- From: Bob MacGregor <macgregor@ISI.EDU>
- Date: Thu, 15 Aug 2002 14:50:30 -0700
- To: "Deborah McGuinness" <dlm@KSL.Stanford.EDU>, "Ian Horrocks" <horrocks@cs.man.ac.uk>
- Cc: "R.V.Guha" <guha@guha.com>, <www-rdf-logic@w3.org>
This discussion started not as a question about the merits of DLs, but asked what you get when you sacrifice the ability to treat classes/predicates as arguments to other predicates. Slightly paraphrasing: > > > Clearly, not allowing this feature (classes and arc labels as > > > first class objects) buys description logics something. Please correct me if I'm wrong, but my recollection is that CLASSIC allowed second-order syntax, and in fact made some claims as to the utility of doing so. I my recollection is correct, then its not the case that we have to make this particular sacrifice to achieve the "benefits" of a DL. Rather, the trade-off exists only for certain subclasses of DLs. - Bob ----- Original Message ----- From: "Deborah McGuinness" <dlm@KSL.Stanford.EDU> To: "Ian Horrocks" <horrocks@cs.man.ac.uk> Cc: "R.V.Guha" <guha@guha.com>; <www-rdf-logic@w3.org> Sent: Thursday, August 15, 2002 14:31 Subject: Re: Classes and predicates as first class objects > > to support Ian's last statement that DLs are and have been used in a wide > variety of applications and also because people had previously asked for some > example applications, > i include a paragraph from a message i sent a while ago on a related topic > (full message available from > http://lists.w3.org/Archives/Public/www-rdf-logic/2001Feb/0044.html) > > This was just a list of some variety of applications of an earlier description > logic - CLASSIC - but it shows applications with references in broad areas. > > "I have helped people use CLASSIC in a series of large applications; the > largest and longest lived was a family of configurators called PROSE/QUESTAR > [1]. This included 17 configurators, some of which were used for a decade. > They were used by AT&T and Lucent. Other major application areas include data > > archeology [2], software discovery [3], query expansion [4], query answering > [5], plan representation [6], knowledge based software engineering [7], and > other domains. We also spent time considering the usability issues of the > language [8,9]." > > Most if not all of these applications (and the application areas in general) > benefited greatly from having the qualities that Ian refers to of reliable and > efficient reasoning. > > Deborah > > [1] Deborah L. McGuinness and Jon Wright. ``An Industrial Strength Description > > Logic-based Configurator Platform''. IEEE Intelligent Systems, Vol. 13, No. 4, > > July/August 1998, pp. 69-77. ) > > [2] Ronald J. Brachman, Peter G. Selfridge, Loren G. Terveen, Boris Altman, > Alex Borgida, Fern Halper, Thomas Kirk, Alan Lazar, Deborah L. McGuinness, > Lori Alperin Resnick. ``Integrated Support for Data Archaeology.'' In > International Journal of Intelligent and Cooperative Information Systems, 2:2 > 1993, pages 159--185. > > [3] P. Devanbu, R.J. Brachman, P.G. Selfridge, B.W. Ballard: "LaSSIE: A > knowledge-based software information system" Communications of the ACM, > 34(5):35--49, May 1991. > > [4] Deborah L. McGuinness. ``Ontological Issues for Knowledge-Enhanced > Search''. In the Proceedings of Formal Ontology in Information Systems, June > 1998. Also in Frontiers in Artificial Intelligence and Applications, > IOS-Press, Washington, DC, 1998. > > [5] Alon Y. Levy, Anand Rajaraman and Joann J. Ordille, ``Query Answering > Algorithms for Information Agents'' Proceedings of the 13th National > Conference on Artificial Intelligence, AAAI-96, Portland, Oregon, August, > 1996. > > [6] P. Devanbu , D. Litman , CLASP - a plan representation and classification > scheme for a software information System, Published in Artificial > Intelligence , 1996 > > [7] P. Devanbu , M. Jones , The use of description logics in KBSE systems. > Published in ACM Transactions on Software Engineering and Methodology , 1997 > > [8] Deborah L. McGuinness and Peter F. Patel-Schneider. ``Usability Issues in > Knowledge Representation Systems''. In Proceedings of the Fifteenth National > Conference on Artificial Intelligence, Madison, Wisconsin, July, 1998. This is > > an updated version of ``Usability Issues in Description Logic Systems'' > published in Proceedings of International Workshop on Description Logics, Gif > sur Yvette, (Paris), France, September, 1997. > > [9] Ronald J. Brachman, Alex Borgida, Deborah L. McGuinness, and Peter F. > Patel-Schneider. "Reducing" CLASSIC to Practice: Knowledge Representation > Theory Meets Reality. In Artificial Intelligence 114(1-2) pages 203-237, > October > > Ian Horrocks wrote: > > > On August 14, R.V.Guha writes: > > > > > > > > > Much of the debate around layering of OWL on top of RDF and RDFs boils > > > down to whether the Semantic Web should treat classes and arc labels as > > > first class objects, about which arbitrary new kinds of statements can > > > be made. > > > > > > This is an important architectural choice which has to take into account > > > results from systems that have been built. Looking at what was learnt > > > from such systems would probably be productive ... > > > > > > RDF, which has been largely influenced by the experimental "scruffy" > > > side of AI has gone the route of many experimental AI systems (starting > > > from KRL, RLL, .... CycL) and incorporated these as first class objects. > > > In my experience, and the experience of the builders of these systems, > > > this has been a useful feature. Description Logics, which come from the > > > more "neat" side of AI chose not to allow this ... > > > > > > Clearly, not allowing this feature buys description logics something. > > > Ian, maybe you could explain exactly what this is and how it has been > > > found useful in large DL systems that have been built? > > > > Work on DLs has resulted in the development of a family of logical > > languages with precisely defined semantics and well understood > > computational properties. They are (almost invariably) decidable > > subsets of FOL and are closely related to propositional modal and > > dynamic logics. For many of these languages, provably sound and > > complete decision procedures have been devised. Several DL systems > > have been based on optimised implementations of these algorithms, thus > > providing users with reasoning services that are both reliable and > > efficient. These systems are being used in a wide range of > > applications, e.g., in medical-informatics, bio-informatics, chemical > > engineering and geographical information systems. > > > > Ian > > > > > > > > thanks, > > > > > > guha > > > > > > > > > > > > > > -- > 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/index.html > (voice) 650 723 9770 (stanford fax) 650 725 5850 (computer fax) 801 705 > 0941 > >
Received on Thursday, 15 August 2002 17:48:54 UTC