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RE: Question about MARCXML to Models transformation

From: Young,Jeff (OR) <jyoung@oclc.org>
Date: Sun, 6 Mar 2011 17:16:40 -0500
Message-ID: <52E301F960B30049ADEFBCCF1CCAEF590BB02496@OAEXCH4SERVER.oa.oclc.org>
To: "Tillett, Barbara" <btil@loc.gov>, "Karen Coyle" <kcoyle@kcoyle.net>, "Thomas Baker" <tbaker@tbaker.de>
Cc: <gordon@gordondunsire.com>, <public-lld@w3.org>
Sorry, I took another look at the FRBR Final Report and see there is
indeed a many-to-many relationship between Expression and Manifestation.
It's not hierarchical and therefore XML Schema would suck all the more
(not that it was ever tempting in the first place).

I'm still trying to make sense of WEMI, but treating "has publisher" and
"place of publication" as literals implies they have no bearing on WEMI
splits. If these properties aren't factors, it makes me wonder which if
any are. It never occurred to me that WEMI entity production wouldn't
leave traces in the properties. Maybe I've been looking under the wrong
rocks?

Jeff

> -----Original Message-----
> From: Tillett, Barbara [mailto:btil@loc.gov]
> Sent: Sunday, March 06, 2011 3:44 PM
> To: Young,Jeff (OR); Karen Coyle; Thomas Baker
> Cc: gordon@gordondunsire.com; public-lld@w3.org
> Subject: RE: Question about MARCXML to Models transformation
> 
> I basically agree, but want to point out that FRBR's WEMI are not
> strictly hierarchical but rather a network graph (don't forget about
> the many to many relationships for the WEMI - it's not just one to one
> or one to many or many to one - there are also many to many).
> 
> Also "relational database" does not mean it has relationships...it
> means it's based on relational algebra with joins, unions,
> intersections, etc., of tables (sets of data).  I'm really looking
> forward to breaking away from relational database models to get to
> something that handles the complex graph structures of the
> bibliographic universe better.  It's probably because I'm rather fond
> of topological spaces and non-Euclidean geometries and see a better
fit
> in that realm, but computer science isn't there yet.  I think the
> Semantic Web has the potential to free us from the relational model,
> while improving connections and links of relationships...but I still
> see current iterations as not really "there" yet.  Gordon's work is a
> brilliant step to demonstrating and documenting the logic relations
> (transitive, equivalent, etc.), cardinalities, etc.  It really helps
us
> "see" the model and note where adjustments would make it even better.
> 
> FRBR has declared certain attributes for the entities, and I
completely
> agree some of those could better evolve into relationships (like
> corporate bodies with a relationship/role of "is publisher" to a
> particular manifestation rather than leaving them as attributes of a
> manifestation) - we started to do that with RDA, but stopped short as
> being too drastic a change from FRBR for this first round...but I am
> sure it will be revisited once we have more registries like VIAF and
> the RDA registries that make linking and declaration of relationships
> easier and more stable, and schemas and systems that can actually do
> something with such structures. - Barbara
> ________________________________________
> From: public-lld-request@w3.org [public-lld-request@w3.org] On Behalf
> Of Young,Jeff (OR) [jyoung@oclc.org]
> Sent: Sunday, March 06, 2011 4:15 AM
> To: Karen Coyle; Thomas Baker
> Cc: gordon@gordondunsire.com; public-lld@w3.org
> Subject: RE: Question about MARCXML to Models transformation
> 
> I think Karen brings some nebulous issues into focus. Sorry if my
> thoughts are cryptic. I can try to clarify them if needed.
> 
> > It's rather clear that FRBR was not designed with the open world
> model
> > in mind -- in fact, it was designed around a late 90's concept of
> > relational databases.
> 
> The Semantic Web is also "relational", so that aspect doesn't bother
> me.
> I agree that "relational databases" impose closed world assumptions,
> but
> I'm not sure this limitation affects how designers go about their
> modeling. For example, reusable OWL can be rationalized from legacy
> relational databases using D2RQ:
> 
> http://www4.wiwiss.fu-berlin.de/bizer/d2rq/spec/
> 
> > It is very top-down in that XML-ish way and most
> > commonly it is assumed that each of the FRBR entities will be a
> > record.
> 
> FRBR in general is relational, but the WEMI classes specifically are
> unquestionably hierarchical. I would agree that XML Schemas warps our
> thinking, but WEMI is starting to make sense to me as a hierarchy. My
> complaint now is the lack of meaningful WEMI subclasses that could
make
> the model much easier to understand and deal with.
> 
> > I say that latter because of the fact that the WEMI entities,
> > while having inter-dependencies, also have specific relationships to
> > other WEMI entities (as well as to the group 2 and 3 entities). So
an
> > expression will have a relationship to a work and to one or more
> > manifestations -- that's what I think of as a *structural*
> > relationship --
> 
> I agree with this interpretation and provide these RDF examples for
> illustration.
> (Beware: my "frbr" namespace elements are ad hoc.)
> 
> <expression-1> a frbr:Expression ;
>         frbr:isARealizationOf <work-1> ;
>         frbr:isEmbodiedIn <manifestation-1> ;
>         frbr:isEmbodiedIn <manifestation-2> .
> <work-1> a frbr:Work .
> <manifestation-1> a frbr:Manifestation .
> <manifestation-2> a frbr:Manifestation .
> 
> > but it can also have bibliographic relationships to
> > other expressions (like: one expression is the translation of
another
> > expression, or is an updated edition).
> 
> Here's what the additional triples would look like:
> 
> <expression-1>
>         frbr:hasATranslation <expression-2> ;
>         frbr:hasARevision <expression-3> .
> <expression-2> a frbr:Expression .
> <expression-3> a frbr:Expression .
> 
> > The fact is that it will be very hard to have an expression without
a
