Lesson Plan – Friday October 10

1. Project update

2. Planning in Plan Space

3. Case-Based, Partial-order, and Hierarchical Planning

*****************************************************

Project due date changed to Wednesday.

Apologize for no blocks world visualizer.

Homeworks coming back on Monday.

Web page now has:

- Lesson plans

- Extensive set of Powerpoint slides from previous quarters

*****************************************************

Planning in Plan Space

Idea: Node == Partially-constructed plan, not the world!

Operators: Ways to modify a plan

- Add an action (where)

- Delete an action

- Change a parameter of an action

Heuristic: measure of how “correct” a plan is

- Do actions have false preconditions?

- Can every proposition be “explained”?

EXAMPLE: LOGISTICS

Airports: Seatac, JFK, LAX

Cities: Seattle, Tacoma, NYC, Long Island, LA, Hollywood

Objects: Airplanes, Trucks, Packages

Actions: Load / Unload, Drive, Fly

Initial: At(P1, Seattle)

Goal: At(P1, NYC)

Middle-out planning: start with action Fly(Seatac, JFK)

*****************************************************

Case-Based Planning

IDEA: Library of useful plans. Find “closest match” to initial & goal state.

(STRIPS 1969 – but overlooked! PRODIGY 1993 – Velosa & Carbonell)

EXAMPLE: Find and modify plan:

Load(P9,Truck33,Hollywood);

Drive(P9, Hollywood, LAX);

Unload(P9,Truck33,LAX)

Load(P9,Plane16,LAX)

Fly(Plane16,LAX,JFK)

Unload(P9, Plane16, JFK)

Load(P9, Truck44, JFK)

Drive(Truck44, JFK, NYC)

Unload(P9, Truck44)

*****************************************************

Partial Order Planning: Instead of SEQUENCE of actions, allow actions in a partial-plan to be partially-ordered. WHY? DELAY UNNECESSARY DECISIONS! (UC-POP – Weld 1992)

EXAMPLE:

Initial: At(Plane33,Seatac) & At(Plane99,Seatac)

Goal: At(Plane33, LAX) & At(Plane99, JFK)

*****************************************************