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Re: Ordnance Survey data as Linked Data (RE: How do you deprecate URIs? Re: OWL-DL and linked data)

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Sun, 13 Jul 2008 15:50:56 -0700
Message-ID: <487A86D0.5050909@openlinksw.com>
To: Hugh Glaser <hg@ecs.soton.ac.uk>
CC: Afraz Jaffri <afraz.jaffri@tiscali.co.uk>, "public-lod@w3.org" <public-lod@w3.org>, "semantic-web@w3.org" <semantic-web@w3.org>, Ian Millard <icm@ecs.soton.ac.uk>

Hugh Glaser wrote:
> OK Kingsley, it's done (or rather I hope it is!).
> Interestingly we never really viewed the html as a web page, it was always a way of looking at the RDF, in the same sort of way that we might use tabulator.
> We would be quite happy to withdraw the html pages altogether.
> But for the moment it now has the rel links (and you have encouraged us to do it earlier rather than later!).
>
> By the way, I couldn't get your issues URI to work, whatever I did.
> Best
> Hugh
>   
Hugh,

Yes, it's done as exemplified by this browser session URI:
http://demo.openlinksw.com/rdfbrowser2/?uri%5B%5D=http%3A%2F%2Fos.rkbexplorer.com%2Fdescription%2Fosr7000000000017765&

HTML as Link to RDF Data Sources is a big thing :-)  It's an area 
typically overlooked (inadvertently most of the time). As part of LOD we 
need to emphasize best practices for publishing HTML that exposes 
associations with RDF data sources :-)  DBpedia's HTML pages have 
maintained this linkage from the get-go. Also note, Chris Bizer and 
Richard Cyganiak have both been beating this drum for a very long time.

Methinks, that the unobtrusive manifestation of the "Linked Data Web" 
depends highly on the linkage between HTML and RDF information 
resources. This is why I am ensuring that our user agents are able to 
make a best effort to discern the following from HTML pages:

1. What the page is about (Subject matter and Named Entity wise)
2. What Data Sources the page is associated with (as seeAlso)
3. Alternative representations of the page (as in "alternate" 
representations)

Increasingly we sniff out the following in (X)HTML information resources:

1. <link rel="[appropriate-predicate]" .../>
2. RDFa (in your case <span/> usage around your table columns would do fine)
3. GRDDL
4. Plain Old Semantic HTML (POSH)

And then depending on the RDF we get, we might perform additional 
processing using services such as UMBEL, DBpedia, OpenCalais as part of 
the journey towards high context fidelity "Linked Data Spaces" presented 
to the Web Users.

BTW - We now have a signed version of the OpenLink Data Explorer plugin 
for Firefox <https://addons.mozilla.org/en-US/firefox/addon/8062>. Thus, 
if you install and you use the "View | Linked Data Sources" (main menu 
or context menu) option when viewing 
<http://os.rkbexplorer.com/description/osr7000000000017765>, you will 
also see a live example of HTML's utility as vehicle of Linked Data 
discovery.

Links:

1. http://ode.openlinksw.com/  - OpenLink Data Explorer Home page (here 
you can find What, Why, and How information)


