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Hi everyone,

Since MacKenzie brought up the IU and our work on METS to IMS and RSS
and the relationship to RSS, let me jump in a bit with more later. I
also don't claim to give any definitive answers -- but  I was doing a
lot of thinking about RDF a while back and wrote up my thoughts about
RDF coming from a non-RDF XML perspective.  I believe that it's still an
accurate reflection of my current thoughts -- and the writeup might be
helpful to you.  It's on my wiki:

http://raymondyee.net/wiki/FiguringOutRdf

I'd be very interested in any reactions you might have.

One of the big issues for me is to figure out how to handle both
XML-based metadata and the (presumably) increasing amount of RDF-based
metadata we'll begin seeing.  Let me get back to you all when I have
more thoughts on the topic.

-Raymond


MacKenzie Smith wrote:

> Hi Jinfang,
>
>> anybody here can talk about something between METS and RDF? how are they
>> different? since they both can combine different kinds of metadata
>> together.
>> Besides the difference that METS can encode the structure of
>> resources, are
>> there any other differences between them?
>
>
> I'll take a stab at this because it's been on my mind lately... just
> my thoughts; not a definitive answer to your question.
>
> First of all METS is about expressing /structural metadata/ for
> digital objects -- usually complex digital objects consisting of many
> different physical files that are somehow interconnected. As a
> practical matter it also provides a way to relate descriptive,
> technical, and administrative metadata to that digital object.
>
> METS is currently defined as a XML schema, but the only part of the
> schema that's required is the structural metadata (and the file
> inventory that goes with it). You can include the other kinds of
> metadata if you want, and they can be expressed in any other XML
> schema that has an associated name space.
>
> RDF isn't associated with any particular kind of metadata, but
> practically speaking it is usually expressed with its own XML schema,
> RDFS, and is most often used for descriptive metadata (I think, but I
> could be way off here).
>
> There were attempts in the past to encode structural metadata with RDF
> (in Europe) which found that it added a lot of overhead to the
> processing of the metadata, which is about all you use structural
> metadata for (e.g. building a "page turner" display, or reconstructing
> a website).
>
> That said, you could easily drop RDFS-encoded metadata for an object
> into a METS file, or you could convert a METS file into RDFS if you
> did a METS->RDFS mapping.
>
> The reason to consider that possibility is the tools... right now, it
> seems easier to write custom tools for METS-encoded objects, or to use
> METS as a simple transfer syntax between digital library applications.
> In the future, as RDF tools and platforms mature, it might make sense
> to leverage them by coming up with an RDF schema for METS that we can
> all live with and migrating our METS objects to that binding...
> shouldn't be hard at all. But the compelling reason to do that now has
> yet to emerge.
>
> There's a project at Berkeley's Interactive University (led by Raymond
> Yee) which is looking at METS mapping to IMS and RSS, so he may also
> be thinking about the RDF-izing of METS-encoded digital objects and
> will hopefully speak up...
>
> I hope this helps you a bit,
>
> MacKenzie
>
> MacKenzie Smith
> Associate Director for Technology
> MIT Libraries
> Building 14S-308
> 77 Massachusetts Avenue
> Cambridge, MA  02139
> (617)253-8184
> [log in to unmask]
>


--
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Raymond Yee                          44 Barrows Hall, #3810
Technology Architect                            UC Berkeley
Interactive University Project      Berkeley, CA 94720-3810
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http://iu.berkeley.edu/rdhyee           413-541-5683  (fax)