Re: OWL-S preconditions - practical issues

>I think of a precondtion as something that has to be true
>before a service can be invoked (if we're thinking of
>planning operators as representing services, for example),
>while an effect is something the service invocation makes true.
>
>A constraint could be used in either way; but what I had
>in mind was that an operator could have (< ?n1 5), not as
>a pre-condition, but as something that would be asserted,
>if the operator were used, as something that was true
>after the service invocation.  Other constraints might
>allow a more precise determination of the value, but it
>would have to be less than 5.
>
>I'm not sure that's enough to make it an effect as such,
>rather than some kind of post-condition, because presumably
>the way it's made true that ?n1 is < 5 is by giving ?n1
>some specific value that is less than 5, and it's giving it
>that value that's the effect, strictly speaking.

Whether it's an effect or post-condition, do you know of planners that 
allow such conditional expressions in the postconditions/effects of operators?


>One problem for a planner is that if it wants, say, ?n1 to be
>less than 10, one way to get that is to use something that makes
>?n1 less than 5, and that requires a reasoner that could make
>such connections.
>
>-- Jeff

I'm guessing "and most planners aren't capable of such reasoning" is implied?

- Dónal

Received on Sunday, 27 June 2004 10:51:32 UTC