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Re: "what is an ontology?" stuff in requirements abstract/intro

From: Jeff Heflin <heflin@cse.lehigh.edu>
Date: Sat, 16 Feb 2002 15:57:52 -0500
Message-ID: <3C6EC7D0.FCE74B80@cse.lehigh.edu>
To: Leo Obrst <lobrst@mitre.org>
CC: Deborah McGuinness <dlm@ksl.stanford.edu>, Ludger van Elst <elst@dfki.uni-kl.de>, www-webont-wg@w3.org
Leo, Deborah, Ludger, et al.

Thanks for the input on definitions of ontologies. While I agree that
Gruber's work was seminal, his classic definition "an ontology is an
explicit specification of a conceptualization" just confuses most
people, including many computer scientists. Given the intended audience
of this document, I think such a definition would be a mistake. I think
Leo's description is the right level, and will add it to the document.

ACTION: Add (with some editing) Leo's "What is an ontology" text from
below to the requirements document.

Jeff

Leo Obrst wrote:
> 
> One of the problems in general is that these definitions are pretty
> meaningless to the unenlightened masses. I know: in many venues, I've
> had to tamp/dumb down (this is not really pejorative: why expect anyone
> outside our community to know the details?) the definition/exposition of
> what an ontology is and why is it useful. This is as true in business as
> it is in government.
> 
> A paraphrase of my usual spiel (with parenthetical comments bracketed)
> at the ontology-naive level:
> 
> ---
> What's an Ontology?
> 
> An ontology defines the common words and concepts (meanings) used to
> describe and represent an area of knowledge. Ontologies are used by
> people, databases, and applications that need to share domain
> information (a domain is just a specific subject area or area of
> knowledge, like medicine, tool manufacturing, real estate, automobile
> repair, financial management, etc.)  Ontologies include computer-usable
> definitions of basic concepts in the domain and the relationships among
> them. They encode knowledge in a domain and also knowledge that spans
> domains. So, they make that knowledge reusable.
> 
> An ontology includes the following kinds of concepts:
> ·       Classes (general things) in the many domains of interest
> ·       Instances (particular things)
> ·       The relationships among those things
> ·       The properties (and property values) of those things
> ·       The functions of and processes involving those things
> ·       Constraints on and rules involving those things
> 
> [I usually give an example here of an ontology which has the above
> items, in an English quasi-logical form.]
> 
> Ontologies are usually expressed in a logic-based language, so that
> fine, accurate, consistent, sound, and meaningful distinctions can be
> made among the classes, instances, properties, attributes, and
> relations. Some ontology tools can perform automated reasoning using the
> ontologies, and thus provide advanced services to intelligent
> applications such as: conceptual/semantic search and retrieval
> (non-keyword based), software agents, decision support, speech and
> natural language understanding, knowledge management, intelligent
> databases, and electronic commerce.
> 
> One way to look at ontologies is as metadata schema (metadata is just
> data about data, mostly about its content; a schema is just a blueprint
> for particular data), that is, a way of structuring and representing the
> semantics (meaning) for metadata elements. What is normally known as an
> ontology can range from the simple notion of a Taxonomy (knowledge with
> minimal hierarchic or parent/child structure), to a Thesaurus (words and
> synonyms), to a Conceptual Model (with more complex knowledge), to a
> Logical Theory (with very rich, complex, consistent, meaningful
> knowledge).
> 
> [I introduce the notion of 'metadata', which many audiences have some
> familiarity with, and relate it in simple terms to 'database schema',
> which they may also have some knowledge of. I also sketch what I call
> the "Ontology Spectrum", a way of relating notions such as 'taxonomy',
> 'thesaurus', 'conceptual model', 'logical theory' in an ascending way so
> that naive audiences can relate what they know to the bigger picture of
> what 'ontologies' are all about.]
> 
> Ontologies figure prominently in the emerging "Semantic Web" as a way of
> representing the semantics of documents and enabling the semantics to be
> used by web applications and intelligent agents.
> Ontologies can prove very useful for a community as a way of structuring
> and defining the meaning of the metadata terms that are currently being
> collected and standardized. Using ontologies, tomorrow's applications
> can be "intelligent", in the sense that they can more accurately work at
> the human conceptual level.
> ---
> 
> Hope this helps some,
> Leo
> 
> Deborah McGuinness wrote:
> >
> > I also typically refer to Gruber's definition when I introduce ontologies -
> > I think citing his work is important.
> > When i introduce ontologies to people unfamiliar with our field, I also
> > think it is useful to mention that ontology has been around in the
> > philosophical literature for a long time and our definition departs from
> > theirs.
> > I also typically point to collections of work on ontologies, e.g., fois
> > books.
> >
> > I wrote a paper on Ontologies Come of Age[1], which could be one of the
> > things pointed to if you like and of course it points to much previous work.
> >
> > [1]
> > http://www.ksl.stanford.edu/people/dlm/papers/ontologies-come-of-age-abstract.html
> >
> > d
> > Ludger van Elst wrote:
> >
> > > Hi Webont-Members,
> > >
> > > > "what is an ontology?" stuff in requirements abstract/intro
> > > > From: Dan Connolly <connolly@w3.org>
> > > ...
> > > > let's
> > > > see if there's some text to grab... yes:
> > > >
> > > >   Put simply, an ontology is just a set of
> > > >   standard vocabularly terms along with some
> > > >   formal definitions of the terms.
> > > >
> > > > Lightly edited:
> > > >
> > > >   An ontology is vocabularly of terms along
> > > >   with some formal definitions of the terms.
> > >
> > > I am a little bit surprised that - though nearly all papers about
> > > ontologies refer to Tom Gruber´s "shared conceptualization" definition -
> > > all proposals in this group only capture the "conceptualization" aspect
> > > but don´t mention the "sharing" aspect.
> > > In the requirements document there is a paragraph titled "3.1 Shared
> > > Ontologies" which would - accepting Tom's definition - expand to "3.1
> > > Shared Shared Conceptualizations".
> > > In my opinion, a good definition of the term ontology should cover both
> > > aspects, sharing and conceptualizing. Otherwise, we should consequently
> > > only talk about conceptualizations (e.g., "A conceptualization is
> > > vocabularly of terms along with some formal definitions of the terms."),
> > > not ontologies.
> > >
> > > What do you think about this topic?
> > >
> > > Best regards,
> > >  Ludger
> > >
> > > ______________________________________________________________________
> > > Ludger van Elst
> > > Deutsches Forschungszentrum für Künstliche Intelligenz GmbH
> > > Erwin-Schrödinger-Straße Geb. 57/377, D-67608 Kaiserslautern, Germany
> > > Tel.  : 0631 205-3474
> > > E-mail: elst@dfki.uni-kl.de
> > > WWW   : http://www.dfki.uni-kl.de/~elst/
> > > ______________________________________________________________________
> >
> > --
> >  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
> 
> --
> _____________________________________________
> Dr. Leo Obrst           The MITRE Corporation
> mailto:lobrst@mitre.org Intelligent Information Management/Exploitation
> Voice: 703-883-6770     7515 Colshire Drive, M/S W640
> Fax: 703-883-1379       McLean, VA 22102-7508, USA
Received on Saturday, 16 February 2002 15:57:57 GMT

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