Leo, If I can offer up a couple of observations related to your "underlying methodology" comments, I can think of two aspects of an ontology that might prove useful to an effort at categorizing "types" of an ontology. The first relates to the perspective, or goals, of the designer of the ontology. It is apparent that an ontology of industrial compounds would be quite different if it were developed for a chemist than if it were developed for a wholesale supply company. Perhaps there are a few characteristics that can generally define the perspective of an ontological representation - such as "composition", or "function". It might be that this is too individual to capture in a "typing" of ontologies, but it may be that in a few key ways, similar to whatever differences exist for ontologies based more on objects or more on processes (with apologies to 4D-ists who see little difference between the two), it might prove useful. The second relates to whether an ontology is "descriptive" (describing the communications that already exist within a domain, and the entities and relationships that are supported within the existing modes of that communication), or "prescriptive" (describing the domain in as objective a manner as possible, given an objective set of referents, regardless of the ability of systems, etc, to communicate at that granularity of understanding). The first of these two seems to me to be the more practical of the two, while the second seems to be the (potentially) more epistemologically accurate. Chuck Charles Turnitsa Project Scientist Virginia Modeling, Analysis & Simulation Center Old Dominion University Research Foundation 7000 College Drive Suffolk, Virginia 23435 (757) 638-6315 (voice) (757) 686-6214 (fax) cturnits@xxxxxxx
-----ontology-summit-bounces@xxxxxxxxxxxxxxxx wrote: -----
To: "Ontology Summit 2007 Forum" <ontology-summit@xxxxxxxxxxxxxxxx>
From: "Obrst, Leo J." <lobrst@xxxxxxxxx>
Sent by: ontology-summit-bounces@xxxxxxxxxxxxxxxx
Date: 24/01/2007 03:34PM
Subject: Re: [ontology-summit] Defining "ontology"
Hi, Deborah, yes, I would be interested in such a revised paper. In
fact, I think that this Ontology Summit effort is focused on nearly
exactly that purpose, to describe the range of notions that people
sometimes call "ontology" and perhaps "type" those notions along a
multi-dimensional continuum/spectrum: type 1, type 2, etc. So perhaps
the paper could be an outcome of this discussion group's effort.
One notion that is lacking in our discussion so far and lacking even
from the informal-formal dimension is the "source" or "underlying
methodology" of the "ontology" (I use quotes around these because they
all probably need to be defined, perhaps as part of our effort here).
So, for example, the informal-formal poles do not capture how the
"ontology" is developed. One could characterize this notion of
"methodology" as the "empirical/rationalist" or "bottom-up/top-down"
perspective or predilection. Folksonomies, e.g., would probably be on
the empirical/bottom-up side; logical theories (formal ontologies)
would be on the rationalist/top-down side.
And there are other such dimensions.
Thanks,
Leo
_____________________________________________
Dr. Leo Obrst The MITRE Corporation, Information Semantics
lobrst@xxxxxxxxx Center for Innovative Computing & Informatics
Voice: 703-983-6770 7515 Colshire Drive, M/S H305
Fax: 703-983-1379 McLean, VA 22102-7508, USA
-----Original Message-----
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Deborah
L. McGuinness
Sent: Monday, January 22, 2007 10:27 PM
To: Ontology Summit 2007 Forum
Subject: Re: [ontology-summit] Defining "ontology"
hi - i am catching up on email so sorry to come in mid stream. i have
not gone back through the whole thread but figured i would chime in now
while the discussion is on a spectrum.
i have gotten a LOT of leverage out of the notion of an ontology
spectrum.
In 1999 a number of us were on an ontology panel at aaai. as homework
for the panel, we had a pre-meeting about what each of us were willing
to call ontologies. It might be useful to explain my perspective when i
participated (which actually still reflects my perspective now on the
topic).
this was just after i had done a fairly comprehensive consulting
project
looking at "naturally occurring" things that might be considered
ontologies as a LARGE crawl to obtain starting points for a very
comprehensive ontology.
