Introduction to Artificial Intelligence

Definitions

There are hundreds of definitions of artificial intelligence. Most contain a bias as to whether the writer of the definition sees AI as dealing with thinking versus acting, and whether he or she sees it as trying to model humans or capturing intelligence (rationality) abstractly.

	Humanly	Rationally
Thinking	Thinking humanly — cognitive modeling. Systems should solve problems the same way humans do.	Thinking rationally — the use of logic. Need to worry about modeling uncertainty and dealing with complexity.
Acting	Acting humanly — the Turing Test approach.	Acting rationally — the study of rational agents: agents that maximize the expected value of their performance measure given what they currently know.

Some definitions

The study of agents that receive percepts from the environment and perform actions. (Russell and Norvig)
The science and engineering of making intelligent machines, especially intelligent computer programs (John McCarthy)
The ability of a digital computer or computer-controlled robot to perform tasks commonly associated with intelligent beings (Encyclopædia Britannica)
The study of ideas to bring into being machines that respond to stimulation consistent with traditional responses from humans, given the human capacity for contemplation, judgment and intention (Latanya Sweeney)
The scientific understanding of the mechanisms underlying thought and intelligent behavior and their embodiment in machines (American Association for Artificial Intelligence)
A branch of science which deals with helping machines find solutions to complex problems in a more human-like fashion (AI depot)
A field of computer science that seeks to understand and implement computer based technology that can simulate characteristics of human intelligence and human sensory capabilities (Mick Dobra)

Eight more can be found here. And a handful more here.

Concerns

AI has both scientific (nature of intelligence) and an engineering (design and production of intelligent agents) aspects.

AI Science: The Nature of Intelligence

AI researchers study the nature of intelligence. They don't (necessarily) try to build androids because

It was the study of the principles of aerodynamics, not the attempt to make mechanical birds, that enabled human flight.
We already know how to make new humans anyway (sorry, no hyperlinks here).

Intelligence involves sensing, thinking, and acting

SENSING	THINKING	ACTING
Translation of sensory inputs (percepts) into a conceptual representation Computer Vision Speech Recognition Language Understanding	Manipulation of the conceptual representation Knowledge Representation Problem Solving/Planning Learning (making improvements based on the results of past actions)	Translation of intent into (physical) actions (reflexive or deliberative) Robotics Speech and Language Synthesis

AI Engineering: Intelligent Agents

An agent is something that senses and acts.

Agents can be organic, robotic, or pure software.
Not all agents are intelligent.
Intelligent agents are agents that can operate autonomously in complex environments.
AI is concerned with the production of intelligent agents.

Areas of Study

In no particular order, nor with any thought of completeness, here are a few:

Vision
Speech recognition
Robotics
Problem Solving
Searching a Solution Space
Planning
Learning
Natural Language Processing
Natural Language Understanding
Knowledge Representation
Automated Reasoning
Inference, both in monotonic and non-monotonic logics
Common Sense Reasoning
Uncertainty and Probability
Genetic Programming
Artificial Life
Ontology
Epistemology
Expert Systems
Solving problems with no tractable deterministic algorithmic solutions

Influences

From Section 1.2 of Russell and Norvig:

Philosophy — considers the nature of knowledge, thought, and learning
Mathematics — considers the notions of formal logic, algorithms, computational complexity, and probability
Economics — studies how agents attempt to maximize their own well-being, even when given uncertain information and in the presence of allies and adversaries
Neuroscience — studies the workings of the human brain
Psychology — studies how humans and animals think and act (process information)
Linguistics — deals with language in a formal-enough way that it can be processed by machine
Computer Engineering — looks to increase the efficiency of computing devices
Control Theory and Cybernetics — consider how autonomous machines can operate

Brief History

Highlights

1940's — Interest in neurons, neural networks and their relationship to mathematics and learning
1950 — Turing's paper
1956 — Dartmouth conference
1950's and 1960's — enthusiasm and optimism; big promises
Late 1960's and 1970's — Realization that further progress was really hard; disillusionment
1980's — Expert Systems, neural networks, etc.; AI now a little different; quiet successes
1990's to present — Intelligent agents

Applications

Today AI is in

Game playing (Chess, Go, Risk, Bridge, Checkers, ...)
Systems that read handwritten addresses to speed mail sorting
Search Engines
Theorem Proving
Cars (stability traction, braking assist, even driving...)
Aircraft autolanders
Medical Diagnosis
Expert Systems
Information Retrieval Systems
Story writers, poetry writers, ...
Music Composition
Annoying auto-correct agents in word processors
Crisis management
Space Exploration
Finance
Retailing
Manufacturing
Inventory Control
Pharmaceutical Research
Genetic Research
(Micro)Surgery
Insurance Underwriting
Environmental Monitoring
Protein Structure Determination
Scheduling Systems
Assisted Living Support
Dispensing Legal Advice
Essay Evaluation
Detection of Steganography
Cryptanalysis
Translation
Military Planning
Surveillance
Traffic Control