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Chris, I've been following your blog posts for the last couple weeks
or so and have been trying to come up with a coherent and useful
reply, but I guess I'll take a stab here.

I'll kick things off with saying that I'm skeptical of what advantage
or utility a MODS ontology would bring (for many of the same reasons I
have reservations regarding the RDA vocabulary/ies) - to me it feels
like like it's just dressing up the same old library documents as LOD
resources without really investing the time and energy to model them
in the most appropriate way.  That being said, I understand that you
have this data modeled this way already (so you have an incentive) and
once I've seen that, maybe I will see the light and can be convinced
that this is not a bad way to go.

Also, you're probably aware of this, but the Simile project had an
RDFizer for MODS:  http://simile.mit.edu/wiki/MARC/MODS_RDFizer

A few of the things that have come to me are:

1) What kind of things would these resources be?
<http://example.org/ex/1> <rdf:type> <http://purl.org/MODS/Record> ?
Or would MODS have subclasses?  If so, what?  These:
http://www.loc.gov/standards/mods/mods-outline.html#typeOfResource ?
Would you actually be able to figure out anything about the resource
merely from identifying its type?  Does MODS define a formal data
model (a la http://lackoftalent.org/michael/blog/2009/08/10/is-marc-a-data-model/)?

2) MODS documents are generally containers that carry several discrete
resources:  bibliographic data regarding the primary resource (let's
say, a "book"); authors; publishers; subjects; record metadata
(source, language of the metadata, creation date, etc.) and so on.
Would a MODS ontology try to model the entirety of the graph expressed
by a document?  If so, can the components stand independently?  Can I
have just a MODS:Name?  Would I *want* just a MODS:Name (or
MODS:Subject or MODS:RecordInfo, etc.)?

3) What, specifically, is missing from DCTerms that would make a MODS
ontology needed?  What, specifically, is missing from Bibliontology or
MusicOntology or FOAF or SKOS, etc. that justifies a new and, in many
places, overlapping vocabulary?  Would time be better spent trying to
improve the existing vocabularies?

4) What is compelling about MODS that makes it desirable to serialize
as RDF?  Is it the structure?  The relationships?  Would it be
possible that a desirable outcome of an rdf-ized MODS be merely a
small set of properties (for example) that glues together a set of
external vocabularies into something that would work as an acceptable
surrogate to a MODS XML document?

My interpretation of the crux of your argument is "our stuff is either
MODS or can easily be transformed to MODS".  It just seems to me that
once you've really atomized the record data into its component parts
you will have something that will be enough of a departure from MODS
that it will be difficult to see the resemblance.

So I'll kick things off with that and see where that leads.

Thanks,
-Ross.

On Tue, Aug 11, 2009 at 6:23 PM, Chris Frymann<[log in to unmask]> wrote:
> Hi All,
>
> I just recently subscribed to this list and have been watching for a
> few days, expecting that I would do so for a while longer before
> jumping in.  However I couldn't help but take special note of recent
> posts with mention of MARCXML and MODS and discussion, at least
> indirectly, of how those formats "play" with "linked-data" standards.
> Since that is an area close to where I have been working lately, I
> thought I'd offer a comment and also ask for some friendly feedback.
>
> First my comment:
>
> Here at UC San Diego Libraries, where I work, we have been generating
> RDF data for a couple of years now, and more recently working with
> triplestores and SPARQL.  We also, no surprise, have lots of MARC
> data, and have developed some local strategies for migrating MARC to
> MODS to RDF with a very local conversion scheme.  In order to learn
> more about OWL and ontologies, and possibly to create a more generally
> useful/acceptable expression of our MARC/MODS data as RDF I launched
> into a project to convert the
>
>        Library of Congress MODS XML schema
>                http://www.loc.gov/standards/mods/v3/mods-3-3.xsd
>
> into a formal OWL ontology.  At one level this can be approached as a
> rather mechanical process, on the other hand, I made some adjustments
> to MODS predicate naming, with the intent of providing more meaning to
> individual MODS-based RDF triples.  I won't try to explain that
> further here, but if anyone has additional interest, more information
> is available on my effort to produce and provide validity for a MODS
> ontology on my blog, starting at a post entitled:
>
>    Another Step Toward Lifting Library Metadata into the Cloud
>        http://www.chrisfrymann.com/2009/07/22/mods-ontology-2/
>
> and in following posts with comments and replies from and to Bruce
> D'Arcus, especially regarding Bibliographic Ontology.
>
> That's the end of my comment.  So now my question(s), or request for feedback.
>
> Can we identify, some generally agreed on automateable strategy for
> converting MARC/MODS to RDF (without having to limit to Dublin Core).
> Or, in case I'm missing something, what work has already been done in
> that direction?
>
> As a corollary, I would appreciate thoughts any of you have on the
> value of continuing the effort to develop a MODS ontology?  I attended
> the Semantic Technology Conference recently where I was a speaker in
> a:
>
>        Session on Digital Libraries
>                http://www.semantic-conference.com/session/1990/
>
> and received quite a bit of interest at the conference, though I met
> very few from the library community there.
>
> I had hoped to provide something that could:
>
>        * Potentially be more universal than our current local approach to
> expressing MODS in RDF
>
>        * Assign class and predicate names in an attempt to make dealing with
> blank noes and SPARQL queries simpler and more natural, given the (to
> me) somewhat complicated structure of MODS.
>
>        * Provide a formal OWL base for assigning owl:sameAs relationships,
> alternate rdfs:label values, etc.
>
> However, I am very mindful of (and sympathetic to) thoughts such as
> the following from Ed Summers, regarding:
>
> "...taking a more organic approach to vocabulary selection, mixing and
> matching vocabulary elements rather than imposing a particular
> metadata world-view"
>
> That would make sense to me if there was a generally accepted way to
> automate the conversion.
>
> Sorry for the somewhat long introductory comment and thanks in advance
> for any helpful thoughts or suggestions.
>
> Chris Frymann
> Digital Library Architect
> University of California San Diego Libraries
>
> Email: [log in to unmask]
> Blog: http://chrisfrymann.com
>