute
Received on Wednesday, 9 May 2012 21:56:53 GMT

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