Transcript ch-8-FIT-pt2

8
chapter
Binary Representation of Information
bit:
0
byte:
0110 11000
"word": 01011100 11101111 00010000
11110000
Digital Information (Binary)
There are 10 different kinds of people in the
world: those who know binary and those
who don't. --Anon
Slide 8-2
Digital Information (Binary)
Von Neumann Architecture
A. CPU; B. RAM; C. I/O; D. Bus
What Can Computers Do?
1.
I/O operations
2.
Storage ops. (RAM, disk, disc, ...)
3.
Arithmetic ops. (+, -, *, /, %, ^, ...)
4.
Logic ops. (<, <=, ==, !=, >=, >, AND, OR, ...)
==> Computers are technologically complex but
conceptually simple
Slide 8-3
Digital Information (Binary)
Pictures of the Tinker Toy computer.
How the Tinker Toy computer works.
Slide 8-4
Digital Information Processing
Performance Speeds
How Fast Are Computers?
Two measures of throughput
MIPS: 2 ^ 3 ==> 8
FLOPS: 3.14159 ^ 2.718 =
22.45186162
Supercomputers: MFLOPS;
GFLOPS; TFLOPS; PFLOPS.
The Prefixes of the S.I.
Slide 8-5
Digital Information Processing
Performance Speeds
Q: If a supercomputer can execute 1
GFLOPS, one instruction requires how
much time to execute?
A: 1 nanosecond.
Q: If a supercomputer can execute 1
PFLOPS, one instruction requires how
much time to execute?
A: ???
Slide 8-6
Information Processing Speeds
 People
MFLOPS: recite 1..1M; 2 sec/recitation;
2Msec = 33,333 min. == 23 days
GFLOPS: recite 1..1G; 3 sec/recitation;
3Gsec = 50M min. == 34K days = 100 yrs
TFLOPS: recite 1..1T; 6 sec/recitation; 6Tsec
= 200K yrs
Slide 8-7
Neurobiology
1011 neurons,
each connected to 104
others
Switching Speed: 10-3 sec.
vs.computer: 10-10 sec.
Yet humans are able to make
surprisingly complex
decisions, surprisingly
quickly.
(eg) 10-1 sec. for infant to
visually recognize its
mother
Slide 8-8
Neurobiology
the informationprocessing abilities of
biological systems
must follow from
highly parallel
processes distributed
over many neurons
 Artificial Neural
Networks
Slide 8-9
Artificial Intelligence Research:
Basic Premise
Genus:
Species:
Information Processing System
(IPS)
/
\
Biological
Computers
Systems
 Both species governed by same principles
Slide 8-10
AI Research
Scientific Metaphors
The heart is a pump
The brain is a computer (IPS)
Metaphor  “The heart has its reasons of
which reason knows nothing.”
-- Blaise Pascal
Slide 8-11
Digeratus: Alan Turing
During WWII Turing worked at Bletchley Park, Britain's
codebreaking centre, & was responsible for German
naval cryptanalysis. He devised a number of
techniques for breaking German ciphers, including
the method of the bombe, an electromechanical
machine that could find settings for the Enigma
machine.
Slide 8-12
The Turing Test for Intelligence:
"Computing machinery and
intelligence." (1950)
The Turing test is a proposal for a test of a
machine's capability to demonstrate
intelligence:
A human judge engages in a natural
language conversation with one human
and one machine, each of which try to
appear human; if the judge cannot
reliably tell which is which, then the
machine is said to pass the test.
Slide 8-13
Slide 8-14
Five Categories of Information
1.
2.
3.
4.
5.
Rover photos of Mars. Category: ?
100 Kdigits of PI. Category: ?
Clerk's Prolog, Canterbury Tales.
Category: ?
Prelude & Fugue in C, J.S. Bach.
Category: ?
A statement in a computer program.
Category: ?
Slide 8-15
Five Categories of Information
Q: Which of the 5 categories is this?
01011100 11101111 00010000 11110000
A: It could be any one of the 5
(eg) How bit maps are used to represent images in
computers.
Slide 8-16
Why Do Computers Use Binary?
Nine Rungs of the Computer Inferno
1. Physics level.
2. Device Level: Transistors
3. Gate Level: AND, OR
PandA = TandF (p. 212)
“Logic is the foundation of reasoning, and the foundation of
computing.
By associating true with presence & False with Absence, we
can use the physical world to implement the logical world.
This produces Information Technology.”
Slide 8-17
Why Do Computers Use Binary?
4. Machine Level:
full adder
a water adder
flip-flop (stores one bit)
Slide 8-18