In that effort i looked in excruciating detail at a number of mostly
taxonomies like yahoo shopping, lycos, amazon, as well as a number of
subject specific taxonomies and things i consider light weight
ontologies - class hierarchies where the classes have a small number of
properties, sometimes with value restrictions. i was working in the
context of a startup with a very broad user base so somewhat by
necessity, i needed to consider what the general public might consider
an ontology and how a broad set of people might use it.
i also was in the midst of a large ontology-driven project - hpkb -
where my team had to answer questions using 80 kbs as input. the
knowledge bases were all essentially kif statements (or they had been
translated into kif) and they were generated by people at least
reasonably trained in kr and the kbs had a lot of structure. so i had
been doing A LOT of ontology and knowledge base merging at that time in
my life - an it was driven somewhat by two fairly different desires and
needs for ontologies - 1 heavy weight theorem proving to generate
answers and 2 very light weight ontology-enhanced search. (i still find
myself driven by these 2 needs on a very regular basis).
the ai panel members (welty, gruninger, uschold, lehman, and myself)
came up with an ontology spectrum that i have grown to like quite a bit
- but of course that is because it reflects a lot of my personal
experiences with structured declarative knowledge representations from
extremely lightly structured things to very principled, detailed
structured artifacts. the belief i came to then and the one i still
stand by now is that we are more likely to have structured knowledge
get
used in applications if we work with the notion of a spectrum and help
people move along it as their needs and education permits.
I gave a talk in early 2000 about the pull i was experiencing for
ontologies at a dagstuhl meeting and used the spectrum as an organizer.
I wrote a paper describing my view of each of the points on that
spectrum along with some examples of my experiences in each of those
points. i wrote the paper in 2000 with a small update in 2001 but the
actual published version of it came out in a book from that even MUCh
later - actually 2003.
an online "preprint" version is up at:
http://www.ksl.stanford.edu/people/dlm/papers/ontologies-come-of-age-mi
t-press-(with-citation).htm
one reason i bring up that paper is that i still find that a lot of
people tell me they get value out of that paper i think for 2 reasons -
1. the simple spectrum (yes - i think one dimension of expressiveness
is
really too limiting... but it is convenient pedagogically.)
2 the examples of each point on the spectrum.
i would be happy to co-author a next generation of something like that
paper.... and in fact, i have been asked for such a paper on a regular
basis with more examples and more current references.
deborah
Obrst, Leo J. wrote:
> Charles,
> I agree with you. A number of us through the years have come up with
> similar ontology continuums or spectrums. I prefer my Ontology
> Spectrum*, but that's natural, I guess. It was developed over time to
> act as an educational aid. I found that many folks understood notions
> such as taxonomies, database schemas, UML models, but they didn't
know
> how these related to the new kid on the block, ontologies. Was a
> thesaurus an ontology? No. Was a UML model: no, not yet. And term vs.
> concept (placeholder for real world referent) is a crucial
> distinction. The former is a word/phrase (string, utterance) that
> indexes the latter, which is a representation of the meaning of that
> term (at least approximately). The important point is that these
> concepts/placeholders are meant to stand in for real world referents,
> since ontology is about the things of the world. I also attach a
newer
> slide that tries to show those distinctions, along with their typical
> use cases: OntologySpectrumApplication-Obrst06.jpg.
> Thanks,
> Leo
> *If you look at the current Wikipedia article on the subject, it's
not
> completely accurate: http://en.wikipedia.org/wiki/Semantic_spectrum.
I
> independently developed the Ontology Spectrum in Fall, 1999, and it
> really represents one dimension, though it is depicted diagonally
(for
> increased space) as though it were two dimensional: the one dimension
> is in terms of expressivity of the model. Also the 4 way stations of
> taxonomy, thesaurus, conceptual model, and logical theory are
semantic
> models; that is why I don't include glossaries, term lists, etc.,
> directly -- they are not models but are human language lists and
> definitions. Mike Uschold, Mike Gruninger, and Chris Welty and I have
> talked about this topic of the co-invention of the semantic/ontology
> spectrum for quite some time. Personally, I prefer my Ontology
> Spectrum because I overlay onto the specific models additional
> information, such as the kind of parent-child relation, related
> database and modeling languages, and logic information. But all of
> these ontology spectrum/semantic continuums are sound: they represent
> the best distillations of solid generalizations especially good for
> educational purposes.You are probably referring to the presentations
I
> gave at Ontolog last Jan 19/26 2006: "*What is an ontology? - A
> Briefing on the Range of Semantic Models*",
> http://ontolog.cim3.net/cgi-bin/wiki.pl?ConferenceCall_2006_01_12.
