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Re: Calling the rdf file an ontology?

From: Leo Sauermann <leo@gnowsis.com>
Date: Wed, 18 Jul 2007 00:04:01 +0200
Message-ID: <469D3CD1.6060008@gnowsis.com>
To: "" <reto@gmuer.ch>
CC: Yoshio Fukushige <fukushige.yoshio@jp.panasonic.com>, semantic-web@w3.org, Tim Berners-Lee <timbl@w3.org>
which leads us to the relevant literature, I hope you have already
pointed it out before:

cool uris for the semantic web - about uris in general
http://www.dfki.uni-kl.de/~sauermann/2006/11/cooluris/

Best Practice Recipes for Publishing RDF Vocabularies
http://www.w3.org/TR/swbp-vocab-pub/

I assume you have read those, they go into DETAIL and they solve open
questions.

best
Leo

It was Reto Bachmann-Gmu"r <reto@gmuer.ch>" who said at the right time
17.07.2007 19:03 the following words:
> Yoshio Fukushige wrote:
>   
>> Thank you, Reto and Tim, for your advices.
>>
>> If I understand them correctly:
>>
>> (1) One can get a serialization of an ontology by dereferencing the ontology's URI,
>> which is (usually?) the non-local-name part of the URI's for the terms it defines.
>>   
>>     
> It is true that, one can usually get triples describing a term by
> dereferencing the non-local-name part of the URI's of the term, but in
> general its not required for an ontology to be a dereferenceable resource.
>
> I don't know if or under what conditions the graph resulting from the
> dereferenciation of the URI are to be considered of type owl:Ontology.
>   
>> (2) It is wise not to include .rdf (or any other extensions) in the URI of an ontology,
>> so as to allow content negotiations.
>>   
>>     
> HTTP allows content-negotiation independently of style of the URI, it's
> just no longer a "cool URI".
>   
>> So I will avoid asserting the .rdf files as ontologies.
>>
>> What I wanted to do was:
>>
>> - to put the definition of a single term into a single (rdf)file (for ease of maintenance 
>> and to let users to get the minimum amount of data necessary)
>>
>> - to ask the users to write minimum lines when they want to load the whole vocabulary
>>
>> - to remain in DL
>>
>> I came up with the following idea and would like to know how it looks to you:
>> good/bad practice? good points/drawbacks? points to care?
>>
>> (I think I can avoid the disadvantage pointed by Tim: "one needs a namepsace URI per term")
>>
>> # I know the drawbacks in using slash namespaces used with PURLs...
>>
>> Many thanks in advance.
>>
>>   
>>     
> In your examples you unnecessarily declare the prefix ont and voc.
> Serializations of graphs using your terms would just include the prefix
> for "http://ont.example.org/myOnt/voc/", following your pattern this URI
> is neither dereferenceable nor an ontology; this is of. As Tim pointed
> the approach using HTTP 303 responses has disadvantages in performance
> over the pattern using hashes, on the other side only the 303-approach
> allows efficient use of namespaces.
>   
>> ------------ start of my idea -----------
>> (i)
>> Define each term (Class of property) in a file
>>
>> For an Ontology for the Bear class,
>> in http://ont.example.org/myOnt/ont/Bear.rdf,
>>
>> -----------
>> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>> 	xmlns:owl="http://www.w3.org/2002/07/owl#"
>> 	xmlns:ont="http://ont.example.org/myOnt/ont/"
>> 	xmlns:voc="http://ont.example.org/myOnt/voc/">
>>
>> 	<owl:Ontology rdf:about="http://ont.example.org/myOnt/ont/Bear"/>
>>
>> 	<owl:Class rdf:about="http://ont.example.org/myOnt/voc/Bear"/>
>>
>> </rdf:RDF>
>> -----------
>>
>> and for an Ontology for the Donkey class,
>> in http://ont.example.org/myOnt/ont/Donkey.rdf,
>>
>> -----------
>> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>> 	xmlns:owl="http://www.w3.org/2002/07/owl#"
>> 	xmlns:ont="http://ont.example.org/myOnt/ont/"
>> 	xmlns:voc="http://ont.example.org/myOnt/voc/">
>>
>> 	<owl:Ontology rdf:about="http://ont.example.org/myOnt/ont/Donkey"/>
>>
>> 	<owl:Class rdf:about="http://ont.example.org/myOnt/voc/Donkey"/>
>>
>> </rdf:RDF>
>> -----------
>>
>> (ii)
>> Then for the whole ontology that includes all the term definitions,
>> in http://ont.example.org/myOnt/ont/all.rdf
>> -----------
>> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>> 	xmlns:owl="http://www.w3.org/2002/07/owl#"
>> 	xmlns:ont="http://ont.example.org/myOnt/ont/"
>> 	xmlns:voc="http://ont.example.org/myOnt/voc/">
>>
>> 	<owl:Ontology rdf:about="http://ont.example.org/myOnt/ont">
>> 		<owl:imports rdf:resource="http://ont.example.org/myOnt/ont/Bear"/>
>> 		<owl:imports rdf:resource="http://ont.example.org/myOnt/ont/Donkey"/>
>> 	</owl:Ontology>
>> </rdf:RDF>
>> -----------
>>
>> (iii)
>> Lastly, add the rewrite directives such as
>>
>> ----
>> RewriteBase /myOnt
>>
>> RewriteRule voc/(*) ont/$1.rdf
>> RewriteRule ont/$ ont/all.rdf
>> ---
>>
>> (I'm not certain about the rule grammer, though)
>>
>> (iv)
>> When using the vocabulary,
>> by declaring the common namespace for the terms,
>> one doesn't need to declare each namespaces,
>> like in
>> -----------
>> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>> 	xmlns:owl="http://www.w3.org/2002/07/owl#"
>> 	xmlns:voc="http://ont.example.org/myOnt/voc/">
>>
>> 	<voc:Bear rdf:about="#Pooh"/>
>> 	<voc:Donkey rdf:about="#Eeyore"/>
>>
>> </rdf:RDF>
>> -----------
>>
>> (v)
>> Then by requesting, for example,
>>
>> GET /myOnt/Bear HTTP/1.1
>> Host: ont.example.org
>> Accpet: application/rdf+xml
>>
>> one will get 
>>
>> HTTP/1.x 303 See Other
>> Location http://ont.example.org/myOnt/ont/Bear.rdf
>>
>> and then by requesting the redirected URI, one will get
>> the Bear.rdf file which is the minumum ontology defining the term.
>>
>> On the other hand, when requesting
>>
>> GET /myOnt/ont HTTP/1.1
>> Host: ont.example.org
>> Accept: application/rdf+xml
>>
>> one will get http://ont.example.org/myOnt/ont.rdf
>> with the HTTP header containing
>>
>> HTTP/1.x 200 OK
>> Content-Type: application/rdf+xml
>>
>> (Of course what one get is the list of importing declarations,
>> and one needs to issue HTTP requests for each minimum files.
>> But this time, it is the ontologies that are requested, 
>> so 303 round-trips won't occur)
>>
>> ------------ end of my idea -----------
>>
>> Yoshio Fukushige
>> fukushige.yoshio@jp.panasonic.com
>>
>>
>> On Mon, 16 Jul 2007 12:44:06 +0200
>> Reto Bachmann-Gm〓 <reto@gmuer.ch> wrote:
>>   
>>     
> ...
>   
Received on Tuesday, 17 July 2007 22:05:25 UTC

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