Artificial Intelligence Introduction to Artificial Intelligence Dr. Shahriar Bijani Shahed University Spring 2017

Outline Course overview What is AI? A brief history Introduction to AI Course overview What is AI? A brief history Predictions and Reality Shahed University, Spring 2017

Course overview Introduction and Agents (chapters 1,2) Introduction to AI Introduction and Agents (chapters 1,2) Search (chapters 3,4,5,6) Logic (chapters 7,8,9) Knowledge Representation (chapter 10) Planning (chapters 11,12) Uncertainty (chapters 13,14) Learning (chapters 18,20) Natural Language Processing (chapter 22,23) Other Topics (Neural Nets, ….) Shahed University, Spring 2017

Found on the Web … Intelligent behavior Computer Humans Introduction to AI AI is the reproduction of the methods of human reasoning or perception Using computational models to simulate intelligent (human) behavior and processes AI is the study of mental abilities through the use computational methods Intelligent behavior Humans Computer Shahed University, Spring 2017

What is AI? Introduction to AI Discipline that systematizes and automates intellectual tasks to create machines that: Act like humans Act rationally Think like humans Think rationally Shahed University, Spring 2017

Act Like Humans Introduction to AI The goal of AI is to create computer systems that perform functions that are assumed to require intelligence when done by humans  Methodology: Take a task at which people are better, e.g.: Prove a theorem Play chess Plan a surgical operation Diagnose a disease Navigate in a building and make a computer do it Shahed University, Spring 2017

Act Like Humans : Turing Test Introduction to AI Alan Turing (1950) "Computing machinery and intelligence": "Can machines think?"  "Can machines behave intelligently?" Operational test for intelligent behavior: the simulation game The computer is asked questions by a human interviewer. It passes the test if the interviewer or cannot tell whether the responses come from a person Shahed University, Spring 2017

Act Like Humans : Turing Test Introduction to AI Required capabilities: natural language processing, knowledge representation, automated reasoning, learning No physical interaction total Turing Test, needs computer vision & robotics Shahed University, Spring 2017 What does it say about the interrogator’s own intelligence? Chinese Room (J. Searle)

What is AI? Introduction to AI Discipline that systematizes and automates intellectual tasks to create machines that: Act like humans Act rationally Think like humans Think rationally Shahed University, Spring 2017

Thinking humanly: cognitive modeling Introduction to AI How the computer performs functions does matter Comparison of the traces of the reasoning steps (cognitive science) 1960s "cognitive revolution": information-processing psychology Cognitive science: computer models (from AI) + experiments from Psychology Requires scientific theories of internal activities of the brain, by: 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 But, do we want to duplicate human imperfections? Shahed University, Spring 2017

Discourse on the Method, by Descartes (1598-1650) Introduction to AI If there were machines which bore a resemblance to our bodies and imitated our actions as closely as possible for all practical purposes, we should still have two very certain means of recognizing that they were not real men. The first is that they could never use words, or put together signs, as we do in order to declare our thoughts to others… Secondly, even though some machines might do some things as well as we do them, or perhaps even better, they would inevitably fail in others, which would reveal that they are acting not from understanding, … Shahed University, Spring 2017

Discourse on the Method, by Descartes (1598-1650) Introduction to AI If there were machines which bore a resemblance to our bodies and imitated our actions as closely as possible for all practical purposes, we should still have two very certain means of recognizing that they were not real men. The first is that they could never use words, or put together signs, as we do in order to declare our thoughts to others… Secondly, even though some machines might do some things as well as we do them, or perhaps even better, they would inevitably fail in others, which would reveal that they are acting not from understanding, … Shahed University, Spring 2017

Discourse on the Method, by Descartes (1598-1650) Introduction to AI If there were machines which bore a resemblance to our bodies and imitated our actions as closely as possible for all practical purposes, we should still have two very certain means of recognizing that they were not real men. The first is that they could never use words, or put together signs, as we do in order to declare our thoughts to others… Secondly, even though some machines might do some things as well as we do them, or perhaps even better, they would inevitably fail in others, which would reveal that they are acting not from understanding, … Shahed University, Spring 2017

What is AI? Introduction to AI Discipline that systematizes and automates intellectual tasks to create machines that: Act like humans Act rationally Think like humans Think rationally Shahed University, Spring 2017

Thinking rationally: "laws of thought" Introduction to AI Aristotle: what are correct arguments/thought processes? Logicians developed various forms of logic: notation and rules of derivation for thoughts; By 1965, programs existed that could solve any problem described in logical notation. Problems: It is not easy to state informal knowledge in the formal terms required by logical notation (particularly when it is less than 100% certain). There is a big difference between being able to solve a problem "in principle" and doing so in practice. Shahed University, Spring 2017

What is AI? Introduction to AI Discipline that systematizes and automates intellectual tasks to create machines that: Act like humans Act rationally Think like humans Think rationally Shahed University, Spring 2017

Acting rationally: rational agent Introduction to AI 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 Shahed University, Spring 2017

Rational agents An agent is an entity that perceives and acts Introduction to AI An agent is an entity that perceives and acts This course is about designing rational agents Abstractly, an agent is a function from percept histories to actions: [f: P*  A] For any given class of environments and tasks, we seek the agent (or class of agents) with the best performance computational limitations make perfect rationality unachievable  design best program for given machine resources Shahed University, Spring 2017 Agent attribute vs. program: operating under autonomous control, perceiving their environment, persisting over a prolonged time period, adapting to change & being capable of taking on another’s goals.

