Computer Science Unit 3 Vocabulary

assignment

sets a variable to a value or mathematical expression

concatenation

putting two strings together to create a new string

index

the index of a list is the number or position of an element in the list

list

a list stores multiple items under one variable and uses an index to number and access them

operator

symbols like +, -, / , and * used for math

string

a sequence of characters that can be stored in a list or variable

substring

part of an existing string

variable

names a memory location to hold different values in your program

algorithm

step by step procedure for solving a particular problem

API (Application Programming Interface)

for a program or web service defines how other programs can communicate with it and use it

bit

short for binary digit

byte

one byte has 8 bits

computer bug

an informal term for an error in computer hardware or software, coined by Grace Hopper

cryptography

“secret writing” the art and science of writing secret messages

data abstraction

provides a general way to access a collection of data

data type

stored in a variable, for example number, string, boolean, or list

debugging

process of removing errors from computer hardware or software

expression

mathematical thing that involves values, variables, and operators

lossless compression

data compression technique in which no data is lost

lossy compression

data compression technique in which some amount of data is lost

pixel

short for picture element, a single point in a graphic image

pseudocode

blend of English and code used to write down an algorithm for a program

run length coding

compression algorithm that represents an image in terms of the length of runs of identical pixels

ADT (Abstraction Data Type)

defines a general data type like list that describes a collection of data without worrying about the specific implementation

analog

refers to data with values that change continuously, or smoothly, over time like sound and music files

ASCII (American Standard Code for Information Interchange)

a code for representing English characters as numbers, with each letter assigned a number from 0 to 127

bitmap

type of memory organization or image file format used to store digital images

cloud computing

relies on sharing resources online on the Internet rather than having data and process located on a personal computer

digital signal processing

refers to manipulating analog information

digital

system based on discontinuous data or events. Computers are digital machines because at the basic level they can distinguish between just two values, 0 and 1

download

to download data is copy data (usually an entire file) from an online source to a personal computer

even parity

the number of 1s in the sequence add up to an even number

GPS (Global Positioning System)

allows people to pinpoint their geolocation on Earth using satellites

megabyte

a unit for characterizing the amount of data (roughly 1 million bytes or more precisely 2^20 bytes, which 1, 048, 576 byes)

megapixel

1 million pixels, used in reference to the resolution of a graphic device

modeling

the process of representing a real-world object of phenomena as a set mathematical equations

OCR (optical character recognition)

the process of reading text from paper and translating the images into a form that the computer can manipulate

odd parity

the number of 1s in the sequences add up to an odd number

parity bit

a bit that acts as a check on a set of binary values, calculated in such a way that the number of 1s in the set plus the parity but should always be even (even parity) or should always be off (odd parity)

parity

usually means the fact of being even or odd

raster

rectangular area of a display screen actually being used to display images

render

refers to the process of adding realism to a computer graphics by adding 3D qualities, such as shadows and variations in color and shade

sampling

sampling analog data refers to measuring values of the analog signal at regular intervals (usually in time or space) called samples in order to digitize it into a binary representation

spam

electronic junk mail or junk newsgroup postings

steganography

the art and science of hiding information by embedding messages within other, seemingly harmless messages

upload

to upload data means to transmit data from a computer to an online repository or service such as a bulletin board service, or drop box, or network