Print

Print


On 1/8/15 12:45 AM, [log in to unmask] wrote:
> Karen,
>
> you can use constraints in RDF. Do not put the blame on RDF, it is 
> just a modeling language. RDF is not per se just for inferencing new 
> facts but it can also be instrumented by rules that can be interpreted 
> for restricting classes to domains, checking properties for valid 
> values and so on. It depends on how rules are interpreted and the 
> reasoner works.
>
> Here is an example product for implementing integrity constraints on 
> RDF (maybe there are more):
>
> http://docs.stardog.com/#_validating_constraints

Joerg, Stardog uses ICV, which is a closed world interpretation of OWL. 
This is NOT valid RDF or OWL as defined in the W3C standards. The W3C 
working group on validation [1] is not in agreement as to whether 
re-interpretation of OWL for closed world application is a good idea. I 
see it as dangerous because it encourages people to define their 
ontology for a closed world and forget that when exported to the open 
world the OWL statements mean entirely different things. I also think 
that it is "anti-standard" to create two meanings for a single property 
or class because it can easily lead to confusion - if I use 
owl:minCardinality do I mean it in the open world sense or the closed 
world sense? How can you know if the IRI for both is the same?

>
> The operations over library data I expect are pretty clear to me, they 
> were formulated in the Paris Principles in 1961
>
> "Functions of the Catalogue
> The catalogue should be an efficient instrument for ascertaining
> 2.1 whether the library contains a particular book specified by
> (a) its author and title, or
> (b) if the author is not named in the book, its title alone, or
> (c) if author and title are inappropriate or insufficient for 
> identification, a suitable
> substitute for the title; and
> 2.2 (a) which works by a particular author and
>  (b) which editions of a particular work are in the library."

This is almost word-for-word what CA Cutter said in 1875.[2] I honestly 
think we should be further along at this point. And it doesn't say how 
it is to be accomplished. In Cutter's day it was accomplished in a 
linear card catalog, with human users as the interpreters of the meaning 
of one card following another. It was a technologically appropriate 
method for the time.

>
> In the meantime, they have been reformulated as International 
> Cataloguing Principles (ICP) in 
> http://www.ifla.org/files/assets/cataloguing/icp/icp_2009-en.pdf
>
> With SPARQL, RDF stores can be queried. For tasks of document-based 
> information retrieval, SPARQL complicates the matter for users and 
> implementors and is also not very efficient, for example performing 
> GROUP BY or ORDER BY. Also, I am not interested in presenting triples 
> to patrons, I want to present documents with answers according to the 
> Paris Principles / ICP. Therefore, I load RDF as JSON-LD into 
> Elasticsearch for faster and more convenient document retrieval with 
> filters, rankings, and aggregations, which offer more powerful 
> solutions to requirements such as

Actually, SPARQL is one of the preferred methods for validating RDF 
data. The best known version of that is SPIN.[3] And I don't know why 
SPARQL would require you to present triples to patrons, as if anyone 
would expect that. JSON-LD is just triples re-serialized as JSON.

>
> - when queried, the catalogue should display a complete result set 
> with most relevant documents first
Good luck defining relevant!


> - the catalogue should allow to display all relevant works grouped by 
> authors and all relevant editions grouped by work
See Patrick Wilson on the difficulty of defining editions. [4]

> - the catalogue should allow to reorder, page, refine, and extend 
> result sets by simple operations by the user
> - a union catalogue should ascertain the complete list of libraries 
> that hold a particular edition of a work and display the services 
> offered by the library for that item

