Is Artificial Intelligence Real?

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18 Οκτ 2013 (πριν από 3 χρόνια και 8 μήνες)

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Is Artificial
Intelligence
Real?

13



2001 Prentice Hall

13.
2

Learning Objectives


Explain what artificial intelligence means


Explain the tow basic approaches of artificial
intelligence research


Describe several hard problems that artificial
intelligence research has not yet been able to solve


Describe several practical applications of artificial
intelligence


Explain what robots are and give several examples
illustrating what they can


and cannot
-

to



2001 Prentice Hall

13.
3

Chapter Outline


Thinking About Thinking Machines


Natural
-
Language Communication


Knowledge Bases and Expert
Systems


Pattern Recognition: Making Sense
of the World


The Robot Revolution


AI Implications and Ethical
Questions


A machine
may be
deemed
intelligent
when it can
pass for a
human
being in a
blind test.”


Alan Turing




2001 Prentice Hall

13.
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Thinking Machines


Can machines think?


To answer that question,

we must explore:


Definitions of intelligence


The Turing test


What artificial

intelligence (AI) is



2001 Prentice Hall

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Some definitions of intelligence include:


Ability to learn from experience


Power of thought


Ability to reason


Ability to perceive relations


Power of insight


Ability to use tools


Intuition

Definitions of Intelligence



2001 Prentice Hall

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The Turing Test

In 1950, British
mathematician Alan
Turing proposed a
test to determine
if a machine had
intelligence



2001 Prentice Hall

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What Is Artificial
Intelligence?


Artificial intelligence is the study of:



ideas which enable computers to do the
things that make people intelligent.





Patrick Henry Winston



how to make computers do things at which,
at the moment, people are better.





Elaine Rich



the computations that make it possible to
perceive, reason, and act.





Patrick Henry Winston




2001 Prentice Hall

13.
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Two Approaches to AI


Simulate Human Mental Processes


Design Non
-
human Mental Processes



2001 Prentice Hall

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Designing Intelligent Machines


Some branches of AI research include:


Games


Natural Languages


Knowledge Bases

and Expert Systems


Pattern Recognition


Neural Networks


Robotics



2001 Prentice Hall

13.
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Opening Games


Simple games

have limited domains.
This allows AI researchers to develop
strategies for:


Searching possible moves


Heuristics (“rules of thumb”)


Recognizing patterns (new or old one?)


Machine learning (machine becomes a
better player over time)



2001 Prentice Hall

13.
11

Natural
-
Language
Communication


AI researchers would like to develop a
machine that understands the words spoken
by a person (natural language)


Challenges to developing

this kind of machine come from:


Machine Translation Traps


Conversation without Communication


Nonsense and Common Sense



2001 Prentice Hall

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Machine Translation Traps


Required a “parsing program” to break down
words from one language and convert them
into another


The meaning was lost in the translation.


For example:


Out of sight, out of mind
=

Invisible idiot


The spirit is willing, but the flesh is weak
=

The
wine is agreeable, but the meat is rotten



2001 Prentice Hall

13.
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Conversation without
Communication


AI researchers attempted to
“converse” with a machine using the
software program
ELIZA


ELIZA

had a limited natural language
vocabulary


In order to communicate with humans,
ELIZA

had to ask and be asked
questions



2001 Prentice Hall

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Conversation without
Communication


However,
ELIZA

had no understanding
of what was being communicated


I need some help, that much
seems certain


WHAT WOULD IT MEAN TO YOU
IF YOU GOT SOME HELP


Patient
:

ELIZA
:



2001 Prentice Hall

13.
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Nonsense and Common Sense


AI researchers attempted to learn
more about natural languages by using
the program
RACTER

to write a book


However, despite a large and perfect
English language vocabulary,
RACTER’s

book was nonsense


Machines are good at syntax but cannot
compete with humans at semantics


Bill sings to Sara, Sara
sings to Bill. Perhaps they
will do other dangerous
things together. They may
eat lamb or stroke each
other. They may chant of
their difficulties and their
happiness. They have love
but they also have
typewriters. That is
interesting.”



A poem by RACTER



2001 Prentice Hall

13.
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Knowledge Bases and

Expert Systems


Machines are good at storing and
retrieving facts and figures


People are good at storing and
manipulating knowledge


Knowledge bases contain facts and a
system of rules for determining the
changing relationship between those
facts



2001 Prentice Hall

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Knowledge Bases and

Expert Systems


Expert systems

are software

programs

designed to

replicate human

decision
-
making

processes



2001 Prentice Hall

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Examples of Expert Systems


Medicine
:
medical facts
and knowledge
have been
entered into an
expert system
to aid physicians
in diagnosing

their patients



2001 Prentice Hall

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Examples of Expert Systems


Factories
: expert systems are
used to locate parts, tools, and
techniques for the assembly of
many kinds of products


Financial
: automation of
banking functions and
transactions is being done by
many expert systems



2001 Prentice Hall

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Expert Systems in Perspective


An expert system can:


