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Re: Abstract Core Ontology for SWSL Processes

From: pat hayes <phayes@ihmc.us>
Date: Fri, 16 Jan 2004 17:16:41 -0600
Message-Id: <p06001f17bc2e1d269c64@[10.0.100.76]>
To: Austin Tate <a.tate@ed.ac.uk>
Cc: public-sws-ig@w3.org

>While we are at it... I am not keen on calling things preconditions, 
>effects... these are just two instances of the more general class of 
>world state constraints that may be on time points or sets of time 
>points related to a process or activity.

Right on!!

Processes are a class of things which are extended in time and which 
have temporal parts, and these parts have various properties and 
relationships to other things.  Much the best way to think about it.

>  You can have world state constraint on the end time point of an 
>activity, or on a range form the begin to the end time points, or 
>effects that occur as soon as the activity begins.  As well as the 
>more traditional world state constraint on the begin of ac activity 
>(usually called a precondition) and world state constraint from the 
>end time point of an activity (usually called a postcondition or 
>effect).
>
>The same goes for the different ways in which Inputs, Outputs, 
>Resources and other "used" entities can be modelled.
>
>I have argued that SWSL should simply allow a process description to 
>be made up of:
>
>a) a set of activities to be performed, each of which are considered 
>to have a begin and end time point

Suggestion: each process occupies (? lasts for, endures during, 
takes) a time-interval, and intervals have begin and end timepoints 
(and indeed are defined by them, uniquely.) Intervals are handy 
things to have in the ontology anyway.

>
>b) a set of constraints (of predefined and extendible types) on and 
>between those activities and the objects/entities in the world 
>associated with them
>
>c) a set of annotations (of predefined and extendible types) on the above
>
>We would then re-engineer back those predefined things we want from 
>OWL-S to make sure we cover the specific instance everyone knows and 
>loves... but in a more coherent and very extendible framework.

I entirely agree.  Notice that the same overall framework applies 
both to 'processes' and to 'objects/entities'.  Some things can be 
looked at in either way, in fact, and the same framework applies to 
them independently of whether you classify them as object-like or 
process-like. Saves a ton of unnecessary classifications and 
duplication. The flow in the pipeline starts in Uzbekistan and moves 
until it gets to Monrovia....or wait a minute, was that a process 
with its preconditions in Uz and its postconditions in Mon...? Or was 
there a process of starting, and a moving flow, and another process 
of arriving? Or was there the oil on the one hand, and the process of 
the oil's moving on the other? Nah, there was oil in the pipe and 
during some interval, it moved. Call it a process or call it a chunk 
of oil, it doesn't really matter: what matters is where it was when, 
why it moved when it did, how fast it was going, stuff like that. 
Properties of temporal parts of it, in any case.

Pat

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Received on Friday, 16 January 2004 18:16:43 GMT

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