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Re: OWL-S preconditions - practical issues

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Fri, 25 Jun 2004 13:20:10 -0400
Message-Id: <E9985D16-C6CB-11D8-98A7-000D93C1F7A6@isr.umd.edu>
Cc: public-sws-ig@w3.org
To: Jeff Dalton <jeff@inf.ed.ac.uk>

On Jun 25, 2004, at 12:57 PM, Jeff Dalton wrote:

>
> Quoting Donal Murtagh <domurtag@cs.tcd.ie>:
>
>> The problem with planners is that compatibility of preconditions and
>> effects is based on (lexical) name matching. Although SHOP2 can
>> evaluate simple expressions such as ((eval (< ?n1 5)) in the
>> precondition of an operator, AFAIK, it is not possible to assert
>> an effect which is a conditional expression, e.g. to state that
>> "the effect of this process/operator is that (< ?n1 5) is true".
>
> Something like that could be treated in a planner as a constraint.
>
> I don't know off-hand of any planner that handles such numeric
> constraints, though some resource constraints might be equivalent.
>
> Also, a planner doesn't have to use name-matching.  I don't
> see any reason why a description logic reasoner, for example,
> couldn't be used.

See:
	http://www.mindswap.org/papers/SWS-ISWC04.pdf

> I do wonder how existing reasonsers, such as Pellet, could be
> used, because planners want to reason about change over time.
> (has-colour block-A blue) might be true at one point, and
> false at another, while (has-colour block-A green) might become
> true.

Er... see:
	http://www.mindswap.org/papers/SWS-ISWC04.pdf

> But perhaps this just reflects my ignorance of existing reasoners
> such as Pellet.
>
>> More generally, has there been any attempt to translate OWL-S
>> preconditions/effects to SHOP2 syntax?
>
> I hope to try something like that for O-Plan / I-Plan once its
> clearer how OWL-S preconditions and effects can be specified.
> I don't yet know how difficult it will be.

We will do this for our Pellet/SHOP hybrid. We have done it for some 
initial experiments, but the code is not ready to be share (i.e, Evren 
hand compiled some of the queries). We should have a reasonably usable 
system in about a month. We're also waiting a bit on the next java 
version of SHOP2 which 1) supposed SHOP2 rather than SHOP, and 2) is 
way way faster.

Cheers,
Bijan Parsia.
Received on Friday, 25 June 2004 13:20:42 UTC

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