CS-150 – Data Representation: Vocabulary Flashcards

A set of vocabulary flashcards covering the main terms and definitions from the CS-150 lecture on Data Representation.

Analog Data

Continuous information that varies smoothly and is directly analogous to the original phenomenon.

Digital Data

Discrete information broken into separate elements, usually stored as binary digits.

Bit (Binary Digit)

The smallest unit of storage, having two possible states, typically 0 (low voltage) or 1 (high voltage).

Byte

A collection of 8 bits; the standard basic addressable unit in modern computers.

Word (Computer Architecture)

The native, fixed-size group of bits a processor handles (e.g., 32-bit or 64-bit).

Digitise

Convert an analogue entity into a structured sequence of binary digits.

Discretise

Transform a continuous space into an equivalent discrete space for easier computation.

Sign-Magnitude

Binary format in which the most-significant bit is the sign (0 = positive, 1 = negative) and remaining bits give magnitude.

Two’s Complement

Binary representation that lets positive and negative integers wrap around modulo 2ⁿ; simplifies arithmetic and has one zero only.

Unsigned Integer

Integer type that stores only non-negative values, giving a range of 0 to 2ⁿ − 1 for n bits.

Signed Integer

Integer type (usually two’s complement) that stores both positive and negative values within a fixed range.

Integer Overflow

Condition where an arithmetic result exceeds the representable range of the given integer size.

Negation in Two’s Complement

Flip all bits (one’s complement) and add 1 to obtain the negative of a value.

Radix Point

General term for the ‘decimal point’; separates integer and fractional parts in any base.

Floating-Point Representation

Stores real numbers as sign × mantissa × base^exponent with limited bits for mantissa and exponent.

Fixed-Point Representation

Keeps a fixed number of fractional digits rather than scaling with an exponent; common in accounting.

Mantissa (Significand)

The significant digits of a floating-point number, often normalised to start with 1.x in binary.

Exponent (Floating Point)

The signed integer that scales the mantissa by shifting the radix point by base^exponent.

IEEE 754 Float

Single-precision (32-bit) floating-point format defined by IEEE 754 standard.

IEEE 754 Double

Double-precision (64-bit) floating-point format offering more mantissa and exponent bits than float.

Scientific Notation (Computing)

Floating-point form where one non-zero digit precedes the radix point; written as m E e in calculators.

ASCII

7-bit character encoding standard from the 1960s for English letters, digits, and control codes.

Unicode

Universal character set covering 143,000+ characters from 154 scripts, encoded via UTF-8, UTF-16, UTF-32, etc.

UTF-8

Variable-length Unicode encoding using 1–4 bytes per code point; backward-compatible with ASCII.

RGB Colour Model

Represents colours as intensities of red, green, and blue light, often 8 bits per channel.

Colour Depth

Number of bits used per colour component (e.g., 24-bit RGB = 8-8-8) determining palette size.

Pixel

The smallest addressable dot in a digital image or display, holding a colour value.

Resolution

Total number of pixels in an image or display (e.g., 1920 × 1080).

Raster Graphics

Image format that stores colour for each pixel; common types include BMP, GIF, JPEG, PNG, TIFF.

Vector Graphics

Image format describing shapes via mathematical objects (lines, curves); scales without pixelation (e.g., SVG).

JPEG

Lossy image compression scheme that averages colour frequencies to exploit human vision characteristics.

Pixelation

Visible blocky artifacts that occur when raster images are displayed larger than their resolution.

Pulse Code Modulation (PCM)

Digitisation of analogue signals by periodic sampling and quantisation; basis of WAV/CD audio.

Sampling Rate

Number of samples per second in PCM; CDs use 44.1 kHz to capture audible frequencies.

Lossless Compression

Data compression that allows exact reconstruction of original data (e.g., FLAC, ZIP).

Lossy Compression

Compression that discards some information to reduce size, tolerable in images, audio, video (e.g., JPEG, MP3).

Compression Ratio

Size(compressed data) ÷ size(original data); lower values indicate better compression (module-specific definition).

Run-Length Encoding (RLE)

Lossless technique replacing consecutive repeated values with a flag, the value, and the count.

Keyword Encoding

Lossless method that substitutes frequent patterns with special single-character tokens.

Prefix Code

Variable-length encoding where no code is a prefix of another, enabling unique decoding.

Huffman Encoding

Algorithm building an optimal prefix tree to assign shorter codes to more frequent symbols.

Video Codec

Software/hardware that compresses and decompresses digital video using temporal and spatial compression.

Temporal Compression

Video technique that exploits similarity between successive frames to reduce data size.

Spatial Compression

Video technique that compresses redundant information within a single frame.