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Re: Contextualization ---> Optional bundle in Specialization

From: Paul Groth <p.t.groth@vu.nl>
Date: Wed, 27 Jun 2012 20:21:32 +0200
Message-ID: <363BF7EB-818E-4F03-AFD8-2FC7936EE4F5@vu.nl>
CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, Provenance Working Group WG <public-prov-wg@w3.org>
To: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
So the use case is the issue?

I really don't get how the example breaks any semantics. Sorry...

So I think that your approach to allowing a qualified specialization would be fine with me especially if we add a inBundle predicate that identifies a bundle. but Tim was really really against this because of the increased number of triples.

Paul


On Jun 27, 2012, at 19:48, Graham Klyne <graham.klyne@zoo.ox.ac.uk> wrote:

> On 27/06/2012 18:39, Paul Groth wrote:
>> Hi Graham
>> 
>> These are two different urls so they identify different things.
> 
> Not necessarily,  There is no unique-name assumption in RDF.  They could denote 
> the same thing.
> 
>> The fact that we add some properties like bundle or specializationof doesn't break anything. I can do that with any resource on the web, no?
> 
> Adding the properties per se doesn't break anything, but when they are presented 
> as addressing a use-case that I don't believe can be addressed by RDF semantics, 
> they run the risk of encouraging people to creating RDF data that doesn't mean 
> what they think it means when interp[reted in accordance with RDF semantics.
> 
> #g
> --
> 
>> Paul
>> 
>> On Jun 27, 2012, at 19:09, Graham Klyne<graham.klyne@zoo.ox.ac.uk> wrote:
>> 
>>> 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.
>>> 
>>> I'm afraid I still have a problem with this.
>>> 
>>> Considering your bundle tool:analysis01:
>>> [[
>>> bundle tool:analysis01
>>>     agent(tool:Bob-2011-11-16, [perf:rating="good"])
>>>     specializationOf(tool:Bob-2011-11-16, ex:Bob, ex:run1)
>>> 
>>>     agent(tool:Bob-2011-11-17, [perf:rating="bad"])
>>>     specializationOf(tool:Bob-2011-11-17, ex:Bob, ex:run2)
>>> endBundle
>>> ]]
>>> 
>>> The problem is that, if subject to RDF semantics for URI interpretation, I can
>>> see no semantic distinction is possible between
>>> 
>>>   tool:Bob-2011-11-16
>>> and
>>>   tool:Bob-2011-11-17
>>> 
>>> I.e. they are both specializations of ex:Bob, and that is all we can know about
>>> them, as (by the nature of the semantics of URI interpretation) the denotation
>>> of ex:Bob that appears in ex:run1 is the same as the denotation of ex:Bob that
>>> appears in ex:run2.
>>> 
>>> ...
>>> 
>>> 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 Wednesday, 27 June 2012 18:21:56 UTC

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