Re: Effects in OWL-S

In our AI planning work, we just call them all world state conditions and 
world state effects.  We do not talk about them as pre-, post- etc.

Conditions on the world state can be stated as applying at the begin time 
point of an activity or the end time point.  Notice I say "at" the time 
point... rather than before or after the time point by the way.  I.e. its 
an instantaneous point at which the conditions are stated as holding.

Effects that purport to change the world state can occur also at the begin 
time point or the end time point.  Of course you have to decide whether to 
believe you model of effects or whether to set up condition monitoring 
mechanisms to ensure they actually occurred.

I think its a serious limitation to think only of conditions on the begin 
time point and effects on the end time point.  Even if we also allow 
conditions on the end time point, we still leave out effects on the world 
state that can or should be modelled as occurring earlier.

We have to mess about a bit to be able to translate this more flexible 
conditions/effects model (which we have used in our planners for over 20 
years) into OWL-S with its more limited view of IOPE.

Austin

--
Prof. Austin Tate, Artificial Intelligence Applications Institute, Informatics,
University of Edinburgh, Appleton Tower, Crichton Street, Edinburgh EH8 9LE, UK
Tel: +44 131 650 2732 Fax: +44 131 650 6513 E-mail: a.tate@ed.ac.uk

Received on Wednesday, 28 April 2004 04:08:38 UTC