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[LC response] To Jeremy Carroll

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Thu, 19 Mar 2009 12:08:09 +0000
Message-Id: <1B2B1532-6027-4CF4-8559-9658E8F48938@comlab.ox.ac.uk>
Cc: public-owl-comments@w3.org
To: Jeremy Carroll <jeremy@topquadrant.com>
Dear Jeremy,

Thank you for your comment
      <http://lists.w3.org/Archives/Public/public-owl-comments/ 
2009Jan/0051.html>
on the OWL 2 Web Ontology Language last call drafts.

We will deal with your specific comments regarding the various  
documents in a separate email. In this email we will address your  
more general remarks regarding motivation. In particular, you claim  
that "The rationale document (and the design) has not taken into  
account the cost of new features particularly to those who do not  
need them". We note, however, that the story you use to illustrate  
this claim applies equally well to OWL DL and OWL Full and to OWL1  
with OWL Lite. For syntax, one could have ontologies published in  
Turtle, NTriples, Manchester Syntax, etc. Furthermore, one could  
point to extensions like Protege's extensions for QCRs and user  
defined datatypes and, for that matter, OWL 1.1 and even current  
versions of OWL.

Thus, we do not believe that the story gives new information or a new  
perspective. One of the goals of OWL 2 from the beginning was to  
reduce or eliminate, as much as possible, these costs by producing a  
standard new version to converge on. We believe the overall  
advantages and, especially, the new clarity of the specification will  
make it easier for tool developers to cope with real world ontologies  
and for new tool developers to enter the market. Furthermore, the  
working group has continually worked to mitigate the transition  
costs. OWL 2 deliberately avoids radical new features (such as non- 
monotonic features, or an entirely new, stratified metamodeling  
system, or fuzzy extensions). Even features that are well understood  
and have strong utility and demand were dropped or weakened in  
response to the sorts of analyses you ask for, e.g., property punning  
or required n-ary data predicates.

Returning to the motivation for new language features, the New  
Features and Rationale document (NF&R) [1] is being extended to  
better document the motivation for the new features of OWL 2. We  
should also mention that NF&R should be read in conjunction with the  
OWL Use Cases and Requirements document [2], which already motivates  
some of these new features, e.g., extended annotations. The make up  
of the OWL working group is indicative of broad support for OWL 2,  
not just from academia but also from industry, and we also received  
many supportive comments in response to the call for review (see  
[3]). Finally, your own comment expresses support for several of the  
new features, including qualified cardinality constraints, property  
chain inclusion axioms, (unary) datatypes, annotations and profiles.

Finally, you questioned the role of OWLED and its representativeness  
w.r.t. the OWL community. The current wording of the Overview of the  
New Features and Requirements mentions several underpinnings of the  
new features of OWL 2. Only part of this experience came through the  
OWLED workshops from 2005, 2006, 2007, and 2008DC, and only part of  
that influenced the OWL member submission. There is desire for the  
new features of OWL 2, and implementation experience as well. The  
long-term business viability of OWL 2 remains to be determined, of  
course, but the working group believes that there is sufficient  
evidence to proceed.

In view of the above, the OWL WG does not intend to make any changes  
to the design of OWL 2 in response to your comment.

[1] http://www.w3.org/2007/OWL/wiki/New_Features_and_Rationale
[2] http://www.w3.org/TR/webont-req/
[3] http://www.w3.org/2007/OWL/wiki/Support


Please acknowledge receipt of this email to <mailto:public-owl- 
comments@w3.org> (replying to this email should suffice). In your  
acknowledgment please let us know whether or not you are satisfied  
with the working group's response to your comment.

Regards,
Ian Horrocks
on behalf of the W3C OWL Working Group
Received on Thursday, 19 March 2009 12:08:51 GMT

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