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Re: the precondition property in OWL-S 1.0

From: Monika Solanki <monika@dmu.ac.uk>
Date: Sat, 08 Nov 2003 10:14:38 +0000
Message-ID: <3FACC20E.40807@dmu.ac.uk>
To: David Martin <martin@ai.sri.com>
Cc: public-sws-ig@w3.org


David Martin wrote:

>
> [Note: this thread is moving to public-sws-ig.  After this message, 
> replies should only be sent to public-sws-ig.]
>
> Marta Sabou wrote:
>
>>
>>
>>  Monika, Drew,
>>
>>  I completely agree with the proposed solution. This should 
>> definitely be
>> implemented in the next release.
>
>
> I also agree, except note that there are 2 proposals "on the table":
>
> I think Monika suggested this:
>
>     Process - hasPrecondition - Precondition
> where Precondition is a subclass of Condition
>
> whereas Drew seems to be suggesting this:
>
>     Process - hasPrecondition - Condition
>
> (with no Precondition class anywhere).

I think we should retain the Precondition class and the hasPrecondition 
property. This is because, although Precondition is effectively a 
Condition, however it is a "special" kind of Condition. In the process 
model, Condition is a general thing, which  is also  used for 
Conditional Effects and Conditional Outputs.

>
> That reminds me - we still have an open issue about the class of an 
> effect (that is, the range of ceEffect).  Currently it's just "Thing", 
> which isn't very satisfying. Do people feel that it's OK to have 
> Condition for this range, or do we need something distinct?
>
> - David
>
>>
>>  Cheers,
>>
>> Marta
>>
>>
>>   Drew McDermott wrote:
>>
>>>   [Monika Solanki, in re DAML-S spec]
>>>   Currently in the 1.0 version of the process model, we have the 
>>> following
>>>
>>>     <owl:Class rdf:ID="Precondition" />
>>>   - <owl:ObjectProperty rdf:ID="preCondition">
>>>     <rdfs:domain rdf:resource="#Precondition" />
>>>     <rdfs:range rdf:resource="#Condition" />
>>>     </owl:ObjectProperty>
>>>
>>>   Where, Condition is defined as,
>>>
>>>   - <owl:Class rdf:ID="Condition">
>>>     <rdfs:comment>This is a "place-holder" for now, which awaits 
>>> further
>>>   work from the DAML/OWL community. An instance of Condition is a 
>>> logical
>>>   formula that evaluates to true or false. Eventually we expect this 
>>> to be
>>>   defined elsewhere, as part of a OWL extension allowing for logical
>>>   expressions.</rdfs:comment>
>>>     </owl:Class>
>>>
>>>   Somehow I am not able to grasp the utility of the property
>>>   "preCondition".  Since in this model, we have IOPEs as Classes,
>>>   therefore I believe all we need to do is make Precondition a 
>>> subclass of
>>>   Condition.
>>>
>>>    <owl:Class rdf:ID="PreCondition">
>>>     <rdfs:subClassOf rdf:resource="#Condition" />
>>>     </owl:Class>
>>>
>>>   The property preCondition, introduces redundancy as it is ranging 
>>> over
>>>   the class "Condition" anyways.
>>>
>>>   Feedback appreciated in case I missed something.
>>>
>>> You're right, as far as I can see.  The important property is
>>> hasPrecondition, which connects a Condition to a
>>> Process or Process step.  There is no reason for the class
>>> Precondition to exist, let alone a property preCondition linking a
>>> Precondition to a Condition (itself?).
>>>
>>> -- 
>>>                                             -- Drew McDermott
>>>                                                Yale University CS Dept.
>>
>>
>>
>

-- 
**>><<**>><<**>><<**>><<**>><<**>><<**>><<**
Monika Solanki
Software Technology Research Laboratory(STRL)
De Montfort University
Hawthorn building, H00.18
The Gateway
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk
web: http://www.cse.dmu.ac.uk/~monika
**>><<**>><<**>><<**>><<**>><<**>><<**>><<**
Received on Saturday, 8 November 2003 05:08:12 GMT

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