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Re: [provo] Difference between wasInformedBy and wasStartedByActivity (ttl examples)

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Tue, 8 May 2012 15:58:05 +0000
To: Paolo Missier <Paolo.Missier@ncl.ac.uk>
CC: Daniel Garijo <dgarijo@delicias.dia.fi.upm.es>, Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>, Timothy Lebo <lebot@rpi.edu>, Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>, Jun Zhao <jun.zhao@zoo.ox.ac.uk>, W3C provenance WG <public-prov-wg@w3.org>
Message-ID: <EMEW3|51c20554ac8a3d28d1bbb4ca7a0c9d26o47Gw908L.Moreau|ecs.soton.ac.uk|16C05B44-9490-4C61-885E-0D0626F3A93D@ecs.soton.ac.uk>
Hi all,

Yes overloading was ruled out.

Another option in the spirit of what Tim suggested is:

wasStartedBy(a2,e,a1,t,attrs)

With optional activity a1, entity e, time t.

We would allow
wasStartedBy(a2,e,-,t,attrs):The current form
wasStartedBy(a2,-,a1,t,attrs): equivalent to wasstartedbyactivity
wasStartedBy(a2,e,a1,t,attrs): the form where entity is explicit as requested by some

Thoughts?

Professor Luc Moreau
Electronics and Computer Science
University of Southampton
Southampton SO17 1BJ
United Kingdom

On 8 May 2012, at 16:42, "Paolo Missier" <Paolo.Missier@ncl.ac.uk<mailto:Paolo.Missier@ncl.ac.uk>> wrote:

Hi,

that activities are not entities was decided a long time ago, I think  (I have no access to the archives at the moment). changing that would have unclear implications on the "provenance of activities".
I also seem to remember that wasStartedBy was indeed initially overloaded as suggested here, and that was found to be confusing.

-Paolo


On 5/8/12 3:02 PM, Daniel Garijo wrote:
Hi Stian,
instead of removing the constraint that entity and activity are disjoint we could
also (as another possibility) have activities OR entities as possible domain
of wasStartedBy. Now that we agreed on having an OWL-RL ++ profile,
this would be possible.

Thus, we would drop wasStartedByActivity, since wasStartedBy would
cover already the desired functionality, right?

Thanks,
Daniel

2012/5/8 Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk<mailto:soiland-reyes@cs.manchester.ac.uk>>
On Mon, May 7, 2012 at 3:48 PM, Timothy Lebo <lebot@rpi.edu<mailto:lebot@rpi.edu>> wrote:

> +1, repositioning wasStartedByActivity as a "blurrier" form of wasStartedBy seems to finally find a place for it in the model.
> Though, like Khalid, I'm not sure it will be used much, or correctly.

It will certainly still be confusing, as it was for me. As you said,
most wasStartedBy() would also come with a twin used() relationship
(and therefore imply a wasInformedBy() relation).   At some point
wasStartedBy was sub-property of wasInformedBy (making the choice
simple) - but not anymore.

As Luc raised, why not also wasEndedByActivity,  wasStartedByAgent etc.?


So it might just not be worth it to keep wasStartedByActivity(). It's
a bad sign if it's confusing to even the ontology designers, then how
is any meaningful provenance exchange happen, where one party apply
wasInformedBy like wasStartedByActivity, and the other the opposite?



A second solution would be to remove the constraint that activity and
entity are disjoint. Then you could say wasStartedBy(a2, a1),
wasEndedBy(a2, a3) etc. - the activity can play the role of an entity
as well, rather than inventing invisible phantom token entities. We
are talking blurry provenance here, right, we don't know quite the
nature of the interaction.



> How can it be reframed so that wasStartedByActivity can "grow" in details like Derivation does with hadActivity, hadUsage, and hadGeneration?

By adding a separate wasStartedBy() I would believe you have given all
the information (as an activity can only be started once).  Or is it
allowed to be wasStartedBy() two or more entities..? Luc?


--
Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester





--
-----------  ~oo~  --------------
Paolo Missier - Paolo.Missier@newcastle.ac.uk<mailto:Paolo.Missier@newcastle.ac.uk>, pmissier@acm.org<mailto:pmissier@acm.org>
School of Computing Science, Newcastle University,  UK
http://www.cs.ncl.ac.uk/people/Paolo.Missier
Received on Tuesday, 8 May 2012 16:00:07 GMT

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