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Re: Cool URIs, the Semantic Web and Everything

From: Leo Sauermann <leo.sauermann@dfki.de>
Date: Tue, 25 Dec 2007 21:41:14 +0100
Message-ID: <47716AEA.7060602@dfki.de>
To: Richard Cyganiak <richard@cyganiak.de>
CC: "Hausenblas, Michael" <michael.hausenblas@joanneum.at>, Leo Sauermann <sauermann@dfki.uni-kl.de>, semantic-web@w3.org

Hi all,

yep, having an example does help much now, your homepage.

I ran the URI through Ivan's converter:
http://www.w3.org/2007/08/pyRdfa/extract?uri=http%3A%2F%2Fsw-app.org%2Fmic.xhtml%23i&format=pretty-xml&submit=go%21

Its valid RDFa (or?)

answers below.


It was Richard Cyganiak who said at the right time 23.12.2007 16:25 the 
following words:
>
> On 23 Dec 2007, at 08:22, Hausenblas, Michael wrote:
>> Although feeling uncomfortable being labelled as the 'complainant' :)
>
> As an author, I know that every work of interest will draw some 
> complaints, some justified and some not. And I prefer a clearly voiced 
> complaint over nebulous expressions of doubt. Therefore, when you see 
> room for improvement, please complain loudly and clearly ;-)
>
>> I guess that this wording would improve the text.
>>
>> Now, due to X-mas approaching, let's relax and quiz a bit
>> (multiple choice):
>>
>>
>> Q.I: What is http://sw-app.org/mic.xhtml#i?
>>
>> 1. A URI
>> 2. A URL
>> 3. A foaf:Person
>> 4. Michael Hausenblas
>> 6. An XHTML fragment
>
> It's a URI.

A URI.

>
>> Q.II:  What does http://sw-app.org/mic.xhtml#i identfiy?
>>
>> 1. A foaf:Person
>> 2. Michael Hausenblas
>> 4. An XHTML fragment
>> 5. Depends on who looks at it: A Web UA 'sees' a XHTML fragment,
>>   a SW agent a thing of type foaf:Person
>> 6. Dunno until I do an HTTP GET
>
I would say:

A foaf:person: according to the representation returned by the 
information resource at the URI.
It returns a valid RDFa encoding of a statement saying that the uri is a 
foaf:person.
>   


> This is impossible to answer, because the URI's configuration is 
> broken. Even the author of the document seems to be confused about 
> what he wants the URI to identify.
>
> There is an XHTML representation, and it has a id="i", which indicates 
> that the URI identifies an XHTML fragment.
>
> But the XHTML document also encodes an RDF graph using RDFa. In it, 
> the author tries to use the same URI to denote a person. He claims 
> that a document fragment is a person. That's a nonsensical statement.
>
> Fortunately, this is easy to fix: Remove the id="i" from the document, 
> or change it to a different ID, and everything is fine. After that 
> fix, the answer would be 1, 2 and 6.
>
> Richard

I don't know about removing the ID, maybe this would be good. But I 
would not make a "must" out of it, why not keep both

