Re: OWL-S preconditions - practical issues

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.

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.

-- Jeff

Received on Friday, 25 June 2004 12:57:28 UTC