W3C home > Mailing lists > Public > www-webont-wg@w3.org > February 2002

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

From: Raphael Volz <rvo@aifb.uni-karlsruhe.de>
Date: Fri, 15 Feb 2002 21:59:42 +0100
To: "Leo Obrst" <lobrst@mitre.org>
Cc: <www-webont-wg@w3.org>
Message-ID: <DMECLAFLIOFJEFFIAJPCEEPKCIAA.rvo@aifb.uni-karlsruhe.de>
Should we add a glossary to the requirements.

-----Ursprüngliche Nachricht-----
Von: www-webont-wg-request@w3.org
[mailto:www-webont-wg-request@w3.org]Im Auftrag von Leo Obrst
Gesendet: Donnerstag, 14. Februar 2002 23:58
An: Deborah McGuinness
Cc: Ludger van Elst; www-webont-wg@w3.org
Betreff: Re: "what is an ontology?" stuff in requirements abstract/intro


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-abstrac
t.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 Friday, 15 February 2002 16:00:09 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:57:47 GMT