0.0 THE QUEST FOR ARTIFICIAL INTELLIGENCE A HISTORY OF IDEAS AND ACHIEVEMENTS Web Version Print version published by Cambridge University Press http://www.cambridge.org/us/0521122937 Nils J. Nilsson Stanford University 1 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. Pleasedonotreproduceorcitethisversion. September13,2009. PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0 For Grace McConnell Abbott, my wife and best friend 2 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. Pleasedonotreproduceorcitethisversion. September13,2009. PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0.0 Contents I Beginnings 17 1 Dreams and Dreamers 19 2 Clues 27 2.1 From Philosophy and Logic . . . . . . . . . . . . . . . . . . . . . 27 2.2 From Life Itself . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.2.1 Neurons and the Brain . . . . . . . . . . . . . . . . . . . . 34 2.2.2 Psychology and Cognitive Science . . . . . . . . . . . . . 37 2.2.3 Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.2.4 Development and Maturation . . . . . . . . . . . . . . . . 45 2.2.5 Bionics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.3 From Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 2.3.1 Automata, Sensing, and Feedback . . . . . . . . . . . . . 46 2.3.2 Statistics and Probability . . . . . . . . . . . . . . . . . . 52 2.3.3 The Computer . . . . . . . . . . . . . . . . . . . . . . . . 53 II Early Explorations: 1950s and 1960s 71 3 Gatherings 73 3.1 Session on Learning Machines . . . . . . . . . . . . . . . . . . . . 73 3.2 The Dartmouth Summer Project . . . . . . . . . . . . . . . . . . 77 3.3 Mechanization of Thought Processes . . . . . . . . . . . . . . . . 81 4 Pattern Recognition 89 3 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0 CONTENTS 4.1 Character Recognition . . . . . . . . . . . . . . . . . . . . . . . . 90 4.2 Neural Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 4.2.1 Perceptrons . . . . . . . . . . . . . . . . . . . . . . . . . . 92 4.2.2 ADALINES and MADALINES . . . . . . . . . . . . . . . 98 4.2.3 The MINOS Systems at SRI . . . . . . . . . . . . . . . . 98 4.3 Statistical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . 102 4.4 Applications of Pattern Recognition to Aerial Reconnaissance . . 105 5 Early Heuristic Programs 113 5.1 The Logic Theorist and Heuristic Search . . . . . . . . . . . . . . 113 5.2 Proving Theorems in Geometry . . . . . . . . . . . . . . . . . . . 118 5.3 The General Problem Solver . . . . . . . . . . . . . . . . . . . . . 121 5.4 Game-Playing Programs . . . . . . . . . . . . . . . . . . . . . . . 123 6 Semantic Representations 131 6.1 Solving Geometric Analogy Problems. . . . . . . . . . . . . . . . 131 6.2 Storing Information and Answering Questions . . . . . . . . . . . 134 6.3 Semantic Networks . . . . . . . . . . . . . . . . . . . . . . . . . . 136 7 Natural Language Processing 141 7.1 Linguistic Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 7.2 Machine Translation . . . . . . . . . . . . . . . . . . . . . . . . . 146 7.3 Question Answering . . . . . . . . . . . . . . . . . . . . . . . . . 150 8 1960s’ Infrastructure 155 8.1 Programming Languages . . . . . . . . . . . . . . . . . . . . . . . 155 8.2 Early AI Laboratories . . . . . . . . . . . . . . . . . . . . . . . . 157 8.3 Research Support . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 8.4 All Dressed Up and Places to Go . . . . . . . . . . . . . . . . . . 163 III Efflorescence: Mid-1960s to Mid-1970s 167 9 Computer Vision 169 9.1 Hints from Biology . . . . . . . . . . . . . . . . . . . . . . . . . . 171 4 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0.0 CONTENTS 9.2 Recognizing Faces . . . . . . . . . . . . . . . . . . . . . . . . . . 172 9.3 Computer Vision of Three-Dimensional Solid Objects . . . . . . 173 9.3.1 An Early Vision System . . . . . . . . . . . . . . . . . . . 173 9.3.2 The “Summer Vision Project” . . . . . . . . . . . . . . . 