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Re: [URW3 public] OWL extensions [was Re: [URW3] ... three questions based on the last telecon]

From: Umberto Straccia <umberto.straccia@isti.cnr.it>
Date: Wed, 18 Jul 2007 19:54:32 +0200
To: public-xg-urw3@w3.org
Message-id: <18D5884B-2051-434F-A433-021C99CFD840@isti.cnr.it>

I am more in favor of having no OWL/RDFS language extension at all,  
but encoding the data, according to a core uncertainty ontology,  
which we may develop as outcome (see my previous email.... or just  
below). To my opinion, this is by far much more extensible/flexible  
than any OWL/RDFS language extension and  certainly faster and easier  
to be accepted by any non-uncertainty community.

Cheers,

	-Umberto Straccia


%----Straccia's previous email

The OWL ontology can be used to describe different types of  
uncertainty, but can also to used to describe HOW uncertain  
information is represented in OWL (without any language extension) or  
RDF/RDFS.

To be explicit, suppose I would like to express the concept of YOUNG  
using an explicit fuzzy membership function such as a left-shoulder  
function with parameter a=20, b=30 (below 20 someone is young to  
degree 1, after 30 he is young to degree 0, in between we use linear  
interpolation).

Now, we have two options

a) either we suggest an extension to OWL (more precisely OWL-DL) or  
RDF/RDFS to explicitly accommodate such functions (i.e. we propose a  
language construct for that)
b) or we develop an OWL-DL ontology (or RDF/RDFS ontology) describing  
HOW to represent such information into the current standardized OWL- 
DL language. In our specific case, we may say that

LeftShoulderFunction ISA FuzzyMembershipFunction
			 WITH HasParameterA of type Float
			 WITH HasParameterB of type Float


Then we can represent Young with

Young ISA VagueConcept
	  WITH HasFuzzyMembershipFunction of type LeftShoulderFunction WITH  
HasParameterA = 20
								       WITH HasParameterB = 30

It is then up to a parser to correctly interpret the statements and  
then to load them into an underlying reasoning system.

In this way our objective is (using the use cases) to develop an  
ontology, which describes HOW different notions of imperfect  
knowledge is represented in OWL-DL (RDF/RDFS).

	-Umberto.


%----


On Jul 18, 2007, at 7:30 PM, Giorgos Stoilos wrote:

>
> Hi Ken,
>
> This sounds reasonable enough. But let me also stress another issue.
>
> A proposed extension should be as minimal as possible in order to  
> enjoy
> acceptance by the non-uncertainty community and persuade people  
> that it
> could be adopted in their tools with a minimal effort. So also  
> replying to
> Peter's mail, I do not agree with extensions like  
> owl_ursw:usualy_oneOf,
> owl_ursw:often_oneOf, owl_ursw:probably_subClassOf, which to me do  
> not seem
> minimal.
>
> -gstoil
>
>> -----Original Message-----
>> From: public-xg-urw3-request@w3.org [mailto:public-xg-urw3- 
>> request@w3.org]
>> On Behalf Of Ken Laskey
>> Sent: Wednesday, July 18, 2007 3:02 PM
>> To: Peter.Vojtas@mff.cuni.cz
>> Cc: public-xg-urw3@w3.org
>> Subject: [URW3 public] OWL extensions [was Re: [URW3] ... three  
>> questions
>> based on the last telecon]
>>
>>
>> Let me make a suggestion of a minimum criteria for adding extensions:
>>
>> an extension can be proposed only if you can show its use in the
>> context of an already discussed use case.
>>
>> This is motivated by several thoughts:
>> 1. we will have solid examples of the extension;
>> 2. we can more easily compare value of the extension against others
>> proposed;
>> 3. we move forward our analysis of the use cases;
>> 4. if proposed extensions can be demonstrated only in the context of
>> use cases already discussed, some of you will have the motivation to
>> volunteer for leading the discussion at future telecons :-)
>>
>> Do we have agreement on this proposal?
>>
>> Ken
>>
>> P.S. per survey results, I will be setting up telecons for August 1,
>> August 22, September 5, and September 19.
>>
>> On Jul 18, 2007, at 7:20 AM, Peter Vojtas wrote:
>>
>>>
>>> Colleagues,
>>>            let me note that this wonderfull discussion has  
>>> started by
>>> questions about the nature of "sentence" and "proposition", and I  
>>> have
>>> added a word used by W3C documents "statement" and as an example a
>>> triple. Of course a RIF rule can be also a subject to attachment  
>>> of an
>>> uncertainty.
>>>      I think this can be satisfactory solved by using current W3C
>>> standards and interpretation of them.
>>>
>>>      Now the problem has shifted a little bit further, to  
>>> ontology. My
>>> impression is that we need to have some (easy) examples in the  
>>> begining
>>> (Ken already assigned some sentences in his use case by uncertainty
>>> type
>>> and nature).
>>>      I like Mitch's ontology and so far only few extensions were
>>> sugested - to have properties includesSentence, isaboutSentence  
>>> and a
>>> new sort of uncertainty models namely Similarity (maybe some  
>>> other will
>>> appear later - what are our criteria to enter new elements to
>>> ontology).
>>> The reification discussion was only an example from my part, and can
>>> be soved
>>> by Uncertainty has_derivation objective/subjective.
>>>
>>>      I have also an idea and would like to ask ou for opinion.  
>>> Most of
>>> Ontological knowledge is described by expressions about being an
>>> element
>>> and being a subset (equal to), e.g.
>>>
>>> owl:oneOf, rdf:type, ... rdfs:subClassOf, ...
>>>
>>> what do you think about extensions like
>>>
>>> owl_ursw:usualy_oneOf, owl_ursw:often_oneOf,
>>> owl_ursw:probably_subClassOf
>>>
>>> or we are just going to assign uncertainty to the statement
>>> A rdf:type B, C rdfs:subClassOf D, ...
>>>
>>> I agree that sentences can be structured by logical connectives,  
>>> and I
>>> would be here very flexible and allow also fuzzy aggregation
>>> operators.
>>>
>>> On the one side we are not going to specify syntax but we have to  
>>> show
>>> current standards are not necessary (of course not because of the
>>> syntax of current standards - using W3C syntax we have in mind that
>>> their semantics does not suffice)
>>>
>>> Greetings Peter
>>>
>>>
>>>
>> --------------------------------------------------------------------- 
>> ---
>> -----
>> Ken Laskey
>> MITRE Corporation, M/S H305      phone: 703-983-7934
>> 7151 Colshire Drive                         fax:       703-983-1379
>> McLean VA 22102-7508
>
>
>
Received on Wednesday, 18 July 2007 17:51:05 GMT

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