Help train new employees


Reduce the number of human errors


Take care of routine tasks so
workers can focus on more
challenging jobs


Provide expertise when no experts
are available



2001 Prentice Hall

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Expert Systems in Perspective


Preserve the knowledge of experts after
those experts leave an organization


Combine the knowledge of several
experts


Make knowledge available to more people



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Pattern Recognition:


Making Sense of the World


Pattern recognition

involves
identifying recurring patterns in input
data with the goal of understanding
or categorizing that input


Image Analysis

identifies objects

and shapes



2001 Prentice Hall

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Pattern Recognition:


Making Sense of the World


Optical Character Recognition

(OCR)
identifies words and numbers


the page image must be scanned into the
computer’s memory


OCR software identifies the text and
converts documents into editable text


Handwritten text is difficult to read and
the results are not as reliable as
typewritten text



2001 Prentice Hall

13.
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Pattern Recognition:


Making Sense of the World


Speech Recognition
identifies spoken
words


Speech

Synthesis

generates

synthetic

speech



2001 Prentice Hall

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Neural Networks


Neural networks

are distributed,
parallel computing systems based on
the structure of the human brain


A
neural network

consists of
thousands of microprocessors called
neurons


A
neural network

learns by trial and
error, just as the brain does



2001 Prentice Hall

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Neural Networks


Concepts are

represented as

patterns of activity

among neurons


A neural net can

still function if part

of it is destroyed



2001 Prentice Hall

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The Robot Revolution


The word
robot

comes from the
Czech word for forced labor


Today’s
robots

combine many AI
technologies, including:


Vision, hearing, pattern recognition,
knowledge engineering, expert decision
making, natural language understanding,
and speech



2001 Prentice Hall

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The Robot Revolution


While a computer performs mental
tasks, a
robot

is a computer
-

controlled

machine

designed to

do manual

tasks



2001 Prentice Hall

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What Is a Robot?


A
robot

differs from other computers in
its input and output peripherals


Robot

input

includes sensors

(heat, light, motion)


Robotic

output is

usually sent to joints,

arms, or other moving

parts




2001 Prentice Hall

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What Is a Robot?


These peripherals make robots ideally
suited for:


Saving labor costs (robots can work 24
hours a day)


Improving the quality and productivity of
repetitive jobs


Hazardous or uncomfortable jobs



2001 Prentice Hall

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Steel
-
Collar Workers


Despite sophisticated input and output
devices, robots still cannot compete with
humans for jobs requiring exceptional
perceptual or fine
-
motor skills


But for people who earn their living doing
manual labor, robots are a threat


Displaced workers are not limited to
factories



2001 Prentice Hall

13.
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AI Implications and

Ethical Questions



There are certain
tasks which
computers ought not
[to] be made to do,
independent of
whether computers
can be made to do
them.”


Joseph Weizenbaum



2001 Prentice Hall

13.
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AI Implications and

Ethical Questions


In the future, we are likely to see products
with embedded AI


Some futurists predict that silicon
-
based
intelligence will replace human intelligence


Whether AI becomes embedded in
products or evolves into a new form of
intelligent life, what becomes of human
values?



2001 Prentice Hall

13.
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Selected Answers to Review
Questions

(Q) What are the disadvantages of the approach
to AI that attempts to simulate human
intelligence? What is the alternative?

(A) Using AI to simulate human intelligence has
three problems. The first is that most people
have trouble knowing and describing how they
do things. Human intelligence includes
unconscious thought, instant insight, and other
mental processes that are difficult and even
impossible to understand or describe.




2001 Prentice Hall

13.
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Selected Answers to Review
Questions

(A)
---

Continued

The second problem is that
even the most powerful supercomputers don’t
have the brain’s ability of parallel processing,
breaking a complex job into smaller and simpler
jobs and completing those jobs simultaneously,
The third problem is that a human’s way doing
something is not usually the best way for a
computer to do it. The alternative is to create
programs that can function intelligently when
confined to limited domain.



2001 Prentice Hall

13.
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Selected Answers to Review
Questions

(Q) What is the relationship between syntax and
semantics? Can you construct a sentence that
follows the rules of English syntax but has
nonsense semantics?

(A) Syntax is a set of rules for constructing
sentences from words. Semantics is the
underlying meaning of words and phrases. Yes,
noun, verbs, and so forth can be strung
together using correct syntax without creating
a meaningful sentence.



2001 Prentice Hall

13.
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Selected Answers to Review
Questions

(Q) What is a knowledge base? What is an expert
system? How are the two related?

(A) A knowledge base is a database that also
contains a system of rules for determining and
changing the relationship between facts stored.
An expert system is a program that replicates
the decision
-
making process of a human expert.
A knowledge base is the foundation of an expert
system. This knowledge base represents ideas
from a specific field of expertise.



2001 Prentice Hall

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Selected Answers to Review
Questions

(Q) What are some of the problems that make
machine vision so challenging?

(A) Machine vision means identifying objects and
shapes in a scene. Of course scenes can be
complicated by shadows, obscuring objects,
lighting changes, movement, and so forth. For
humans, identifying what we see is generally
effortless. For computers, it becomes a
monumental task of pattern recognition and
inference.