Propositional logic
J Propositional logic is declarative
J Propositional logic is compositional:
First-Order Logic
q
meaning of B1,1 P1,2 is derived from meaning of B1,1 and of P1,2
J Meaning in propo
Tree search: Reminder
Informed Search
Russell and Norvig 3rd ed., chap. 3.5-3.6
function TREE-SEARCH(problem) return a solution or failure
initialize the frontier using the initial state of problem
lo
Optimization Problems
Optimization Problems and
Other Forms of Search
n
Previously: systematic exploration of search space.
Path to goal is solution to problem
For some problems path is irrelevant.
q
9/20/13
Navigating through a search tree
A
Uninformed Search
C
B
D
Russell and Norvig 3rd ed. chap. 3.3-3.4
E
J
I
H
K
Navigating through a search tree
G
F
L
Navigating through a search tree
A
A
B
C
Puzzles!
Problem Solving by Searching
Russell and Norvig 3rd ed., chap. 3.1-3.2
The missionaries and cannibals
problem
n
n
Goal: transport the missionaries and
cannibals to the right bank of the river
Agents
Whats an agent?
n
Russell and Norvig:
An agent is anything that can be viewed as perceiving
its environment through sensors and acting on that
environment through actuators. (p. 32)
n
Examples:
9/3/13
What is python
An intro to python
n
n
n
An interpreted, object-oriented, high-level programming
language
Simple, easy to learn syntax
Highly readable, compact code - looks like pseudo-code!
q
q
Games
n
Adversarial Search and Game
Playing
Games: multi-agent environment
q
q
q
n
Russell and Norvig, 3rd edition, Ch. 5
What do other agents do and how do they affect our
success?
Cooperative vs. co
CSP example: map coloring
Constraint Satisfaction Problems (CSPs)
Russell and Norvig Chapter 6
Given a map of Australia, color it using three
colors such that no neighboring territories have
the same
Probabilistic Agent
Probabilistic Reasoning in
Bayesian Networks
sensors
?
environment
agent
actuators
Russell and Norvig Chapter 14
Problem
n
n
n
At a certain time t, the KB of an agent is
some colle
11/18/13
Inference in BN
Bayesian Networks: Inference
n
n
Set E of evidence variables that are observed,
e.g., cfw_JohnCalls,MaryCalls
Query variable X, e.g., Burglary, for which we
would like to know
Uncertainty
Uncertainty
Russell & Norvig Chapter 13
Lecture 33: November 13, 2013
Uncertainty
Let At be the action of leaving for the airport t minutes before
flight
Will At get you there on time?
A p
FOL to PL
n
Inference in first-order logic
First order inference can be done by
converting the knowledge base to PL and
using propositional inference.
q
How to convert universal quantifiers?
n
q
Russe
10/15/13
Knowledge & Reasoning
Logical Agents
To address these issues we will introduce:
n A knowledge base (KB): a list of facts that
are known to the agent.
n Rules to infer new facts from old facts
Logical equivalence
n
Proof Methods for
Propositional Logic
Two sentences are logically equivalent iff they are true in the same
models: iff and
Russell and Norvig Chapter 7
CS440 Fall 2013
1
Validit
Textbook
CS440 - Introduction to
Artificial Intelligence
n
Textbook: S. Russell and
P. Norvig. Artificial
Intelligence: A Modern
Approach. Prentice Hall,
2010, 3rd edition.
1
Course website
n
Course s