Re: GRDDL and OWL/XML

Harry the OWL WG has GRDDL on the agenda in 7 hours time, if you could 
send a message like this, I believe it would be helpful to the 
discussion (with whatever riders are needed to address DanC's procedural 
point). I have withdrawn my previous dissent to the single point.

Jeremy

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 Wednesday, 21 May 2008 09:49:15 UTC