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Re: PURLs don't matter, at least in the LOD world

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Fri, 17 Feb 2012 19:56:35 +0000
To: "Young,Jeff (OR)" <jyoung@oclc.org>
CC: "<public-lod@w3.org>" <public-lod@w3.org>
Message-ID: <EMEW3|200c958f2b3440551f0832c4e7af08dfo1GJuc02hg|ecs.soton.ac.uk|0FF382D2-2A2E-467C-AD13-1FAB0B1F7B4D@ecs.soton.ac.uk>
Hi Jeff,
On 17 Feb 2012, at 19:24, Young,Jeff (OR) wrote:

> Hugh,
> 
> I commonly use PURLs when I'm modeling RDF vocabularies as described
> here:
> 
> http://www.w3.org/TR/swbp-vocab-pub/#purls
(Yes, I was avoiding commenting on the 302 problem. :-) )
> 
> This allows me to prototype the vocabulary on my workstation without
> concern for where it ultimately ends up. Any instance data I generate
> along the way will remain unaffected since I've used PURL as the
> vocabulary namespace.
Ah yes, thanks.
I remember someone saying they did this.
I can see the advantage where one doesn't have a target domain in mind during development.
Best
hugh  
> 
> Jeff
> 
>> -----Original Message-----
>> From: Hugh Glaser [mailto:hg@ecs.soton.ac.uk]
>> Sent: Friday, February 17, 2012 1:48 PM
>> To: public-lod@w3.org
>> Subject: PURLs don't matter, at least in the LOD world
>> 
>> (Sorry if there is a paper/discussion on this that I have missed
>> somewhere. And I may have some of this wrong, as I have essentially
> not
>> used PURLs.)
>> M Scott Marshall and others' comments have prompted me to put pen to
>> paper and ask what the list thinks on this.
>> 
>> It has long puzzled me why people seem to think that PURLs (and
>> Handles, etc.) solve some actual problem.
>> Leaving aside the question of whether it actually adds extra fragility
>> as to whether purl.org will continue to exist.
>> (Personally I would bet the Library of Congress will last longer than
>> purl.org, but I would have to wait too long to collect on the bet to
>> make it worthwhile.)
>> 
>> In the Linked Data world, at least, what does a PURL give protection
>> from?
>> 
>> Let's say I have http://dbpedia.org/resource/Tokyo. I can:
>> a) Use the URI without any URI resolution at all, and it is really
>> useful to do so (as commented, foaf:name is used a lot, and it does
> not
>> depend on anything being at the other end to resolve to);
>> b) I can resolve to find out what DBPedia thinks it "means" (returns
> as
>> RDF);
>> c) I can use it as an ID for another source to find out what that
> other
>> source thinks it "means".
>> 
>> Now let's say dbpedia.org goes Phut!
>> What I lose is facility (b)
>> 
>> What happens if I have http://purl.org/dbpedia/Tokyo, which is set to
>> go to http://dbpedia.org/resource/Tokyo?
>> I have (a), (b) and (c) as before.
>> Now if dbpedia.org goes Phut!, we are in exactly the same situation -
>> (b) gets lost.
>> 
>> Both of these situation can be fixed by persuading someone (the
>> registrar for dbpedia.org or the purl.org organisers respectively) to
>> allow someone else to take over purl.org/dbpedia or dbpedia.org
>> respectively.
>> But once dbpedia.org goes Phut!, you get a dead link whatever you do,
>> until someone takes it over.
>> 
>> Not much to be gained for the overheads of having the purl?
>> 
>> I can see that in the Web of Text, a URI that has gone 404 is rather
>> painful.
>> And I know that people who have curated data find dying links painful,
>> and seem to find Handles etc some sort of comfort for their concerns,
>> even though they don't necessarily solve the perceived problem, in my
>> view.
>> But in the Web of Data, given a good guess at somewhere else (such as
>> the LoC, or even the Virtuoso endpoint or sameAs.org), I stand a good
>> chance of finding a skos:*Match or even an owl:sameAs that will get me
>> back on track again.
>> 
>> Is there something I am missing about PURLs?
>> 
>> Best
>> Hugh
>> --
>> Hugh Glaser,
>>             Web and Internet Science
>>             Electronics and Computer Science,
>>             University of Southampton,
>>             Southampton SO17 1BJ
>> Work: +44 23 8059 3670, Fax: +44 23 8059 3045
>> Mobile: +44 75 9533 4155 , Home: +44 23 8061 5652
>> http://www.ecs.soton.ac.uk/~hg/
>> 
>> 
> 
> 

-- 
Hugh Glaser,  
             Web and Internet Science
             Electronics and Computer Science,
             University of Southampton,
             Southampton SO17 1BJ
Work: +44 23 8059 3670, Fax: +44 23 8059 3045
Mobile: +44 75 9533 4155 , Home: +44 23 8061 5652
http://www.ecs.soton.ac.uk/~hg/
Received on Friday, 17 February 2012 19:57:10 UTC

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