- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Mon, 28 Apr 2003 08:16:26 -0400
- To: webont <www-webont-wg@w3.org>
WOWGers- Summary: Adding QCRs to OWL is likely to add 3-4 MONTHS to the time until we move OWL to PR. Are they worth it? What is an alternative? Details: It is clear that every proposal to date for QCRs would require more than syntactic sugar. Due to the nature of the graphs we have chosen to use to date, we would either need to add new constructors (like the Q constructors in D+O), make changes to our treatment of current constructs (like changing all restrictions to be qualified in some sense), or invent some new syntax that requires reworking of normative sections of our documents (such as Ian's most recent proposal). While none of these require major semantic change, they all require changes at the syntactic and graph level that go beyond what could comfortably be defended as "editorial" change. We then add to this fact that, although there have been implementations of QCRs, none have been doen in the correct syntax (as we don't yet have one). Worse, going over the list of D+O tools that I had hoped to cite in our implementation report, it is unclear any of them actually handle the Q-constructs in any real sense. The validator allows them, but doesn't check for violations, the "instance" based tools appear to check cardinality constraints in some form (for example RIC enforces cardinality, but not qualified cardinality), and their is no evidence in the toolset on the D+O page that a reasoner that handles the qualified cardinality constraints (including instances) exists. As such, we would almost definitely need to do the following: Upon end of current LC, we would need to make changes for QCRs and do a second LC -- If nothing else tests for QCRs would have to be added to the Test document. It would be a mistake to release Test as LC now if we know it is going to change with a new feature that requires new tests and changes old ones. This means at end of current LC we add a second LC period of a minimum of 4 weeks. On close of that LC, we would have to move to CR (not PR). While we might be able to get away with a 4 week CR period, a longer CR period is typical, and there would be time between the second LC and the new CR. Thus, I believe our schedule would need to be May 9, close current LC. June 1, new LC begins end of June - new LC ends mid-July (earliest) - CR begins end-August - CR ends (note, this is optimistic as getting much done in Aug is hard) This means rather than having OWL at Rec by end of summer, we'd be looking at having it at Proposed Recommendation by September. Alternative: Since OWL DL is SHIQ (maybe SHIOQ) we know QCRs are in our current semantic coverage. This means that we should be able to develop an idiom within our current language to handle them (even if it means creating extra classes). We have talked often about the need for an idioms page. We could create that page, and make a recommendation for how to handle QCRs be one of the entries on that page. We could have Guide, Ref and Features (non-normative documents) point at that page and have discussion of a recommendation for QCRs. Note that this is consistent with past practice of our WG, within W3C process, and would not add any delay to OWL release. Proposal: I propose we change the closing status of issue 3.2 to POSTPONED. We create the idioms page and a discussion of QCRs go there. A pointer to that discussion is added to the issues page, and can be referred to in our non-normative documents if desired. -- 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 240-731-3822 (Cell) http://www.cs.umd.edu/users/hendler
Received on Monday, 28 April 2003 08:16:36 UTC