Re: Activity composition

Perhaps wasGeneratedBy should not be functional?

I think supporting activity composition will be heavily requested by the provenance community.  I know projects at RPI/HAO  that I am a part of and provenance projects at CSIRO have recognized it as an important (potentially critical) aspect in generating provenance presentations/visualizations for end users.

Perhaps if a :a2 generated an entity :e2 that was a specialization of :e1?

We ~should~ be able to record provenance at different, and logically connected, levels of abstraction, and activity composition seems a natural component for doing so.

--Stephan

On May 9, 2012, at 3:56 PM, Jim McCusker wrote:

> 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 (sameAs).
> 
> Jim
> 
> 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
> http://krauthammerlab.med.yale.edu
> 
> PhD Student
> Tetherless World Constellation
> Rensselaer Polytechnic Institute
> mccusj@cs.rpi.edu
> http://tw.rpi.edu