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RE: Question about MARCXML to Models transformation

From: Karen Coyle <kcoyle@kcoyle.net>
Date: Sun, 06 Mar 2011 15:20:46 -0800
Message-ID: <20110306152046.737324h8b4giueha@kcoyle.net>
To: "Young,Jeff (OR)" <jyoung@oclc.org>
Cc: public-lld@w3.org
Quoting "Young,Jeff (OR)" <jyoung@oclc.org>:

>
> 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, you completely lost me on this, so I'm going to begin by asking  
what you mean by "splits" -- then I probably will have other  
questions. :-)

kc


>
> 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
>> >
>> >
>>
>>
>>
>
>
>
>



-- 
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 23:21:22 GMT

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