11. Intelligent Agents
11. Intelligent Agents
• PAGE (Percepts, Actions, Goals, Environment)
• Environment types
• Agent functions and programs
• Agent types
Malek Mouhoub, CS820 Winter 2004
1
11. Intelligent Agents
Sensors
Percepts
?
Environment
agent
actions
Effectors
Figure 1:
Interaction between agent and environment through sensors and effectors.
Malek Mouhoub, CS820 Winter 2004
2
11. Intelligent Agents
PAGE
Must first specify the setting for intelligent agent design.
Consider, e.g., the task of designing an automated taxi:
• Percepts : video, accelerometers, gauges, engine sensors,
keyboard, GPS, . . .
• Actions : steer, accelerate, brake, horn, speak/display, . . .
• Goals : safety, reach destination, maximize profits, obey laws,
passenger comfort, . . .
• Environment : US urban streets, freeways, traffic, pedestrians,
weather, customers, . . .
Malek Mouhoub, CS820 Winter 2004
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11. Intelligent Agents
Agent Type
Percepts
Actions
Goals
Environment
Medical diagnosis
Symptoms,
Questions, tests,
Healthy patient,
Patient hospital
system
findings, patient’s
treatments
minimize costs
answers
Satellite image
Pixels of varying
Print a
Correct
Images from
analysis system
intensity, color
categorization of
categorization
orbiting satellite
scene
Part-picking robot
Refinery controller
Pixels of varying
Pick up parts and
Place parts in
Convoyer belt
intensity
sort into bins
correct bins
with parts
Temperature,
Open, close
Maximize purity,
Refinery
pressure readings
valves; adjust
yield safety
temperature
Interactive English
tutor
Malek Mouhoub, CS820 Winter 2004
Typed words
Print exercises,
Maximize
suggestions,
student’s score on
corrections
test
set of students
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11. Intelligent Agents
Environment types
• Accessibility versus inaccessibility.
• Deterministic versus nondeterministic.
• Episodic versus non episodic.
• Static versus dynamic.
• Discrete versus continuous.
Malek Mouhoub, CS820 Winter 2004
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11. Intelligent Agents
Agent functions and programs
An agent is completely specified by the agent function
mapping percept sequences to actions
(In principle, one can supply each possible sequence to see what it
does. Obviously, a lookup table would usually be immense.)
One agent function (or a small equivalence class) is rational
Aim: find a way to implement the rational agent function concisely
An agent program takes a single percept as input, keeps internal
state.
Malek Mouhoub, CS820 Winter 2004
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11. Intelligent Agents
Agent types
Four basic types in order of increasing generality:
• simple reflex agents
• reflex agents with state
• goal-based agents
• utility-based agents
Malek Mouhoub, CS820 Winter 2004
7
11. Intelligent Agents
Simple reflex agents
Sensors
Agent
What action I
should do now
Environment
Condition-action rules
What the world
is like now
Effectors
Malek Mouhoub, CS820 Winter 2004
8
11. Intelligent Agents
Reflex agents with state
Sensors
State
How the world evolves
What my actions do
Condition-action rules
Agent
Malek Mouhoub, CS820 Winter 2004
What action I
should do now
Environment
What the world
is like now
Effectors
9
11. Intelligent Agents
Goal-based agents
Sensors
State
How the world evolves
What my actions do
What it will be like
if I do action A
Goals
What action I
should do now
Agent
Malek Mouhoub, CS820 Winter 2004
Environment
What the world
is like now
Effectors
10
11. Intelligent Agents
Utility-based agents
Sensors
State
How the world evolves
What my actions do
Utility
What it will be like
if I do action A
How happy I will be
in such a state
What action I
should do now
Agent
Malek Mouhoub, CS820 Winter 2004
Environment
What the world
is like now
Effectors
11