PLANNING APPLICATIONS

Spacecraft Assembly, Integration, and Verification

    Optimum-AIV
	generates plan and monitors execution
	if activity reveals unexpected information then it 
		replans based on new information

Job Shop Scheduling

    TOSCA
	takes raw materials and components and generates a 
		plan to assemble them into finished products (Hitachi)
	partial-order, least commitment decision making
	planning (what actions will be performed) vs. 
		scheduling (the order of the actions)

Scheduling for Space Missions

    very limited resource -- want to make best use of it
	European Earth Resource Observation
	Hubble Space Telescope (two stage planner)

Buildings

    System for Interactive Planning and Execution
	needed O(n2.5) time for a n-story building (Why?)



			EXTENDING BASIC PLANNING

Hierarchical plans

Top-down design -- large problems need to be broken 
down into smaller ones which can be solved independently.

Complex conditions

Need to identify conditions for action execution and 
multiple possible outcomes.

Time

Actions take time to execute and check, our GPS and 
STRIPS just executes as time is not a factor.

Resources

Must be able to deal with allocation of multiple scare 
resources (money, labor, construction space, ...)


What if humans are the actors in plans?

Augmenting Human Planning
	PERT charts, critical path computations
	Workflow systems



			HIERARCHICAL DECOMPOSITION

Basic top-down design ...



			CONDITIONAL PLANNING

What is it?
	allow for conditional branching in plans

Why is it needed?
	there can be multiple methods for achieving a goal
	which will work or be preferable in different situations

How?
	use value of percepts (state of the environment) to 
	trigger different actions in the plan.

Approach can be extended to have more general control 
flow (loops).

	problem becomes similar to automatic programming



				REPLANNING

What?
	Allow for replanning during the execution of a plan. 

Why?
	Unpredictable events/results and may occur or new 
	information may become available during plan 
	execution. Actions do not always have predefined 
	outcomes.

How?
	Use appropriate percepts to determine whether 
	outcome expected from actions are those that really 
	occur. If not, replan based on new information.

Execution monitoring (testing preconditions) vs. 
action monitoring (testing results)

Bounded indeterminacy (finite # of possible outcomes) vs. 
unbounded indeterminacy (innumerable # of outcomes)

Conditional planning vs. replanning