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Re: Rules WG -- draft charter -- NAF

From: Jack Berkowitz <jack.berkowitz@networkinference.com>
Date: Thu, 13 Nov 2003 19:10:54 +0000
Message-Id: <1AE1B0AF-160D-11D8-827D-000393DBBFD8@networkinference.com>
Cc: Sandro Hawke <sandro@w3.org>, phayes@ihmc.us, adrianw@snet.net, www-rdf-rules@w3.org
To: Benjamin Grosof <bgrosof@mit.edu>

Just a couple of basic comments on the draft that has been circulated.  
The first is a critique.  The second I need some help understanding.

You state in the draft:

"Semantic Web Services work such as OWL-S [[[benj: [give OWL-S ref] and 
the Semantic Web Services Initiative (SWSI) [give SWSI ref, esp. to the 
draft requirements spec of its Language Commmittee] ]]] has found that 
while OWL allows a lot to be stated, there is a clear need for rules 
for this work. [[[benj: Rules in particular are critically needed for 
representing several aspects of such service descriptions, e.g., 
security/trust policies, proposed or committed contracts/deals, 
exception handling, and semantic translation between composed 
sub-services. /* These are identified in the SWSI requirements 
documents */ "

I do not feel that this justification is accurate, in particular with 
regards to the "e.g." elements.  We are today able to represent 
security policies, proposed/committed contracts, and semantic 
translations using OWL-DL and encoding this elements as axiomatic 
expressions in a very direct fashion and without issue.  In turn, 
knowledge of these can be obtained through querying our inference 
platform.  As stated, the justifications do not stand up.  However, if 
you were to amend your justification to areas that are clearly in the 
domain of Logic Programs -- the ENACTMENT of policies or alternate 
courses of action in reaction to problems, then I believe your 
statement will be more robust.

furthermore in the draft, you explicitly call out elements regarding 
query and operators, with the following:

"A standard library of built-in terms such as integer sum, string 
concatenation, and the like, based on the XML Query functions and 
operators is in scope, since it clearly contributes to interoperability 
and utility of rules technology. These functions shall be implemented 
as RDF properties (using RDF Lists to handle n-ary functions, as 
implemented in cwm). While it is not required that the URIs of the RDF 
properties be the same as those of the XQuery functions and operators, 
where RDF functions and operators terms correspond to XQuery ones, the 
semantics should be exactly equivalent. @@justify - conversion, reuse 
of code etc."

In my opinion, partly this is the wrong approach, but I freely admit 
that I am missing something, so read my understandings and then correct 
me, please:

The W3C has just managed to get XQuery energized, yet we are looking to 
redo that work in yet another recommendation or method?  Why?  Rather 
than specify that a re-implementation of the semantics of XQuery be 
done, why not study the requirements of Xquery that capture the 
additional semantics and uses needed for OWL & OWL-RULES and make a 
cogent argument to the XQuery working group to formally extend their 
recommendation to encompass additional capabilities?  If someone needs 
exact semantics, why can't they just us XQuery as is??  We have hybrid 
reasoning working here with a Logic Program that calls out to an XQuery 
to hit a compiled OWL knowledge base, and it works fine.

People are going to be spending the next two years building 
applications using XQuery to hit XML sources as they transition off of 
straight SQL.  In the next two years, you are hopefully going to see 
several million people with some ability to use XQuery.  Therefore, 
companies today are moving in that direction (like us).  If there is 
yet another query method, at a minimum, this will force me to change 
software and retrain integrators all over again.  The cost impact will 
be prohibitive.

The W3C membership is already asking integrators and developers to 
learn XQuery.  Saying to them that they need to learn and implement yet 
another query-oriented or operation-oriented methodology in order to 
get to the semantic web seems to be yet another barrier in an already 
bumpy road.  We should be striving for less recommendations, but ones 
that hang together.

Best regards,
Jack Berkowitz
Vice President, Engineering
Network Inference (Holdings) Ltd
+44 (0)20 7616 0700
Received on Thursday, 13 November 2003 14:11:01 UTC

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