> > work because of the way the properties are spread across the Group 1
> > entities: an expression does not have relationship to a primary
> > creator (e.g. author), only a work does. Ditto subjects: only Work
> > entities have the "has subject" property that links to topical
> > entities.
> 
> I'm willing to go so far as believing it is *impossible* to have an
> Expression without a Work because *all* conceivable Expressions have
> creator and subject relationships in theory: even the fictional ones.
I
> think we need to beware that FRBR doesn't strive to be a metadata
> exchange format, it strives to be a model of common sense reality
(more
> or less).
> 
> > A Manifestation doesn't have a language of text; that
> > belongs to the Expression. The necessary elements to describe a
> > resource
> 
> Riddle: When is a resource not a resource?
> Answer: When the modeler(s) declare it to be a property or set of
> properties instead.
> 
> Fortunately, no modeler in history ever had the last word. :-)
> 
> > are spread across the 3 (WEM) group 1 entities, making it
> > very difficult to treat them separately. To give you an idea of what
> > each entity "means", here are some key attributes for each:
> >
> > Work
> >   - work title
> >   - key for a musical work
> >   - coordinates for a cartographic work
> >   - with relationships to
> >      -- creator of the work
> >      -- topics of the work (subject headings and classifications)
> 
> The terms "musical work", "cartographic work", and various other
> rationalized "foo work" qualifiers imply subclasses of FRBR Work. I
> think it's worth attempting.
> 
> >
> > Expression
> >   - language of the expression (if text)
> >   - form of the expression (text, sound, image)
> 
> Likewise, "text expression", "sound expression", "image expression",
> and
> other qualifications all imply subclasses of FRBR Expression.
> 
> > Manifestation
> >   - title of the manifestation (may be different to the work title)
> >   - edition
> >   - publisher, date of publication
> >   - physical format (size, units, other measurements)
> >   - ISBN, ISSN, etc.
> 
> My feeling is that some of these "attributes" (owl:DatatypeProperty)
> SHOULD be modeled as relationships/associations instead
> (owl:ObjectProperty). For example, I think "publishers" should be
> modeled as a frbr:CorporateBody (or a subclass thereof) and "place of
> publication" should be modeled as frbr:Place. Limiting the individuals
> in the CorporateBody and Place classes to known subjects of a Work
> doesn't make sense in an open world model. Most real world objects can
> be dumbed-down to literals when necessary.
> 
> >
> > There are many more attributes, but these are the common ones and
the
> > ones that I think may help people understand the issue. The data
> > record that libraries create today contains data elements from all
of
> > these entities, mixed together and usually not clearly identified as
> W
> > or E or M. To create library data under FRBR it will be necessary to
> > ALWAYS have Work+Expression+Manifestation entities. (I'm skipping
> Item
> > in the interest of brevity, but we should assume that it is part of
> > the picture.)
> 
> For better or worse it's not that simple. As Tom Baker pointed out in
> another thread, ontologies aren't exchange formats, they are models in
> which some entities can be inferred.
> 
> >
> > Now, it would be great to investigate the inferences that one can
> make
> > with FRBR. For example, if you say:
> >
> > resourceA / frbrer:hasSubject /
> > http://id.loc.gov/authorities/sh85148177
> >
> > then the inference is that resourceA is a Work. (I believe the way
to
> > say this is that "hasSubject" has the domain "Work". Right, Gordon?)
> 
> FRBRer coins separate "has as subject" properties for each range
class,
> but as you would expect the domain is always Work.
> 
> > You cannot then say:
> >
> > resourceA / frbrer:hasPublisher / "Random House"
> >
> > because *that* statement would mean that resourceA is a
> Manifestation,
> > and Manifestation and Work are disjoint.
> 
> The FRBRer OWL doesn't currently declare Work and Expression to be
> owl:disjointWith one another, but I think that was Gordon's plan.
> Here's
> some support for your understanding:
> http://www.w3.org/TR/owl2-primer/#Class_Disjointness.
> 
> > So in a sense you are forced
> > (whether OWL forces you or not is another question), but the FRBR
> > logic forces you to create a new entity for the Manifestation
> > *portion* of your description. In addition, to connect the
> > Manifestation to the Work (since you need the creator and subjects
to
> > complete your description), you may need to create an entity for the
> > Expression. (RDA allows Manifestations to "Manifest" Works, but I
> > think FRBR in its present state still requires M -> E -> W.)
> 
> I believe it's possible to create an inferred shortcut like this in
> OWL,
> but it's just a convenience property.
> 
> >
> > This is, of course, unless I have totally missed something in the
> > nature of FRBR, and if so I would love to hear that my worst fears
> > about it do not come to bear.
> 
> I think you've created a useful and accurate summary. :-)
> 
> Jeff
> 
> >
> > kc
> >
> > >
> > > It relates to Dan's point that schema designers in the new
> > > idiom are not actually issuing "shipping orders" for data
> > > integrity in the imperative style to which they are accustomed
> > > -- even if, as I suspect, they may sometimes _believe_ that
> > > this is is the effect of declarations such as the above.
> > >
> > > As Jeff has pointed out, one might conceivably use the OWL to
> > > construct syntactic validators to impose such data integrity,
> > > but these are necessarily over and above whatever the OWL
> > > itself actually says.
> > >
> > > Tom
> > >
> > >
> > >
> >
> >
> >
> > --
> > Karen Coyle
> > kcoyle@kcoyle.net http://kcoyle.net
> > ph: 1-510-540-7596
> > m: 1-510-435-8234
> > skype: kcoylenet
> >
> >
> 
> 
> 
Received on Sunday, 6 March 2011 22:17:10 GMT

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