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Re: Some thoughts about the revised provenance Model document

From: Paul Groth <p.t.groth@vu.nl>
Date: Fri, 30 Sep 2011 09:33:37 +0200
Message-ID: <4E8570D1.1070706@vu.nl>
To: Graham Klyne <GK@ninebynine.org>
CC: 'W3C provenance WG' <public-prov-wg@w3.org>
Hi Graham,

I think the purpose of characteristic attributes is to define what your 
describing the provenance of.

So when I hand you provenance information for example for a web page, 
you'll know that I'm describing the provenance of x attributes of the 
web page and not everything there.
Paul


Graham Klyne wrote:
> Jim,
>
> If I understand you correctly, the significance of attributes is for discovery
> of of related resources.
>
> My understanding is that the primary purpose of provenance is to establish a
> basis for trust, a reason to believe (or not) some information that is presented
> about some subject.  It's not clear to me what need there is to use attributes
> for resource discovery to achieve this end.  (But I may well be missing
> something here.)
>
> So, on this basis, there may be perfectly good reasons to have defined
> attributes and values for discovery purposes, I'm not seeing why they are needed
> to achieve the goals of *provenance* information.
>
> (But it's getting late here, and maybe I'm missing some key point in your message.)
>
> In summary: I think your concerns are reasonable, but what makes them in scope
> specifically for *provenance* information?
>
> #g
> --
>
> On 29/09/2011 18:44, Myers, Jim wrote:
>> Graham,
>>
>> How would we use provenance to find, for example, how Luc got to Boston? It's clear if we have fixed attributes for name and location such that we could query for an entity with name Luc that has an ivpOf relationship with an entity in Boston and then look at the provenance from there. How would it work without fixed attributes in the prov model? I'm guessing that you're thinking that we can find those attributes outside the language somewhere (e.g. non-prov RDF statements) but what are the minimal requirements there and what language/models exist that meet them? Can we only model provenance of things for which ontologies have been developed? Presumably it has to be possible to associate descriptive metadata with the entities through some path (what relationship(s)?)? And it has to be clear which metadata is fixed? You mention being able to infer across ivpOf relationships - is there one set of inference rules for all possible descriptive metadata? Or do we need to be able

> to distinguish further between types of metadata?
>> -->   As you can probably guess from the questions above, I'm concerned that kicking fixed attributes out will end up being more complex and place a higher burden on users than keeping them in, but I may be misunderstanding how such an alternative would work. Part of that concern is that I think I hear that modeling experts in this group can handle defining classes for different types of entities that would allow discovery by attribute, but I'm concerned that being able to do this becomes a requirement for using provenance (versus asserting entities defined solely by attributes(entity, name=Luc)  or perhaps in a mixed mode (e.g. an entity representing Luc that 'hasBaseType' foaf:person and one representing him in Boston that also hasBaseType foaf:person and location=Boston as a fixed attribute.) Again - perhaps I'm misunderstanding how discovery based on descriptive information could be done if we don't have fixed characterizing attributes in the prov standard....
>>
>>    Jim
>>
>>> 3. Do we need to model "Characterizing attributes"?
>>>
>>> The notions of "characterizing attributes" have developed to derive the
>>> relationship between different entities that are views of some common
>>> thing in the world.  I am not convinced that we need to model these
>>> attributes, and I'm not sure the way they are modelled can necessarily apply
>>> in all situations that applications might wish to represent.
>>>
>>> At heart:  when it comes to exchanging provenance information, why do we
>>> *need* to know exactly what makes one entity a constrained view of
>>> another?  What breaks (at the level of exchanging provenance information) if
>>> we have no access to such information?  How are applications that exchange
>>> provenance information about entities for which they don't actually know
>>> about these attributes to know about their correspondences with real-world
>>> things?
>>>
>>> I think the role of attributes here is mainly to *explain* some aspects of the
>>> provenance model, but they do not need to be part of the model.
>>>
>>> To my mind, a simpler approach would be to allow for assertion of an IVPof
>>> type of relationship between entities, from which some useful inferences
>>> about any attributes present might flow, but I don't see the need for the
>>> attributes to be in any sense defining of the entities.
>>>
>>> <aside>
>>> My suggested definition of IVPof might be something like this:
>>>
>>>      A IVPof B  iff  forall p : (Entity ->   Bool) . p(B) =>   p(A)
>>>
>>> where A, B are Entities, and the values of p are predicates on Entities.
>>> </aside>
>>>
>>> ...
>>>
>>> #g
>>>
>>
>>
>

-- 
Dr. Paul Groth (p.t.groth@vu.nl)
http://www.few.vu.nl/~pgroth/
Assistant Professor
Knowledge Representation & Reasoning Group
Artificial Intelligence Section
Department of Computer Science
VU University Amsterdam
Received on Friday, 30 September 2011 07:34:12 GMT

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