1. ICS 101 Fall 2011 Introduction to Artificial Intelligence Asst. Prof. Lipyeow Lim Information & Computer Science Department University of Hawaii at Manoa 10/11/20111Lipyeow Lim -- University of Hawaii at Manoa

2. What is Artificial Intelligence ? 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa2

3. What is human intelligence ? 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa3

4. What are signs (activities, abilities etc) of human intelligence ? Exercise 1: Write down four examples in your worksheet 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa4

5. Approaches to A.I. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa5 Human-orientedRationalist Thinking Acting Thinking HumanlyThinking Rationally Acting HumanlyActing Rationally

6. Definitions of AI (a) “The exciting new effort to make computer think... machines with minds, in the full and literal sense.” (Haugeland, 1985) “[The automation of] activities that associate with human thinking, activities such as decision-making, problem solving, learning...” (Bellman, 1978) “The art of creating machines that perform functions that require intelligence when performed by people.” (Kurzweil, 1990) “The study of how to make computers do things, at the moment, people are better.” (Rich and Knight, 1991) 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa6

7. Definitions of AI (b) “The study of mental faculties through the use of computational models.” (Charniak and McDermott, 1985) “The study of the computations that make it possible to perceive, reason, and act.” (Winston, 1992) “Computational Intelligence is the study of the design of intelligent agents.”(Poole et al., 1998) “AI... is concerned with intelligent behavior in artifacts.” (Nilsson, 1998) 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa7

8. Acting Humanly: Turing Test (1950) Operational test of intelligence Anticipated all major arguments against AI in following 50 years Suggested major components of AI: knowledge, reasoning, language understanding, learning 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa8 Human Interrogator Human A.I. ?

9. Thinking Humanly : Cognitive Science AI thinks like humans do How do humans think ? How can we find out ? – Introspection – Psychological experiments – Brain imaging The goal is to formulate computer programs that mimic how humans think and hence achieve AI! 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa9

10. Thinking Rationally Aristotle: what are correct arguments/thought processes? – Syllogism: Socrates is a man; All men are mortal Therefore Socrates is mortal – Field of logic AI programs represent knowledge using formal logic and solves problems using logical inference/reasoning. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa10

11. Acting Rationally Acting rationally == doing the right thing What is the “right thing” ? – Logical / rational – maximize goal achievement, given the available information This approach is the focus of many AI efforts! AI programs are rational agents : programs that act so as to achieve the best outcome or best expected outcome 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa11

12. AI Today Robotic Vehicles: Google Self-Drive Car Speech Recognition: Call routing, Call center Autonomous planning: Mars Rover Game Playing: Deep Blue, Watson Spam Fighting Logistic Planning: Dynamic Analysis & Replanning Tool (DART) Robotics : Roomba Machine Translation 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa12

13. Intelligent Agents Perceives its environment through sensors Acts upon the environment through actuators Percepts – perceptual input at any given instant Agent program implements how to map a sequence of percepts to an action 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa13 Agent Environment Agent Program Sensors Actuators Actions Percepts

14. Example: Vacuum Robot Vacuum Robot (“agent”) needs to keep two rooms A & B clean. It can sense which room it is in and whether the carpet in that room is dirty. It can either go Right, go Left, or Suck. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa14 AB ************

15. Example: Vacuum Robot Agent Program Percept SequenceAction [A,Clean]Go Right [A, Dirty]Suck [B, Clean]Go Left [B, Dirty]Suck [A, Clean], [A, Clean]Go Right 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa15 Agent Environment Agent Program Sensors Actuators Actions Percepts AB *********

16. Representation & Search Newell & Simon argue that intelligent activity (human or machine) is achieved by: 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa16 – Representing significant aspects of a problem using symbol patterns – Generating potential solutions by applying operations on the representation – Selecting a solution by searching among these possibilities

17. Example: Tic-Tac-Toe 2 Player Game: Each gets a symbol 0 or X Each player tries to get 3 of his/her symbol in a row/column/diagonal in a 3 by 3 grid. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa17 Player A X 0 X 0X X 0X 0X 0X 0X X Player BPlayer APlayer B Player A Player A Wins !

