Introduction to Artificial Intelligence

Agents

Henry Kautz

(Model-Based Agent)

(Planning Agent)

(Decision-Theoretic Agent)

How should the agent be designed if…

• It has location and dirt sensors, but no internal state?

• It has no sensors, but knows the starting state?

• It has no sensors, and does not know the starting state?

Constants = names for particular objects. Eg: COSTCO9, IPOD6

Predicates = are true or false of particular objects. Eg: At, Sells, Have

Literal = predicate applied to constant(s) or variable(s). Eg: At(p), At(COSTCO9)

Ground literal = predicate applied to constant(s). Eg.: At(COSTCO9)

STRIPS state = set of all of the ground literals that are true in that state.Eg: { At(COSTCO9), Sells(COSTCO9,IPOD6), Sells(WALMART4,TV6) }

, ~Sells(p,x)

~Sells(p,x)

, ~Sells(p,x)

~Sells(p,x)

Precondition = must be true in order for action to be possible

Add effect = makes a ground literal true

Delete effect = makes a ground literal false

{ At(COSTCO9), Sells(COSTCO9,IPOD6), Sells(WALMART4,TV6) }

Buy(IPOD6)

{ At(COSTCO9), Have(IPOD6), Sells(WALMART4,TV6) }

Shakey Making Coffee

• Shakey the robot has to bring coffee to Prof. Kautz.    In order to make the coffee, Shakey will need to gather coffee filters, coffee, and Prof. Kautz's mug and bring them to the coffee maker in the kitchen.  The coffee and filters are in the supply room, but it is locked.  To unlock the supply room, Shakey will need to get the key from Prof. Kautz's office.

• Shakey starts in the kitchen.  His goal is to fill Prof. Kautz's mug with freshly made coffee and bring the filled mug to Prof. Kautz's office.