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[ontolog-forum] Ontologies are not algorithms (cont'd from the ontology-

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Peter Yim <peter.yim@xxxxxxxx>
Date: Wed, 1 Feb 2012 17:10:37 -0800
Message-id: <CAGdcwD2c+787pcz3RjU+DQs+Zd8iT3m7SSpfjKBD4728bcTnXA@xxxxxxxxxxxxxx>
... Please continue the subject conversation here, Folks!
--    (01)


---------- Forwarded message ----------
From: Obrst, Leo J. <lobrst@xxxxxxxxx>
Date: Wed, Feb 1, 2012 at 4:46 PM
Subject: Re: [ontology-summit] Fwd:  Ontologies are not algorithms
To: Ontology Summit 2012 discussion <ontology-summit@xxxxxxxxxxxxxxxx>    (02)


I agree, but we had to give folks some knowledge.    (03)

This could be continued on the Ontolog Forum, more generally.    (04)

Thanks,
Leo    (05)


-----Original Message-----
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Peter
Yim
Sent: Wednesday, February 01, 2012 7:42 PM
To: Ontology Summit 2012
Subject: [ontology-summit] Fwd: Ontologies are not algorithms    (06)

Dear Leo, Jack and All,    (07)

I agree with Nicola's
(ref. http://ontolog.cim3.net/forum/ontology-summit/2012-02/msg00007.html )    (08)

> [NG] ... In any way, this is not a topic to be addressed in this summit.
> So, if people are still interested, I would suggest them to move the 
>discussion
> to the general Ontolog list.    (09)

... and am moving this conversation to the [ontolog-forum] mailing list.    (010)

ALL: please pick up the conversation from there (if folks would still
want to delve in the subject matter).    (011)

Thanks in advance. =ppy    (012)

p.s. if you are not subscribed to the [ontolog-forum] list (i.e. not a
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--    (013)


---------- Forwarded message ----------
From: Obrst, Leo J. <lobrst@xxxxxxxxx>
Date: Wed, Feb 1, 2012 at 3:33 PM
Subject: Re: [ontology-summit] Ontologies are not algorithms
[was:   Ontolgizing rain & snow]
To: Ontology Summit 2012 discussion <ontology-summit@xxxxxxxxxxxxxxxx>    (014)


And by the way, rules do  the heavy-lifting in reasoning over
ontologies and their instances. But rules (axioms, inference rules,
consequence relations) are just as declarative as ontologies, i.e.,
ontologies expressed in a logic, thereby being a "logical theory", use
the declarative apparatus of logic.    (015)

So the transformation I spoke of are transformations from one
declarative representation to another (mostly or entirely) declarative
representation. Otherwise, humans do all the programming imperatively,
looking only at the ontologies, conceptual models, conceptual schemas
as "guidance". And from that process, there are many algorithms that
could be created, perhaps infinitely many, depending on the
space/complexity of the computation.    (016)

I hope this helps to clarify things.    (017)


Thanks,
Leo    (018)

-------------    (019)


From: Obrst, Leo J.
Sent: Wednesday, February 01, 2012 6:27 PM
To: Ontology Summit 2012 discussion
Subject: RE: [ontology-summit] Ontologies are not algorithms [was:
Ontolgizing rain & snow]    (020)


Jack,    (021)


Algorithms are ways to do things. How.    (022)

Ontologies, as a subclass of declarative methods, are ways to describe
things. What.    (023)

>From an ontology, one can spawn multiple algorithms that use the
ontology, but this requires a set of transformations from the
declarative to the imperative. And it will be multiple, because for
any statement of what to do there are many ways how to do it.    (024)

If you are working in a declarative paradigm, then the way to do it is
is to apply declarative transformations as far as you can, to get
close to a runtime how that preserves the what as much as possible.    (025)

