[OAI-implementers] XML Schema for OAI compliance with NSDLharvesting

Carl Lagoze lagoze@cs.cornell.edu
Thu, 13 Dec 2001 10:54:12 -0500


Thank you for your input here.  Your knowledge of the application
profile concept is certainly better than mine and I look forward to your
input helping come up with a satisfactory solution.

I understand that, as you say, an application profile is defined at the
schema level and that instance data for each respective application
profile is conformant with the schema.  

That is fine for intra-profile interoperability.  Our problem in OAI is
that, as you know, we would like to establish a modicum of cross-domain
interoperability.  Therein lies the discomfort of loosing up our
mandatory DC defined by a reasonably simple schema, as in
http://www.openarchives.org/OAI/1.1/dc.xsd, to dc following application
schema.  As far as I know, and correct me if I'm wrong, interoperability
amongst application profiles, is uncharted territory.

That said, for the OAI to continue with the concept of a "single
required metadata format for interoperability" it appears that good old
simple dc or some other suitable cross-domain metadata format (not
embedded in multipel application profiles) is the only feasible choice.
BTW, it could be argued that the whole notion of a "single required
metadata format for interoerability" is in itself a somewhat quixotic
comcept given the universe of things to describe, but that is another


> -----Original Message-----
> From: Rachel Heery [mailto:r.heery@ukoln.ac.uk]
> Sent: Thursday, December 13, 2001 9:25 AM
> To: oai-implementers@oaisrv.nsdl.cornell.edu
> Subject: RE: [OAI-implementers] XML Schema for OAI compliance with
> NSDLharvesting
> On Thu, 13 Dec 2001, Carl Lagoze wrote:
> > - The latest DC thinking now includes the notion of "application
> > profiles", saying that a "metadata record" may include dc 
> elements (all
> > optional, all repeatable) that can be mixed and matched 
> with metadata
> > elements from one or more other metadata vocabularies.  The 
> nature of
> > the mixing is, I believe, unspecified by DC - i.e., the application
> > profile notion may allow for a dc element to be nested 
> within the value
> > structure of an element from another vocabulary (such as the dc-ed
> > vocabulary mentioned in Tim's note).  For example, imagine 
> a metadata
> > record such as:
> Just for some background.... within the DCMI community, and within the
> SCHEMAS project, we have found the concept of application 
> profiles useful
> to understand the way standard data element sets are implemented 'in
> practice'. An application profile is understood in this context as a
> schema optimised in its content for a particular application or domain
> i.e. a schema defined by a 'community of use' to specify the 
> data elements
> (terms) used by their application.
> In reality we find that implementations use standard metadata 
> element sets
> (like DC, IMS etc) in an application specific way. For example by
> specifying some data elements are mandatory, some should use 
> values taken
> from a particular schema like Library of Congress subject 
> headings etc,
> some might even contain data elements from different namespaces.
> Its significant to realise that the application profile is 
> defined at the
> schema level.. any instance metadata is then created 'in 
> compliance' to
> that schema. Within the context of SCHEMAS project we have 
> experimented
> with publishing application profiles as RDF schemas, and 
> looked at sharing
> schemas within a schema registry. [1]
> For more info on application profiles see:
> What terms does your metadata use? Application profiles as 
> machine-understandable narratives
>      T. Baker, M. Dekkers, R. Heery, M. Patel, G. Salokhe 
> -November 2001 
>      Journal of Digitial Information, Vol 2. Issue 2. 
>      HTML: <URL:http://jodi.ecs.soton.ac.uk/Articles/v02/i02/Baker/>  
> Rachel
> 1. http://www.schemas-forum.org/registry/desire/index.php3
> --------------------------------------------------------------
> -------------
> Rachel Heery
> University of Bath                              tel: +44 
> (0)1225 826724
> Bath, BA2 7AY, UK                               fax: +44 
> (0)1225 826838
> http://www.ukoln.ac.uk/
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