Artificial Intelligence&

Expert Systems

Lecture 1

Jayantha AmararachchiSenior Lecturer (Higher Grade) /

Coordinator-Malabe Campus

What will cover today?

• Course overview

• What are Intelligent Systems?

• A brief history

• Turing Test

• Intelligent agents

What is “Artificial Intelligence”?

• Since ancient days, man has been building machines by looking at the physical features/characteristics of creatures (animals, birds etc) in nature. For example the aero plane was invented by studying how a bird flies and the boat was constructed by studying how fish float in the water.

• After achieving success in above examples, the same approach was continued and man started to look at how other creatures ‘behave’. That is how man started to build machines influenced by the ‘intelligence’ of creatures in nature!

What is Artificial Intelligence? …

Q. What is intelligence?

• A1. 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.

• A2. According to the environmental changes,that provides most suitable answer/actionquickly

What is Artificial Intelligence? …

• There are no clear agreements on the definition of AI

Q. What is artificial intelligence?

A1. It is the science and engineering of making intelligent machines, especially intelligent computer programs.

A2. AI is the study of how to make computers do things better which at the moment people do.

What is Artificial Intelligence? …

A3.AI is a collection of hard problems which can be solved by humans and other living things, but for which we don’t have good algorithms.e. g., – understanding spoken natural language,– medical diagnosis, – circuit design, – learning, – self-adaptation,– reasoning, – chess playing, – proving math theories, etc.

Introduction to AI

Big questions

•Can machines think?

•If so, how?

•If not, why?

•What does this say about human beings?

Introduction to AI …

Applications (AI agents)

• Chess

• Taxi Driver – ALVINN (Automated Land Vehicle In Neural Network)

• Medical Diagnosis

• Interactive tutor

• Auto Pilot

• Robot – Emergency

• Home appliances

What’s easy and what’s hard?

• It’s easier to mechanize many of the high level cognitive tasks associate with “intelligence” in people

– e. g., proving theorems, playing chess, some aspect of medical diagnosis, etc.

• It’s very hard to mechanize tasks that animals can do easily– walking around without running into things– catching prey and avoiding predators– interpreting complex sensory information (visual, hearing,

…)– modeling the internal states of other animals from their

behavior– working as a team (ants, bees)

Foundations of AI

ComputerScience &

Engineering

AI

Mathematics

CognitiveScience

Philosophy

Psychology Linguistics

BiologyEconomics

History of AI

• AI has roots in a number of scientific disciplines– computer science and engineering (hardware and

software)– philosophy (rules of reasoning)– mathematics (logics, algorithms, optimization)– cognitive science and psychology (modeling high level

human/animal thinking)– neural science (model low level human/animal brain

activity)– linguistics

• The birth of AI (1943 – 1956)– Allen Turing: Turing machine and Turing test (1950)– Claude Shannon: information theory; possibility of chess

playing computers

History of AI …

• Early enthusiasm (1952 – 1969)– Marvin Minsky (first neural network machine);

Alan Newell and Herbert Simon (GPS);– Emphasize on intelligent general problem solving

GPS;Lisp (AI programming language);Resolution by John Robinson (basis for automatic theorem proving);heuristic search (A*, AO*, game tree search)

• Emphasis on knowledge (1966 – 1974)– domain specific knowledge is the key to overcome existing

difficulties– knowledge representation (KR) paradigms– declarative vs. procedural representation

History of AI …

• Knowledge-based systems (1969 – 1999)– DENDRAL: the first knowledge intensive system

(determining 3D structures of complex chemical compounds)

– MYCIN: first rule-based expert system (containing 450 rules for diagnosing blood infectious diseases)EMYCIN: an ES shell

• AI became an industry (1980 – 1989)– wide applications in various domains– commercially available tools

History of AI …

• Current trends (1990 – present)

– more realistic goals

– more practical (application oriented)

Turing Test

• Three rooms contain a person, a computer, and an interrogator.

• The interrogator can communicate with the other two by teleprinter.

• The interrogator tries to determine which is the person and which is the machine.

• The machine tries to fool the interrogator into believing that it is the person.

• If the machine succeeds, then we conclude that the

machine can think.

Acting Humanly

• Turing test (1950)

Turing test (‘50)

Turing Test …

Turing test problems & conclusions

Predicted that by 2006 a machine might have a 40% chance of fooling a lay person for 5 min

Eliza

• ELIZA: A program that simulated a psychotherapist interacting with a patient and successfully passed the Turing Test.

• Coded at MIT during 1964-1966 by Joel Weizenbaum.

Eliza • E: I am the psychotherapist. Please, describe your problems. Each time you are finished talking, type RET twice.

• P: I'm having a hard time with my students• E: Why do you say that?• P: Well, they keep asking me for money• E: Maybe your plans have something to do with this.• P: what plans?• E: Is it because of your life that you say what plans?• P: No, it's because I didn't know what you were talking

about• E: Is it because you didn't know what I was talking

about that you came to me?• P: no, it's because i wanted to see if you could pass the

turing test• E: Does it bother you that you wanted to see if I could

really pass the turing test?• P: …..• E: How do you reconcile problems at school?• P: This is a waste of time. Good bye• E: My secretary will send you a bill.

• E: I am the psychotherapist. Please, describe your problems. Each time you are finished talking, type RET twice.

• P: I'm having a hard time with my students• E: Why do you say that?• P: Well, they keep asking me for money• E: Maybe your plans have something to do with this.• P: what plans?• E: Is it because of your life that you say what plans?• P: No, it's because I didn't know what you were talking

about• E: Is it because you didn't know what I was talking

about that you came to me?• P: no, it's because i wanted to see if you could pass the

turing test• E: Does it bother you that you wanted to see if I could

really pass the turing test?• P: …..• E: How do you reconcile problems at school?• P: This is a waste of time. Good bye• E: My secretary will send you a bill.

• This is a transcript of a conversation with an Eliza-like program found in Emacs

• Try typing

Meta-x doctor

in your favorite Emacs.

The Loebner Contest

• A modern version of the Turing Test, held annually, with a $100,000 cash prize.

• http://www.loebner.net/Prizef/loebner-prize.html• Restricted topic (removed in 1995) and limited

time. • 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…)

What can AI systems do

Here are some example applications

• Computer vision: face recognition from a large set• Robotics: autonomous (mostly) automobile• Natural language processing: simple machine

translation• Expert systems: medical diagnosis in a narrow domain• Spoken language systems: ~1000 word continuous

speech• Learning: text categorization into ~1000 topics• Games: Grand Master level in chess (world

champion), checkers, etc.

What can’t AI systems do yet?

• Understand natural language robustly (e.g., read and understand articles in a newspaper)

• Surf the web• Interpret an arbitrary visual scene• Learn a natural language• Construct plans in dynamic real-time domains• Perform life-long learning