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RE: the precondition property in OWL-S 1.0

From: Huhns, Michael <huhns@engr.sc.edu>
Date: Sat, 8 Nov 2003 10:53:11 -0500
Message-ID: <4007EAAD1092A0409D5D24B2446AD504013BC39D@mail1.engr.sc.edu>
To: "Monika Solanki" <monika@dmu.ac.uk>
Cc: <public-sws-ig@w3.org>

Hi Monika,

If a Precondition is a special kind of Condition, then it must have some
property (or a restriction on some property) that makes it special.
What is this?  That is, given a logical formula that evaluates to true
or false, what property does it have that would enable you to determine
whether it is a Condition or Precondition?

Cheers,
Mike Huhns

-----Original Message-----
From: public-sws-ig-request@w3.org [mailto:public-sws-ig-request@w3.org]
On Behalf Of Monika Solanki
Sent: Saturday, November 08, 2003 5:15 AM
To: David Martin
Cc: public-sws-ig@w3.org
Subject: Re: the precondition property in OWL-S 1.0




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 10:54:24 GMT

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