1. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 1 Introduction to Artificial Intelligence LECTURE 1: Introduction What is AI? Foundations of AI The History of AI State of the Art

2. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 2 Definitions of AI Develop programs/systems that perform/act like humans Develop programs/systems that peform/act rationally Understand human intelligence Formalize the laws of thought and action INTELLIGENT AGENTS

3. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 3 HUMAN COMPUTER/ HUMAN - types in questions - receives answers on screen - processes questions - returns answers What is AI? The Turing Test If the human cannot tell if it is a computer or a human, the program exhibits intelligence

4. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 4 Examples of task for AI Play games –tic-tac-toe, chess, backgammon, poker Process natural language –control tower conversation, stock market briefs Industrial applications –plant diagnostics, plan for manufacturing Expert-level performance –molecular biology, computer configuration

5. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 5 Why is AI different than conventional programming? Strive for –GENERALITY –EXTENSIBILITY Capture rational deduction patterns Tackle problems with no algorithmic solution Represent and manipulate KNOWLEDGE, rather than DATA A new set of representation and programming techniques: HEURISTICS

6. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 6 Example: TIC-TAC-TOE

7. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 7 Program 1: hard wired Code a table of all possible board positions and the transitions between them (state diagram) Given a position, look in the table for the next move and return Properties: –time efficient, requires lots of storage –not extensible: requires a table for other games

8. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 8 Program 2: less hard wired Use procedures designed for the game: –try to place two marks in a row –if opponent has two marks in a row, place mark in third space Pattern matching to recognize board positions Can encode different playing strategies Better space efficiency, less time efficiency Still game-dependent

9. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 9 Program 3: AI-like Represent the state of the game: – current board position –next legal positions Use an evaluation function: –Rate the next move according to how likely it will lead to a win –look-ahead of possible oponent moves More general because it embodies a general strategy.

10. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 10 Foundations of AI Philosophy: Aristotle, mechanistic views, materialism, positivism, rationality. Mathematics: algorithms, logic, formalization of mathematics, incompleteness, decision theory. Psychology: behaviorism, cognitive science. Linguistics: grammars, syntax and semantics. Computer Science: computers, software, theory Others: neuroscience, economics, game theory.

11. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 11 A brief history of AI (1) Gestation (43-56): –automata theory, neural networks, checkers, theorem proving. –Shannon, Turing, Von Neumann, Newell and Simon, Minsky, McCarthy, Darmouth Workshop. Great expectations (52-69): –computers can do more than arithmetics! –General Problem Solver (GPS), better checkers –LISP (LISt Processing language)

12. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 12 A brief history of AI (2) –Microworlds: ANALOGY, blocks world

13. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 13 A brief history of AI (3) A dose of reality (66-74): –ELIZA: human-like conversation. –limitations of neural networks, genetic algorithms, machine evolution. –acting in the real world: robotics. Knowledge-based systems (69-79): –domain focus: experts systems vs. General Problem Solvers. –DENDRAL, MYCIN, XCON, etc.

14. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 14 A brief history of AI (4) Commercial AI: the ‘80s boom (80-90) –DEC’s R1 computer configuration program –many expert systems tools companies (mostly defunct): Symbolics, Teknowledge, etc. –Japan’s 5th generation project: PROLOG. –limited success in autonomous robotics and vision systems.

15. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 15 A brief history of AI (5) The 90’s: specialization, quiet progress –neural networks, genetic algorithms –probabilistic reasoning and uncertainty –learning –planning and constraint solving –agents –autonomous robotics: NAV autonomous driving van, crater exploration, robot soccer –IBM’s Deep Blue beats Kasparov!

16. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 16 State of the Art Embedded AI: many use AI techniques without saying it is AI! –Credit card approval (American Express) –Consumer electronics (fuzzy logic) Healthy research in many areas: intelligent agents, machine learning, man-machine interfaces, etc. More integrative view: acting in the real world (robots, self diagnosing machines)

17. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 17 To find out more about AI –“Godel, Escher, Bach” D. Hoftstadter –Annual AI conferences : American Assoc of Artificial Intelligence (AAAI) Int. Joint Conf. On Artificial Intelligence (IJCAI) –Specialized conferences: Machine Learning, Knowledge Representation, Vision, Robotics, etc. – A dozen journals: the main one is Artificial Intelligence

18. Introduction to AI, H. Feili (hfaili@mehr.sharif.edu) 18 ?