Chapter 3 Book Notes

Front 1

Data

Back 1

Basic values or facts

Front 2

Information

Back 2

Data that has been organized and/or processed in a way that is useful in solving some kind of problem.

Front 3

Types of Information

Back 3

* Numbers
* Text
* Audio
* Images and graphics
* Video

Front 4

Data Compression

Back 4

Process of reducing the amount of space needed to store a piece of data.

Front 5

Bandwidth

Back 5

Restrictions that define the maximum number of bits or bytes that can be transmitted from one place to another in a fixed amount of time.

Front 6

Compression Ratio

Back 6

Gives an indication of how much compression occurs. It is the size of the compressed data divided by the size of the original data.

Front 7

Lossless Compression

Back 7

A data compression technique in which here is no loss of information.

Front 8

Lossy Compression

Back 8

A data compression technique in which there is a loss of information.

Front 9

Analog Data

Back 9

A continuous representation of data.

Front 10

Digital Data

Back 10

A discrete representation of data. That is, not continuous. This is the data represented in the computer.

Front 11

Digitize

Back 11

The act of break information down into discrete pieces

Front 12

Digital Signals

Back 12

Electronic signals used in the computer that have either a high or a low state, hence binary representation.

Front 13

Pulse-Code Modulations

Back 13

Variation in a signal that jumps sharply between two extremes.

Front 14

Reclock

Back 14

The act of reasserting an original digital signal before too much degradation occurs.

Front 15

Signed-Magnitude Representation

Back 15

Number representation in which the sign representes the ordering of the number (negative or positive) and the value represents the magnitude.

Front 16

Fixed-Sized Numbers

Back 16

A way to represent negative numbers as just integer values, where half of them represent negative numbers

Front 17

Two's Complement

Back 17

A representation of negative numbers such that the negative of 'I' is 2 raised to k minus I.
negative(I) = 2^k - I

Front 18

Overflow

Back 18

A situation where a calculated value cannot fit into the number of digits reserved for it. Example of a problem with trying to map a infinite world on a finite machine.

Front 19

Radix Point

Back 19

The dot that separates the whole part from the fractional part in a real number in any base. Basically the decimal point.

Front 20

Decimal Places in Binary

Back 20

The positions to the right of the radix point in binary are the halves position (2^-1) or the quarters position (2^-2)

Front 21

Floating Point

Back 21

A way to represent real numbers in the computer. This is the formula:
sign * mantissa * 2^exp. Called floating point because the number of digits is fixed by the radix point floats.

Front 22

Scientific Notation

Back 22

An alternative floating point representation.

Front 23

What is the continuous, analog, entity when representing text?

Back 23

The document a user is working on

Front 24

What are the discrete, or digital, elements when representing text?

Back 24

The separate characters that need to be represented and stored in the computer's memory.

Front 25

Word Processing

Back 25

Different than representing text, word procressing is what Word does--formatting and adding images and stuff.

Front 26

Character Set

Back 26

A list of the characters and the codes used to respresent each one.

Front 27

ASCII Character Set

Back 27

American Standard Code for Imformation Interchange. Originally used seven bits to represent each character, allowing for 128 unique characters.

Front 28

Check Bit

Back 28

Used in the original ASCII character set to help ensure proper data transmission.

Front 29

Latin-1 Extended ASCII Character Set

Back 29

Updated eight-bit version of the ASCII character set that represented 256 characters, accented letters, and special symbols.

Front 30

Unicode Character Set

Back 30

Another character set for international use. Represents characters from all languages using 16 bits per character. It is also flexible so that it can use more space per character if needed to represent additional characters. Unicode is a superset of ASCII - first 256 characters are the same so they can fit together.

Front 31

What are the three types of text compression?

Back 31

1. Keyword Encoding
2. Run-Length Encoding
3. Huffman Encoding

Front 32

Keyword Encoding

Back 32

Replacing a frequently used word with a single character. To decompress the document, reverse the process.

Front 33

Limitations to Keyword Encoding

Back 33

1. The characters we use to encode the keywords cannot be part of the original text.
2. Uppercase and lowercase are represented differently so you'd need a different symbol
3. No gain from encoding one letter words.

Front 34

Run-Length Encoding

Back 34

Replacing a long series of a repeated character with a count of the repetition.

Front 35

Flag Character

Back 35

Used in run-length encoding where a sequence of repeated characters is replaced with this flag character and followed by a digit indicating the number of times it's repeated.
Example: *A7 (* = flag character)

Front 36

Huffman Encoding

Back 36

Uses a variable-length binary string to represent a character so that frequently used characters have short codes.

Front 37

Sampling

Back 37

Digitizing a sound signal by periodically measuring the voltage of the signal and recording the appropriate numeric value.

Front 38

RGB Color Representation in the Computer

Back 38

Red, green, blue values, which are actually three numbers that indicate the relative contribution of each of these three primary colors.

Front 39

Color Depth

Back 39

The amount of data that is used to represent a color.

Front 40

HiColor

Back 40

16-bit color depth.

Front 41

TrueColor

Back 41

24-bit color depth.

Front 42

Pixels

Back 42

Individual dots used to represent a picture; stands for picture elements.

Front 43

Resolution

Back 43

The number of pixels used to represent a picture

Front 44

Raster-Graphics format

Back 44

Storing image information pixel by pixel. Raster-graphics file formats include bitmap, GIF, and JPEG.

Front 45

Vector Graphics

Back 45

Representation of an image in terms of lines and shapes.

Front 46

Video Codec

Back 46

Methods used to shrink the size of a movie. Stands for Compressor/Decompressor.

Front 47

Temporal Compression

Back 47

Movie compression technique based on differences between consecutive frames.

Front 48

Spatial Compression

Back 48

Movie compression technique based on the same compression techniques used for still images.