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[protege-owl] Query about constructing an ontology based on received OWL-DL fragments on your behalf

William Fitzgerald wfitzgerald at 4c.ucc.ie
Tue Feb 7 09:33:16 PST 2012


Thanks Timothy for taking the time to reply.

On 07/02/12 16:35, Timothy Redmond wrote:
>
>> (1) Is it reasonable to compose an ontology in this way? That is, to be able to receive fragments
>> to add to your local ontology. Of course there are various axioms etc that may also need to be
>> passed with respect to knowledge about classes, properties and individuals. One issue would be to
>> know how much knowledge must one receive about a class, property or individual to provide the
>> intended semantics and so forth. However, that aside, is what I am saying above in principle
>> sensible or even desirable?
>
> This sounds like a sensible thing to me. These "fragments" that you are talking about are called
> axioms in the OWL DL terminology.

Great. I have an application in the computer security area with which to apply this too ;-)

>
> One question is how you are going to do this. I would strongly advise you not to move them with a
> text editor in RDF/XML. RDF/XML is one of the hardest serialization formats to work with both
> programatically and from a user perspective. If you are going to use a text editor I would suggest
> you use another serialization format that is easier to work with such as OWL/XML. Protege 4 supports
> a variety of serialization formats most of which are easier to understand than RDF/XML. (On the
> other hand, when you share the file you will probably want to use RDF/XML. It has become the
> standard format for sharing OWL files.)

Perfect, I will look at XML/OWL. I have predominately worked with ontologies using the older Protege 
3 rather than Protege 4. This was due to what I wanted in terms of SWRL. However, I know that 
SWRLTab is due to be ported soon and Protege 4 as I understand it supports a subset of SWRL (DL-Safe 
rules) as is. So its time to look at Protege 4 ;-)


>
> In addition, a set of tools that you should be aware of in this context are the OWL modularity
> tools. These allow you to provide a set of entities (classes and properties say) and extract from an
> ontology a set of axioms that say everything that is known about those entities based on the larger
> ontology. Sorry I didn't express that well but I believe there is a Protege plugin that does this.

Excellent, I'll look around for such plugins.

>
> A good approach would be to use a tool to copy the axioms from one ontology to another. Protege 4
> allows you to move axioms from one ontology to another. But it was not clear to me that you could
> copy the axioms which is what you really want.

Hmmm, I'll know more as I play around with Protege 4 and perhaps I can consider workarounds if needs be.

>
>> Having defined a class Fiesta, I changed within Protege the URI from
>> http://www.car.com/car.owl#Fiesta to http://www.ford.com/ford.owl#Fiesta. I then added to the XML
>> file generated by protege the following xmlns:ford="http://www.ford.com/ford.owl#".
>
> I think that changing the names like this muddies the waters.

I agree entirely. However, as a test and rather than creating a file with possibly incorrect RDF/XML 
syntax, I decided to let the Protege tool generate a sample file that I knew would be correct. I 
just wanted to inspect how the xml file would look. Based on this file, I was then able to manually 
create a similar file with which to copy and paste into another ontology. Its was more about teasing 
out the idea in my own mind. But your right and I certainly do not intend to go down the route of 
defining and managing raw XML files :-)

>> What I noticed was, with the locally defined class "Car" in the OWL-XML file used "rdf:ID",
>> however when simulating the addition of an owl fragment for class "Fiesta" the OWL-XML file used
>> "rdf:about".
>
> As you might have noticed from my note, OWL/XML is different from RDF/XML. The OWL/XML format does
> not use rdf:ID and rdf:about.

Having just installed protege 4, I noticed that I can choose an OWL/XML serialisation over and 
RDF/XML version, and their shape (for want of a better word) is completely different.

Thanks, you have given me food for thought.
Regards,
Will.

-- 
____________________________________________
William M. Fitzgerald (BSc (Hons), MSc, PhD)
Postdoctoral Research Fellow,
Cork Constraint Computation Centre,
Department of Computer Science,
University College Cork,
Cork,
Ireland.
--------------------------------------------
http://www.williamfitzgerald.net
____________________________________________


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