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

From: Trevor Martin <Trevor.Martin@bristol.ac.uk>
Date: Thu, 19 Jul 2007 09:22:12 +0100
Message-Id: <36B408D5-1C0E-44B2-B18C-C8C3B47B6ACF@bris.ac.uk>
Cc: "'Umberto Straccia'" <umberto.straccia@isti.cnr.it>, <public-xg-urw3@w3.org>
To: Giorgos Stoilos <gstoil@image.ece.ntua.gr>

This is precisely the choice faced by implementers of logic  
programming + uncertainty languages .... you can extend the language  
and the inference mechanism or express and process the uncertainty  
within the standard language.

tall(John) : 0.7

vs

tall(John, 0.7)

(... in both cases, without saying what 0.7 represents)

The former approach gives you more control, reduces to "standard"  
notation when the uncertainty is omitted and (I think) makes the  
semantics clearer;
the latter involves no change to existing notation (hence is easier  
to  sell ) but gets messy when only some of the representation  
requires the uncertainty and obscures the meaning of the annotation.

Trevor

(PS apologies for the fact that I have been quiet so far, fuzz-ieee  
next week has taken a lot more of my time than expected)


On 19 Jul 2007, at 08:43, Giorgos Stoilos wrote:

>
>
>
>> -----Original Message-----
>> From: public-xg-urw3-request@w3.org [mailto:public-xg-urw3- 
>> request@w3.org]
>> On Behalf Of Umberto Straccia
>> Sent: Wednesday, July 18, 2007 8:55 PM
>> To: public-xg-urw3@w3.org
>> Subject: Re: [URW3 public] OWL extensions [was Re: [URW3] ... three
>> questions based on the last telecon]
>>
>>
>> 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.
>>
>
> My point was *not* that your proposal is not feasible. To the  
> contrary it is
> very nice. My point was that at the end of the day it will turn our  
> to be
> almost (and maybe exactly) the same thing to agree upon using an  
> OWL concept
> like LeftShoulderFunction for left shoulder functions, which crisp  
> tools
> will have to learn to toss away while fuzzy tools to correctly  
> interpret
> compared to having a language (extension) tag like <owlx:
> LeftShoulderFunction> which again crisp tools will have to skip  
> while fuzzy
> to parse and interpret.
>
> I think that only after thorough thinking, practical investigations  
> and
> practice we could learn which one is better. At this point I see  
> just some
> pros and cons for both of them.
>
> Cheers,
> -gstoil
>
>
>> 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
>>>
>>>
>>>
>
>
>



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m
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Intelligence is Fuzzy : www.fuzzieee2007.org
Received on Thursday, 19 July 2007 19:16:02 GMT

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