ICS 101 Fall 2011 Introduction to Artificial Intelligence

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

2. What is Artificial Intelligence ? Lipyeow Lim -- University of Hawaii at Manoa

3. What is human intelligence ? Lipyeow Lim -- University of Hawaii at Manoa

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

5. Approaches to A.I. Human-oriented Rationalist Thinking Humanly Thinking Rationally Thinking Acting Humanly Acting Rationally Acting Lipyeow Lim -- University of Hawaii at Manoa

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) Lipyeow Lim -- University of Hawaii at Manoa

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) Lipyeow Lim -- University of Hawaii at Manoa

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

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! Lipyeow Lim -- University of Hawaii at Manoa

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. Lipyeow Lim -- University of Hawaii at Manoa

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 Lipyeow Lim -- University of Hawaii at Manoa

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 Lipyeow Lim -- University of Hawaii at Manoa

13. Intelligent Agents Agent Percepts • 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 Sensors Environment Agent Program Actuators Actions Lipyeow Lim -- University of Hawaii at Manoa

14. Example: Vacuum Robot A B • 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. ************ ************ Lipyeow Lim -- University of Hawaii at Manoa

15. Example: Vacuum Robot Agent Program Agent Percepts A B Sensors Environment Agent Program Actions Actuators ********* ********* Lipyeow Lim -- University of Hawaii at Manoa

16. 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 Lipyeow Lim -- University of Hawaii at Manoa

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. Player B Player A Player B Player A Player A Wins ! Player A Lipyeow Lim -- University of Hawaii at Manoa

18. Example: State Space for Tic-Tac-Toe ... ... ... ... ... ... Lipyeow Lim -- University of Hawaii at Manoa

19. Exercise A B • Draw the state space for the vacuum robot starting from the following initial state for the next two state transitions. ************ ************ Lipyeow Lim -- University of Hawaii at Manoa

20. Podcast Supplement Asst. Prof. Lipyeow Lim Information & Computer Science Department University of Hawaii at Manoa Lipyeow Lim -- University of Hawaii at Manoa

21. Approaches to A.I. Human-oriented Rationalist Thinking Humanly Thinking Rationally Thinking Acting Humanly Acting Rationally Acting Lipyeow Lim -- University of Hawaii at Manoa

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

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! Lipyeow Lim -- University of Hawaii at Manoa

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. Lipyeow Lim -- University of Hawaii at Manoa

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! AI programs are rational agents : programs that act so as to achieve the best outcome or best expected outcome Lipyeow Lim -- University of Hawaii at Manoa

26. Intelligent Agents Agent Sensors Percepts • 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 Environment Agent Program Actuators Actions Lipyeow Lim -- University of Hawaii at Manoa

27. Example: Vacuum Robot (“Agent”) Agent Percepts A B • 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. Sensors Environment Agent Program Actions Actuators ********* ********* Lipyeow Lim -- University of Hawaii at Manoa

28. Example: Vacuum Robot Agent Program Agent Percepts A B Sensors Environment Agent Program Actions Actuators ********* ********* Lipyeow Lim -- University of Hawaii at Manoa

29. Example: Tic-Tac-Toe Agent Human 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 Lipyeow Lim -- University of Hawaii at Manoa

30. Example: Car Driving Agent Agent Percepts • 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 Sensors Environment Agent Program Actions Actuators Lipyeow Lim -- University of Hawaii at Manoa

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 Lipyeow Lim -- University of Hawaii at Manoa

32. Example: Vacuum Robot A A A A B B B B • 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 Right Suck Suck ***** ***** ***** ***** Lipyeow Lim -- University of Hawaii at Manoa

33. Example: Vacuum Robot State Space R S A A A A A A A A B B B B B B B B L R S R R S R S L L R L L S ***** ***** ***** ***** ***** ***** L R S ***** ***** L L R S Lipyeow Lim -- University of Hawaii at Manoa

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 Player A Player B Player A Player B Player A Player A Wins ! Lipyeow Lim -- University of Hawaii at Manoa

35. Example: State Space for Tic-Tac-Toe ... ... ... ... ... ... Lipyeow Lim -- University of Hawaii at Manoa

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 Lipyeow Lim -- University of Hawaii at Manoa