Introduction to AIWhat is AI?Found on the Web …Why AI?Weak vs. Strong AIAI CharacterizationsAct Like HumansTuring TestChessPerspective on Chess: ProPerspective on Chess: ConThink Like HumansThink/Act RationallySlide 14History of AIBits of HistorySlide 17Slide 18Slide 19Predictions and Reality … (1/3)Predictions and Reality … (2/3)Predictions and Reality … (3/3)Why is AI Hard?ElizaColby’s PARRYParry meets Eliza…Slide 29CMSC 421Goals for ClassSyllabusWhat you’re responsible forQuizAbout MyselfIntroduction to AIIntroduction to AIRussell and Norvig: Chapter 1 CMSC421 – Fall 2005What is AI?What is AI?Found on the Web …Found on the Web …AI is the simulation of intelligent human processesAI is the reproduction of the methods or results of human reasoning or intuitionAI is the study of mental faculties through the use computational methodsUsing computational models to simulate intelligent behaviorMachines to emulate humansIntelligent behaviorHumansComputerWhy AI?Cognitive Science: As a way to understand how natural minds and mental phenomena worke.g., visual perception, memory, learning, language, etc.Philosophy: As a way to explore some basic and interesting (and important) philosophical questionse.g., the mind body problem, what is consciousness, etc.Engineering: To get machines to do a wider variety of useful thingse.g., understand spoken natural language, recognize individual people in visual scenes, find the best travel plan for your vacation, etc.Weak vs. Strong AIWeak AI: Machines can be made to behave as if they were intelligentStrong AI: Machines can have consciousnesssubject of fierce debate, usually among philosophers and nay-sayers, not so much among AI researchers!E.g. recent Red Herring article and responseshttp://groups.yahoo.com/group/webir/message/1002AI CharacterizationsAI Characterizations Discipline that systematizes and automates intellectual tasks to create machines that:Act like humans Act rationallyThink like humansThink rationallyAct Like HumansAct Like HumansAI is the art of creating machines that perform functions that require intelligence when performed by humansMethodology: Take an intellectual task at which people are better and make a computer do itTuring test•Prove a theorem•Play chess•Plan a surgical operation•Diagnose a disease•Navigate in a buildingTuring TestTuring TestInterrogator interacts with a computer and a person via a teletype. Computer passes the Turing test if interrogator cannot determine which is which.Loebner contest: Modern version of Turing Test, held annually, with a $100,000 prize. http://www.loebner.net/Prizef/loebner-prize.htmlParticipants include a set of humans and a set of computers and a set of judges.Scoring: Rank from least human to most human. Highest median rank wins $2000. If better than a human, win $100,000. (Nobody yet…)ChessChessName: Garry KasparovTitle: World Chess ChampionCrime: Valued greed over common senseHumans are still better at making up excuses.© Jonathan SchaefferPerspective on Chess: ProPerspective on Chess: Pro“Saying Deep Blue doesn’t really think about chess is like saying an airplane doesn't really fly because it doesn't flap its wings”Drew McDermott© Jonathan SchaefferPerspective on Chess: Perspective on Chess: ConCon“Chess is the Drosophila of artificial intelligence. However, computer chess has developed much as genetics might have if the geneticists had concentrated their efforts starting in 1910 on breeding racing Drosophila. We would have some science, but mainly we would have very fast fruit flies.”John McCarthy© Jonathan SchaefferThink Like HumansThink Like HumansHow the computer performs functions does matterComparison of the traces of the reasoning stepsCognitive science  testable theories of the workings of the human mind•Connection with Psychology•General Problem Solver (Newell and Simon)•Neural networks•Reinforcement learning But:• Role of physical body, senses, and evolution in human intelligence?• Do we want to duplicate human imperfections?Think/Act RationallyThink/Act RationallyAlways make the best decision given what is available (knowledge, time, resources)Perfect knowledge, unlimited resources  logical reasoningImperfect knowledge, limited resources  (limited) rationality•Connection to economics, operational research, and control theory•But ignores role of consciousness, emotions, fear of dying on intelligenceAI CharacterizationsAI Characterizations Discipline that systematizes and automates intellectual tasks to create machines that:Act like humans Act rationallyThink like humansThink rationallyHistory of AIJean-Claude Latombe: I personally think that AI is (was?) a rebellion against some form of establishment telling us “Computers cannot perform certain tasks requiring intelligence”Bits of HistoryBits of History1956: The name “Artificial Intelligence” was coined by John McCarthy. (Would “computational rationality” have been better?)Early period (50’s to late 60’s): Basic principles and generalityGeneral problem solvingTheorem provingGamesFormal calculusBits of HistoryBits of History1969-1971: Shakey the robot (Fikes, Hart, Nilsson) Logic-based planning (STRIPS)Motion planning (visibility graph)Inductive learning (PLANEX)Computer visionBits of HistoryBits of HistoryKnowledge-is-Power period (late 60’s to mid 80’s): Focus on narrow tasks require expertiseEncoding of expertise in rule form:If: the car has off-highway tires and4-wheel drive andhigh ground clearanceThen: the car can traverse difficult terrain (0.8)Knowledge engineering5th generation computer projectCYC system (Lenat)Bits of HistoryBits of HistoryAI becomes an industry (80’s – present): Expert systems: Digital Equipment, Teknowledge, Intellicorp, Du Pont, oil industry, …Lisp machines: LMI, Symbolics, …Constraint programming: ILOGRobotics: Machine Intelligence Corporation, Adept, GMF (Fanuc), ABB, …Speech understandingInformation Retrieval – Google, …Predictions and Reality … Predictions and Reality … (1/3)(1/3)In the 60’s, a famous AI professor from MIT said: “At the end of the summer, we will have developed an electronic eye”As of 2002, there is still no general computer vision system capable of understanding complex dynamic scenesBut computer systems routinely perform road traffic monitoring, facial recognition,