AI prehistory Introduction to AI 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 Shahed University, Spring 2017

A Short history of AI 1940-1950: Early days 1943: McCulloch & Pitts: Boolean circuit model of brain 1950: Turing's “Computing Machinery and Intelligence” 1950—70: Excitement: Look, Ma, no hands! 1950s: Early AI programs, including Samuel's checkers program, Newell & Simon's Logic Theorist, Gelernter's Geometry Engine 1956: Dartmouth meeting: “Artificial Intelligence” adopted 1965: Robinson's complete algorithm for logical reasoning 1970—90: Knowledge-based approaches 1969—79: Early development of knowledge-based systems 1980—88: Expert systems industry booms 1988—93: Expert systems industry collapse: “AI Winter” 1990—: Statistical approaches Reappearance of probability, focus on uncertainty General increase in technical depth Agents and learning systems… “AI Spring”? 2000—: Human-level AI back on the agenda MT was a Million dollar computer with less computation than your phone

Predictions and Reality … (1/3) Introduction to AI In the 60’s, a famous AI professor from MIT said: “At the end of the summer, we will have developed an electronic eye” Up to now, there is still no general computer vision system capable of understanding complex dynamic scenes But computer systems routinely perform road traffic monitoring, facial recognition, medical image analysis, part inspection, motion capture, … Shahed University, Spring 2017

Predictions and Reality … (2/3) Introduction to AI In 1958, Herbert Simon (CMU) predicted that within 10 years a computer would be Chess champion This prediction became true in 1998 AI techniques (search, planning, probabilistic reasoning) are used in many video games Shahed University, Spring 2017

Predictions and Reality … (3/3) Introduction to AI In the 70’s, many believed that computer-controlled robots would soon be everywhere from manufacturing plants to home Shahed University, Spring 2017

Predictions and Reality … (3/3) Introduction to AI In the 70’s, many believed that computer-controlled robots would soon be everywhere from manufacturing plants to home Today, some industries (automobile, electronics) are highly robotized, but home robots are still a thing of the future Shahed University, Spring 2017

Predictions and Reality … (3/3) Introduction to AI In the 70’s, many believed that computer-controlled robots would soon be everywhere from manufacturing plants to home Today, some industries (automobile, electronics) are highly robotized, but home robots are still a thing of the future But robots have rolled (are rolling) on Mars, fly autonomously, Shahed University, Spring 2017

Predictions and Reality … (3/3) Introduction to AI In the 70’s, many believed that computer-controlled robots would soon be everywhere from manufacturing plants to home Today, some industries (automobile, electronics) are highly robotized, but home robots are still a thing of the future But robots have rolled (are rolling) on Mars, fly autonomously, while others perform brain and heart surgery … Shahed University, Spring 2017

Predictions and Reality … (3/3) Introduction to AI In the 70’s, many believed that computer-controlled robots would soon be everywhere from manufacturing plants to home Today, some industries (automobile, electronics) are highly robotized, but home robots are still a thing of the future But robots have rolled (are rolling) on Mars, fly autonomously, while others perform brain and heart surgery … and humanoid robots are available for rent Shahed University, Spring 2017 (http://world.honda.com/news/2001/c011112.html)

Natural Language Speech technologies (e.g. Siri) Automatic speech recognition (ASR) Text-to-speech synthesis (TTS) Dialog systems Language processing technologies Question answering Machine translation Web search Text classification, spam filtering, etc…

Vision (Perception) Object and face recognition Scene segmentation Image classification Demo1: VISION – lec_1_t2_video.flv Images from Erik Sudderth (left), wikipedia (right) Demo2: VISION – lec_1_obj_rec_0.mpg

Robotics Robotics Technologies In this class: Part mech. eng. Part AI Demo 1: ROBOTICS – soccer.avi Demo 4: ROBOTICS – laundry.avi Demo 2: ROBOTICS – soccer2.avi Demo 5: ROBOTICS – petman.avi Demo 3: ROBOTICS – gcar.avi Robotics Part mech. eng. Part AI Reality much harder than simulations! Technologies Vehicles Rescue Soccer! Lots of automation… In this class: We ignore mechanical aspects Methods for planning Methods for control Images from UC Berkeley, Boston Dynamics, RoboCup, Google

Logic Logical systems Methods: Theorem provers NASA fault diagnosis Question answering Methods: Deduction systems Constraint satisfaction Satisfiability solvers (huge advances!) Image from Bart Selman

Game Playing Classic Moment: May, '97: Deep Blue vs. Kasparov First match won against world champion “Intelligent creative” play 200 million board positions per second Humans understood 99.9 of Deep Blue's moves Can do about the same now with a PC cluster Open question: How does human cognition deal with the search space explosion of chess? Or: how can humans compete with computers at all?? 1996: Kasparov Beats Deep Blue “I could feel --- I could smell --- a new kind of intelligence across the table.” 1997: Deep Blue Beats Kasparov “Deep Blue hasn't proven anything.” Huge game-playing advances recently, e.g. in Go! Text from Bart Selman, image from IBM’s Deep Blue pages

Decision Making Applied AI involves many kinds of automation Scheduling, e.g. airline routing, military Route planning, e.g. Google maps Medical diagnosis Web search engines Spam classifiers Automated help desks Fraud detection Product recommendations … Lots more! All applications can be thought of as decision making or useful sub-components of decision making

Designing Rational Agents An agent is an entity that perceives and acts. A rational agent selects actions that maximize its (expected) utility. Characteristics of the percepts, environment, and action space dictate techniques for selecting rational actions This course is about: General AI techniques for a variety of problem types Learning to recognize when and how a new problem can be solved with an existing technique Agent ? Sensors Actuators Environment Percepts Actions

Pac-Man as an Agent Agent Environment Sensors ? Actuators L1D2 = python demos.py Select Lecture 1  select demo 2 Percepts ? Actions Pac-Man is a registered trademark of Namco-Bandai Games, used here for educational purposes Demo1: pacman-l1.mp4 or L1D2