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Re: Proposed (parital) response to Ken Laskey and questions for WG

From: Jim Hendler <hendler@cs.umd.edu>
Date: Mon, 14 Jul 2003 17:09:14 -0400
Message-Id: <p05200f17bb38ca6843c9@[10.0.0.229]>
To: Jeff Heflin <heflin@cse.lehigh.edu>, WebOnt <www-webont-wg@w3.org>

Jeff - I'm okay with this response except for one part (on the 
"typically" issue) - see below:

At 3:14 PM -0400 7/14/03, Jeff Heflin wrote:
[snip]


>
>>  <original section="2.2" paragraph="3">
>>  An example of such knowledge would be that a "Late Georgian chest of
>>  drawers" is typically made of mahogany. This knowledge is crucial for real
>>  semantic queries, e.g. a user query for "antique mahogany storage
>>  furniture" could match with images of Late Georgian chests of drawers, even
>>  if nothing is said about wood type in the image annotation.
>>  </original>
>>
>>  <comment>
>>  OWL supports equivalence relationships but not probablistic relationships
>>  such as "typically made of mahogany".  The concept "typically"would likely
>>  be application-specific reasoning which might be supported by a value
>>  mapping ontology, but this logic goes beyond OWL capabilities.  Suggest
>>  adding to the end of the paragraph:
>>
>>  While OWL in its present form does not intrinsically support such
>>  probablistic or conditional associations useful in real semantic queries,
>>  application-specific semantics could be encoded in OWL to support such
>>  functionality.
>>  </comment>
>
>Actually, the use case was talking about defeasible inheritance
>reasoning, not probability. Although probability can be clearly of use
>in some use cases, the working group did not consider it an important
>requirement, although support for probabilistic information is implied
>by Requirement R12. Attaching Information to Statements. Therefore, I
>decline the change.

while I agree with what you say, I do think Ken is right to think 
that "typically made of" might imply probability -- and I don't agree 
that we did not consider this important -- it wasn't discussed (and 
would likely have been ruled out of scope if it had been).  I think 
we should addrerss this differently.  Here's two possibilities:

We  could add a parenthetical at the end of this section addressing 
probabilities -- i.e. we could say something like:

"in the image annotation.  (Note that we focus here on the notion of 
"default" reasoning.  Similar functionality might be provided by the 
addition of probabilistic information to statements (see R12 below)."

or we could change the word from typical to something more directly 
connoting defaults:

"...a `Late Georgian chest of drawers', in the absence of other 
information, would be assumed to be `made of mahogany.'  This 
knowledge ... "

I slightly prefer the latter of these, suspect Ken would prefer the 
former - but I would approve the overall response if you made either 
of these two.
  -JH



-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  *** 240-277-3388 (Cell)
http://www.cs.umd.edu/users/hendler      *** NOTE CHANGED CELL NUMBER ***
Received on Monday, 14 July 2003 17:09:17 GMT

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