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Actions in LUPS. Actions and their effects are described by one or more LUPS commands, allowing to model: Simple actions Update actions Complex effects of actions Non-deterministic effects of actions. Actions in LUPS. Simple actions “ causes F if F 1 ,...,F k ”
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Actions in LUPS • Actions and their effects are described by one or more LUPS commands, allowing to model: • Simple actions • Update actions • Complex effects of actions • Non-deterministic effects of actions
Actions in LUPS • Simple actions “ causes F if F1,...,Fk” always F when F1,...,Fk, • Update Actions “ updates with L ¬ L1,...,Lk if F1,...,Fk” always L ¬ L1,...,Lkwhen F1,...,Fk , “
Actions in LUPS • Complex effects of actions “1 or 2 causes L1 if F1,...,Fk” “1 and 2 causes L2 if F1,...,Fk” always L1when F1,...,Fk, 1 ,not 2 always L1when F1,...,Fk, not 1 , 2 always L2when F1,...,Fk, 1 , 2
Actions in LUPS • Non-deterministic effects of actions “ causes L1 or L2 if F1,...,Fk” always L1 ¬ a(I)when F1,...,Fk, (I) always L2 ¬ b(I)when F1,...,Fk, (I) always a(I)¬ not b(I)when F1,...,Fk, (I) always b(I)¬ not a(I)when F1,...,Fk, (I) • the non-deterministic effect of action is transformed into the non-deterministic choice between two actions (a and b) with deterministic effects
Action Updates & Plans • An action update is a set of LUPS commands of the form: U = {assert event : L } • Each action update can be viewed as a set of actions to be performed in parallel. • A plan is a sequence of action updates: U= {U1,...,Um }
Planning Solution • The result of applying a plan U to an update program U=U1 ... Ui is given by the update program: Result(U, U)= U1 ... Ui U1... Um • Given the update program U, the plan U is a solution to the goal holds (L1,…, L) at q ?, iff q (Result(U, U)) smL1,…, L
Abductive Solutions • Uses the translation of update programs and queries into normal logic programs written in a meta-language. • Defines the set of abducibles based on the set of possible actions. • Correct according to a Theorem in the paper. • Implemented by means of the interpreter for the abduction procedure ABDUAL (Alferes et al. 1999)