Artificial Intelligence: Definition Lecture Notes Artificial Intelligence: Definition Dae-Won Kim School of Computer Science & Engineering Chung-Ang University
What are AI Systems?
Deep Blue defeated the world chess champion Garry Kasparov in 1997
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
Proverb solves crossword puzzles better than most humans
Sony’s AIBO and Honda’s ASIMO
Web Agents & Search engines: Google, Yahoo
Recognition Systems: Speech, Character, Face, Iris, Fingerprint
Virtual Reality and Computer Vision
Potted History of AI 1943 McCulloch & Pitts: Boolean circuit model of brain 1950 Turing’s “Computing Machinery and Intelligence” 1950s Early AI programs 1956 Dartmouth meeting: “Artificial Intelligence” adopted 1965 Robinson’s complete algorithm for logical reasoning 1966 AI discovers computational complexity Neural network research almost disappears 1969 Early development of knowledge-based systems 1980 Expert systems industry booms 1988 Expert systems industry busts: “AI Winter” 1985 Neural networks return to popularity 1988 Resurgence of probability, soft computing. 1995 Agents, agents, everywhere … with Data Mining 2000 Bioinformatics powered by Human Genome Project 2003 Human-level AI back on the agenda: challengeable
Some researchers consider AI as one of the four concepts:
1. Systems that think like humans
2. Systems that think rationally
3. Systems that act like humans
4. Systems that act rationally
AI: Acting humanly
Turing (1950): “The Turing Test”
Can machines think?
Can machines behave intelligently?
Turing test is The ‘Imitation’ Game
In 2014, something has happened. Predicted that by 2000, a machine might have 30% chance of fooling a lay person for 5 min. In 2014, something has happened. http://www.bbc.com/news/technology-27762088
Problem: Turing test is NOT …
Turing test is NOT reproducible and amendable to mathematical analysis
AI: Thinking humanly
It requires scientific theories of internal activities of the brain
What level of abstraction? “Knowledge” or “circuits”.
How to validate? Requires something
Requires: Cognitive Science Predicting and testing behavior of human subjects (top-down)
Requires: Cognitive Neuroscience Direct identification from neurological data (bottom up)
Problem: Thinking humanly is NOT
Both are distinct from AI in CS The available theories do not explain anything resembling human-level general intelligence.
AI: Thinking rationally
Laws of Thought: “What are correct arguments/thought processes?” by Aristotle
Several Greek schools developed various forms of logic:
Logic: notation and rules of derivation of thoughts
Problem: Thinking rationally is NOT
Not all intelligent behavior is mediated by logical deliberation
AI: Acting rationally
Rational behavior: doing the RIGHT thing
The RIGHT thing: that which is expected to maximize goal achievement, given the available information
An agent is an entity that perceives and acts.
Agents include humans, robots, programs, systems, etc.
This course is about designing rational agents/SWs/programs/platforms.
Abstractly, an agent is a function from percept histories to actions f : P A
The agent program runs on the physical architecture to produce f
For any given class of tasks and environments, we seek the agent with the best performance.
Problem: Acting rationally is NOT
Computational limitations make perfect rationality unachievable e.g.) NP-hard problems
Design best program for given machine resources
Which of the following can be done at present? Play a decent game of table tennis Drive safely along a curving mountain road Drive safely along Telegraph Avenue Buy a week’s worth of groceries on the web Discover and prove a new mathematical theorem Design and execute a research program in biology Write an intentionally funny story Give legal advice in a specialized area of law Translate spoken English into Swedish in real time Perform a complex surgical operation Converse successfully with another person for an hour
School of Computer Science & Engineering Artificial Intelligence Intelligent Agents Dae-Won Kim School of Computer Science & Engineering Chung-Ang University
The agent function maps from percept histories to actions: f : P A
A Vacuum-cleaner Agent
Perception: ? Actions: ?
Perception: location and contents [A, Dirty]. Actions: Left, Right, Suck, NoOp
Problem: A Vacuum-cleaner Agent
What is the right function?
Let’s talk about Rationality
A rational agent chooses whichever action maximizes the expected value of the performance measure given the percept sequence to date
What is performance measure?
1 point per square cleaned up in time T?
Minus 1 point per move?
Penalize for > k dirty squares?
Therefore, we can say
Rational omniscient
Perception may not supply all information
Rational clairvoyant
Action outcomes may not be as expected
Hence, rational perfect
To design a rational agent, we must specify the task environment (PEAS)
Performance measure Environment Actuators Sensors
Consider the task of designing the Google driverless car
P: safety, comfort, profits, legality E: streets, freeways, traffic, weather A: streering, accelerator, break S: velocity, GPS, engine sensors
Consider the task of designing an automated internet shopping agent: e.g., Recommender system
P: price, quality, efficiency E: WWW sites, vendors A: display to user, follow URL S: HTML, XML pages
Agent Types: four basic types in order of increasing generality
Simple reflex agents Reflex agents with state Goal-based agents Utility-based agents
Simple Reflex Agents 1. If a student sleeping, then assign a penalty. 2. When applied to Vehicle driving?
Reflex Agents with State 1. Check the student’s academic history, habits.. 2. Vehicle driving ?
Goal-based Agents 1. Consider goals: be a good professor in AI class 2. Vehicle driving ?
Utility-based Agents 1. Utility: performance measure 2. How good grade I will assign / Prof. I could be.
Learning Agents All agents will be turning into learning agents.