Kingsley
> On 13/07/2008 18:56, "Kingsley Idehen" <kidehen@openlinksw.com> wrote:
>
>
>
> Afraz Jaffri wrote:
>   
>> Sorry, the link i gave was to the HTML description,the URI of the
>> resource is
>>
>> http://os.rkbexplorer.com/id/osr7000000000017765
>> then:
>> [aoj04r@cohen ~]$ curl -I -H "Accept: application/rdf+xml" http://os.
>> rkbexplorer.com/id/osr7000000000017765
>> HTTP/1.1 303 See Other
>> Date: Sun, 13 Jul 2008 10:44:10 GMT
>> Server: Apache/2.0.52 (Red Hat)
>> X-Powered-By: PHP/4.3.9
>> Location: /data/osr7000000000017765
>> Connection: close
>> Content-Type: text/html; charset=UTF-8
>>
>> Afraz.
>>
>>     
> Afraz,
>
> Yes, but it is also good practice to link the HTML description with the
> RDF representation of the description. This enables the RDF discovery to
> start from the HTML description.
>
> This is all that is required:
>  <link rel="alternate"  type="application/rdf+xml"
> href="http://os.rkbexplorer.com/data/osr7000000000017765" />
>
> Of course you can also use RDFa to similar effect by making a seeAlso claim.
>
> Kingsley
>   
>> Afraz Jaffri wrote:
>>
>>     
>>> We are pleased to announce a Linked Data site for the Ordnance
>>>
>>>       
>> Survey,
>>
>>     
>>> available at:
>>>
>>> http://os.rkbexplorer.com
>>>
>>> with links from over 8000 URIs to Geonames URIs. Take 'Hampshire'
>>>
>>>       
>> as
>>
>>     
>>> an example:
>>>
>>>
>>>       
>> Afraz,
>>
>>     
>>> http://os.rkbexplorer.com/description/osr7000000000017765
>>>
>>>
>>>
>>>       
>> kidehen$ curl -I -H "Accept: application/rdf+xml"
>> http://os.rkbexplorer.com/description/osr7000000000017765
>> HTTP/1.1 406 Not Acceptable
>> Date: Sat, 12 Jul 2008 20:31:35 GMT
>> Server: Apache/2.0.52 (Red Hat)
>> X-Powered-By: PHP/4.3.9
>> Content-Type: text/html; charset=UTF-8
>> Connection: close
>>
>> Why no 303 or use of <link rel="[relavant-predicate]" .../>  so that
>> User Agents can locate <http://os.rkbexplorer.
>> com/data/osr7000000000017765> .
>>
>> My issues are summarized here:
>>
>> http://demo.openlinksw.com/rdfbrowser2/?uri%5B%5D=http%3A%2F%2Fos.
>> rkbexplorer.com%2Fdescription%2Fosr7000000000017765&uri%5B%5D=http%3A%
>> 2F%2Fos.rkbexplorer.com%2Fdata%2Fosr7000000000017765&
>>
>> Kingsley
>>
>>     
>>> It might also be the right time, with all the owl:sameAs
>>>
>>>       
>> discussion,
>>
>>     
>>> to practically demonstrate how our coreference system works. In the
>>> above example the link created is between 'Hampshire the county'
>>>
>>>       
>> from
>>
>>     
>>> the OS and 'Hampshire the second order administrative division'
>>>
>>>       
>> from
>>
>>     
>>> Geonames. We do not know if these two entities are exactly the
>>>
>>>       
>> same,
>>
>>     
>>> so instead of using owl:sameAs we use our own coref:duplicate
>>> predicate.
>>>
>>> One of the features of our system is that knowledge about
>>>
>>>       
>> coreference
>>
>>     
>>> is separated from the knowledge of the actual entity. In the RDF
>>>
>>>       
>> for
>>
>>     
>>> the above URI at http://os.rkbexplorer.com/data/osr7000000000017765
>>> you
>>> will find:
>>>
>>> <coref:coreferenceData rdf:resource="http://os.rkbexplorer.
>>> com/crs/osr7000000000017765"/>
>>>
>>> Resolving this URI will give you a 'bundle' containing the
>>>
>>>       
>> duplicates:
>>
>>     
>>> <coref:Bundle>
>>>     <coref:canon rdf:resource="http://os.rkbexplorer.
>>> com/id/osr7000000000017765"/>
>>>     <coref:duplicate rdf:resource="http://os.rkbexplorer.
>>> com/id/osr7000000000017765" />
