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Re: PAC & PAI + DAML-S issues

From: David Martin <martin@ai.sri.com>
Date: Wed, 20 Aug 2003 22:43:45 -0700
Message-ID: <3F445C11.4000705@ai.sri.com>
To: Charlie Abela <abcharl@keyworld.net>
Cc: Web Services List <www-ws@w3.org>

Charlie Abela wrote:

> 
> Hi,
> 
> I have some points to put forward:
> 
> I have read the mail from Dean regarding instance Vs class representation
> and I think that the instance definition format is quite appealing and
> straightforward as Dean pointed out. I would like to have some clarification
> though on the PAC-3 pros as defined in Dean's mail, regarding the fact that
> the class defintion format provides instances as "execution traces" (and
> their relationship to processes) "for free"

Hi Charlie --

The explanation for that remark is quite simple.  Currently, in defining 
a process in DAML-S or OWL-S, we conceptualize a process as the class of 
its execution instances (or, synonymously, "execution traces").  That 
means that our current modeling approach allows not only for the 
specification of the process (as a class) but also for the specification 
of an individual execution trace (as an instance of that class).  That's 
what I meant by "for free": that we already have an ontology that 
supports the specification of individual execution traces.  That was one 
of the primary motivations, in the first place, for modeling processes 
as classes in DAML-S/OWL-S.

If we switch to processes-as-instances, we will have to create a new 
ontology (or extensions to the current process ontology) to support the 
specification of individual execution traces.

Thanks for pointing out the discrepancy in the Congo example.  I believe 
you are correct about this, but I haven't looked carefully.  A member of 
the DAML-S Coalition is looking at this.

Regards,
David


Now for some other issue regarding the files CongoProcess.daml and
> CongoProcessDataFlow.daml. The property fullCongoBuyBookISBN seems to me as
> being used as a property in CongoProcessDataFlow.daml,
> <process:sameValues rdf:parseType="daml:collection">
>   <process:ValueOf process:atClass="#FullCongoBuy"
> process:theProperty="#fullCongoBuyBookISBN" />
> 
> though I think the property to use in this case would be
> <daml:Property rdf:ID="fullCongoBuyBookISBNOutput">
> 
> and it is also referenced as being a Class since it is used as follows in
> CongoProcess.daml
> <daml:Restriction>
>   <daml:onProperty
> rdf:resource="http://www.daml.org/services/daml-s/0.9/Process.daml#coOutput"
> />
>   <daml:toClass rdf:resource="#fullCongoBuyBookISBN" />
>   </daml:Restriction>
> 
> A similar discrepancy seems to exist the owl-s versions. Or maybe I am
> missing something?
> 
> Regards,
> 
> Charlie
> 
> -------------------------------------------------
> Charlie Abela
> Research Student,
> Dept. of Computer Science and AI
> University of Malta,
> MSD06. Malta
> Web: http://alphatech.mainpage.net
> Email: abcharl@keyworld.net
> 
> 
> 
Received on Friday, 22 August 2003 18:23:16 GMT

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