W3C home > Mailing lists > Public > public-lld@w3.org > April 2011

Re: Recommendations: URIs

From: Richard Light <richard@light.demon.co.uk>
Date: Wed, 27 Apr 2011 10:26:49 +0100
Message-ID: <q9IIqXjZF+tNFwgb@light.demon.co.uk>
To: Karen Coyle <kcoyle@kcoyle.net>
Cc: public-lld@w3.org
In message <20110426170419.20255artp3h78m83@kcoyle.net>, Karen Coyle 
<kcoyle@kcoyle.net> writes
>Thanks for the comment. It seems to me that you are making a 
>distinction between ontologies (and value vocabularies) and instance 
>data -- do I have that right? And that we should emphasize creating 
>URIs for ontologies FIRST, with URIs for instance data having a second 
>That makes sense to me. Do folks generally agree on that? In terms of 
>FRBR (for the FRBoRg among us) that would mean that we would not insist 
>on creating URIs for bibliographic resources (WEMI), knowing  that 
>having URIs for entities like Persons would facilitate matching  and 

Well, to take a specific case, I would say that publishers of 
authorities which are in general use should take urgent steps to 
re-publish them as LD.  Take LCSH as an example: without standard URIs 
for LCSH headings, libraries which have been diligently using LCSH for 
their subject headings would have difficulties when publishing this 
information as LD.  If they had to mint their own URIs for LCSH 
headings, they would have lost the benefit of using a standard.

A related point is that such publishers should provide mechanisms to 
facilitate the conversion of user data to LD form.  Thus users might 
have used the LCSH heading "Parks--Delaware" in their data; they need 
(for example) a web service which makes it easy to submit this data and 
get back the URI "http://id.loc.gov/authorities/sh94007324#concept".


>Quoting Emmanuelle Bermes <manue@figoblog.org>:
>>  Dear Karen & everyone,
>> Thank you for starting this very important discussion on
>> recommendations. This is going to be one of the most important parts
>> of the final report of the group, so let's hope there will be a lot of
>> comments - or only confirmation of aproval, from both people from the
>> group and others (that's why we chose to discuss the recommendations
>> on the community list, so everyone, feel free to comment).
>> Regarding URIs...
>> It seems to me that there are 2 different things here :
>> - assigning URIs for metadata elements sets in due time, and declaring
>> them in registries so that they can be discovered and managed
>> - policy / guidelines / patterns for assigning URIs to resources (instances).
>> In the Benefits section, we put strong emphasis on URIs being one of
>> the main advantages of Linked Data, because URIs provide means to
>> uniquely identify and link to works, places, people, events, etc.
>> I think that it's not exactly the same thing to design URIs for
>> metadata elements and for resources such as works, places, people,
>> events, etc. For example, what would mean "assigning URIs in due time"
>> when speaking about resources such as works, authors, books, documents
>> ? Designing persistent, trusted URIs for resources: shouldn't that be
>> the first requirement for creating a Linked Data project ? Aren't
>> there cases where it is better to mint local URIs for resources,
>> rather than re-use existing ones ?
>> So wouldn't it be useful to make a distinction between assigning &
>> maintaining URIs for metadata standards, and designing URIs for a
>> particular dataset ?
>> Il also wanted to point to the recent recommendation on museum URIs
>> from the Cidoc [1].
>> Emma
>> [1] http://www.cidoc-crm.org/URIs_and_Linked_Open_Data.html
>> On Fri, Apr 22, 2011 at 6:16 PM, Karen Coyle <kcoyle@kcoyle.net> wrote:
>>> There has been a small group working on defining the LLD Issues[1] for our
>>> report, followed by the Recommendations[2]. Since these are both long and
>>> complex wiki pages, we felt it would be better to post individual topics for
>>> discussion here on the list (although it would probably be a good idea for
>>> everyone to give a quick glance at the ToC of each page to get an overview
>>> and context for the discussion).
>>> To start, here are three recommendations relating to use of identifiers and
>>> in particular URIs, that we can discuss as a unit:
>>> *Create URIs for library resources in good time*
>>> Library data cannot be used in a linked data environment if URIs for
>>> specific resources and the concepts of library standards are not available.
>>> The official owners of resource data and standards should assign URIs in
>>> good time, as application developers and other users of such data will not
>>> delay their activities. They are more likely to assign URIs themselves,
>>> outside of the owning institution. When owners are not able to assign URIs
>>> in good time, they should be prepared to allow others to do so, to avoid
>>> proliferation of URIs for the same thing and encourage re-use of URIs
>>> already assigned.
>>> *Develop policies for namespaces*
>>> Organizations and individuals who create and maintain URIs for resources and
>>> standards will benefit if they develop policies for the namespaces used to
>>> derive those URIs. Policies might cover
>>>    * Use of patterns to design URIs, based on good practice guidelines.
>>>    * Persistence of URIs.
>>>    * Good practice guidelines and recipes for constructing ontologies and
>>> structured vocabularies.
>>>    * Version control for individual URIs and the namespace itself.
>>> *Declare namespaces and URIs in metadata registries*
>>> Owners of namespaces will benefit if they declare URIs and associated data
>>> in one or more metadata registries, although this is not a requirement for
>>> effective use of linked data. Registries make it easier for potential users
>>> to find, identify, select, and obtain URIs for their own applications. They
>>> can store information about a namespace as a whole, including intended
>>> audience, context, and ownership. Registries may provide additional
>>> facilities for maintaining a namespace, including editing screens, version
>>> control, and change notification. Registries bring namespaces from different
>>> sources together and help encourage mixing and matching of URIs to suit
>>> specific purposes, and thus encourage re-use of existing URIs.
>>> -----
>>> Please post any comments, suggestions, etc., that you have!
>>> kc
>>> [1] http://www.w3.org/2005/Incubator/lld/wiki/Draft_issues_page
>>> [2] http://www.w3.org/2005/Incubator/lld/wiki/Draft_recommendations_page
>>> --
>>> Karen Coyle
>>> kcoyle@kcoyle.net http://kcoyle.net
>>> ph: 1-510-540-7596
>>> m: 1-510-435-8234
>>> skype: kcoylenet

Richard Light
Received on Wednesday, 27 April 2011 09:27:22 UTC

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