>>>     <coref:duplicate rdf:resource="http://sws.geonames.org/2647554/"
>>>
>>>       
>> />
>>
>>     
>>>     <coref:lastUpdated>2008-07-10 11:39:44</coref:lastUpdated>
>>>   </coref:Bundle>
>>>
>>> As you can see one URI is chosen as the canonical URI to use. The
>>> separation of coreference means, to a limited extent, that the
>>>
>>>       
>> context
>>
>>     
>>> of duplication can be preserved. If I wanted to say that under some
>>> other context there were other URIs that were deemed to be the same
>>> then I can simply create another bundle with another <coref:
>>> coreferenceData> predicate in the RDF for the entity. Of course, the
>>> question of how to show the context is yet to be solved...
>>>
>>> There may be some errors in the equivalences. All feedback is
>>> greatfully received :)
>>>
>>> In relation to another question about how owl:sameAs is currently
>>> being used, there are some examples in our LDOW paper:
>>> http://eprints.ecs.soton.ac.uk/15181/
>>>
>>> in particular http://dbpedia.org/resource/Welsh and http://dbpedia.
>>> org/resource/Lilac
>>>
>>> Regards,
>>> Afraz
>>>
>>>
>>>
>>>
>>>       
>>>> -----Original Message-----
>>>> From: public-lod-request@w3.org [mailto:public-lod-request@w3.org]
>>>>
>>>>
>>>>         
>>> On
>>>
>>>
>>>       
>>>> Behalf Of Harry Halpin
>>>> Sent: 09 July 2008 10:55
>>>> To: Hugh Glaser
>>>> Cc: Bijan Parsia; Peter Ansell; semantic-web at W3C; public-lod@w3.
>>>>
>>>>
>>>>         
>>> org
>>>
>>>
>>>       
>>>> Subject: Re: How do you deprecate URIs? Re: OWL-DL and linked data
>>>>
>>>>
>>>> Hugh Glaser wrote:
>>>>
>>>>
>>>>         
>>>>> Thanks guys, a really interesting and important discussion.
>>>>> However, after the last couple of postings I have the feeling I
>>>>>
>>>>>
>>>>>           
>>> may
>>>
>>>
>>>       
>>>> agree
>>>>
>>>>
>>>>         
>>>>> with both of you.
>>>>> Is that possible?
>>>>>
>>>>>
>>>>>
>>>>>           
>>>> Bijan et. al. are right about the semantics of owl:sameAs, but as
>>>>
>>>>
>>>>         
>>> I've
>>>
>>>
>>>       
>>>> said before, I think that something weaker needs to be coined
>>>> ("lod:equivalentTo") that states that two URIs refer to the same
>>>>
>>>>
>>>>         
>>> thing
>>>
>>>
>>>       
>>>> but that any semantic entailments *may* not hold (i.e. user
>>>>
>>>>         
>> beware).
>>
>>     
>>>> That's a dangerous thing, I agree, but it seems to be what the
>>>>
>>>>
>>>>         
>>> Linked
>>>
>>>
>>>       
>>>> Data community needs and what's happening organically in the wild
>>>>
>>>>
>>>>         
>>> with
>>>
>>>
>>>       
>>>> the (ab)use of owl:sameAs.
>>>>
>>>>
>>>>
>>>>         
>>>>> Hugh
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>           
>>> __________________________________________________________
>>>
>>> Free games for a wet weekend - http://www.tiscali.co.uk/play
>>> __________________________________________________________
>>>
>>>
>>>
>>>
>>>
>>> __________________________________________________________
>>>
>>> Free games for a wet weekend - http://www.tiscali.co.uk/play
>>> __________________________________________________________
>>>
>>>
>>>
>>>
>>>
>>>
>>>       
>>
>>     
>
>
> --
>
>
> Regards,
>
> Kingsley Idehen       Weblog: http://www.openlinksw.com/blog/~kidehen
> President & CEO
> OpenLink Software     Web: http://www.openlinksw.com
>
>
>
>
>
>
>
>
>   


-- 


Regards,

Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Sunday, 13 July 2008 22:51:52 UTC

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