175 9.3.3 Image Filtering . . . . . . . . . . . . . . . . . . . . . . . . 176 9.3.4 Processing Line Drawings . . . . . . . . . . . . . . . . . . 181 10 “Hand–Eye” Research 189 10.1 At MIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 10.2 At Stanford . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 10.3 In Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 10.4 Edinburgh’s “FREDDY” . . . . . . . . . . . . . . . . . . . . . . . 193 11 Knowledge Representation and Reasoning 199 11.1 Deductions in Symbolic Logic . . . . . . . . . . . . . . . . . . . . 200 11.2 The Situation Calculus . . . . . . . . . . . . . . . . . . . . . . . . 202 11.3 Logic Programming . . . . . . . . . . . . . . . . . . . . . . . . . 203 11.4 Semantic Networks . . . . . . . . . . . . . . . . . . . . . . . . . . 205 11.5 Scripts and Frames . . . . . . . . . . . . . . . . . . . . . . . . . . 207 12 Mobile Robots 213 12.1 Shakey, the SRI Robot . . . . . . . . . . . . . . . . . . . . . . . . 213 12.1.1 A∗: A New Heuristic Search Method . . . . . . . . . . . . 216 12.1.2 Robust Action Execution . . . . . . . . . . . . . . . . . . 221 12.1.3 STRIPS: A New Planning Method . . . . . . . . . . . . . 222 12.1.4 Learning and Executing Plans . . . . . . . . . . . . . . . 224 12.1.5 Shakey’s Vision Routines . . . . . . . . . . . . . . . . . . 224 12.1.6 Some Experiments with Shakey . . . . . . . . . . . . . . . 228 12.1.7 Shakey Runs into Funding Troubles . . . . . . . . . . . . 229 12.2 The Stanford Cart . . . . . . . . . . . . . . . . . . . . . . . . . . 231 13 Progress in Natural Language Processing 237 13.1 Machine Translation . . . . . . . . . . . . . . . . . . . . . . . . . 237 13.2 Understanding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 5 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. Pleasedonotreproduceorcitethisversion. September13,2009. PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0 CONTENTS 13.2.1 SHRDLU . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 13.2.2 LUNAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 13.2.3 Augmented Transition Networks . . . . . . . . . . . . . . 244 13.2.4 GUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 14 Game Playing 251 15 The Dendral Project 255 16 Conferences, Books, and Funding 261 IV Applications and Specializations: 1970s to Early 1980s 265 17 Speech Recognition and Understanding Systems 267 17.1 Speech Processing . . . . . . . . . . . . . . . . . . . . . . . . . . 267 17.2 The Speech Understanding Study Group . . . . . . . . . . . . . . 270 17.3 The DARPA Speech Understanding Research Program . . . . . . 271 17.3.1 Work at BBN . . . . . . . . . . . . . . . . . . . . . . . . . 271 17.3.2 Work at CMU . . . . . . . . . . . . . . . . . . . . . . . . 272 17.3.3 Summary and Impact of the SUR Program . . . . . . . . 280 17.4 Subsequent Work in Speech Recognition . . . . . . . . . . . . . . 281 18 Consulting Systems 285 18.1 The SRI Computer-Based Consultant . . . . . . . . . . . . . . . 285 18.2 Expert Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 18.2.1 MYCIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 18.2.2 PROSPECTOR . . . . . . . . . . . . . . . . . . . . . . . . . 295 18.2.3 Other Expert Systems . . . . . . . . . . . . . . . . . . . . 300 18.2.4 Expert Companies . . . . . . . . . . . . . . . . . . . . . . 303 19 Understanding Queries and Signals 309 19.1 The Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309 19.2 Natural Language Access to Computer Systems . . . . . . . . . . 313 19.2.1 LIFER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 6 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0.0 CONTENTS 19.2.2 CHAT-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 19.2.3 Transportable Natural Language Query Systems . . . . . 318 19.3 HASP/SIAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 20 Progress in Computer Vision 327 20.1 Beyond Line-Finding . . . . . . . . . . . . . . . . . . . . . . . . . 327 20.1.1 Shape from Shading . . . . . . . . . . . . . . . . . . . . . 