RE: [OEP] OWL and Semantic interoperability $swbpd

Thanks Deborah.

 

Can you please give some good examples of the richness that OWL provides
for supporting semantic interoperability. Then I will include them.  

 

It was not my intention to be negative or controversial.

 

I want to start off the note with the things that OWL does well, and
then  note the limitations.

 

Thanks,

Mike

 

 

-----Original Message-----
From: Deborah L. McGuinness [mailto:dlm@ksl.stanford.edu] 
Sent: Monday, February 07, 2005 10:00 AM
To: Uschold, Michael F
Cc: Jim Hendler; public-swbp-wg@w3.org; Jones, David H
Subject: Re: [OEP] OWL and Semantic interoperability $swbpd

 

a couple of points that come out for me from the thread so far:

1 - i am also reactive to the feeling that is left from the note that
owl is inferior.   
i find its expressive power to be superior to other things that people
have tried to use for semantic interoperability in at least the database
world.
2 - we might try to keep subjective words like inferior out of the note 
3 - i think it is clear that we need to be precise with what
definition(s) we are considering for semantic interoperability
4 - if we are using a kind of mapping as a definition, i like think one
of the strong claims of owl (and all description logics)
is that they can be used to express  necessary conditions for membership
in a class, and
necessary and sufficient conditions for membership in a class,
and then provide subsumption and recognition reasoners to identify when
classes are subclasses of other and to identify when
instances are members of a class.
Additionally, OWL provides convenient ways to make equivalence
statements that can be used to facilitate mappings.
(additionally it provides convenient ways to make different from
statements.)

one can look at history and go back to the prose family of configurators
that used an early DL - CLASSIC - and could have been viewed to be
solving semantic interoperability problems since it interfaced with
dozens of databases.

Deborah

Uschold, Michael F wrote:



Thanks Jim for your input.
 
More concrete dicussion can take place when the note has some meat on it
for you and others to assess. However, I can respond to some of your
points.
See [MFU] below. 
 
 
-----Original Message-----
From: Jim Hendler [mailto:hendler@cs.umd.edu] 
Sent: Sunday, February 06, 2005 2:29 PM
To: Uschold, Michael F
Cc: public-swbp-wg@w3.org
Subject: Re: [OEP] OWL and Semantic interoperability
 
for the note is:
  

	This note addresses the role of OWL in overcoming problems of
semantic
	heterogeneity.  We briefly characterize what we mean by semantic
	interoperability, and what the challenges are. We describe some
OWL
	constructs that are designed to support semantic
interoperability and
	illustrate them with examples. We highlight their strengths and
	limitations.  The main message is that OWL is no silver bullet
for the
	general problem of achieving semantic interoperability.  The
support
	provided is very limited.  Many of these limitations will be
overcome
	    

by
  

	the Semantic Web Rule Language (SWRL) that is currently under
	development.
	    

 
Mike - let me put this in a friendly way -- I don't like this at all. 
First of all, when you compare OWL to any of the alternatives it is 
way better - 
[MFU] 
Which alternatives to OWL is OWL superior to? In what way? Perhaps you
have something different in mind by 'semantic interoperability' than I
do.
 
When I compare OWL to alternatives (such as CWM or SWRL, and perhaps
FLogic) for providing semantic interoperability , OWL comes up short
(see below).
==
 
If you stopped after the sentence "OWL is no silver 
bullet ..." I'd be fine.  However, you go on to say "the support 
provided is very limited" which I don't agree with, and which also is 
a subjective statement at best.  
 
[MFU] By limited, I meant it cannot support some extremely simple and
minor things that are critical to many real world interoperability
scenarios. e.g.  doing arithmetic to convert between different units
(e.g. feet/meters). One can do this very easily using CWM, and SWRL.
That assertion is not subjective. Going from this fact to an
interpretation that OWL is "very limited" is open to discussion, and
perhaps should be re-worded for different emphasis. For example: "OWL
provides x,y and z to support interoperability. a,b,and c are not
supported by OWL. The extent to which this is a limitation depends on
the nature of one's application." would probably be better. In the
experience of myself and some of my colleagues, OWL's support for
interoperability is indeed very limited. Without simple arithmetic and
rules, most of what we need is not supported. 
 
I would be very grateful if you [Jim or anyone] could give some examples
of non-toy real-world problems of interoperability that can be solved
with ONLY the support that OWL provides. That would be a good way to
start off on a postive note; and then move on to some of the
limitations, concluding that OWL is no silver bullet, and that some kind
of rule language is needed to perform interoperability beyond what OWL
currently gives.
 
===
 
I would even further object to the 
last sentence - first, SWRL has no official status and may not even 
be the eventual choice for a standard, second SWRL has not been 
tested in interoperability issues, and it is unclear to me why more 
expressivity should increase the ability to do reuse -- if anything I 
would actually expect the reverse in practice...
[MFU] I mean to say that more expressivity increases the ability to
express and execute mappings between one ontology and another for the
purpose of interoperability. I'm not making any claims about reuse.
 
===
  So let's keep this factual and focused, and leave the hypotheticals 
out of WG notes
[MFU] That is my intent. I will rely on you and others to identify
hypothethicals that may unintentionally find their way into the note.
===
  -JH
p.s. And in case anyone is interested, I would like to deny in the 
strongest possible terms that "The support provided (for 
interoperability) in OWL is very limited",  the URI/RDF basis of OWL 
makes the sharing of terms possible in a way that no KR langauge in 
the past has ever had, and is a good part of the reason that OWL is 
now the most used KR langauge in the history of AI.
 
[MFU] Again, I'm not making claims about reuse and sharing, per se. What
do you see as the relationship/connection between reuse/sharing and
interoperability?  This note does not focus on reuse/sharing per se. It
is no doubt part of the bigger picture of semantic interoperability that
I should perhaps explore more. 
 
As I read and reread your comments, it seems likely that we have two
fairly different things in mind by 'semantic interoperability'. What do
YOU have in mind?  Perhaps when you think of semantic interoperability,
you are mainly thinking of the reuse and sharing of ontologies and
ontology terms using the URI/RDF basis?  Perhaps THIS is what you see as
being superior to all the alternatives? On that we can agree.
 
The way that OWL is inferior, is in its abilty to express mappings
between ontologies to that applications using different ontologies can
interoperate. This is what I mean by semantic interoperability. 
===
 
 
 
 
Professor James Hendler                   Director, Semantic Web and 
Agent Technologies
Maryland Information and Network Dynamics Lab.   301-405-2696
8400 Baltimore Ave, Suite 200                    301-314-9734 (Fax)
College Park, MD 20742
http://www.cs.umd.edu/users/hendler
 
  





-- 
 Deborah L. McGuinness 
 Co-Director Knowledge Systems Laboratory 
 Gates Computer Science Building, 2A Room 241 
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 email: dlm@ksl.stanford.edu
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