CS Illuminated - Chapter 3 Vocabulary

data

basic values or facts

information

data that has been organized or processed in a useful manner

multimedia

several different media types

data compression

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

bandwidth

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

compression ratio

the size of the compression data divided by the size of the uncompressed data

lossless compression

a data compression technique in which there is no loss of information

lossy compression

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

analog data

a continuous representation of data

digital data

a discrete representation of data

digitize

the act of breaking information down into discrete pieces

pulse-code modulation

variation in a signal that jumps sharply between two extremes

reclock

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

signed-magnitude representation

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

ten's complement

a representation of negative numbers such that the negative of I is 10 raised to a minus I

overflow

a situation where a calculated value cannot fit into the number of digits reserved for it

radix point

the dot that separates the whole part from the fractional part in a real number in any base

floating point

a representation of a real number that keeps track of the sign, mantissa, and exponent

scientific notation

an alternative floating-point representation

character set

a list of the characters and the codes used to represent each one

keyword encoding

replacing a frequently used word with a single character

run-length encoding

replacing a long series of a repeated character with a count of the repetition

Hoffman encoding

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

pixels

individual dots used to represent a picture; stands for picture elements

resolution

the number of pixels used to represent a picture

raster-graphics format

storing image information pixel by pixel

vector graphics

representation of an image in terms of lines and shapres

video codec

methods used to shrink the size of a movie

temporal compression

movie compression technique based on differences between consecutive frames

spatial compression

movie compression technique based on the same compression techniques used for still images