Lesson Plan – Friday October
10
1. Project update
2. Planning in Plan Space
3. Case-Based, Partial-order, and Hierarchical Planning
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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
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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)
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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)
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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)
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