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[ontolog-forum] RE: Questions for Conrad Bock's upcoming presentation o

To: "Nicolas F Rouquette" <nicolas.rouquette@xxxxxxxxxxxx>, <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Conrad Bock" <conrad.bock@xxxxxxxx>
Date: Thu, 27 Jan 2005 13:43:28 -0500
Message-id: <NDBBJCCGLKIFNFMGDBHNCEGEGPAA.conrad.bock@xxxxxxxx>
Resending    (01)

Nicolas,    (02)

 > - PSL + Protege-OWL: has it been done? if not, are there some issues 
 > still to be resolved to stay within OWL-DL for automated 
 > reasoning purposes?    (03)

I gather you're asking if the PSL axioms can be represented in OWL.
Some of them can (see the UML diagrams in
http://www.nist.gov/msidlibrary/doc/semantic_domain.pdf, which can be
translated to OWL).  But PSL core has an axiom requiring irreflexivity,
used on the temporal relation of time points, which I think is not
possible in OWL.  OWL only supports symmetry and transitivity as global
characterisitics of properties.    (04)

Another case is constraints that hold between two individuals due to
their relation to a third.  For example, the begin time of an execution
of a PSL activity must be before or the same as the end time.  This kind
of constraint is also applicable to part whole taxonomies in the
engineering domain.  For example, the engine and wheels in a car must be
connected together.  This isn't possible in OWL, that I'm aware of, but
is supported in UML 2 (http://www.jot.fm/issues/issue_2004_11/column5).
It seems like a very straightforward inference, see Expressions 1 and 2
in the previous link.  I've implemented it several times in frame
systems, but don't have a tractability proof for subsumption.    (05)

 > - PSL & application-specific views of what is a process
 > Depending on the level of abstraction and the scope of factors
 > considered, we can have multiple process models of the same
 > conceptual "process" phenomena.  In engineering, these variations are
 > often due to domain-specific perspectives (e.g., thermal, mechanical,
 > data processing, ...) about the same "thing" (e.g., a spacecraft, a
 > car, a toaster oven, apples & oranges,....)    (06)

Yes, any part of a process can conform to multiple PSL process
constraints at the same time.  This contrasts with common programming
languages and typical process models, where each step is due to a single
process.  For example, taking a patient's temperature might be a step in
a diagnosis procedure, and in PSL this step could conform to many
process constraints.  These could include a simple one that requires all
patients to have their temperature taken during office visits, as well
as more complex ones where the particular medical diagnosis requires
taking the temperature.  See section 4.3
http://www.nist.gov/msidlibrary/doc/nistir7152.pdf for an application of
this to input/output specification.    (07)

Can discuss more tomorrow,    (08)

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