best
Leo

>
>
>>
>>
>>
>> Cheers,
>>     Michael
>>
>> ----------------------------------------------------------
>> Michael Hausenblas, MSc.
>> Institute of Information Systems & Information Management
>> JOANNEUM RESEARCH Forschungsgesellschaft mbH
>> Steyrergasse 17, A-8010 Graz, AUSTRIA
>> ----------------------------------------------------------
>>
>>> -----Original Message-----
>>> From: Richard Cyganiak [mailto:richard@cyganiak.de]
>>> Sent: Friday, December 21, 2007 5:26 PM
>>> To: Hausenblas, Michael
>>> Cc: Leo Sauermann; semantic-web@w3.org; Leo Sauermann
>>> Subject: Re: Cool URIs, the Semantic Web and Everything
>>>
>>> Michael,
>>>
>>> On 21 Dec 2007, at 08:23, Hausenblas, Michael wrote:
>>>> In Cool URIs you are
>>>> referring to a certain
>>>> setup ('deployment scenarios in which the RDF data and the
>>> HTML data
>>>> is served separately').
>>>> Also the figure right before section 3.1 suggests that there is an
>>>> explicit RDF document and an HTML document, each with a
>>> distinct URL.
>>>> As you know, this is not the case with RDFa.
>>>
>>> Would changing the sentence
>>>
>>> "In those cases [RDFa, microformats and GRDDL] the RDF data
>>> is extracted from the returned HTML document."
>>>
>>> to
>>>
>>> "In those cases, the RDF data is extracted from the HTML
>>> document and no separate RDF document is needed."
>>>
>>> address your complaint?
>>>
>>> The rest of the document's narrative is consistent with use
>>> of RDFa, as far as I can tell.
>>>
>>> Best,
>>> Richard
>>>
>>>
>>>>
>>>>
>>>> So, that is were my confusion stems from. I know that due to time
>>>> constraints you decided that this is the way it is. It
>>> would still be
>>>> nice to learn why the figure right before section 3.1
>>> (sorry, no label
>>>> available) 'shows the desired relationships between a
>>> resource and its
>>>> describing documents'.
>>>>
>>>> Cheers,
>>>>     Michael
>>>>
>>>> [1]
>>> http://lists.w3.org/Archives/Public/semantic-web/2007Dec/0121.html
>>>>
>>>> ----------------------------------------------------------
>>>> Michael Hausenblas, MSc.
>>>> Institute of Information Systems & Information Management JOANNEUM
>>>> RESEARCH Forschungsgesellschaft mbH
>>>>
>>>> http://www.joanneum.at/iis/
>>>> ----------------------------------------------------------
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Leo Sauermann [mailto:sauermann@dfki.uni-kl.de]
>>>>> Sent: Thursday, December 20, 2007 12:36 PM
>>>>> To: Hausenblas, Michael
>>>>> Cc: semantic-web@w3.org; Leo Sauermann
>>>>> Subject: Re: Cool URIs, the Semantic Web and Everything
>>>>>
>>>>> Hausenblas, Michael schrieb:
>>>>>
>>>>>     Leo,
>>>>>     
>>>>>     Thanks for your explanation. I remain not totally convinced :)
>>>>>     
>>>>>
>>>>> good, then give a practical example (using concrete RDFa
>>> code) where
>>>>> you think some work needs to be done and provide a
>>> suggestion how to
>>>>> solve it. That you are not convinced may be caused by
>>> various reasons
>>>>> we don't know about, shine light on them.
>>>>>
>>>>>
>>>>>
>>>>>     
>>>>>     So, *if* we agree on what you said, IMHO we should
>>>>>     reconsider the following paragraph in 'Cool URIs' [1]:
>>>>>     
>>>>>     'The solutions described in the following apply to deployment
>>>>> scenarios
>>>>>     in which the RDF data and the HTML data is served
>>> separately, such
>>>>> as a
>>>>>     standalone RDF/XML document
>>>>>     along with an HTML document. The metadata can also be
>>> embedded in
>>>>> HTML,
>>>>>     using technologies such as
>>>>>     RDFa [RDFa Primer], microformats and other documents to
>>> which the
>>>>> GRDDL
>>>>>     [GRDDL] mechanisms can be applied.
>>>>>     In those cases the RDF data is extracted from the returned HTML
>>>>>     document.'
>>>>>     
>>>>>
>>>>> I see no reason for changes until you exactly specify where this
>>>>> paragraph contradicts http-range-14 or other TAG
>>> resolutions or W3C
>>>>> recommendations.
>>>>>
>>>>> the point is that RDF/XML, N3, RDFa and GRDDL are
>>> mimetypes encoding
>>>>> RDF triples while URIs are something used inside these RDF
>>> triples,
>>>>> so at the beginning both are completly different and do not affect
>>>>> each other.
>>>>>
>>>>> "Cool uris" is about URIs and not about RDF serialization.
>>>>>
>>>>> best
>>>>> Leo
>>>>>
>>>>>
>>>>>
>>>>>     
>>>>>     Still unsure if this is just the tip of the iceberg ...
>>>>>     
>>>>>
>>>>>     
>>>>>     Cheers,
>>>>>         Michael
>>>>>     
>>>>>     [1] http://www.w3.org/TR/2007/WD-cooluris-20071217/#solutions
>>>>>     
>>>>>     ----------------------------------------------------------
>>>>>      Michael Hausenblas, MSc.
>>>>>      Institute of Information Systems & Information Management
>>>>>      JOANNEUM RESEARCH Forschungsgesellschaft mbH
>>>>>     
>>>>>      http://www.joanneum.at/iis/
>>>>>     ----------------------------------------------------------
>>>>>     
>>>>>     
>>>>>     
>>>>>
>>>>>         -----Original Message-----
>>>>>         From: Leo Sauermann [mailto:sauermann@dfki.uni-kl.de]
>>>>>         Sent: Thursday, December 20, 2007 3:43 AM
>>>>>         To: Hausenblas, Michael
>>>>>         Cc: semantic-web@w3.org; Leo Sauermann
>>>>>         Subject: Re: Cool URIs, the Semantic Web and Everything
>>>>>        
>>>>>         Hi Michael, RDFa people,
