[OEP] Other QCR approaches

Following last OEP telecon:

At 14:29 -0400 8-06-2005, Christopher Welty wrote:
>
>Aldo, please send an email message regarding your QCR comments made during
>the last telecon.
>

my comment was about another approach for QCR in OWL, which is not 
yet covered by Guus' note: http://www.cs.vu.nl/~guus/public/qcr.html.

In the note, Guus presents three approaches:

1) generic someValuesFrom
2) dedicated subproperties for the sake of introducing QCRs
3) DAML+OIL-like QCRs

in my experience, I apply (whenever possible) a fourth type, which 
avoids the cumbersome generation of several-to-too-many subproperties:

4) decouple a DAML+OIL-like typed QCR into allValuesFrom + OWL QCR. 
This is not applicable to any of Alan's use cases btw, but only in 
simpler cases. For example:

A typical date (as a meeting btw two prospective lovers) has exactly 
two participants ->

Class(TypicalDate
     subClassOf(Restriction(
       hasParticipant) cardinality(2)))
     subClassOf(Restriction(
       hasFinger allValuesFrom(Person))))

Of course, this is extensionally (but not intensionally) equivalent 
to approach 2, but allows to reuse existing properties whenever 
possible.

I also apply sometimes a reified approach:

5a) reify cardinality as a property, for example:

DatatypeProperty(reifiedCardinality
    range(xsd:int))

Class(NormalHand
     subClassOf(Restriction(
         hasPart someValuesFrom (intersectionOf
          Finger
          Restriction(
           reifiedCardinality oneOf(5)))))
     subClassOf(Restriction(
         hasPart someValuesFrom (intersectionOf
          Thumb
          Restriction(
           reifiedCardinality oneOf(5))))))

5b) reify cardinality as a property, and reify the Q(C)R as a class, 
for example:

Class(NormalHandedness
     subClassOf(Restriction(
       settingFor someValuesFrom(intersectionOf
        Hand
        Restriction(
         hasPart someValuesFrom(Finger)
        Restriction(
         hasPart someValuesFrom(Thumb))
     subClassOf(Restriction(
       settingFor someValuesFrom(intersectionOf
        Finger
        Restriction(
         reifiedCardinality oneOf(5)))))
     subClassOf(Restriction(
       settingFor someValuesFrom(intersectionOf
        Thumb
        Restriction(
         reifiedCardinality oneOf(5)))))
     subClassOf(Restriction(
       settingFor cardinality(6))))


Approach (5b) uses a pattern similar to the approach 2 from the n-ary 
relations note, but it also reifies cardinality restrictions as in 
(5a).
In general, I notice that (5b) is more precise than (5a), because it 
separately states the actual exact cardinality for this definition of 
normal handedness. Moreover, other assertions on hands can be made 
without them impacting on the definition of normal handedness.
The approach in (5b) comes from a more general pattern that can be 
applied to other parametric constraints, like time-indexed 
properties, and many other applications. The exemplification with 
time-indexed properties could be part of a dedicated note, which I'm 
proposing in a separate message.

Sorry for this quick and probably messed-up explanation, but I wanted 
to submit it before the OEP telecon (in five minutes ...).
Cheers
Aldo
-- 



Aldo Gangemi
Research Scientist
Laboratory for Applied Ontology
Institute for Cognitive Sciences and Technology
National Research Council (ISTC-CNR)
Via Nomentana 56, 00161, Roma, Italy
Tel: +390644161535
Fax: +390644161513
also.gangemi@istc.cnr.it
http://www.istc.cnr.it/createhtml.php?nbr=71