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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.


> 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:

> 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.

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

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