Re: GRDDL and OWL/XML

Thanks for the work and summary!
I'll keep following the thread to see whether anything else shows up.
-Alan

On May 16, 2008, at 12:08 PM, Harry Halpin wrote:

> Bijan (cc'ing Alan over this issue),
>
>   After waiting a few days, it appears this discussion has come to  
> some sort of end - so I'll summarize what I think the message to the  
> OWL2 WG over this debate is from the remaining active members of the  
> GRDDL WG on this list.
>
>   In effect, while it appears active GRDDL WG members on the list   
> recognize the dangers posed by someone thinking an conformant GRDDL  
> transformation in XSLT for OWL2/XML to RDF is more "normative" than  
> some other transformation, it appears to be the feeling of the  
> majority of the people from the GRDDL Working Group that the  
> benefits of having such a GRDDL transformation accessible from the  
> namespace document of OWL2's XML syntax outweigh the costs.
>
> This is in particular  *if* the OWL2 Working Group believes that RDF- 
> aware agents may want to access information in OWL2 in RDF and may  
> not have their own locally installed OWL2 XML to RDF transformer.
>
> So:
>
>   1) It seems general opinion in the GRDDL WG that having a GRDDL  
> Transformation Property point to a non-executable list of  
> implementations is not a useful use of GRDDL, and the GRDDL WG did  
> not explicitly discuss this possibility when creating the GRDDL  
> Specification or test-cases. A GRDDL transformation, while not  
> necessarily XSLT, is usually executable, and currently all examples  
> are in XSLT.
>
>   2) However, while the "cost" of alienating developers of other non- 
> GRDDL transformations may exist, this is a misunderstanding about  
> the "normative" nature of GRDDL transformations. In particular, a  
> list of other conformant implementations could be accessible at the  
> namespace document. Also, a few sentences explaining GRDDL and the  
> fact that it is no more "normative" than other implementations could  
> be included in the namespace document. If this does actually cause  
> problems, these problems could be dealt with re the usual feedback  
> channels of the W3C. The advantage of having a GRDDL from OWL 2 to  
> RDF is that it is to a larger audience (RDF users without an  
> explicit OWL 2 to RDF transform), who might otherwise be unable to  
> have what benefits OWL 2. in RDF, can have these benefits with a  
> minimal of work.
>
>   3) Re the possibility of the OWL namespace document being  
> overloaded by requests for the transform, we do in the specification  
> encourage caching of GRDDL transformations. Regards the possibility  
> of GRDDL transformations being "automatically" run, this is a matter  
> of local policy. Current libraries such as Redland and Jena do allow  
> GRDDL to be turned on explicitly by the local client.
>
>   Although this is not the solution that Bijan wants per se, think  
> this is the general opinion of the GRDDL WG members who have  
> responded so far on this list, except for possibly Jeremy Carroll.  
> Thanks for the provocative and intelligent critiques and comments re  
> GRDDL and OWL 2.
>
>   The choice of whether or not to include a GRDDL transformation  
> that is an XSLT from OWL2 XML to RDF is, of course, in the competent  
> hands of the OWL 2 WG. However, I do hope this feedback helps  
> clarify things.
>
>         -harry
>
>
>
>
>
>
> Bijan Parsia wrote:
>>
>> On May 13, 2008, at 5:09 PM, Jeremy Carroll wrote:
>>> Dan Connolly wrote:
>>>
>>>>> People are reading the SHOULD as a MUST.
>>>> Really? I am not. I just haven't seen a good reason to make
>>>> an exception in this case.
>>>
>>> +1
>>>
>>> (the definition of SHOULD is very good in my view, see RFC 2119,  
>>> which I am sure Bijan knows ...)
>>
>> Sure.
>>
>> It would help me if I could see a hypothetical circumstances what  
>> you think the case is successfully made to go against the SHOULD.
>>
>> In the OWL/XML case we have:
>>    1) an existing specification (at the W3C) for a format closely  
>> identified with semweb
>>    2) widely available (in multiple ways) implementations
>>    3) a culture of manually invoked translation (e.g., between  
>> Turtle versions and OWL/RDF, etc.)
>>    4) no clear use case for other sorts of user programs wherein  
>> they would have grddl but not be able to manage other ways of  
>> getting translation
>>        And no clamor from users of those tools who are also OWL  
>> users. Alan Ruttenberg *is* an OWL user, but my understanding is  
>> that he's concerned more with legacy OWL oriented tools that only  
>> consume RDF/XML.
>>    5) a somewhat complex transformation
>>
>> (And let us presume there is an existing, seemingly decent, XSLT to  
>> hand. Or two!)
>>
>> I think without a thumb on the scale (i.e., that we have a default  
>> to override via a SHOULD) that the case is clear. (Do we agree?)  
>> With the thumb on the scale, I also think it's clear, but evidently  
>> you and Dan don't agree. (i.e., there are problems, and no clear  
>> upsides, and the downsides of not doing it are easily mitigated.)   
>> What other facts (or sorts of fact) would tip the scale for you? If  
>> there are none, or they are outlandish (e.g., space aliens say we  
>> shouldn't), then you and dan are treat this SHOULD as a  de facto  
>> MUST. Or, at least, I cannot discern the actual difference.
>>
>> If it's a de facto should, you should make it an actual should.  
>> It's really misleading and confusing otherwise.
>>
>> Cheers,
>> Bijan.
>>
>>
>

Received on Saturday, 17 May 2008 09:20:34 UTC