人工智能的课件CH1Introduction.ppt

1、智能计算研究中心1.Introduction ToArtificial intelligenceAutumn 2012Instructor:Wang XiaolongHarbin Institute of Technology,Shenzhen Graduate SchoolIntelligent Computation Research Center(ICRC,HITSGS)Introduction To Artificial intelligenceCourse OutlineWhy Study AI?What is AI?What can AI do?What tasks require

2、 AI?How to achieve AI?Branches of AIExamples of AIAI in ChinaAI in HITIntroduction To Artificial intelligenceWhy Study AI?Search enginesLaborScienceMedicine/DiagnosisAppliancesWhat else?Introduction To Artificial intelligenceWhy Study AI?(Cont.)Sony AIBOhttp:/Introduction To Artificial intelligenceW

3、hy Study AI?(Cont.)US militaryIntroduction To Artificial intelligenceWhy Study AI?(Cont.)Natural Language Question Answeringhttp:/www.ai.mit.edu/projects/infolab/http:/Introduction To Artificial intelligenceWhy Study AI?(Cont.)Robot TeamsUSC robotics LabIntroduction To Artificial intelligenceWhat is

4、 AI?The exciting new effort to make computers thinks machine with minds,in the full and literal sense”(Haugeland 1985)“The art of creating machines that perform functions that require intelligence when performed by people”(Kurzweil,1990)“The study of mental faculties through the use of computational

5、 models”(Charniak et al.1985)A field of study that seeks to explain and emulate intelligent behavior in terms of computational processes”(Schalkol,1990)Systems that think like humansSystems that think rationallySystems that act like humansSystems that act rationallyViews of AI fall into four categor

6、ies:The textbook advocates acting rationallyIntroduction To Artificial intelligenceWhat is AI?(Cont.)Acting Humanly:The Turing TestAlan Turings 1950 article Computing Machinery and Intelligence discussed conditions for considering a machine to be intelligent.“Can machines think?”“Can machines behave

7、 intelligently?”The Turing test(The Imitation Game):Operational definition of intelligence.Computer needs to possess:Natural language processing,Knowledge representation,Automated reasoning,and Machine learningPredicted that by 2000,a machine might have a 30%chance of fooling a lay person for 5 minu

8、tesAnticipated all major arguments against AI in following 50 yearsAre there any problems/limitations to the Turing Test?problems with the Turing Test:1.Turing test is not reproducible,constructive,and amenable to mathematic analysis.2.What about physical interaction with interrogator and environmen

9、t?Introduction To Artificial intelligenceWhat is AI?(Cont.)Acting Humanly:The Full Turing TestThe computer passes the test if a human interrogator,after posing some written questions,cannot tell whether the written responses come from a person or not.Requires physical interaction and needs perceptio

10、n and actuation.What would a computer need to pass the Turing test?Natural language processing:to communicate with examiner.Knowledge representation:to store and retrieve information provided before or during interrogation.Automated reasoning:to use the stored information to answer questions and to

11、draw new conclusions.Machine learning:to adapt to new circumstances and to detect and extrapolate patterns.Vision(for Total Turing test):to recognize the examiners actions and various objects presented by the examiner.Motor control(total test):to act upon objects as requested.Other senses(total test

12、):such as audition,smell,touch,etc.Introduction To Artificial intelligenceWhat is AI?(Cont.)Thinking Humanly:Cognitive Science1960“Cognitive Revolution”:information-processing psychology replaced behaviorism.Cognitive science brings together theories and experimental evidence to model internal activ

13、ities of the brain.What level of abstraction?“Knowledge”or“Circuits”?How to validate models?Predicting and testing behavior of human subjects(top-down)Direct identification from neurological data(bottom-up)Building computer/machine simulated models and reproduce results(simulation)Thinking Rationall

14、y:Laws of ThoughtAristotle(450 B.C.)attempted to codify“right thinking”What are correct arguments/thought processes?E.g.,“Socrates is a man,all men are mortal;therefore Socrates is mortal”Several Greek schools developed various forms of logic:notation plus rules of derivation for thoughts.Problems:1

15、.Uncertainty:Not all facts are certain(e.g.,the flight might be delayed).2.Resource limitations:-Not enough time to compute/process -Insufficient memory/disk/etc -Etc.Introduction To Artificial intelligenceWhat is AI?(Cont.)Acting Rationally:The Rational Agent Rational behavior:Doing the right thing

16、!The right thing:That which is expected to maximize the expected return Provides the most general view of AI because it includes:Correct inference(“Laws of thought”)Uncertainty handling Resource limitation considerations(e.g.,reflex vs.deliberation)Cognitive skills(NLP,AR,knowledge representation,ML

