1. AI CSC361: Intelligent Agents1 Intelligent Agents -1 CSC361

2. AI CSC361: Intelligent Agents2 Intelligent Agents What are Agents? Structure of an Agent. What to consider when designing an agent? Types of Agents

3. AI CSC361: Intelligent Agents3 What is an Agent? An agent is anything that can be viewed as perceiving its environment through sensors and acting upon that environment through actuators.

4. AI CSC361: Intelligent Agents4 What is an Agent? Examples: –Human agent: Sensors  eyes, ears, and other organs; Actuators  hands, legs, mouth, and other body parts. –Robotic agent: Sensors  cameras and infrared range finders; Actuators  various motors connected to arms.

5. AI CSC361: Intelligent Agents5 What is an Agent? Percept: agents’ input at any instant of time. Percept Sequence: complete history of what the agent has perceived so far. Behavior: what action, when? Agent function: maps from percept sequences to actions. [f: P*  A ]….. determines agents’ behavior.

6. AI CSC361: Intelligent Agents6 What is an Agent? Agent Program runs on the physical architecture to produce f agent = architecture + program Environment: Surroundings in which the agent has to operate.

7. AI CSC361: Intelligent Agents7 Vacuum-Cleaner Agent Percepts: location and contents, e.g., [A,Dirty] Actions: Left, Right, Suck, NoOp

8. AI CSC361: Intelligent Agents8 Vacuum-Cleaner Agent The agent can be implemented using a table. Or the agent function may be implemented in some other way. How to build the table?  Table could be very long.

9. AI CSC361: Intelligent Agents9

10. 10 Is an Agent Good or Bad? How to judge an agents’ behavior?  Note: We are not talking about intelligent agents … just agents. An agent should strive to "do the right thing", based on what it can perceive and the actions it can perform. The right action is the one that will cause the agent to be most successful. Performance measure: An objective criterion for success of an agent's behavior.

11. AI CSC361: Intelligent Agents11 Is an Agent Good or Bad? Examples: performance measure of a vacuum-cleaner agent could be amount of dirt cleaned up, amount of time taken, amount of electricity consumed, amount of noise generated, etc. What could be the performance agent for a human agent?

12. AI CSC361: Intelligent Agents12 Is an Agent Good or Bad? Rational agent: If an agent performs actions which maximize its performance measure the agent is called rational agent. Rational agent is a good agent. Autonomous agent: An agent is autonomous if its behavior is determined by its own experience (with ability to learn and adapt). Autonomous agent is good agent.

13. AI CSC361: Intelligent Agents13 What to consider when designing an agent? We must consider PEAS: Performance measure, Environment, Actuators, Sensors. Consider the task of designing an automated taxi driver: –Performance measure: Safe, fast, legal, comfortable trip, maximize profits –Environment: Roads, traffic, pedestrians, customers –Actuators: Steering wheel, accelerator, brake, signal, horn –Sensors: Cameras, sonar, speedometer, GPS, odometer, engine sensors, keyboard

14. AI CSC361: Intelligent Agents14 What to consider when designing an agent? Consider the task of designing a medical diagnosis system. –Performance measure: Healthy patient, minimize costs, lawsuits –Environment: Patient, hospital, staff –Actuators: Screen display (questions, tests, diagnoses, treatments, referrals) –Sensors: Keyboard (entry of symptoms, findings, patient's answers)

15. AI CSC361: Intelligent Agents15 What to consider when designing an agent? Consider the task of designing a part- picking robot. –Performance measure: Percentage of parts in correct bins –Environment: Conveyor belt with parts, bins –Actuators: Jointed arm and hand –Sensors: Camera, joint angle sensors

16. AI CSC361: Intelligent Agents16 What to consider when designing an agent? Consider the task of designing a Interactive English tutor. –Performance measure: Maximize student's score on test –Environment: Set of students –Actuators: Screen display (exercises, suggestions, corrections) –Sensors: Keyboard

17. AI CSC361: Intelligent Agents17 How to implement an Agent? An agent is completely specified by the agent function mapping percept sequences to actions. action  f (percept-sequence). Aim: find a way to implement the rational agent function concisely.

18. AI CSC361: Intelligent Agents18 How to implement an Agent? Table-lookup agent: looks up the action entry corresponding to the current percept sequence. Drawbacks: –Huge table –Take a long time to build the table –No autonomy –Even with learning, need a long time to learn the table entries

19. AI CSC361: Intelligent Agents19 How to implement an Agent? Agent function implemented as a program in a programming language. Advantage: –can implement the agent function concisely.

20. AI CSC361: Intelligent Agents20

21. AI CSC361: Intelligent Agents21 What are the different types of agents? Two basic types in order of increasing generality: –Simple reflex agents –Model-based reflex agents –etc.

22. AI CSC361: Intelligent Agents22 Simple Reflex Agent

23. AI CSC361: Intelligent Agents23 Model-based Reflex Agent