> _____________________________________________
> Dr. Leo Obrst The MITRE Corporation, Information Semantics
> lobrst@xxxxxxxxx Center for Innovative Computing & Informatics
> Voice: 703-983-6770 7515 Colshire Drive, M/S H305
> Fax: 703-983-1379 McLean, VA 22102-7508, USA
>
>
-----------------------------------------------------------------------
-
> *From:* ontology-summit-bounces@xxxxxxxxxxxxxxxx
> [mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] *On Behalf Of
> *Charles D Turnitsa
> *Sent:* Monday, January 22, 2007 1:39 PM
> *To:* Ontology Summit 2007 Forum
> *Subject:* Re: [ontology-summit] Defining "ontology"
>
> One of the big schisms in types of ontology that I see is a
> difference in an ontological representation (model) that is
> intended to organize knowledge at the level of terms, and a model
> that is intended to organize knowledge at the level of meaning.
>
> If you look at the Ontology Spectrum that was presented to the
> Ontolog group last year by Dr. Leo Obrst, you see a progression
of
> ontology representation techniques, from controlled vocabularies
> and simple data models, up through thesauri, taxonomy techniques,
> up to axiomatized systems and logic based models (and beyond).
One
> of the big shifts I have seen is the difference in emphasis of
> lower level models (thesauri and controlled vocabularies, for
> instance) on terms, and the attempt of upper level models (axiom
> based systems, logic models) on definitions. For different
> communities, differently focused applications, both appear
equally
> useful, but they are very different.
>
> From all of this, possibly an axis of differentation for
> ontologies can exist to show the focus of what the ontology is
> defining, and the depth of it's intended use.
>
> Chuck
>
> Charles Turnitsa
> Project Scientist
> Virginia Modeling, Analysis & Simulation Center
> Old Dominion University Research Foundation
> 7000 College Drive
> Suffolk, Virginia 23435
> (757) 638-6315 (voice)
> (757) 686-6214 (fax)
> cturnits@xxxxxxx <mailto:cturnits@xxxxxxx>
>
> -----ontology-summit-bounces@xxxxxxxxxxxxxxxx wrote: -----
>
> To: Ontology Summit 2007 Forum
<ontology-summit@xxxxxxxxxxxxxxxx>
> From: Patrick Durusau <patrick@xxxxxxxxxxx>
> Sent by: ontology-summit-bounces@xxxxxxxxxxxxxxxx
> Date: 19/01/2007 08:53AM
> Subject: [ontology-summit] Defining "ontology"
>
> Greetings,
>
> I am concerned with the suggestions that it is possible to
> create a
> continuum along which to organize what are known as
> "ontologies" in one
> or more circles.
>
> At least unless we are willing to concede that the creation
of
> such a
> continuum is itself an imposition of assumptions from an
> undisclosed
> ontology.
>
> I am sure there are those who would say that folksonomies are
> "missing"
> features that are present in "formal" ontologies. Perhaps,
but
> folksonomies predate "formal" ontologies by several millenia
> and have
> proven robust enough for many purposes. If the goal is to
> represent the
> opinions of the many rather than the few, perhaps it is
"formal"
> ontologies that "missing" features.
>
> I am not taking a position one way or the other. But, I do
> think it is
> important to realize that any attempt to construct a
continuum
> is with
> an unstated choice of a winner before the the continuum is
> populated.
>
> Hope everyone is looking forward to a great weekend!
>
> Patrick
>
> --
> Patrick Durusau
> Patrick@xxxxxxxxxxx
> Chair, V1 - Text Processing: Office and Publishing Systems
> Interface
> Co-Editor, ISO 13250, Topic Maps -- Reference Model
> Member, Text Encoding Initiative Board of Directors,
2003-2005
>
> Topic Maps: Human, not artificial, intelligence at work!
>
>
>
>
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