Are individuals part of ontologies? Do individuals carry semantics?

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Are individuals part of ontologies? Do individuals carry semantics?

Gerhard Austaller-2
Hi

There a some definitions on what ontologies are but they are quite
similar. These definitions say that ontologies conatin concepts,
properties, relations and axioms. But I am wondering if individuals can
also be part of ontologies. At least some examples make me think so.

I hope I can make my point clear with an example. E.g. we agree on an
ontology on communication. There we  would also have a concept
"KindOfCommunication". According to some ontologies I saw, there would
be several individuals like "singing", "screaming", "talking" and these
individuals belong to the ontology. Despite of the stupid modelling, is
it ok to define individuals belonging to an ontology?

Gerhard

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Re: Are individuals part of ontologies? Do individuals carry semantics?

Kostas Vavliakis



Hello,

I believe that classes and properties form the schema of the ontology. Once
the schema of the ontology is defined then is can be filled up with data
(instances).So I don't believe that instances carry semantics, but they are
characterized by the semantics of the ontology.
You can consider it something like relational databases, where tables, names
of the columns, primary keys etc form the database schema and you add your
data in the rows of tables.

Kostas.


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gerhard
Austaller
Sent: Tuesday, July 11, 2006 6:34 PM
To: [hidden email]
Subject: [protege-discussion] Are individuals part of ontologies? Do
individuals carry semantics?

Hi

There a some definitions on what ontologies are but they are quite
similar. These definitions say that ontologies conatin concepts,
properties, relations and axioms. But I am wondering if individuals can
also be part of ontologies. At least some examples make me think so.

I hope I can make my point clear with an example. E.g. we agree on an
ontology on communication. There we  would also have a concept
"KindOfCommunication". According to some ontologies I saw, there would
be several individuals like "singing", "screaming", "talking" and these
individuals belong to the ontology. Despite of the stupid modelling, is
it ok to define individuals belonging to an ontology?

Gerhard

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Re: Are individuals part of ontologies? Do individuals carry semantics?

Fermín Galán Márquez

Dear David, Vavliakis,

I think it depends of the authors. For example, citing from
http://protege.stanford.edu/publications/ontology_development/ontology101-no
y-mcguinness.html:

"For the purposes of this guide an ontology is a formal explicit description
of concepts in a domain of discourse (classes (sometimes called concepts)),
properties of each concept describing various features and attributes of the
concept (slots (sometimes called roles or properties)), and restrictions on
slots (facets (sometimes called role restrictions)). An ontology together
with a set of individual instances of classes constitutes a knowledge base.
In reality, there is a fine line where the ontology ends and the knowledge
base begins."

So, for these authors (Noy and McGuinness) ontology don't include instances,
and KB = ontology + instances. Although they also say that there is a "fine
line", implicitelly telling that others authors may think different. In
fact, I don't have references but I'm almost sure have read about the other
approach (intances included in ontology) in some paper or book.

IMHO, I prefer to see ontology as a "schema" (I agree with Vavliakis' :) and
instances as a "snapshot" of the knoledge of the system according to the
semantics of the schema/ontology. If the system has a dynamic behavoiour,
the instances could change (some being destroyed, some being created, some
modifiying their attributes) but the ontology/schema never change.

It's just an opinion... :)

Best regards,

--------------------
Fermín Galán Márquez
CTTC - Centre Tecnològic de Telecomunicacions de Catalunya
Parc Mediterrani de la Tecnologia, Av. del Canal Olímpic s/n, 08860
Castelldefels, Spain
Room 1.02
Tel : +34 93 645 29 12
Fax : +34 93 645 29 01
Email address: [hidden email]

-----Mensaje original-----
De: [hidden email]
[mailto:[hidden email]] En nombre de Vavliakis
Kostas
Enviado el: martes, 11 de julio de 2006 19:01
Para: [hidden email]
Asunto: [protege-discussion] Re: Are individuals part of ontologies? Do
individuals carry semantics?

Hello,

I believe that classes and properties form the schema of the ontology. Once
the schema of the ontology is defined then is can be filled up with data
(instances).So I don't believe that instances carry semantics, but they are
characterized by the semantics of the ontology.
You can consider it something like relational databases, where tables, names
of the columns, primary keys etc form the database schema and you add your
data in the rows of tables.

Kostas.


-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gerhard
Austaller
Sent: Tuesday, July 11, 2006 6:34 PM
To: [hidden email]
Subject: [protege-discussion] Are individuals part of ontologies? Do
individuals carry semantics?

Hi

There a some definitions on what ontologies are but they are quite similar.
These definitions say that ontologies conatin concepts, properties,
relations and axioms. But I am wondering if individuals can also be part of
ontologies. At least some examples make me think so.

I hope I can make my point clear with an example. E.g. we agree on an
ontology on communication. There we  would also have a concept
"KindOfCommunication". According to some ontologies I saw, there would be
several individuals like "singing", "screaming", "talking" and these
individuals belong to the ontology. Despite of the stupid modelling, is it
ok to define individuals belonging to an ontology?

Gerhard

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Re: Are individuals part of ontologies? Do individuals carry semantics?

Mark Wilkinson-3


On Tue, 11 Jul 2006 10:33:09 -0700, Fermín Galán Márquez  
<[hidden email]> wrote:

> IMHO, I prefer to see ontology as a "schema" (I agree with Vavliakis' :)  
> and
> instances as a "snapshot" of the knoledge of the system according to the
> semantics of the schema/ontology. If the system has a dynamic behavoiour,
> the instances could change (some being destroyed, some being created,  
> some
> modifiying their attributes) but the ontology/schema never change.
>
> It's just an opinion... :)


I also feel more comfortable with this world view, though I have close  
collaborators who think otherwise, so it is something I spend a fair  
amount of time struggling with.

I haven't used Protege "in anger" for a while, but the last time I used it  
I noticed that instances were "mixed up" in the ontology-proper when you  
exported the ontology as RDF-XML.  I ended up using the SWOOP ontology  
editor in preference to Protege for exactly that reason - when SWOOP dumps  
the RDF-XML for an ontology + instances, it keeps the instances in a  
separate part of the document (which is ***extremely*** useful behaviour  
IMO!).  Does Protege now do this too?

I also recall asking about a year ago if it would be possible to export  
*only* the instances (e.g. after classification) from the Protege  
interface... is that possible in the newer versions?

Cheers all!

M



--
--
Mark Wilkinson
Assistant Professor, Dept. Medical Genetics
University of British Columbia
PI Bioinformatics
iCAPTURE Centre, St. Paul's Hospital
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Re: Are individuals part of ontologies? Do individuals carry semantics?

starred

> On Tue, 11 Jul 2006 10:33:09 -0700, Fermín Galán Márquez
> <[hidden email]> wrote:
>
> > IMHO, I prefer to see ontology as a "schema" (I agree with Vavliakis' :)
> > and
> > instances as a "snapshot" of the knoledge of the system according to the
> > semantics of the schema/ontology. If the system has a dynamic behavoiour,
> > the instances could change (some being destroyed, some being created,
> > some
> > modifiying their attributes) but the ontology/schema never change.
> >
> > It's just an opinion... :)
>
>
> I also feel more comfortable with this world view, though I have close
> collaborators who think otherwise, so it is something I spend a fair
> amount of time struggling with.
>
> I haven't used Protege "in anger" for a while, but the last time I used it
> I noticed that instances were "mixed up" in the ontology-proper when you
> exported the ontology as RDF-XML.  I ended up using the SWOOP ontology
> editor in preference to Protege for exactly that reason - when SWOOP dumps
> the RDF-XML for an ontology + instances, it keeps the instances in a
> separate part of the document (which is ***extremely*** useful behaviour
> IMO!).  Does Protege now do this too?

Yes, it is. From the menu:

OWL -> Split classes and individuals


>
> I also recall asking about a year ago if it would be possible to export
> *only* the instances (e.g. after classification) from the Protege
> interface... is that possible in the newer versions?

mmm...quite a few time since is I use protégé...I think it is possible to explicitly assert inferred instances and then, export them with split classes and individuals, as described above...

>
> Cheers all!
>
> M
>

Cheers,

Armando

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