- From: Young,Jeff (OR) <jyoung@oclc.org>
- Date: Sun, 6 Mar 2011 18:48:53 -0500
- To: "Karen Coyle" <kcoyle@kcoyle.net>
- Cc: <public-lld@w3.org>
Let's flip "splits" on its head and imagine "merges" instead (owl:sameAs). Imagine that I create stand-alone W-E-M triads for every single Manifestation and then I go back and try to "de-dup" them class-by-class. Which FRBR properties are useful for this purpose, and which ones are along for the ride? If that doesn't help, I can try again. > -----Original Message----- > From: Karen Coyle [mailto:kcoyle@kcoyle.net] > Sent: Sunday, March 06, 2011 6:21 PM > To: Young,Jeff (OR) > Cc: public-lld@w3.org > Subject: RE: Question about MARCXML to Models transformation > > 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 23:49:48 UTC