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This text discusses the working of a box, utilizing the STRIPS representation and limitations. It also highlights scientific computing equations and knowledge-based reasoning.
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Starting state: Objects OO and box B are at L. Goal: Objects OO are at M. Plan: for (O in OO) putin(O,B); move(B,L,M); repeat{choose(OX|removable(OX,B)), takeout(OX,B)} until(empty(B)).
STRIPS representation Action: putin(O,B,L) Preconditions: at(O,L), at(B,L), box(B) Effects: in(O,B), ~at(O,L) Action: move(B,L,M) Preconditions: at(B,L) Effects: at(B,M), ~at(B,L) Action: takeout(O,B,L) Preconditions: in(O,B), at(B,L) Effects: at(O,L), ~in(O,B)
Limitations of STRIPS representation • No geometry. • Discrete atomic actions. • Does not generalize or share knowledge with similar situations.
Scientific Computing Equations: Newton’s laws, impact model. Boundary conditions: Shapes of objects External forces on manipulators. Solve (numerically) for trajectories.
Scientific Computing: Limitations • Requires exact specifications for shape and action. Cannot handle incomplete knowledge or generalization. • Unstable. Answer is not reliable. • Generates lots of useless intermediate states • Only supports prediction, not other types of reasoning: postdiction, diagnosis, design.
Knowledge-based qualitative physical reasoning Representation for partial specifications of shape and action: 3D shape, continuous time Rules to characterize dynamics of domain sufficient to support commonsense inferences Effective reasoning strategies for different tasks.
Variants • Objects can be carried on a tray but greater care is needed. • Large objects can be carried in a milkcrate, but small objects will fall through. • A box with a lid is safe against objects fallling out in transit. etc. Share knowledge.
Sample rule [holds(S,openBox(B,INTERIOR,TOP)) ^ forall(O in OO) [holds(S,in(place(O),INTERIOR)) ^ value(S,zeroVelocity(O))] ^ long([S,S1]) ^ throughout([S,S1], isolated(OO,B)) ^ throughout([S,S1], motionless(B))] => holds(S1,stable(OO U {B})) ^ forall(O in OO) holds(S1,in(place(O),INTERIOR))
And when we’ve finished boxes How do pails and dippers work?