- From: Leo Obrst <lobrst@mitre.org>
- Date: Mon, 10 Mar 2003 19:57:11 -0500
- To: David Martin <martin@ai.sri.com>
- Cc: "Roger L. Costello" <costello@mitre.org>, www-rdf-logic@w3.org
For the historical record, Chris Welty has an old (1995) paper on this topic: Welty, Chris and Ferrucci, Dave. 1994. What's in an Instance? RPI Computer Science Technical Report. Available in [HTML] [PDF]. Off his home page: http://www.cs.vassar.edu/faculty/welty/. Chris originally argued for OWL having a class as instance construct. Leo David Martin wrote: > In the work on DAML-S, we are using classes as individuals in, I think, a > very compelling way, which is somewhat reminiscent of the AirlineFlight > example (discussed in other recent messages on this list). > > In brief, we model a process as the class of its occurrences. For example, > a process called BuyBook, associated with an online retail Web service, > would be represented as a *subclass* (not an instance) of > http://www.daml.org/services/damls/0.7/Process.daml#Process > > A specific occurrence/execution/invocation/instantiation of BuyBook (say, > John Doe buying "war and peace" using credit card cc01) is an *instance* of > BuyBook. > > Of course, we need to say many interesting things about BuyBook, some of > which are modelled quite nicely using basic DAML+OIL, and some of which > aren't. There are indeed places where we want to treat (and do treat) > things like BuyBook as instances -- so that, for example, BuyBook can be > mentioned as the object of some property instance. > > Conceptually, I believe the basic idea is quite nice, but it has caused us > to stretch the limits of valid DAML+OIL in various ways, and we have had > *lots* of discussion about the pros and cons of doing it this way. > (Personally, I find it counterintuitive to always have to think about a > process as the set of its occurrences.) > > I don't have time to elaborate any further at present, but you are invited > to browse our examples and documents on our current release: > > http://www.daml.org/services/daml-s/0.7/ > > Regards, > David Martin > DAML-S Coalition > > "Roger L. Costello" wrote: > > > Hi Folks, > > > > One of the "main" differences between OWL Full and OWL DL/Lite is that > > in OWL Full a class may be treated as both an individual as well as a > > class. I am trying to create an example to demonstrate the use of a > > class as an individual. Specifically, an example to demonstrate the use > > of a River class as an individual. Here is how River is defined: > > > > <rdfs:Class rdf:ID="River"> > > <rdfs:subClassOf rdf:resource="#Stream"/> > > </rdfs:Class> > > > > Can you give me an example that shows this River class being used as an > > instance? Thanks! /Roger -- _____________________________________________ Dr. Leo Obrst The MITRE Corporation mailto:lobrst@mitre.org Intelligent Information Management/Exploitation Voice: 703-883-6770 7515 Colshire Drive, M/S H305 Fax: 703-883-1379 McLean, VA 22102-7508, USA
Received on Monday, 10 March 2003 20:01:52 UTC