John, (01)
Many of us have said this, over and over again, i.e., that a data model is not
an ontology. Just because one can express a database query in SQL (based on the
relational calculus, with enhancements) does not make the representation the
SQL query works over an ontology. Expressible in logic \= ontology. (02)
The closest that relational dabases get to having a semantic model is the
conceptual schema, which is a type of conceptual model (modeled in a graphic
Entity-Relation-Attribute language, with cardinality restrictions). Then
typically the conceptual schema is refined to a logical schema, which is turn
is refined to a physical schema, with the "semantics" being reduced at each
stage. At the end, all you typically have is the physical schema, a data
dictionary in English or another natural language which documents what
everything is supposed to mean, and the graphic of the conceptual schema
(hiding in a desk drawer, never typically updated). Similarly, I dare say, for
object models: once the computer program is generated from the OO model, the
model is filed away as a dusty artefact of the design process. The latter
occurrence doesn't hold of the so-called Model Driven Architecture (MDA)
approach, which says (much like we think in ontological engineering) that the
program should be generated from the model, and when the model is updated, a
new program should be generated. MDA cannot be fully realized yet, because it
is still very difficult to fully generate programs from models. So it's more
of an approach with a dream behind it. (03)
Now the above view does have rare exceptions in the database world: e.g.,
Matthew West's work immediately springs to mind. Similarly, HighFleet (formerly
Ontology Works) tries to bridge the ontology-database connection. Also, of
course deductive databases try to combine logic programming + relational
constructs, though these just focus on the implementational apparatus you would
need for more expressive ontologies, but say nothing in particular about
ontologies. (04)
On your other topic, many of us do not think the Semantic Web has failed, nor
that the original vision has been vitiated by academic lackeys and hijackers.
Also, decidability is not the bugaboo you make it out to be: it is a useful
formal notion, and indeed enables us to make sense of the range of
expressiveness. For very many real applications, one needs to exceed the formal
expressivity of a description logic: so what? By continually bashing the
Semantic Web, you do a disservice. It would be better if you phrased your often
cogent comments as recommendations for improving the Semantic Web. Just
starting over somehow, maybe by having everyone immediately use Common Logic,
and grafting that onto existing relational databases in the world, is not
really a good approach. (05)
By the way, (06)
> (Forall x:Professor) (CSprofessor(x) iff
> ((Exists y:CScourse) teaches(x,y))
> or ((Exists z:CSdepartment) belongsTo(x,z) ) (07)
can be expressed in OWL, with "iff" given the interpretation of "is equivalent
to", i.e., a necessary and sufficient condition. (08)
Thanks,
Leo (09)
>-----Original Message-----
>From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
>bounces@xxxxxxxxxxxxxxxx] On Behalf Of John F Sowa
>Sent: Saturday, March 30, 2013 11:17 AM
>To: '[ontolog-forum] '
>Subject: [ontolog-forum] Why a data model does not an ontology make
>
>The subject line is the title of a talk that Robert Meersman presented
>at the U. of Buffalo. He discussed some issues that I have emphasized,
>but he supports them with a methodology and tools that he and his group
>have implemented and used for practical application development.
>
>Following are the slides:
>
> http://starlab.vub.ac.be/website/files/MeersmanBuffaloAug2007.pdf
>
>Following is a related publication:
>
> http://starpc15.vub.ac.be/website/files/sigmod02.pdf
> Data modeling vs. ontology engineering
>
>Some quotations from the slides and the paper:
>
>Paper, page 1:
>> Unlike data models, the fundamental asset of ontologies is their
>> relative independence of particular applications, i.e. an ontology
>> consists of relatively generic knowledge that can be reused by
>> different kinds of applications/tasks.
>
>Slide 2:
>> Why "the" Semantic Web has failed.
>> * Data models vs. ontologies
>> * Legacy systems
>> * Scalability
>> * Methodology
>
>Note the scare quotes around "the". Robert (and I) were not opposed
>to the basic goals of the Semantic Web, as Tim Berners-Lee presented
>them around 2000. On the contrary, we were very hopeful about them.
>But what was produced failed to address the requirements Tim proposed
>and many others (including Robert and me) believe are essential.
>
>Slide 16:
>> Emphasis on methodology
>> * Consistent linguistic paradigm
>> - Rooted in natural language, not driven by programming agenda
>> * Respect for enterprise legacy systems
>> - Transform/grow, avoid trauma
>> - Handle complexity and scale from day 1
>> * Support by flexible DOGMA workbench
>> - Specific concept servers (lexons, concept definitions,
>> commitments, contexts
>> - As late as possible "conceptual binding" of modeling
>> primitive instances
>
>DOGMA is the name of the methodology and workbench that Meersman and
>his group have developed. I'll avoid endorsing any particular tool,
>but I want to emphasize that tools and methodologies along the lines
>that Robert and his group have developed are *essential* for bringing
>ontologies into mainstream IT.
>
>I would also like to comment on the phrase "rooted in natural language".
>Robert gives several examples of how to map a description in NL to
>very readable diagrams and how to use them as a basis for ontology
>and for application development.
>
>Slides 26 to 30 give some examples in OWL, and later slides show how
>to map OWL to the DOGMA diagrams and methodology.
>
>Just for comparison, following is a controlled English statement for
>the example shown in slides 26 to 28:
>
> A CS professor is a professor who either teaches a CS course
> or belongs to a CS department.
>
>Following is a translation of the sentence to typed first-order logic:
>
> (Forall x:Professor) (CSprofessor(x) iff
> ((Exists y:CScourse) teaches(x,y))
> or ((Exists z:CSdepartment) belongsTo(x,z) )
>
>I strongly agree with the basic points Robert makes. I believe that
>a methodology and a set of tools along the lines he describes would
>be extremely valuable for practical ontology development and use.
>
>Note that he presented these slides in 2007 -- six years ago.
>The Semantic Web would be far more widely used today if the SW
>developers had seriously addressed these issues. Compared to them,
>*decidability* is the reddest of red herrings.
>
>John
>
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