E.g., from a first-order ontology, you use knowledge compilation
techniques (examples: reduce to Horn Logic approximations, use
implicants/implicatures, etc.; there are a range of tools available,
but this is another partial research thread). Or you simply use a
first-order reasoner that uses the ontology directly; however, FOL
reasoners will be slower than other reasoners, because they deal with
more expressive logical expressions.    (026)

Logic programming (Prolog, Answer Set Programming), by circumscribing
the FOL syntax, along with potentially using some non-declarative
constructs (the "cut" operator, ordering restrictions, a form of
negation that is not quite logical, i.e., negation by finite failure),
etc., can closely preserve the ontology and approximate its
declarative entailments, etc., in more efficient runtime reasoning.    (027)

But if you want to transform an ontology to an imperative algorithm:
good luck. Mostly these transformations are done by human programmers.
One can talk about semantics-preserving programs, etc., but it's
pretty much ad hoc-land. One can annotate programs (like
"documentation") as to what the imperative constructs are supposed to
mean, but it is really a very loose correlation.    (028)

That's the difference.    (029)


Thanks,    (030)

Leo    (031)

-------------    (032)



From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Jack
Ring
Sent: Wednesday, February 01, 2012 5:48 PM
To: Ontology Summit 2012 discussion
Subject: Re: [ontology-summit] Ontologies are not algorithms [was:
Ontolgizing rain & snow]    (033)


Dear Nicola,    (034)

Thanks for the response.    (035)

I am aware of several kinds of computational ontologies. I was
interested in a specific example of what you had in mind when
declaring that an ontology is not equivalent to an algorithm.    (036)

Ontologies that I have seen express semantic equivalences and other
relationships. Some are even loaded with first order predicates that
look very much like spaghetti code (which I thought was banned in the
1980's).    (037)

However, I am not interested in arguing the point. The simple fact is
that systems and systems engineering need semantic transformers. If
ontologies don't do semantic transforms (e.g. AP233) then there may be
some residual utility in ontologies in Big Systems but not the degree
I had hoped.    (038)

Jack Ring    (039)

ps. 'algorithm' predates computer science by several centuries.    (040)

-------------    (041)


On Feb 1, 2012, at 2:57 PM, Nicola Guarino wrote:    (042)

Dear Jack,    (043)

            sorry for this late answer to your request. There are
various definitions of (computational) ontologies adopted by the
community, it shouldn't be difficult for you to find them, as well as
actual examples of ontologies.    (044)

            Speaking for myself, I spent a good fraction of my
research career trying to clarify, in a rigorous way, what a
computational ontology is (see for instance the paper by Daniel Oberle
and myself on the Handbook of Ontologies, 2nd edition). Basically, I
agree with the most popular definition "An ontology is a specification
of a conceptualisation", which requires however a careful
clarification of what a conceptualisation is (but this is a long
story, although discussed in various papers). In logical terms, an
ontology is just a logical theory expressing a set of meaning
postulates.    (045)

            In my opinion, none of the current definitions of a
computational ontology is compatible with the idea that ontologies are
algorithms. If you want to use classing terms of computer science, you
can perhaps compare an ontology to a data structure, but not to an
algorithm.    (046)

            In any way, this is not a topic to be addressed in this
summit. So, if people are still interested, I would suggest them to
move the discussion to the general Ontolog list.    (047)

Best,    (048)

Nicola    (049)



-------------    (050)

On 31 Jan 2012, at 04:14, Jack Ring wrote:    (051)


Gee, I made a very explicit statement in my brief last week ---- that
ontology is algorithm --- and you and Nicola immediately and clearly
disagreed. I followed up with a request for an example; of an
ontology so we could get down to specifics but have not yet received
one. Meanwhile an example of Cyc ontology appeared and I gave some
specifics from a systemist viewpoint.    (052)

If you think that emergence, a very important phenomenon in systems,
and system models is not a core issue for ontologists to deal with
then I guess the intersection of SE and ontology in this forum may
turn out to be only the transform from drawing (pump 102) to purchase
order (sku2058), i.e., engineering of systems.    (053)

---
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