1	CS3243 FOUNDATIONS OF ARTIFICIAL INTELLIGENCE AY2004/2005 Semester 2 Introduction: Chapter 1
2	CS3243 Course home page: http://www.comp.nus.edu.sg/~cs3243 IVLE for homework submission and forum communication. Textbook: S. Russell and P. Norvig Artificial Intelligence: A Modern Approach Prentice Hall, 2003, Second Edition Lecturer: Min-Yen Kan (S15 05-05) Grading: Programming assignments (20%, 20%), Midterm test (20%), Final exam (40%) Class participation can only revise your grade upwards Lecture and tutorial attendance is mandatory Midterm test (in class, 1 hr) and final exam (2 hrs) are both closed book
3	Outline Course overview What is AI? A brief history The state of the art
4	Course overview Introduction and Agents (chapters 1, 2) Search (chapters 3, 4, 5, 6) Logic (chapters 7, 8, 9) Uncertainty (chapters 13, 14) Learning (chapters 18, 20) Optional Lectures: Natural Language Processing (chapters 22, 23) Planning and Robotics (chapters 11, 12, 25)
5	What is AI? Views of AI fall into four categories: Thinking humanly Thinking rationally Acting humanly Acting rationally The textbook advocates "acting rationally"
6	Acting humanly: Turing Test Turing (1950) "Computing machinery and intelligence": "Can machines think?" à "Can machines behave intelligently?" Operational test for intelligent behavior: the Imitation Game Predicted that by 2000, a machine might have a 30% chance of fooling a lay person for 5 minutes Anticipated all major arguments against AI in following 50 years Suggested major components of AI: knowledge, reasoning, language understanding, learning
7	Thinking humanly: cognitive modeling 1960s "cognitive revolution": information-processing psychology Requires scientific theories of internal activities of the brain How to validate? Requires 1) Predicting and testing behavior of human subjects (top-down) or 2) Direct identification from neurological data (bottom-up) Both approaches (roughly, Cognitive Science and Cognitive Neuroscience) are now distinct from AI
8	Thinking rationally: "laws of thought" Aristotle: what are correct arguments/thought processes? Several Greek schools developed various forms of logic: notation and rules of derivation for thoughts; may or may not have proceeded to the idea of mechanization Direct line through mathematics and philosophy to modern AI Problems: Not all intelligent behavior is mediated by logical deliberation What is the purpose of thinking? What thoughts should I have?
9	Acting rationally: rational agent Rational behavior: doing the right thing The right thing: that which is expected to maximize goal achievement, given the available information Doesn't necessarily involve thinking – e.g., blinking reflex – but thinking should be in the service of rational action
10	Rational agents An agent is an entity that perceives and acts This course is about designing rational agents Abstractly, an agent is a function from percept histories to actions: [f: P* à A] For any given class of environments and tasks, we seek the agent (or class of agents) with the best performance Caveat: computational limitations make perfect rationality unachievable à design best program for given machine resources
11	AI prehistory Philosophy Logic, methods of reasoning, mind as physical system foundations of learning, language, rationality Mathematics Formal representation and proof algorithms, computation, (un)decidability, (in)tractability, probability Economics utility, decision theory Neuroscience physical substrate for mental activity Psychology phenomena of perception and motor control, experimental techniques Computer building fast computers engineering Control theory design systems that maximize an objective function over time Linguistics knowledge representation, grammar
12	Abridged history of AI 1943 McCulloch & Pitts: Boolean circuit model of brain 1950 Turing's "Computing Machinery and Intelligence" 1956 Dartmouth meeting: "Artificial Intelligence" adopted 1952–69 Look, Ma, no hands! 1950s Early AI programs, including Samuel's checkers program, Newell & Simon's Logic Theorist, Gelernter's Geometry Engine 1965 Robinson's complete algorithm for logical reasoning 1966–73 AI discovers computational complexity Neural network research almost disappears 1969–79 Early development of knowledge-based systems 1980– AI becomes an industry 1986– Neural networks return to popularity 1987– AI becomes a science 1995– The emergence of intelligent agents
13	State of the art Deep Blue defeated the reigning world chess champion Garry Kasparov in 1997 Proved a mathematical conjecture (Robbins conjecture) unsolved for decades No hands across America (driving autonomously 98% of the time from Pittsburgh to San Diego) During the 1991 Gulf War, US forces deployed an AI logistics planning and scheduling program that involved up to 50,000 vehicles, cargo, and people NASA's on-board autonomous planning program controlled the scheduling of operations for a spacecraft Proverb solves crossword puzzles better than most humans