18. Example: State Space for Tic-Tac-Toe 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa18 xxx x... xx 0x0xx 0 x 0 x 0 x 0

19. Exercise Draw the state space for the vacuum robot starting from the following initial state for the next two state transitions. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa19 AB ************

20. Podcast Supplement Asst. Prof. Lipyeow Lim Information & Computer Science Department University of Hawaii at Manoa 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa20

21. Approaches to A.I. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa21 Human-orientedRationalist Thinking Acting Thinking HumanlyThinking Rationally Acting HumanlyActing Rationally

22. Acting Humanly: Turing Test (1950) Operational test of intelligence Anticipated all major arguments against AI in following 50 years Suggested major components of AI: knowledge, reasoning, language understanding, learning 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa22 Human Interrogator Human A.I. ?

23. Thinking Humanly : Cognitive Science AI thinks like humans do How do humans think ? How can we find out ? – Introspection – Psychological experiments – Brain imaging The goal is to formulate computer programs that mimic how humans think and hence achieve AI! 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa23

24. Thinking Rationally Aristotle: what are correct arguments/thought processes? – Syllogism: Socrates is a man; All men are mortal Therefore Socrates is mortal – Field of logic AI programs represent knowledge using formal logic and solves problems using logical inference/reasoning. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa24

25. Acting Rationally Acting rationally == doing the right thing What is the “right thing” ? – Logical / rational – maximize goal achievement, given the available information This approach is the focus of many AI efforts! 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa25 AI programs are rational agents : programs that act so as to achieve the best outcome or best expected outcome

26. Intelligent Agents Perceives its environment through sensors Acts upon the environment through actuators Percepts – perceptual input at any given instant Agent program implements how to map a sequence of percepts to an action to achieve some goal 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa26 Agent Environment Agent Program Sensors Actuators Actions Percepts

27. Example: Vacuum Robot (“Agent”) Goal/outcome: keep two rooms A & B clean. Percepts: which room it is in and whether the carpet in that room is dirty. Actions: go Right, go Left, or Suck. 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa27 Agent Environment Agent Program Sensors Actuators Actions Percepts AB *********

28. Example: Vacuum Robot Agent Program Percept SequenceAction [A,Clean]Go Right [A, Dirty]Suck [B, Clean]Go Left [B, Dirty]Suck [A, Clean], [A, Clean]Go Right 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa28 Agent Environment Agent Program Sensors Actuators Actions Percepts AB *********

29. Example: Tic-Tac-Toe Agent Goal/outcome: Play by the rules and win Percepts: the tic-tac-toe board and the human’s move on the board. Actions: put a “0” on any of the empty cell on the board 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa29 Human Agent 0 X

30. Example: Car Driving Agent Goal/outcome: Navigate and drive to destination safely obeying traffic rules Percepts: its own location, speed, direction, and location, speed, direction of nearby objects Actions: accelerate, decelerate, hardstop, turn x degrees left, turn x degrees right, maintain speed 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa30 Agent Environment Agent Program Sensors Actuators Actions Percepts

31. Representation & Search Newell & Simon argue that intelligent activity (human or machine) is achieved by: – Representing significant aspects of a problem using symbol patterns – Generating potential solutions by applying operations on the representation – Selecting a solution by searching among these possibilities 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa31

32. Example: Vacuum Robot State representation: – Cleanliness status of each room – Location of robot State Transitions (generating possibilities) – Triggered by actions of robot (L, R, S) Goal states (selecting solutions) – Any state where both rooms are clean 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa32 AB ***** Right AB ***** AB Suck AB

33. Example: Vacuum Robot State Space 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa33 AB ***** R AB AB S AB S R AB L AB L L R S R AB S AB L L S R R L LR SS L R

34. Example: Tic-Tac-Toe State representation: – Tic-tac-toe board – Location of X’s and 0’s State Transitions (generating possibilities) – Triggered by players putting X/0 on empty cells Goal states (selecting solutions) – Any state where symbols form a line 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa34 Player A X 0 X 0X X 0X 0X 0X 0X X Player BPlayer A Player BPlayer A Player A Wins !

35. Example: State Space for Tic-Tac-Toe 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa35 xxx x... xx 0x0xx 0 x 0 x 0 x 0

36. Summary Four different approaches to AI – Acting vs Thinking – Human-oriented vs Rationalist Intelligent Agents – Sensors – Actuators – Agent Program Representation and Search – Representing the state of the problem – Generating the state space – Searching the state space for goal states 10/11/2011Lipyeow Lim -- University of Hawaii at Manoa36