8/16/2005 COMPSCI 111 S2C - Lecture 14 1

Artificial Intelligence

An Introduction

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What is intelligence?What is intelligence?

Formal Definitions are difficult

• The ability to think?• The ability to understand?• The ability to act in an intelligent manner?• Who really cares?

What is your own definition of intelligence?

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Internal StructureInternal Structure

Understanding the means by which a decision is made• Does it become "unintelligent" merely because we understand

it?• Can we define intelligence without knowing the source of our

own?Decision Trees / Rule Learners

• Playing Chess• ELIZA• Credit risk

Connectionism• Neural Networks• Self-learning

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Behaviourist / Functionalist Behaviourist / Functionalist

Intelligence is determined by behaviour

Turing Test for Artificial Intelligence (AI)• If the responses from a machine cannot be distinguished from

those of a person, then it is intelligent.• Two rooms, one contains computer, other contains person• Communication via terminal• Subjects guess which room they are connected to• How long do they get?

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Artificial IntelligenceArtificial Intelligence

Already here. Limited, but improving.

We will look at some of the aspects of AI that relate to the creation of a paranoid android.

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Step I: VisionStep I: Vision

Driving, the simplest task• ALVINN in 1997• Drove a car on a motorway• Just controlled steering• Worked by recognising the colour of the

road• 30 x 32 resolution

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Step I: VisionStep I: Vision

Reading handwriting, harder than driving• Offline recognition reads from an image e.g. scanned page• Online recognition sees the motion of a pen• Also called OCR (Optical Character Recognition)• Online is easier as it has

more information to use

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Step I: VisionStep I: Vision

Finding faces, harder than reading• Attempts to find edges of objects• Uses information like “faces come underneath dark blobs”• For humans this can be achieved almost at birth• Not at all reliable in computers

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Step II: SpeakingStep II: Speaking

Synthesizing Speech• 1939, first electronic synthesis• 1951, synthesis using rules • 1980s, speak-and spell the first

mass-produced synthesis• State-of-the-art synthesis by rule

used by Stephen Hawkings• 1990s, synthesis by concatenation• 2005, best synthesis so far

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Step II: SpeakingStep II: Speaking

Natural language understanding• Linguistics (sentence trees, syntax, grammar)• Using storyboards/ scripts for context

Examples• Intelligent database query• Text-based adventure games• Self-help web sites

Natural Language Generation• ELIZA• Loebner Prize (beating the Turing Test).

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Step II: SpeakingStep II: Speaking

Eliza• Created in 1966 by • Uses just a few simple rules• Emulates a psychiatrist• Had to be taken down after people started relying on it for

therapy• Some psychiatrists would not believe that it could not

understand anything

Simple online versions:http://www.manifestation.com/neurotoys/eliza.php3http://www-ai.ijs.si/eliza/eliza.html

http://www.manifestation.com/neurotoys/eliza.php3http://www-ai.ijs.si/eliza/eliza.html

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Loebner Prize 2003 WinnerLoebner Prize 2003 Winner

JUDGE: i think i would like to talk about the weather today. what is it like with you?JABBERWOCK: Much the same as it would be for you. JUDGE: which is what?JABBERWOCK: That's a good question - but perhaps a little bit too short in wordsJUDGE: what is the weather like with you? Is it sunny or raining?JABBERWOCK: Cool, at least here in my roomJUDGE: does that then mean it is hot outside?JABBERWOCK: The weather in here is dry and well tempered

JUDGE: that's nice. have you ever been to Australia?JABBERWOCK: Thank youJUDGE: you seem as though you are half asleep! what do you thinkabout the rugby wolrd cup at the moment? who do you think will win?JABBERWOCK: How would I know who will win?JUDGE: well maybe you have started watching the games? what aboutthe match today. I think south Africa will win, and you?JABBERWOCK: Never mind, it's not important

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Step III: MovingStep III: Moving

Autonomous Motion• Engineering: making moving parts and

controllers• AI: Learning how to use controllers to move• AI: Planning paths through maps / visible

world

Shigeo Hirose

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Step III: MovingStep III: Moving

Learning to Walk• It is very difficult for two-legged creatures to stand• Walking and remaining stable is even harder• Many researchers use Genetic Algorithms to find a set of

walking actions that are most stable / fast• Honda makes some of the most

advanced walkers to date

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Step III: MovingStep III: Moving

Playing Soccer• The Robocup competition is the soccer world cup for robots• Held annually• Goal is to beat the soccer world champion team by 2050

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Step IV: ThinkingStep IV: Thinking

Playing ChessDeep Blue won the world chess championship from Kasparov in 1997 – 31/2games to 21/2.

Artificial IntelligenceWhat is intelligence?Internal StructureBehaviourist / FunctionalistArtificial IntelligenceStep I: VisionStep I: VisionStep I: VisionStep II: SpeakingStep II: SpeakingStep II: SpeakingLoebner Prize 2003 WinnerStep III: MovingStep III: MovingStep III: MovingStep IV: Thinking