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Re: Contextualization ---> Optional bundle in Specialization

From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
Date: Wed, 27 Jun 2012 18:48:09 +0100
Message-ID: <4FEB4759.9000404@zoo.ox.ac.uk>
To: Paul Groth <p.t.groth@vu.nl>
CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, Provenance Working Group WG <public-prov-wg@w3.org>
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 17:49:22 UTC

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