LECTURE 4: PRACTICAL REASONING 1 Practical ... - Sorry

Lecture 4
An Introduction to Multiagent Systems
Lecture 4
An Introduction to Multiagent Systems
¯To represent this environment, need an ontology.
On´xyµ obj x on top of obj y
OnTable´xµobj x is on the table
Clear´xµ nothing is on top of obj x
Holding´xµarm is holding x
¯Here is a representation of the blocks world described above:
Clear´Aµ
On´ABµ
OnTable´Bµ
OnTable´Cµ
¯Use the closed world assumption: anything not stated is
assumed to be false.
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 12
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 13
Lecture 4
An Introduction to Multiagent Systems
Lecture 4
An Introduction to Multiagent Systems
¯Agoal is represented
OnTable´Aµ
as a set of formulae.
¯Here is a goal:
OnTable´Bµ OnTable´Cµ
¯Actions are represented using a technique that was developed in
the STRIPS planner.
Each action has:
– a name
which may have arguments;
– a pre-condition list
list of facts which must be true for action to be executed;
– a delete list
list of facts that are no longer true after action is performed;
– an add list
list of facts made true by executing the action.
Each of these may contain variables.
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 14
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 15