Fundamentals of Data Representation

Abstraction

The process of simplifying complex data into a more general or easier-to-understand format.

Digital Information

Data that represents other forms of data, such as text, images, or sounds, in a format that computers can process.

Number System

A system for expressing numbers using a consistent set of symbols or digits.

Number Base

The number of unique digits or symbols used in a number system.

Decimal Number System

A base-10 number system that uses digits 0 through 9.

Binary Number System

A base-2 number system that uses only the digits 0 and 1.

Bit

The smallest unit of data in computing, represented as either 0 or 1.

ASCII

A character encoding standard that uses binary codes to represent text and control characters.

Pixel

The smallest unit of an image displayed on a screen, each representing a single color.

Pixel Image

An image composed of many tiny pixels, each with a specific color value.

Hexadecimal

A base-16 number system using digits 0-9 and letters A-F.

RGB Color Encoding

A method for encoding colors using values for red, green, and blue, each ranging from 0 to 255.

Data Compression

The process of reducing the size of data to save storage space or improve transmission efficiency.

Lossless Compression

A type of data compression where no information is lost, allowing the original data to be fully restored.

Lossy Compression

A type of data compression that reduces file size by removing some data, which may result in a loss of quality.

Cryptography

The practice of encoding information to protect it from unauthorized access.

Caesar Cipher

A simple encryption method that shifts letters in the alphabet by a fixed number of places.

Symmetric Encryption

An encryption method using a single key for both encryption and decryption.

Asymmetric Encryption

An encryption method that uses two keys: a public key for encryption and a private key for decryption.

Public Key Encryption

A component of asymmetric encryption where the public key is used to encrypt data and can be shared openly.

Key (cyber)

A piece of information used to encrypt or decrypt data.

Decryption

The process of converting encrypted data back into its original format.

Byte

A unit of digital information consisting of 8 bits. A byte can represent 256 different values (0-255).

Bits in a Byte

There are 8 bits in a byte.

Hexadecimal Digit

A single character in the hexadecimal number system, ranging from 0 to F, where A-F represent values 10-15.

Convert Binary to Decimal

To convert binary to decimal, multiply each bit by 2 raised to its position power (starting from 0 on the right), then sum the results.

Decimal Conversion Example

To convert binary 1111 to decimal: 1×23+1×22+1×21+1×20=151 \times 2^3 + 1 \times 2^2 + 1 \times 2^1 + 1 \times 2^0 = 151×23+1×22+1×21+1×20=15.

Pixel Color Representation

Colors in a pixel are represented using combinations of RGB values, where each color channel (Red, Green, Blue) ranges from 0 to 255.

Data Compression Techniques

Compression techniques reduce file size by either removing redundant data (lossy) or compressing data without loss (lossless).

Example of Lossy Compression**

JPEG image format, which reduces file size by discarding some image data, resulting in a potential loss of quality.

Example of Lossless Compression**

PNG image format, which compresses files without losing any image data, allowing for exact restoration.

Encryption Key**

A piece of information used in cryptography to encode or decode data, ensuring that only authorized parties can access the information.

Easy vs. Hard Encryption**

Easy encryption can be quickly broken with minimal effort, while hard encryption requires significant computational resources to decrypt.

Example of Easy Encryption**

A Caesar Cipher with a shift of 1, which can be easily decrypted by trying all possible shifts.

Example of Hard Encryption**

AES (Advanced Encryption Standard) with a 256-bit key, which is highly secure and difficult to break due to its complexity.

Fast Food Systems (Encoding Protocol Example)

Fast food systems use numerical or coded entries to identify menu items and process orders efficiently, similar to how computers use encoding protocols.

Image Resolution

The amount of detail an image holds, determined by the number of pixels in the image. Higher resolution means more pixels and greater detail.

Bit Depth

The number of bits used to represent the color of a single pixel. Higher bit depth allows for more colors and shades, improving image quality.

Hexadecimal Conversion Example

To convert hexadecimal 1F to decimal: 1×161+15×160=311 \times 16^1 + 15 \times 16^0 = 311×161+15×160=31.

Data Integrity

Ensuring that data remains accurate and unaltered during storage, transmission, or processing.

Encryption Algorithm

A set of rules or procedures used for encrypting and decrypting data. Examples include AES, RSA, and DES.

RSA (Rivest-Shamir-Adleman)

A widely used asymmetric encryption algorithm that uses two keys: a public key for encryption and a private key for decryption.

DES (Data Encryption Standard)

An older symmetric encryption algorithm that uses a 56-bit key. It has been largely replaced by more secure algorithms like AES.

Public Key Infrastructure (PKI)

A framework for managing digital certificates and public-key encryption, ensuring secure communications over networks.

Hash Function

A function that converts input data into a fixed-size string of bytes, typically a hash code. Hash functions are used for data integrity and password storage.

Pixel Density

The number of pixels per inch (PPI) in a display or image. Higher pixel density means clearer and more detailed images.

Metadata

Data that provides information about other data, such as file size, format, and creation date, but is not the actual content itself.

Image Filtering

The process of applying algorithms to modify an image, such as blurring, sharpening, or color adjustments.

Compression Ratio

The ratio of the size of the compressed data to the size of the original data. A higher ratio indicates greater compression.

Data Redundancy

The duplication of data within a dataset or storage system to ensure reliability and data integrity.