Re: Effects in OWL-S

At 12:16 30/04/2004 -0400, Drew McDermott wrote:
>I'm not clear on exactly what Austin's model allows.  If it allows
>discrete effects to occur at predictable offsets from the start time
>of an action, then I assume one could express that in terms of a
>series of simpler actions.  It might be a lot clumsier.
>
>I have lobbied within the PDDL community to allow for a notion of
>autonomous process, which is like an action except that it occurs
>whenever its precondition is true.  If the precondition is true over
>an interval, then the process occurs over that interval, and its
>effects can include continouos changes in fluents.  By setting up
>timer effects such as
>
>      (when (=~ (elapsed (proc...)) (+ (start-time) 3))
>         E)
>
>one could have an effect E occur at a fixed interval after the start
>of the process.   You can do a lot of other cool things, too.


In O-Plan [our earlier but more capable planner] we do these sort of things 
by using the activity expansions, some of which can have temporal 
constraints between the sub-activities and dummy nodes (nomenclature is 
from project management systems)whcih  effectively arbitrarily introduce 
extra convenient time points to better express delays, time intervals, and 
other things like this.

Received on Friday, 30 April 2004 12:50:53 UTC