Artificial Intelligence : Introduction Course Instructors: Dr. Mehnaz Adnan Ms. Huma Rizvi Ms. Moona Kanwal Mr. Raza Hassan.

Artificial Intelligence:

Introduction

Course Instructors: Dr. Mehnaz Adnan

Ms. Huma Rizvi

Ms. Moona Kanwal

Mr. Raza Hassan

What is intelligence?

• Intelligence is the computational part of the ability to achieve goals in the world.

• Varying kinds and degrees of intelligence occur in people, many animals and some machines.

What is Artificial Intelligence?

• It is the science and engineering of making intelligent machines, especially intelligent computer programs.

• It is related to the similar task of using computers to understand human intelligence, but AI does not have to confine itself to methods that are biologically observable.

What is AI?

Views of AI fall into four categories:

Thinking humanly Thinking rationally

Acting humanly Acting rationally

The textbook advocates "acting rationally"

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Acting humanly: Turing Test• Turing (1950) "Computing machinery and intelligence":• "Can machines think?" "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

•

IntelligenceIntelligence

• Turing Test: A human communicates with a computer via a teletype. If the human can’t tell he is talking to a computer or another human, it passes.– Natural language processing– knowledge representation– automated reasoning– machine learning

• Add vision and robotics to get the total Turing test.

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

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

Thinking rationally: "laws of thought"

• Aristotle: what are correct arguments/thought processes?1. Not all intelligent behavior is mediated by logical deliberation2. What is the purpose of thinking? What thoughts should I have?

• 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:

Is this machine intelligent or not?''?

• Is intelligence a single thing so that one can ask a yes or no question ``Is this machine intelligent or not?''?

Is this machine intelligent or not?''?

• No. Intelligence involves mechanisms, and AI research has discovered how to make computers carry out some of them and not others.

• If doing a task requires only mechanisms that are well understood today, computer programs can give very impressive performances on these tasks. Such programs should be considered ``somewhat intelligent''.

Isn't AI about simulating human intelligence?

• Sometimes but not always or even usually.

• On the one hand, we can learn something about how to make machines solve problems by observing other people or just by observing our own methods.

Isn't AI about simulating human intelligence?

• On the other hand, most work in AI involves studying the problems the world presents to intelligence rather than studying people or animals.

• AI researchers are free to use methods that are not observed in people or that involve much more computing than people can do.

What about IQ? Do computer programs have IQs?

• No. IQ is based on the rates at which intelligence develops in children.

• It is the ratio of the age at which a child normally makes a certain score to the child's age. The scale is extended to adults in a suitable way.

What about IQ? Do computer programs have IQs?

• IQ correlates well with various measures of success or failure in life, but making computers that can score high on IQ tests would be weakly correlated with their usefulness.

• For example, the ability of a child to repeat back a long sequence of digits correlates well with other intellectual abilities, perhaps because it measures how much information the child can compute with at once. However, ``digit span'' is trivial for even extremely limited computers.

What about other comparisons between human and computer

intelligence? • Arthur R. Jensen [Jen98], a leading researcher

in human intelligence, suggests ``as a heuristic hypothesis''

• that all normal humans have the same intellectual mechanisms and that differences in intelligence are related to ``quantitative biochemical and physiological conditions''. I see them as speed, short term memory, and the ability to form accurate and retrievable long term memories.

• Whether or not Jensen is right about human intelligence, the situation in AI today is the reverse

Does AI aim to put the human mind into the computer?

• Some researchers say they have that objective, but maybe they are using the phrase metaphorically. The human mind has a lot of peculiarities, and I'm not sure anyone is serious about imitating all of them

• Replacing the brain

Does AI aim at human-level intelligence?

• Yes. The ultimate effort is to make computer programs that can solve problems and achieve goals in the world as well as humans. However, many people involved in particular research areas are much less ambitious.

How far is AI from reaching human-level intelligence? When will it

happen? • A few people think that human-level

intelligence can be achieved by writing large numbers of programs of the kind people are now writing and assembling vast knowledge bases of facts in the languages now used for expressing knowledge.

How far is AI from reaching human-level intelligence? When will it

happen? • However, most AI researchers believe that

new fundamental ideas are required, and therefore it cannot be predicted when human level intelligence will be achieved.

• Our best systems have the intelligence of a frog

• Mind you, how many frogs spend all their intelligence controlling a nuclear power plant?

Are computers the right kind of machine to be made intelligent?

• Computers can be programmed to simulate any kind of machine

Are computers fast enough to be intelligent?

• Some people think much faster computers are required as well as new ideas.

• Computers of 30 years ago were fast enough if only we knew how to program them. Of course, quite apart from the ambitions of AI researchers, computers will keep getting faster.

What about parallel machines?

• Machines with many processors are much faster than single processors can be. Parallelism itself presents no advantages, and parallel machines are somewhat awkward to program. When extreme speed is required, it is necessary to face this awkwardness.

What about making a ``child machine'' that could improve by

reading and by learning from experience?

• This idea has been proposed many times, starting in the 1940s. Eventually, it will be made to work.

What about making a ``child machine'' that could improve by

reading and by learning from experience?

• However, AI programs haven't yet reached the level of being able to learn much of what a child learns from physical experience. Nor do present programs understand language well enough to learn much by reading

Philosophical foundation

• Logic,

• methods of reasoning,

• mind as physical system foundations of learning,

• language,

• rationality

Weak and Strong AI Claims

• Weak AI:– Machines can be made to act as if they were

intelligent.

• Strong AI:– Machines that act intelligently have real,

conscious minds.

Weak AI :Can machine act intelligently

• May be :pass turning test• Can machine think?• Answer: ill-defined• Why?

– Consider following– Can machine fly?– Can machine swim?

• The argument from disability– Machine can never do X

• The argument from informality– Human brain is too complex

Strong AI :Can machine really think

• Running sufficient program or knowing the right outputs is not sufficient condition for being a mind

• Chinese Room hypothesis by John Searle

• The Chinese Room

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?

!

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

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

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

Branches of AIBranches of AI

• Learning• Rule-Based Systems• logic• Search• Planning• Ability-Based Areas• Robotics• Agents

Branches of AI

• pattern recognition

• Ontology

• heuristics

• genetic programming

Applications of AI

• game playing

• speech recognition

• understanding natural language

• computer vision

• expert systems

• heuristic classification