<snip>
The history of computing is the history of
"design patterns" at one level that
eventually get built into "higher level
languages" at the next level of abstraction
up.
I think I have a less optimistic view of
progress in computer science. For example,
many of the paradigmatic GoF design patterns
are there to make up for deficiencies in the
OO languages that *succeeded* more expressive
and abstract functional languages.
Amen to that. And we are living through an
exactly similar transition in representational
languages, where DLs are re-inventing axioms of
classical logic.
it's not quite re-inventing, although it may be
that "new features added to a language" are
sometimes being sold as if they were novel.
I think it is often re-inventing. Take the
current fuss about a W3C rule language, and how
to 'add' it to OWL. Both rules and OWL are easily
defined subsets of full FOL, so this ought to be
close to trivial. BUt this isn't how it is being
treated, and it is turning out to be anything but
trivial, and is widely stated to require new,
original research.
As for the n-aries in DLs (which are indeed
trivial in CL), that is possible in DLs in
theory for over 10 years and in software with
iCOM for >7 years -- and do the automated
reasoning over it, unlike with several other
logics.
I like more expressivity as well, but then, I'm
not implementing systems where I'd have to wait
'long' for query answers or see my computer hang
....
I agree, of course there is an
expressivity/efficiency trade-off. And in many
ways, DLs have identified an important 'sweet
spot' between the extremes. But the main role of
a Web logic is to be a semantically clear,
coherent, interchange medium. An expressive logic
with a sound semantics is the best choice for
that; and the various (because there are more
than one) tractable subsets of it can be treated
by efficient reasoners. The problem with the
current SWeb design is that a variety of
'simpler' (actually the less expressive languages
are often syntactically more complex) languages
is still a VARIETY, which wrecks information
interchange.
Pat Hayes
upon classifying 1 instance in an 50-concept
small ontology (with the latest pellet for owl
1.1). I did try to load in Protégé and SWOOP the
FMA-lite, which is a 43MB OWL file. It failed.
Reasoning over sections of the FMA that take
into account only some constructors is possible
[1], which brings us back to your earlier
comment that "people have argued against more
expressive languages, in fact have argued with
great force and vehemence,": if we have to chop
up large ontologies anyway in order to be able
to reason over them, we might as well do that in
a structured manner with some simpler languages
and (semi-)automated conversions for "dumbing
down" a large and/or rich ontology to some
slimmed version that is computationally
tractable; that is, taking best of 'both worlds'
with expressivity where desired/needed and
performance where needed/desired.
[1] Zhang S, Bodenreider O, Golbreich C.
Experience in reasoning with the Foundational
Model of Anatomy in OWL-DL. In:Pacific Symposium
on Biocomputing 2006, Altman RB, Dunker AK,
Hunter L, Murray TA, Klein TE, (Eds.). World
Scientific, 2006, 200-211.
http://helix-web.stanford.edu/psb06/zhang_s.pdf
regards,
marijke
C. Maria Keet
KRDB Research Centre
Faculty of Computer Science
Free University of Bozen-Bolzano
Piazza Domenicani 3
39100 Bozen-Bolzano
Italy
tel: +39 04710 16128
fax: +39 04710 16009
email: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
web: http://www.inf.unibz.it/krdb/
home: http://www.meteck.org <http://www.meteck.org/>
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