kc
[1] https://www.w3.org/2014/data-shapes/wiki/Main_Page
[2] Cutter, Charles Ammi. /Rules for a Dictionary Catalogue/. 
Washington, D.C., 1875.
[3] http://spinrdf.org
[4] Wilson, Patrick. “Interpreting the Second Objective of the Catalog” 
59, no. 4 (1989): 339–353.
>
> The model of RDF triples is nevertheless important, it provides better 
> maintainability and portability of information sets on the Web (e.g. 
> linking to other catalogues, export/import, incremental loads, merging 
> catalogues into a union catalogue, referencing to other data sets like 
> research data), therefore it promises to reduce costs massively (which 
> still has to be proven by calculations). But that is nothing to 
> concern a user with who wants to search the catalogue.
>
> Jörg
>
> On Wed, Jan 7, 2015 at 8:13 PM, Karen Coyle <[log in to unmask] 
> <mailto:[log in to unmask]>> wrote:
>
>     Joe, I like the suggestion of using classes. Some RDF-using
>     communities seem to be very class-heavy, others less so. The
>     implications of lots of classes vs. a few classes still isn't
>     clear to me in terms of how it affects practice, but clearly
>     classes provide functionality that we  may not be used to exploiting.
>
>     On 1/7/15 8:49 AM, Joseph Kiegel wrote:
>
>         I agree with you that mapping BF to "constrained" (typed) RDA
>         will be necessary and useful.
>
>         At the end of my message, I tried to make the point that this
>         won't be possible.  I used classes but it is better to use
>         properties instead.  Once you map
>         rdam:reproductionOfManifestation to bf:reproduction and
>         rdai:reproductionOfItem to bf:reproduction, you can't go back
>         the other way. That is, bf:reproduction does not contain the
>         information you need to choose the correct RDA property in the
>         BF -> RDA mapping.  You no longer know whether you came from
>         reproductionOfManifestation or reproductionOfItem.
>
>
>     I suspect that "mapping" is not the right term here, and maybe
>     that's the issue. If you look at some of the recent presentations
>     that Gordon has done,[1] you see that you can create relationships
>     between terms, e.g. bf:reproduction is a super-property of
>     rdam:reproductionOfManifestation and rdai:reproductionOfItem. You
>     don't change the two RDA properties to bf:reproduction -- they
>     stay what they are, and you navigate the relationship. That
>     doesn't entirely solve the problem, because as is always the case
>     with data it is very hard to go from less specific to more
>     specific. However, I go back to an earlier question, which is:
>     what do we need to do with this data, and under what circumstances
>     do these differences matter? For example, if you have
>
>     resourceA a bf:Work .
>     resourceA bf:workTitle "Moby Dick" .
>     resourceA bf:creator http://..
>     resource7 a rdac:Work .
>     resourceA bf:language "ENG" .
>     resource8 a rdac:Expression .
>     resource8 rdae:language "ENG" .
>     resource8 rdae:expressionOf resource3 .
>     resource3 rdaw:workTitle "Moby Dick" .
>     resource3 rdaw:personalCreator http://...
>
>     You actually have a lot of information here. If this information
>     exists in open linked data space, you can find resources that are
>     in language ENG, and you have essentially the same (well, close to
>     the same) data elements for the RDA and the BF descriptions, even
>     though they are structured differently. In both you have access to
>     the Work and Expression information. (This would be more easily
>     explained with a diagram ;-))
>
>     As Gordon says, however, there may still be differences. bf:Work
>     may not be one-to-one on *all* information with
>     rdac:Work+rdac:Expression. But linked data is designed to be used
>     across heterogeneous data, and allows for gaps and differences. It
>     will probably be no less precise than any previous mappings that
>     we did (e.g. MARC to Dublin Core - from 1100 data elements to 15!).
>
>     The question, therefore, is not "Can I map property1 to propertyZ"
>     but "do I have the information I need?" This involves not just
>     property definitions but the whole meaning provided by the graph.
>
>     This describes an open world usage, and doesn't touch on the
>     question of what data our library system/closed world will use.
>     There can be a considerable difference between the closed world
>     and the open world, and many enterprise systems (banks, medical
>     data...) export to the open world data that is very different from
>     their internal view of their data. What I find unclear at the
>     moment in library-land is: what we are designing for, and, once
>     again, what do we expect to do with it?
>
>
>     kc
>     [1] http://www.slideshare.net/GordonDunsire
>
>
>
>
>
>
>
>
>
>         Joe
>
>         --------------------------------------------------
>         From: "Fallgren, Nancy (NIH/NLM) [E]"
>         <[log in to unmask] <mailto:[log in to unmask]>>
>         Sent: Wednesday, January 07, 2015 8:08 AM
>         To: <[log in to unmask] <mailto:[log in to unmask]>>
