Ethan, if you are interested in "dialoguing" about this topic, I suspect 
this isn't the forum for it. I don't think that W3C has yet set up a 
public list on rdf validation (the meeting participants need to form an 
actual W3C group for that to happen, and I hope that won't take too 
long), but there should be one soon. It's really rather useless to keep 
telling *me* this, since I'm not arguing for any particular technology, 
just reporting what I've learned in the last few weeks about what others 
are doing.

That is, if you are interested in having an exchange of ideas about this 
topic rather than repeatedly trying to convince me that what I'm saying 
is wrong. It's like you're trying to convince me that I really did not 
hear what I did. But I did hear it. Maybe all of those people are wrong; 
maybe you could explain to them that they are wrong. But if you care 
about this, then you need to be talking to them.

kc


On 9/16/13 7:40 AM, Ethan Gruber wrote:
> Using SPARQL to validate seems like tremendous overhead.  From the Gerber
> abstract: "A total of 55 rules have been defined representing the
> constraints and requirements of the OA Specification and Ontology. For each
> rule we have defined a SPARQL query to check compliance." I hope this isn't
> 55 SPARQL queries per RDF resource.
>
> Europeana's review of schematron indicated what I pointed out earlier, that
> it confines one to using RDF/XML, which is "sub-optimal" in their own
> words.  One could accept RDF in any serialization and then run it through
> an RDF processor, like rapper (http://librdf.org/raptor/rapper.html), into
> XML and then validate.  Eventually, when XPath/XSLT 3 supports JSON and
> other non-XML data models, theoretically, schematron might then be able to
> validate other serializations of RDF.  Ditto for XForms, which we are using
> to validate RDF/XML.  Obviously, this is sub-optimal because our workflow
> doesn't yet account for non-XML data.  We will probably go with the rapper
> intermediary process until XForms 2 is released.
>
> Ethan
>
>
> On Mon, Sep 16, 2013 at 10:22 AM, Karen Coyle <[log in to unmask]> wrote:
>
>> On 9/16/13 6:29 AM, [log in to unmask] wrote:
>>
>>> -----BEGIN PGP SIGNED MESSAGE-----
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>>> I'd suggest that perhaps the confusion arises because "This instance is
>>> (not) 'valid' according to that ontology." might be inferred from an
>>> instance and an ontology (under certain conditions), and that's the soul of
>>> what we're asking when we define constraints on the data. Perhaps OWL can
>>> be used to express conditions of validity, as long as we represent the
>>> quality "valid" for use in inferences.
>>>
>> Based on the results of the RDF Validation workshop [1], validation is
>> being expressed today as SPARQL rules. If you express the rules in OWL then
>> unfortunately you affect downstream re-use of your ontology, and that can
>> create a mess for inferencing and can add a burden onto any reasoners,
>> which are supposed to apply the OWL declarations.
>>
>> One participant at the workshop demonstrated a system that used the OWL
>> "constraints" as constraints, but only in a closed system. I think that the
>> use of SPARQL is superior because it does not affect the semantics of the
>> classes and properties, only the instance data, and that means that the
>> same properties can be validated differently for different applications or
>> under different contexts. As an example, one community may wish to say that
>> their metadata can have one and only one dc:title, while others may allow
>> more than one. You do not want to constrain dc:title throughout the Web,
>> only your own use of it. (Tom Baker and I presented a solution to this on
>> the second day as Application Profiles [2], as defined by the DC community).
>>
>> kc
>> [1] https://www.w3.org/2012/12/**rdf-val/agenda<https://www.w3.org/2012/12/rdf-val/agenda>
>> [2] http://www.w3.org/2001/sw/**wiki/images/e/ef/Baker-dc-**
>> abstract-model-revised.pdf<http://www.w3.org/2001/sw/wiki/images/e/ef/Baker-dc-abstract-model-revised.pdf>
>>
>>
>>   - ---
>>> A. Soroka
>>> The University of Virginia Library
>>>
>>> On Sep 13, 2013, at 11:00 PM, CODE4LIB automatic digest system wrote:
>>>
>>>   Also, remember that OWL does NOT constrain your data, it constrains only
>>>> the inferences that you can make about your data. OWL operates at the
>>>> ontology level, not the data level. (The OWL 2 documentation makes this
>>>> more clear, in my reading of it. I agree that the example you cite sure
>>>> looks like a constraint on the data... it's very confusing.)
>>>>
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>> --
>> Karen Coyle
>> [log in to unmask] http://kcoyle.net
>> m: 1-510-435-8234
>> skype: kcoylenet
>>

-- 
Karen Coyle
[log in to unmask] http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet