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[ontolog-forum] FW: RDF & RDFS (was... Is there something I missed?)

To: "Ontolog-Forum-Bounces" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Sean Barker" <sean.barker@xxxxxxxxxxxxx>
Date: Fri, 6 Feb 2009 15:38:44 -0000
Message-id: <OOEEJGAPCAJOKOFFPHLHKEBACAAA.sean.barker@xxxxxxxxxxxxx>
 
Godfrey, Matthew, Ian et al
 
STEP makes a nice distinction between a property,  the representation  of the property and the presentation  of the property
 
For example, in mechanical CAD a physical part has a property = "shape" which has a representation = "surface model" which may be shown on a display  as presentation="shaded image".
 
It may also have property="shape", representation="Constructive Solid Geometry" and presentation="edges"
 
Further, the same representations also be used for other properties such as the envelope for a mechanism, or the cavity inside a part (useful for modelling flow though a jet engine).
 
We could therefore say that an *ontology is a property of a (view of)  universe of discourse ;-) ;  RDF can be used as a representation of the *ontology, and XML as a presentation of that representation.
 
Notes:
1) I use *ontology to indicate Ian's real world meaning, as opposed to ontology meaning a formal system, the preferred usage in this forum.
2) I am using "property" in the STEP sense - "a move in a language game, which allows one to talk about a thing having properties such as shape, material, cost, duration, etc, without admitting these things are subclasses of a general class called 'property'"
3) No need to discuss what is in people's heads - ontologies are manifest in behaviour, particularly processes dependent on classification, such as asking the grocer for three red apples, he goes to the draw marked apples. etc 
 
 

Sean Barker
Bristol, UK



From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Godfrey Rust
Sent: 06 February 2009 07:56
To: [ontolog-forum]
Subject: Re: [ontolog-forum] RDF & RDFS (was... Is there something I missed?)

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Matthew West wrote:
 
Talking about what is in someone’s head just doesn’t cut it I’m afraid. It is at best a loose way of talking. Where you have several things that have something in common, what you do have is an abstraction, and my extensional analysis would make that a class. So if I have 5 copies of the same content, there is a class that represents the pattern that is common to those 5 files. And if I have the “same” ontology that is represented in different languages, then there is  a class that represents that sameness.
 
 
This is consistent with the analysis that is generally used in music, book and journal publishing metadata standards such as ONIX and DDEX, and the widely adopted bibliographic FRBR analysis, of an "abstraction" or "abstract work" with any number of "manifestations". It may apply to the play "Hamlet" or the song "Yesterday", which retain a unique perceived identity but may be expressed in a wide variety of manifestations in different genres, languages and so on, and it may apply as well to an ontology or computer program. As Matthew points out, these function (and very usefully) as abstract classes representing common content: the entire network of music copyright collection societies operates to collect money for the use of just such abstractions.
 
The elusive problem of identity remains, however. The decision about whether a particular manifestation really is the song "Yesterday" or just something that sounds a bit like it is something which exists in someone's head and, in the content industries, is ultimately settled where necessary in a court of a law using reasonable but ultimately arbitrary criteria (such as musicological analysis). Identity between the underlying abstractions of two ontologies is in general more testable.
 
 
Godfrey Rust
Chief Data Architect
Rightscom/Ontologyx
Linton House LG01
164/180 Union Street, London SE1 0LH
www.rightscom.com
Direct +20 8579 8655
Rightscom Office +20 7620 4433
Mobile 07967 963674
 
----- Original Message -----
Sent: Friday, February 06, 2009 7:28 AM
Subject: Re: [ontolog-forum] RDF & RDFS (was... Is there something I missed?)

Dear Pat,

 

PS - I'm not sure about where this idea of a mental model of an ontology
came from. I never mentioned it, and I certainly don't have an ontology in
my head. Of course the ontology has to be represented in some way - CL,
RDFS, OWL, UML, EXPRESS, arse-barcodes, who cares ?

 

What is this thing that is in common between al these different file formats? Where is it, if not in your head?  This is rather like the old chestnut of saying what exactly a program is, if you can write the 'same' program in several wildly different programming languages. For example, quicksort can be implemented in just about any programming language, and its still quicksort. In CS we have the useful distinction between algorithm and program, maybe we need a similar terminological distinction for ontologies. Any suggestions?

 

[MW] Ok. So is the quicksort program in your head the same as the quicksort program in my head (I even remember writing one once in Basic)? Talking about what is in someone’s head just doesn’t cut it I’m afraid. It is at best a loose way of talking. Where you have several things that have something in common, what you do have is an abstraction, and my extensional analysis would make that a class. So if I have 5 copies of the same content, there is a class that represents the pattern that is common to those 5 files. And if I have the “same” ontology that is represented in different languages, then there is  a class that represents that sameness.

 

Regards

 

Matthew West                           

Information  Junction

Tel: +44 560 302 3685

Mobile: +44 750 3385279

matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx

http://www.matthew-west.org.uk/

 

This email originates from Information Junction Ltd. Registered in England and Wales No. 6632177.

Registered office: 2 Brookside, Meadow Way, Letchworth Garden City, Hertfordshire, SG6 3JE.

 

 



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