>         Subject: Re: [BIBFRAME] Constrained vs unconstrained schemas
>
>             Hi All,
>
>             FWIW . . .
>             We are working with the "constrained" version (with a nod
>             to Karen's comments re use of the term 'constrained') of
>             RDA/RDF and mapping that to a BIBFRAME core vocabulary
>             precisely because we don't know what a cataloging input UI
>             will look like post-MARC or how BF will be generated from
>             that input.  Since BF and RDA have different structures,
>             our thinking is to use the "constrained" RDA/RDF so that
>             the RDA data can be reconstructed easily and losslessly
>             back into its WEMI entities structure from BF should that
>             prove useful or necessary.
>
>             -Nancy
>
>             Nancy J. Fallgren
>             Metadata Specialist Librarian
>             Cataloging and Metadata Management Section
>             Technical Services Division
>             National Library of Medicine
>
>             [log in to unmask]
>             <mailto:[log in to unmask]>
>
>             -----Original Message-----
>             From: Gordon Dunsire [mailto:[log in to unmask]
>             <mailto:[log in to unmask]>]
>             Sent: Tuesday, January 06, 2015 7:42 AM
>             To: [log in to unmask]
>             <mailto:[log in to unmask]>
>             Subject: Re: [BIBFRAME] Constrained vs unconstrained schemas
>
>             All
>
>             Many applications based on RDF data will need to know what
>             type of thing is being described by a triple. An
>             application can get that information implicitly, from the
>             domain and range of the triple's property, or explicitly,
>             from a separate triple stating the thing's type. There is
>             no guarantee that such a type triple exists, or is
>             connected to the local graph, or can be retrieved from the
>             global graph.
>
>             The quality (effectiveness, efficiency, etc.) of these
>             applications is likely to depend on the accuracy and
>             completeness of entity typing. More sophisticated
>             applications are likely to depend also on the semantic
>             coherence of the results of typing.
>
>             Publishers of data based on specific ontologies should be
>             able to choose whether to provide type triples implicitly
>             or explicitly. Using properties constrained by domain and
>             range allows implicit typing by applications intended to
>             consume the data. The maintainers of the specific ontology
>             are probably the best agents to provide data publishers
>             and consumers with the RDF element sets for the
>             constrained properties and, indeed, the type classes used
>             to constrain them.
>
>             Publishing data using constrained properties does not
>             prevent its use by applications that are simple,
>             low-quality, or do not require entity typing.
>             Such applications may use RDF maps to dumb-down
>             constrained properties to unconstrained versions, or
>             simply ignore domains and ranges. The RDF maps may be
>             local to the application, or provided by the maintainers
>             of the constrained elements or some other agent.
>
>             I agree that the publishers of library data in RDF should
>             be able to specify how it is intended to be used by
>             libraries: this is a closed-world assumption. The BF model
>             seems to be mainly influenced by the data currently used
>             by library applications based on MARC21; the FRBR model
>             reflects the functional requirements to support world-wide
>             consensus on user tasks. I think both of these bases, data
>             and users, are good indicators of the needs of future
>             library applications. I therefore think it is a benefit
>             that the BIBFRAME Initiative (BFI), IFLA, and the JSC for
>             RDA are providing constrained RDF element sets for BF,
>             FRBR, ISBD, and RDA. I also think the provision of
>             unconstrained element sets is a good thing, together with
>             mappings from constrained to unconstrained properties. I
>             do not know whether BFI intends to publish unconstrained
>             properties. I do know that the FRBR Review Group decided
>             not to do so because of its plans to consolidate the FRBR,
>             FRAD, and FRSAD models (now approaching completion), and
>             that the ISBD Review Group has an unconstrained element
>             set ready for publication in the near future with a
>             corresponding map.
>
>             The JSC and ISBD Review Group have collaborated on a map
>             between the ISBD and RDA elements [1]. The map, based on
>             an updated version of the agreed element alignment [2]
>             will be published in the next few weeks. It necessarily