327 20.1.2 The 21-D Sketch . . . . . . . . . . . . . . . . . . . . . . . 329 2 20.1.3 Intrinsic Images. . . . . . . . . . . . . . . . . . . . . . . . 329 20.2 Finding Objects in Scenes . . . . . . . . . . . . . . . . . . . . . . 333 20.2.1 Reasoning about Scenes . . . . . . . . . . . . . . . . . . . 333 20.2.2 Using Templates and Models . . . . . . . . . . . . . . . . 335 20.3 DARPA’s Image Understanding Program . . . . . . . . . . . . . 338 21 Boomtimes 343 V “New-Generation” Projects 347 22 The Japanese Create a Stir 349 22.1 The Fifth-Generation Computer Systems Project . . . . . . . . . 349 22.2 Some Impacts of the Japanese Project . . . . . . . . . . . . . . . 354 22.2.1 The Microelectronics and Computer Technology Corpo- ration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 22.2.2 The Alvey Program . . . . . . . . . . . . . . . . . . . . . 355 22.2.3 ESPRIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 23 DARPA’s Strategic Computing Program 359 23.1 The Strategic Computing Plan . . . . . . . . . . . . . . . . . . . 359 23.2 Major Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 23.2.1 The Pilot’s Associate. . . . . . . . . . . . . . . . . . . . . 363 23.2.2 Battle Management Systems . . . . . . . . . . . . . . . . 364 23.2.3 Autonomous Vehicles . . . . . . . . . . . . . . . . . . . . 366 23.3 AI Technology Base . . . . . . . . . . . . . . . . . . . . . . . . . 369 23.3.1 Computer Vision . . . . . . . . . . . . . . . . . . . . . . . 370 7 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0 CONTENTS 23.3.2 Speech Recognition and Natural Language Processing . . 370 23.3.3 Expert Systems . . . . . . . . . . . . . . . . . . . . . . . . 372 23.4 Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 VI Entr’acte 379 24 Speed Bumps 381 24.1 Opinions from Various Onlookers . . . . . . . . . . . . . . . . . . 381 24.1.1 The Mind Is Not a Machine . . . . . . . . . . . . . . . . . 381 24.1.2 The Mind Is Not a Computer . . . . . . . . . . . . . . . . 383 24.1.3 Differences between Brains and Computers . . . . . . . . 392 24.1.4 But Should We? . . . . . . . . . . . . . . . . . . . . . . . 393 24.1.5 Other Opinions . . . . . . . . . . . . . . . . . . . . . . . . 398 24.2 Problems of Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . 399 24.2.1 The Combinatorial Explosion . . . . . . . . . . . . . . . . 399 24.2.2 Complexity Theory . . . . . . . . . . . . . . . . . . . . . . 401 24.2.3 A Sober Assessment . . . . . . . . . . . . . . . . . . . . . 402 24.3 Acknowledged Shortcomings . . . . . . . . . . . . . . . . . . . . . 406 24.4 The “AI Winter” . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 25 Controversies and Alternative Paradigms 413 25.1 About Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 25.2 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414 25.3 “Kludginess” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 25.4 About Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 25.4.1 Behavior-Based Robots . . . . . . . . . . . . . . . . . . . 417 25.4.2 Teleo-Reactive Programs . . . . . . . . . . . . . . . . . . 419 25.5 Brain-Style Computation . . . . . . . . . . . . . . . . . . . . . . 423 25.5.1 Neural Networks . . . . . . . . . . . . . . . . . . . . . . . 423 25.5.2 Dynamical Processes . . . . . . . . . . . . . . . . . . . . . 424 25.6 Simulating Evolution . . . . . . . . . . . . . . . . . . . . . . . . . 425 25.7 Scaling Back AI’s Goals . . . . . . . . . . . . . . . . . . . . . . . 429 8 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0.0 CONTENTS VII The Growing Armamentarium: From the 1980s Onward 433 26 Reasoning and Representation 435 26.1 Nonmonotonic or Defeasible Reasoning . . . . . . . . . . . . . . . 435 26.2 Qualitative Reasoning . . . . . . . . . . . . . . . . . . . . . . . . 439 26.3 Semantic Networks . . . . . . . . . . . . . . . . . . . . . . . . . . 441 26.3.1 Description Logics . . . . . . . . . . . . . . . . . . . . . . 