What is AI?cse.hcmut.edu.vn/~tru/KB-SYSTEMS/intro.pdf · Microsoft PowerPoint - intro.ppt Author:...
Transcript of What is AI?cse.hcmut.edu.vn/~tru/KB-SYSTEMS/intro.pdf · Microsoft PowerPoint - intro.ppt Author:...
Cao Hoang Tru
CSE Faculty - HCMUT
1
19 October 2009
What is AI?
Acting rationallyActing humanly
Thinking rationallyThinking humanly
Cao Hoang Tru
CSE Faculty - HCMUT
2
19 October 2009
Acting Humanly: The Turing Test
• Alan Turing (1912-1954)
• “Computing Machinery and Intelligence” (1950)
Human Interrogator
Human
AI System
Imitation Game
Cao Hoang Tru
CSE Faculty - HCMUT
3
19 October 2009
Acting Humanly: The Turing Test
• 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 infollowing 50 years.
• Suggested major components of AI: knowledge, reasoning, language, understanding, learning.
Cao Hoang Tru
CSE Faculty - HCMUT
4
19 October 2009
Thinking Humanly: Cognitive Modelling
• Not content to have a program correctly solving a problem.
More concerned with comparing its reasoning steps to traces of human solving the same problem.
• Requires testable theories of the workings of the human mind: cognitive science.
Cao Hoang Tru
CSE Faculty - HCMUT
5
19 October 2009
Thinking Rationally: Laws of Thought
• Aristotle was one of the first to attempt to codify “right thinking”, i.e., irrefutable reasoning processes.
• Formal logic provides a precise notation and rules for representing and reasoning with all kinds of things in the world.
• Obstacles:− Informal knowledge representation.
− Computational complexity and resources.
Cao Hoang Tru
CSE Faculty - HCMUT
6
19 October 2009
Acting Rationally
• Acting so as to achieve one’s goals, given one’s beliefs.
• Does not necessarily involve thinking.
• Advantages:− More general than the “laws of thought” approach.
− More amenable to scientific development than
human-based approaches.
Cao Hoang Tru
CSE Faculty - HCMUT
7
19 October 2009
AI = Algorithms + Intelligence
Cao Hoang Tru
CSE Faculty - HCMUT
8
19 October 2009
AI = Algorithms + Intelligence
How to
algorithmize
solutions to
the problems
that human
can solve?
Cao Hoang Tru
CSE Faculty - HCMUT
9
19 October 2009
AI = Algorithms + Intelligence
How to
algorithmize
solutions to
the problems
that human
can solve?
Problem
solving as
searching
Cao Hoang Tru
CSE Faculty - HCMUT
10
19 October 2009
What is Knowledge Engineering?
Stuart Russell:
"The process of building a knowledge base"
Cao Hoang Tru
CSE Faculty - HCMUT
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19 October 2009
What is Knowledge Engineering?
John Sowa:
"The application of logic and ontology to the task of building computable models of some domain for some purpose"
(ontology = the study of existence; "a catalog of types of things that are assumed to exist in a domain of interest")
Cao Hoang Tru
CSE Faculty - HCMUT
12
19 October 2009
What is Knowledge Engineering?
A knowledge engineer:
• Investigates a particular domain
• Determines what concepts are important
• Creates a formal representation of the objects and relations
Cao Hoang Tru
CSE Faculty - HCMUT
13
19 October 2009
What is Knowledge Engineering?
Building a knowledge base:
1. Decide what to talk about
2. Decide on a vocabulary of predicates, functions, and constants
3. Encode general knowledge about the domain
4. Encode a description of the specific problem instance
5. Pose queries to the inference procedure and get answers
Cao Hoang Tru
CSE Faculty - HCMUT
14
19 October 2009
Principles of Knowledge Representation
Knowledge Representation is:
1. A surrogate
2. A set of ontological commitments
3. A fragmentary theory of intelligent reasoning
4. A medium for efficient computation
5. A medium of human expressions
Davis, R. & Schrobe, H. & Szolovits, P. (1993), What is a Knowledge Representation?. AI Magazine (14) 17-33.
Cao Hoang Tru
CSE Faculty - HCMUT
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19 October 2009
Homework
Reading:
• Turing, A. (1950), Computing Machinery and Intelligence. Mind (236) 433-460.
• Davis, R. & Schrobe, H. & Szolovits, P. (1993), What is a Knowledge Representation?. AI Magazine (14) 17-33.