>             uses unconstrained properties to link well-formed ISBD and
>             RDA data together, and was a stimulus to the development
>             of the unconstrained ISBD element set. As noted in the
>             pre-print cited by Karen, there is also a map between ISBD
>             and FRBR classes which requires local semantics for
>             "aspect" relationships [3].
>
>             I am not convinced that the assumption that RDA Work and
>             RDA Expression are equivalent to/same as BF Work is a
>             useful or valid one [4]. I think there may be similar
>             problems with RDA Manifestation, RDA Item, and BF Instance.
>             The ISBD/RDA experience shows that careful consideration
>             of implicit semantics in definitions and scope notes is
>             required, as well as explicit semantics in domain, range,
>             and sub-property relationships.
>
>             So I do not advise mapping either the constrained or
>             unconstrained RDA properties to constrained BF properties
>             without further clarification of the class relationships.
>             It is ok to map constrained BF properties to unconstrained
>             RDA properties. A full map between RDA and BF requires the
>             use of unconstrained RDA and BF properties. And, by
>             definition, a roundtrip from constrained to unconstrained
>             to constrained is somewhat lossy (as well as incoherent).
>
>             I think we need further investigation of the relationship
>             between the RDA/FRBR models and BF, probably best carried
>             out by the JSC and BFI. And we need to test
>             interoperability using orthodox RDA and BF data.
>             Fortunately, we now have the beta of version 3 of RIMMF to
>             create orthodox RDA data [5].
>             So perhaps we can do something useful with RDA and BF data
>             after the Jane-athon [6].
>
>             Cheers
>
>             Gordon
>
>             [1] http://www.rda-jsc.org/docs/6JSC-Chair-4.pdf
>             [2]
>             http://www.ifla.org/files/assets/cataloguing/isbd/OtherDocumentation/ISBD2RD
>
>             A%20Alignment%20v1_1.pdf
>             [3]
>             http://www.ifla.org/files/assets/cataloguing/isbd/OtherDocumentation/resourc
>
>             e-wemi.pdf
>             [4]
>             http://www.gordondunsire.com/pubs/pres/RDAMARCBIBFRAME.pptx
>             [5] http://www.rdaregistry.info/rimmf/index.html
>             [6] http://www.rdatoolkit.org/janeathon
>
>             If it is a camel, a weasel, and a whale, then it is a
>             cloud (inferred from Hamlet, Act 3, Scene 2).
>
>
>             -----Original Message-----
>             From: Bibliographic Framework Transition Initiative Forum
>             [mailto:[log in to unmask]
>             <mailto:[log in to unmask]>] On Behalf Of Joseph Kiegel
>             Sent: 05 January 2015 23:21
>             To: [log in to unmask]
>             <mailto:[log in to unmask]>
>             Subject: Re: [BIBFRAME] Constrained vs unconstrained schemas
>
>             Thanks, this helps a lot.  I had viewed domains as more
>             restrictive than they are.
>
>             I agree with your larger question that we need to
>             understand the operations that will be performed on our
>             data in RDF.  Perhaps we can't anticipate what other
>             people will do, but we should be able to specify what
>             libraries will do.
>
>
>             Joe
>
>             --------------------------------------------------
>             From: "Karen Coyle" <[log in to unmask]
>             <mailto:[log in to unmask]>>
>             Sent: Monday, January 05, 2015 1:38 PM
>             To: <[log in to unmask]
>             <mailto:[log in to unmask]>>
>             Subject: Re: [BIBFRAME] Constrained vs unconstrained schemas
>
>                 Joseph, You might want to look at my blog post on RDF
>                 classes:
>
>                 http://kcoyle.blogspot.com/2014/11/classes-in-rdf.html
>
>                 and the article by Baker-Coyle-Petiya
>
>                 http://kcoyle.net/LHTv32n4preprint.pdf
>
>                 There are actually no "constraints" in RDF, just
>                 potential inferences.
>                 The inferences are based on the stated domains and
>                 ranges of the
>
>             properties.
>
>                 There are examples of this in the Baker et al article
>                 using RDA,
>                 FRBRer and BIBFRAME. There is no conflict with a
>                 subject being
>                 inferred as being an instance of more than one class
>                 as long as the
>                 classes themselves are not declared as disjoint. (The
>                 article explains
>                 this better than I can in an email. ) The
>                 documentation for RDA,
>                 BIBFRAME and FRBRer all presents classes as
>                 determinants of data
>                 structure. This, to me, is a common error in RDF