441 26.3.2 WordNet . . . . . . . . . . . . . . . . . . . . . . . . . . . 444 26.3.3 Cyc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446 27 Other Approaches to Reasoning and Representation 455 27.1 Solving Constraint Satisfaction Problems . . . . . . . . . . . . . 455 27.2 Solving Problems Using Propositional Logic . . . . . . . . . . . . 460 27.2.1 Systematic Methods . . . . . . . . . . . . . . . . . . . . . 461 27.2.2 Local Search Methods . . . . . . . . . . . . . . . . . . . . 463 27.2.3 Applications of SAT Solvers . . . . . . . . . . . . . . . . . 466 27.3 Representing Text as Vectors . . . . . . . . . . . . . . . . . . . . 466 27.4 Latent Semantic Analysis . . . . . . . . . . . . . . . . . . . . . . 469 28 Bayesian Networks 475 28.1 Representing Probabilities in Networks . . . . . . . . . . . . . . . 475 28.2 Automatic Construction of Bayesian Networks . . . . . . . . . . 482 28.3 Probabilistic Relational Models . . . . . . . . . . . . . . . . . . . 486 28.4 Temporal Bayesian Networks . . . . . . . . . . . . . . . . . . . . 488 29 Machine Learning 495 29.1 Memory-Based Learning . . . . . . . . . . . . . . . . . . . . . . . 496 29.2 Case-Based Reasoning . . . . . . . . . . . . . . . . . . . . . . . . 498 29.3 Decision Trees. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 29.3.1 Data Mining and Decision Trees . . . . . . . . . . . . . . 500 29.3.2 Constructing Decision Trees . . . . . . . . . . . . . . . . . 502 29.4 Neural Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . 507 29.4.1 The Backprop Algorithm . . . . . . . . . . . . . . . . . . 508 9 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. 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PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937 0 CONTENTS 29.4.2 NETtalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509 29.4.3 ALVINN. . . . . . . . . . . . . . . . . . . . . . . . . . . . 510 29.5 Unsupervised Learning . . . . . . . . . . . . . . . . . . . . . . . . 513 29.6 Reinforcement Learning . . . . . . . . . . . . . . . . . . . . . . . 515 29.6.1 Learning Optimal Policies . . . . . . . . . . . . . . . . . . 515 29.6.2 TD-GAMMON . . . . . . . . . . . . . . . . . . . . . . . . . 522 29.6.3 Other Applications . . . . . . . . . . . . . . . . . . . . . . 523 29.7 Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524 30 Natural Languages and Natural Scenes 533 30.1 Natural Language Processing . . . . . . . . . . . . . . . . . . . . 533 30.1.1 Grammars and Parsing Algorithms . . . . . . . . . . . . . 534 30.1.2 Statistical NLP . . . . . . . . . . . . . . . . . . . . . . . . 535 30.2 Computer Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . 539 30.2.1 Recovering Surface and Depth Information . . . . . . . . 541 30.2.2 Tracking Moving Objects . . . . . . . . . . . . . . . . . . 544 30.2.3 Hierarchical Models . . . . . . . . . . . . . . . . . . . . . 548 30.2.4 Image Grammars . . . . . . . . . . . . . . . . . . . . . . . 555 31 Intelligent System Architectures 561 31.1 Computational Architectures . . . . . . . . . . . . . . . . . . . . 563 31.1.1 Three-Layer Architectures . . . . . . . . . . . . . . . . . . 563 31.1.2 Multilayered Architectures . . . . . . . . . . . . . . . . . 563 31.1.3 The BDI Architecture . . . . . . . . . . . . . . . . . . . . 569 31.1.4 Architectures for Groups of Agents . . . . . . . . . . . . . 572 31.2 Cognitive Architectures . . . . . . . . . . . . . . . . . . . . . . . 576 31.2.1 Production Systems . . . . . . . . . . . . . . . . . . . . . 576 31.2.2 ACT-R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578 31.2.3 SOAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581 VIII Modern AI: Today and Tomorrow 589 32 Extraordinary Achievements 591 10 Copyright(cid:13)c2010NilsJ.Nilsson http://ai.stanford.edu/∼nilsson/ Allrightsreserved. Pleasedonotreproduceorcitethisversion. September13,2009. PrintversionpublishedbyCambridgeUniversityPress. http://www.cambridge.org/us/0521122937
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