- From: Deborah McGuinness <dlm@KSL.Stanford.EDU>
- Date: Wed, 01 May 2002 08:14:38 -0700
- To: www-webont-wg@w3.org
- CC: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
I also presented our strategy to the EU/US joint committee meeting readout yesterday. I reiterated the goals I stated in the email to webont One possible strengthened criteria for the design of Level 1 was proposed - attempt to make level 1 cover the needs of a significant number (50-75%) of our expected user communities. I am not sure that this can be achieved while maintaining the goals that frank mentioned below and the ones i stated in http://lists.w3.org/Archives/Public/www-webont-wg/2002Apr/0362.html I grabbed just the goals here Our small group strategy was to 1 - come up with an agreement on a small language that hopefully many tool developers will support 2 - attempt to get the most useful features in this small language 3 - keep the small language small - thus we explicitly were not taking the strategy of including everyone's favorite constructor for which they could make a compelling argument. 4 - not penalize too heaviliy tool developers who want to add construct XX to the core language. my goal 2 was a softer version of the goal of covering the needs of 50-75% of the users. Frank van Harmelen wrote: > The discussion on how to define the compliance levels of OWL will be an > important issue in the next teleconf. > > This email is as a preparation for the teleconf. > > We should at least decide on how to reach consensus (although I would > prefer to actually cut some knots during the teleconf). > > Frank. > --- > > 1. The strategy for defining compliance levels at the Amsterdam F2F and > immediately afterwards was more or less to include any item in level 1 > for which somebody could make a convincing "frequent/common use" case. > This lead to top-heavy proposals which were hard to justify because > they differed only little from full OWL. > > 2. A subgroup met at KR'02 in Toulouse, and explored an alternative > strategy. > As explained in messages by me, Deb, Ian a.o., the core of the Toulouse > proposal was > to identify a language that would be > > - easy to implement (thus encouraging toolbuilders) > - a sufficient step up from RDF Schema (to justify existence) > - not prejudice the difficulty of any extentions (partly or full) with > other elements of OWL > > This lead to the proposal of "RDF Schema on steroids" as a compliance > level 1 for OWL (see [1] for what this includes). > > 3. Subsequent discussion revealed that various people would like to have > additional items in level 1 (e.g. cardinalities, local range > restrictions). Although none of these by themselves would be hard to > implement, they are all judged to make it hard to add additional > features because of the way the features interact. > > EXAMPLE: an example is local range restrictions. When interpreted as > existential ("slot S must have at least one value of type T") they are > easy to implement, similar when interpreted as universal ("all values of > slot S must be of type T"), but the combination of these two is hard to > implement. Thus, including either in level 1 will make it harder to > extend beyond level 1 and include the other. (Different communities seem > to have different need for either extension). > > 4. The minimal required result at the teleconf is that we agree whether > the "Toulouse approach" is the right one to take. > If yes, we can argue the details of "RDF on steroids" as level 1 > If no, we must formulate another strategy for defining level 1 (keeping > in mind that the "Amsterdam F2F approach" has already shown to lead to > failure). > > Please spend some time thinking all this over before the teleconf. > > Frank. > ---- > [1] http://lists.w3.org/Archives/Public/www-webont-wg/2002Apr/0329.html -- Deborah L. McGuinness Knowledge Systems Laboratory Gates Computer Science Building, 2A Room 241 Stanford University, Stanford, CA 94305-9020 email: dlm@ksl.stanford.edu URL: http://ksl.stanford.edu/people/dlm (voice) 650 723 9770 (stanford fax) 650 725 5850 (computer fax) 801 705 0941
Received on Wednesday, 1 May 2002 11:15:22 UTC