17、,etc.)Advantages:More general Its goal of rationality is well defined Rational agentsIntroduction To Artificial intelligenceWhat Can AI Do?Quiz:Which of the following can be done at present?Play a decent game of table tennis?Drive safely along a curving mountain road?Drive safely along Telegraph Ave

18、nue?Buy a weeks worth of groceries on the web?Buy a weeks worth of groceries at Berkeley Bowl?？Discover and prove a new mathematical theorem?Converse successfully with another person for an hour?？Perform a complex surgical operation?Unload a dishwasher and put everything away?Translate spoken Englis

19、h into spoken Swedish in real time?Write an intentionally funny story?Introduction To Artificial intelligenceWhat tasks require AI?“AI is the science and engineering of making intelligent machines which can perform tasks that require intelligence when performed by humans”Tasks that require AI:Solvin

20、g a differential equationBrain surgeryInventing stuffPlaying Jeopardy Playing Wheel of FortuneWhat about walking?What about grabbing stuff?What about pulling your hand away from fire?What about watching TV?What about day dreaming?Introduction To Artificial intelligenceHow to achieve AI?How is AI res

21、earch done?AI research has both theoretical and experimental sides.The experimental side has both basic and applied aspects.There are two main lines of research:One is biological,based on the idea that since humans are intelligent,AI should study humans and imitate their psychology or physiology.The

22、 other is phenomenal,based on studying and formalizing common sense facts about the world and the problems that the world presents to the achievement of goals.The two approaches interact to some extent,and both should eventually succeed.It is a race,but both racers seem to be walking.John McCarthyJo

23、hn McCarthyIntroduction To Artificial intelligenceBranches of AILogical AI Search Natural language processingPattern recognition Knowledge representation Inference From some facts,others can be inferred.Automated reasoning Learning from experience Planning To generate a strategy for achieving some g

24、oal.Epistemology Study of the kinds of knowledge that are required for solving problems in the world.Ontology Study of the kinds of things that exist.In AI,the programs and sentences deal with various kinds of objects,and we study what these kinds are and what their basic properties are.Genetic prog

25、rammingEmotions?Introduction To Artificial intelligenceExamples of AIQ&AWaston-Named after the founder of IBM-Thomas J.Waston-Won$1,000,000 in Game Jeopardy in 2011,defeated 2 human competeters-Source:encyclopaedia,wikipedia,webpages,structural data-100 algorithms,90 servers,3s response timeJeopardy

26、 Game Rules:-Get points for correct answers-Lose points for incorrect onesIntroduction To Artificial intelligenceExamples of AIQ&AALICE-Artificial Linguistic Internet Computer Entity-Chat robot,computer program-Won 2000,2001,2004 Loebner PrizeIntroduction To Artificial intelligenceExamples of AIQ&AW

27、olfram Alpha-Abundant knowledge base-Ability to do scientific calculationIntroduction To Artificial intelligenceExamples of AIQ&ASiri-Started on iPhone 4S,voice control-Context analysis(eg.weather),Google search-wikipedia,Yelp-Wolfram AlphaIntroduction To Artificial intelligenceAi in China Speech in

28、put 863 Natural language processing Pattern recognition Machine learning Machine TranslationMay I help you?How are you?How old are you?Introduction To Artificial intelligenceAi in HIT Robot Game Machine Translation Sentence input Siguo Game Q&A Search Engine Introduction To Artificial intelligenceAi

29、 in HITl Robot GameIntroduction To Artificial intelligenceAi in HITl Q&AIntroduction To Artificial intelligenceAI PrehistoryPhilosophyLogic,methods of reasoning,mind as physical system foundations of learning,language,rationalityMathematicsFormal representation and proof algorithms,computation,(un)d

30、ecidability,(in)tractability,probabilityEconomicsutility,decision theoryNeurosciencephysical substrate for mental activityPsychologyphenomena of perception and motor control,experimental techniquesComputer Engineeringbuilding fast computersControl theorydesign systems that maximize an objective func

31、tion over timeLinguisticsknowledge representation,grammarIntroduction To Artificial intelligenceAI HistoryIntroduction To Artificial intelligenceAI State of the artHave the following been achieved by AI?World-class chess playingPlaying table tennisCross-country drivingSolving mathematical problemsDi

32、scover and prove mathematical theoriesEngage in a meaningful conversationUnderstand spoken languageObserve and understand human emotionsExpress emotionsDeep Blue defeated the reigning world chess champion Garry Kasparov in 1997 Proved a mathematical conjecture(Robbins conjecture)unsolved for decades

33、 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 NASAs on-board autonomous planning program controlled the schedul

