Hi,
This is a hard one - on a par with debates regarding the re-accessioning
of objects.
Theoretically I agree with Richard, yet practically I concur with Paul.
Of course, in Open Source software development, the community has solved
this issue by using version control software.
Anyway, http://www.microsoft.com/BritishLibrary/ScannedBooks says:
"We are sorry, the page you requested cannot be found."
Hopefully the University of Google scanning in Oxford won't make the same
mistake.
Regards,
James
On Fri, 20 Jun 2008, Richard Light wrote:
> Date: Fri, 20 Jun 2008 13:00:20 +0100
> From: Richard Light <[log in to unmask]>
> Reply-To: Museums Computer Group <[log in to unmask]>
> To: [log in to unmask]
> Subject: Re: [MCG] Linking Open Data
>
> In message <[log in to unmask]>, Paul Walk
> <[log in to unmask]> writes
>>
>> However, I've always been a little unconvinced by the 'Cool URIs don't
>> change' piece (http://www.w3.org/Provider/Style/URI) linked to by the W3C
>> Note you referenced. While I agree with the sentiment, I think the W3C
>> statement does not quite gel with my practical experience.
>>
>> The gluing together of the object identifier with the organisational domain
>> part of a URL is seen by some as a potential problem, and is addressed for
>> example in John Kunze's paper on ARK
>> (http://colab.mpdl.mpg.de/mediawiki/images/e/eb/ESci08_Sem_1_n2t_a_viabl
>> e_pid_solution_Kunze.pdf )
>>
>> The W3C would maintain that this is unnecessary. I tend to lean towards the
>> W3C in this respect - but really because I think the deleterious effect of
>> changing URIs can be overstated, so it's not necessarily worth introducing
>> another layer of complexity.
>
> Paul,
>
> Your comments on feasibility are well taken, but I think that in the
> particular context of the Semantic Web, stable URIs are pretty central to
> whether the whole thing will work at all. This isn't just related to whether
> they resolve to a physical resource (the point John Kunze discusses in the
> presentation you quote): not so long ago the same job was to be done by
> "URNs", which didn't (and in fact couldn't) point to anything.
>
> The other, crucial, job that stable URIs do is that they become a common
> currency, expressing a well-defined class or property. People use them in
> their own RDF, and the magic of Semantic Web data linking starts to happen.
> If your RDF instances are just strings (rather than rdf:about links), it's
> effectively just a local resource. Ditto if all your rdf:about links just
> point to somewhere else in your own data set.
>
> The above comments are based on my own experiments in this area, and may well
> be misguided or plain wrong. If so, I would be delighted to be put right.
> Meanwhile, let me explain what I have been up to since the last message in
> this thread ...
>
> Just to see what is involved in implementing the W3C advice on Cool URIs,
> Open Data, etc., I have built a front end to the Wordsworth Trust to expose
> their collection as RDF. While this is very much a work in progress, it has
> got to the point where there is something to see.
>
> The whole thing is built on the basis that none of the resources identified
> by the URLs actually exist (!) ... in other words the redirection work is all
> done by a customized "404 page not found" error handler. (Since the server
> in question is IIS, this is an Active Server Page.) The object URLs all have
> the form:
>
> http://collections.wordsworth.org.uk/object/[identity number]
>
> e.g.
> http://collections.wordsworth.org.uk/object/GRMDC.C104.15
>
> If you request this URL in a normal web context, you are redirected to the
> object's page on the standard site (try it). If your HTTP request includes
> the header "Accept: application/rdf+xml", it will instead issue a "303 See
> Also" response, and give the URL which delivers RDF:
>
> http://collections.wordsworth.org.uk/object/data/GRMDC.C104.15
>
> You can request this in your browser, and if you have something like the RDF
> Tabulator extension to Firefox, you can see it as a nicely rendered table of
> properties and values. Otherwise you'll get an RDF XML dump - always a
> pleasure ;-) (BTW, I don't get anything using IE - maybe I'm not setting the
> MIME type properly.) You can also open it in the RDF browser provided by
> OpenLink:
>
> http://demo.openlinksw.com/DAV/JS/rdfbrowser/index.html
>
> Once it's loaded some triples, click on the "Raw triples" tab to see them.
>
> Within my transform, I look up the most specific place name in Geonames, and
> if I get a good match I include the Geonames URL in place of the keyword. If
> you follow the "data link" after the Geonames URL, this loads information
> about the place, and then you can switch to the "Yahoo Map" tab and see it as
> the familiar pin on a map. Load a few of the C104 series in the same way,
> and you can see the distribution of this set of prints - all without doing
> extra work on the catalogue record. Similarly, by using the W3C Calendar
> namespace (http://www.w3.org/2002/12/cal/icaltzd) for my dates, I get entries
> on the timeline.
>
> The RDF is produced by an XSLT transform on the live source record (which is
> already XML). At present it almost totally fails to meet my criterion for
> successful Open Linking, but does raise some interesting issues:
>
> 1. The properties I use are mostly taken from DBpedia. They are effectively
> what has been scraped from Wikipedia. Should the museum community be
> publishing an ontology of properties that it is interested in?
>
> 2. Are we interested in finding or creating ontologies for common stuff like
> object type ("simple name") and materials?
>
> 3. How do we deal with the biggies? - people are the obvious one.
>
> In general, the main conclusion I have drawn from this exercise is that if we
> are to contribute to, and benefit from, this initiative, we need to look way
> outside our own little community of practice.
>
> Thanks for reading if you got this far ...
>
> Richard
> --
> Richard Light
> XML/XSLT and Museum Information Consultancy
> [log in to unmask]
>
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