>                 development. That any
>                 subject can be an instance of more than one class is
>                 necessary for the
>                 RDF graph's flexibility, and should be proof that
>                 classes do not
>
>             constraint your data to a single graph structure.
>
>
>                 The declared domains of properties only come into play
>                 if inferencing
>                 is applied. A big question, therefore, is whether any
>                 inferencing will
>                 be done at all over the data. The utility of, for
>                 example, the RDA
>                 classes to me is that it allows you to do simple
>                 queries for
>                 categories of triples, e.g. "give me all of the work
>                 triples for the
>                 manifestation with this ISBN." Other than that you can
>                 ignore the fact
>                 that domains have been declared if they don't serve
>                 your needs.
>
>                 Your question, however, brings up a much larger
>                 question that I
>                 haven't seen discussed anywhere, which is: what kinds
>                 of operations do
>                 we expect to perform over library data in RDF? That
>                 question really
>                 should be answered before domains and ranges are
>                 defined, because that
>                 is the function of those capabilities of RDF.
>
>                 kc
>
>
>
>
>
>
>
>
>
>
>
>                 On 1/5/15 12:52 PM, Joseph Kiegel wrote:
>
>                     A comparison of BIBFRAME and RDA in RDF (referred
>                     to below as RDA),
>                     in an attempt to map RDA to BIBFRAME, raised the
>                     issue of constrained
>                     vs unconstrained schemas.
>
>                     The full set of RDA properties is constrained by
>                     the RDA classes of
>                     Agent, Work, Expression, Manifestation and Item. 
>                     That is, each
>                     property is related to a specific class when
>                     appropriate: e.g.
>                     abridgementOfExpression and abridgementOfWork. A
>                     parallel set of
>                     properties has been created where the constraints
>                     of class are lifted:
>                     e.g. abridgementOf.  This unconstrained version of
>                     RDA loses the
>                     context of some properties but is intended to
>                     facilitate mapping to
>                     schemas that do not use the FRBR model underlying RDA.
>
>                     BIBFRAME is a constrained schema, but constrained
>                     by different classes:
>                     Agent, Work, and Instance.  There is no
>                     unconstrained version of
>                     BIBFRAME.
>
>                     A mapping of RDA to BIBFRAME presents choices and
>                     challenges.
>
>                     Is it better to use constrained RDA, which causes
>                     explicit conflicts
>                     of
>                     domain:  e.g. mapping
>                     rdam:reproductionOfManifestation to
>                     bf:reproduction and rdai:reproductionOfItem to
>                     bf:reproduction?
>
>                     Or is it better to use unconstrained RDA, which
>                     still has conflicts
>                     (an unconstrained domain vs a constrained one in
>                     BIBFRAME): e.g.
>                     mapping rdau:reproductionOf to bf:reproduction?
>
>                     It is not obvious which is the better choice.
>                     Although perhaps we
>                     need both mappings, each with its own problems
>                     regarding original and
>                     destination domains.
>
>                     A corollary of the question is that any roundtrip
>                     RDA -> BF -> RDA is
>                     lossy. If constrained RDA is used as a starting
>                     point, RDA classes
>                     are lost in the mapping itself, and if
>                     unconstrained RDA is used,
>                     classes are lost prior to mapping. Either way, RDA
>                     classes cannot be
>                     recovered in a BF -> constrained RDA mapping.
>
>
>                 -- 
>                 Karen Coyle
>                 [log in to unmask] <mailto:[log in to unmask]>
>                 http://kcoyle.net
>                 m: +1-510-435-8234 <tel:%2B1-510-435-8234>
>                 skype: kcoylenet/+1-510-984-3600 <tel:%2B1-510-984-3600>
>
>
>
>     -- 
>     Karen Coyle
>     [log in to unmask] <mailto:[log in to unmask]> http://kcoyle.net
>     m: +1-510-435-8234 <tel:%2B1-510-435-8234>
>     skype: kcoylenet/+1-510-984-3600 <tel:%2B1-510-984-3600>
>
>

-- 
Karen Coyle
[log in to unmask] http://kcoyle.net
m: +1-510-435-8234
skype: kcoylenet/+1-510-984-3600