>>>>>        
>>>>>         The question is if httpRange-14 [2] is valid in
>>> the case of
>>>>> XHTML+RDFa.
>>>>>        
>>>>>         The answer is that httpRange-14 is to
>>> distinguish URIs for
>>>>> information
>>>>>         resources ("web documents") from real-world
>>> objects (the person
>>>>>         "Alice"). As such, it is a recommendation on URIs.
>>>>>        
>>>>>         RDFa is an encoding of RDF, and typically an
>>> RDFa document has two
>>>>>         relations to URIs:
>>>>>         a) the URI of the RDFa document (=the
>>> information resource where I
>>>>> can
>>>>>         download the RDFa document)
>>>>>         b) the URIs used as subjects, predicates,
>>> objects inside RDF
>>>>>         statements
>>>>>         written inside RDFa documents
>>>>>        
>>>>>         a) is usually a http-200 uri, and a) is an
>>> information resource (=
>>>>> a
>>>>>         document).
>>>>>         In the rdf statemetns written inside  A, you
>>> would use both URIs
>>>>> for
>>>>>         real-world objects and information resources.
>>>>>         example (I don't know  rdfa syntax by heart
>>> now, assume this is
>>>>> rdfa):
>>>>>        
>>>>>         document at www.example.com/homepage/aboutAlice
>>>>>         <html>
>>>>>         <p
>>>>> rdf:about="http://www.example.com/identifiers/alice#this"
>>>>> <http://www.example.com/identifiers/alice#this> >
>>>>>          rdf:type foaf:Person.
>>>>>         </p>
>>>>>         <p
>>>>> rdf:about="http://www.example.com/moreidentifiersusing303/bob"
>>>>> <http://www.example.com/moreidentifiersusing303/bob> >
>>>>>         rdf:type foaf:Person
>>>>>         </p>
>>>>>         </html>
>>>>>        
>>>>>         assuming this would be valid RDFa, the URI
>>> .../aboutAlice is a
>>>>>         http-return-200 informaiton resource
>>>>>         .../alice#this is a real-world object as it is
>>> not a document (as I
>>>>>         understand timbl on that)
>>>>>         ...303/bob is not intuitively distinguishable -
>>> if you ignore the
>>>>>         rdf:type relation you don't know what it is. So
>>> for this uri you do
>>>>> a
>>>>>         HTTP get and the server would return a 303
>>> redirect as described in
>>>>>         "cool uris".
>>>>>         once oyu did the 303, you knowthat ....303/bob
>>> is a real world
>>>>> object.
>>>>>        
>>>>>         so RDFa and 303'/httprange14 are
>>>>> recommendations caring about
>>>>>         different
>>>>>         angles, 303 is only concerned about URIs, RDFa
>>> about an RDF
>>>>>         serialization. Technically they don't interfere.
>>>>>        
>>>>>         If I would use RDFa much and would like cool
>>> uris, I would go for
>>>>>         #-uris, they are simple to use and easy to
>>> embed in RDFa.
>>>>>         but as shown above, you can use any URI you
>>> want inside rdfa.
>>>>>        
>>>>>         best
>>>>>         Leo
>>>>>        
>>>>>        
>>>>>         Hausenblas, Michael schrieb:
>>>>>        
>>>>>
>>>>>             ===
>>>>>             Disclaimer: Michael, with his
>>>>> RDFa-Task-Force-member hat off ;)
>>>>>             ===
>>>>>            
>>>>>             As I gathered "Cool URIs for the
>>>>> Semantic Web" is a Working
>>>>>            
>>>>>
>>>>>         Draft, now.
>>>>>        
>>>>>
>>>>>             Congrats to Leo and his team, great job!
>>>>>            
>>>>>             The following might sound like a naive
>>> question - and I might
>>>>>             have missed something :) - but: Is TAG
>>> finding httpRange-14 [2]
>>>>>             equally valid in the case of XHTML+RDFa?
>>>>>            
>>>>>             I've put together some initial thoughts
>>> at the ESWiki [3]
>>>>>             - any comments welcome!
>>>>>            
>>>>>             Cheers,
>>>>>                 Michael
>>>>>            
>>>>>             [1]
>>>>>            
>>>>>
>>>>>        
>>>>> http://lists.w3.org/Archives/Public/public-swd-wg/2007Dec/0103.html
>>>>>        
>>>>>
>>>>>             [2]
>>>>> http://www.w3.org/2001/tag/issues.html#httpRange-14
>>>>>             [3] http://esw.w3.org/topic/RDFa_vs_RDFXML
>>>>>            
>>>>>            
>>>>> ----------------------------------------------------------
>>>>>              Michael Hausenblas, MSc.
>>>>>              Institute of Information Systems &
>>> Information Management
>>>>>              JOANNEUM RESEARCH Forschungsgesellschaft mbH
>>>>>              Steyrergasse 17, A-8010 Graz, AUSTRIA
>>>>>            
>>>>>              <office>
>>>>>                 phone: +43-316-876-1193 (fax:-1191)
>>>>>                e-mail: michael.hausenblas@joanneum.at
>>>>>                   web: http://www.joanneum.at/iis/
>>>>>            
>>>>>              <private>
>>>>>                mobile: +43-660-7621761
>>>>>                   web: http://www.sw-app.org/
>>>>>            
>>>>> ----------------------------------------------------------
>>>>>            
>>>>>            
>>>>>            
>>>>>
>>>>>        
>>>>>        
>>>>>
>>>>>     
>>>>>     
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>


-- 
____________________________________________________
DI Leo Sauermann       http://www.dfki.de/~sauermann 

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Received on Tuesday, 25 December 2007 20:41:32 GMT

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