34、ing of operations for a spacecraft Proverb solves crossword puzzles better than most humansIntroduction To Artificial intelligenceCourse OverviewGeneral IntroductionGeneral Introduction01-Introduction.01-Introduction.AIMA Ch 1 Course Schedule.Homeworks,exams and grading.Course material,TAs.Why study

35、 AI?What is AI?The Turing test.Rationality.Branches of AI.Research disciplines conn-ected to and at the foundation of AI.Brief history of AI.Challenges for the future.Overview of class syllabus.02-Intelligent Agents.02-Intelligent Agents.AIMA Ch 2 What is an intelligent agent?Examples.Doing the righ

36、t thing(rational action).Performance measure.Autonomy.Environment and agent design.Structure of agents.Agent types.Reflex agents.Reactive agents.Reflex agents with state.Goal-based agents.Utility-based agents.Mobile agents.Information agents.sensorseffectorsAgentIntroduction To Artificial intelligen

37、ceCourse Overview(Cont.)How can we solve complex problems?03-Problem solving and search.03-Problem solving and search.AIMA Ch 3 Example:measuring problem.Types of problems.More example problems.Basic idea behind search algorithms.Complexity.Combinatorial explosion and NP completeness.Polynomial hier

38、archy.04-Uninformed search.04-Uninformed search.AIMA Ch 3 Depth-first.Breadth-first.Uniform-cost.Depth-limited.Iterative deepening.Examples.Properties.05/06-Informed search.05/06-Informed search.AIMA Ch 4 Best-first.A*search.Heuristics.Hill climbing.Problem of local extrema.Simulated annealing.3 l5

39、l9 lUsing these 3 buckets,measure 7 liters of water.Traveling salesperson problemIntroduction To Artificial intelligenceCourse Overview(Cont.)Practical applications of search.Practical applications of search.07/08-Game playing.07/08-Game playing.AIMA Ch 5 The minimax algorithm.Resource limitations.A

40、plha-beta pruning.Elements ofchance and non-deterministic games.tic-tac-toeIntroduction To Artificial intelligenceCourse Overview(Cont.)Building knowledge-based agents:1Building knowledge-based agents:1stst Order Logic Order Logic09-Logical Agents.09-Logical Agents.AIMA Ch 7 Syntax.Semantics.Atomic

41、sentences.Complex sentences.Quantifiers.Examples.FOL knowledge base.Situation calculus.10-First-order logic.10-First-order logic.AIMA Ch 7 Describing actions.Planning.Action sequences.Introduction To Artificial intelligenceCourse Overview(Cont.)Representing and Organizing KnowledgeRepresenting and O

42、rganizing Knowledge11-Building a knowledge base.11-Building a knowledge base.AIMA Ch 8 Knowledge bases.Vocabulary and rules.Ontologies.Organizing knowledge.Kahn&Mcleod,2000An ontologyfor the sportsdomainIntroduction To Artificial intelligenceCourse Overview(Cont.)Reasoning LogicallyReasoning Logical

43、ly12-Inference in first-order logic.12-Inference in first-order logic.AIMA Ch 9 Proofs.Unification.Generalized modus ponens.Forward and backward chaining.Example ofbackward chainingIntroduction To Artificial intelligenceCourse Overview(Cont.)Examples of Logical Reasoning SystemsExamples of Logical R

44、easoning Systems13-Logical reasoning systems.13-Logical reasoning systems.AIMA Ch 10 Indexing,retrieval and unification.The Prolog language.Theorem provers.Frame systems and semantic networks.Semantic networkused in an insightgenerator(Dukeuniversity)Introduction To Artificial intelligenceCourse Ove

45、rview(Cont.)Systems that can Plan Future BehaviorSystems that can Plan Future Behavior14/15-Planning.14/15-Planning.AIMA Ch 11 Definition and goals.Basic representations for planning.Situation space and plan space.Examples.Introduction To Artificial intelligenceCourse Overview(Cont.)Logical Reasonin

46、g in the Presence of UncertaintyLogical Reasoning in the Presence of Uncertainty16/17-Uncertainty.16/17-Uncertainty.AIMA Ch 13/14 Introduction to Uncertainty and Probabilistic ReasoningCenter of largest areaCenter of gravityIntroduction To Artificial intelligenceCourse Overview(Cont.)What challenges

47、 remain?What challenges remain?18-Overview and summary.18-Overview and summary.all of the above What have we learned.Where do we go from here?Introduction To Artificial intelligenceHOMEWORKLearn Python programming language by yourselves.Collect related conferences and journals on AI,each student at least gather 4 kind of conferences or journals,and list their scope.Select 3 from 13 exercises of chapter 1.