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Re: Contextualization ---> Optional bundle in Specialization

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Thu, 28 Jun 2012 05:28:21 +0000
To: Satya Sahoo <satya.sahoo@case.edu>
CC: Graham Klyne <graham.klyne@zoo.ox.ac.uk>, Provenance Working Group WG <public-prov-wg@w3.org>
Message-ID: <EMEW3|32d705275c06ee2cb0580c7133198808o5R6SM08L.Moreau|ecs.soton.ac.uk|E6092E62-7492-47D3-B541-EDE243F08B9A@ecs.soton.ac.uk>
Hi Satya

I really don't understand your point. A long time ago, we have established that attributes are not characterising, meaning that they are not enough to distinguish entities. Instead we rely on identifiers for these.

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

On 28 Jun 2012, at 02:54, "Satya Sahoo" <satya.sahoo@case.edu<mailto:satya.sahoo@case.edu>> wrote:

Hi Luc,

For the avoidance of doubt, I assume you are not stating

specializationOf(luc-in-boston,luc)
specializationOf(luc-in-soton,luc)

Implies that Luc-in-Boston denotes thevsame as Luc-in-soton.

Yes, I am not stating that the above assertions imply that they are the same (or that they are different).

I assume you you are saying that there may be some interpretations according to which they denote the same.

I am fine with this.

  Still, what is broken?

So,  the issue is that the bundles are not additional aspects that can be used to distinguish between tool:Bob-2011-11-16 and tool:Bob-2011-11-17 (it is an attribute that does not affect interpretation of entities).

Best,
Satya


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

On 27 Jun 2012, at 22:53, "Satya Sahoo" <satya.sahoo@case.edu<mailto:satya.sahoo@case.edu>> wrote:

Hi,

Are you trying to say that if

specializationOf(luc-in-boston,luc)
specializationOf(luc-in-soton,luc)

You cannot see any semantic distinction between luc-in-boston and luc-in-soton?????
Surely, there is a difference!

Difference in identifiers (string value) does not mean they will be interpreted differently (semantics), unless the "-boston" and "-soton" have associated formal semantics - with just the above two assertions they do not.

specializationOf(UK, country) (actually should be instantiation in SW...)
specializationOf(UnitedKingdom, country)


Best,
Satya

Likewise, tool:Bob-2011-11-16 and tool:Bob-2011-11-17 can be distinguished by the additional aspect
they present (bundle ex:run1 or bundle ex:run2).

In this example, we have three different identifiers
ex:Bob
tool:Bob-2011-11-16
tool:Bob-2011-11-17
each with a single denotation: i.e. no denotation that is context specific.

I don't see what the issue is.

Luc




Luc


...

I do, however, have a different compromise that provides a hook for introducing possible semantics later, or in private implementations, without sneaking in something that could well turn out to be incompatible with, or just different than, what the RDF group may do for semantics of datasets.

The hook is this: simply allow attributes for the specializationOf relation, but don't define a specific attribute for bundle.  This would allow you to do a private implementation of the scheme you describe, but would not allow it to be mistaken for something that has standardized semantics.  As in:

 specializationOf(tool:Bob-2011-11-17, ex:Bob,
                  [myprivateattribute:bundle=ex:run2])

...

In case you think I'm jumping at shadows here, I'll note that RDF has been here before.  The original 1999 RDF specification described reification without formal semantics.  Reification was intended to allow for capturing this kind of information - i.e. to make assertions about context of use, etc - a kind of proto-provenance, if you like.  But when the group came to define a formal semantics for RDF, there were two possible, reasonable and semantically incompatible approaches; looking at the way that reification was being used "in the wild", it turned out that there was data out there that corresponded to both of these (incompatible) approaches.  This was in the very early days of the semantic web, so the harm done was quite limited.  I think a similar mistake today would cause much greater harm.

I think the appropriate way forward is to take this tool performance analysis use-case to the RDF-PROV coordination group, and ask that it be considered as input when defining semantics for RDF datasets.  I would expect that whatever semantic structure they choose, it should be able to accommodate the use-case. Then, we should be better placed to create an appropriate and compatible contextualization semantics for provenance bundles.  But until then, I think we invite problems by trying to create a standardized data model structure without standardized RDF-compatible semantics to accommodate this use-case.

#g
--

Tracker, this is ISSUE-385

On 27/06/2012 10:49, Luc Moreau wrote:
All,

At the face to face meeting, we have agreed to rename contextualization and mark
this feature
at risk. Tim, Stephan, Paul and I have worked a solution that we now share with
the working group.

Given that contextualization was already defined as a kind of specialization, we
now allow an optional
bundle argument in the specialization relation. (Hence, no need to create a new
concept!)

See section 5.5.1 in the current Editor's draft
http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-dm.html#term-specialization

Feedback welcome.

Regards,
Luc

PS. Tracker, this is ISSUE-385
Received on Thursday, 28 June 2012 05:28:51 UTC

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