CS Principles 2017

Unit 2 - Digital Information

Heuristic: a problem solving approach (algorithm) to find a satisfactory solution where finding an optimal or exact solution is impractical or impossible.
Lossless Compression: a data compression algorithm that allows the original data to be perfectly reconstructed from the compressed data.

Image: A type of data used for graphics or pictures.
metadata: is data that describes other data. For example, a digital image may include metadata that describe the size of the image, number of colors, or resolution.
Pixel: short for "picture element", the fundamental unit of a digital image, typically a tiny square or dot that contains a single point of color of a larger image.

Hexadecimal: A base-16 number system that uses sixteen distinct symbols 0-9 and A-F to represent numbers from 0 to 15.
Pixel: short for "picture element", the fundamental unit of a digital image, typically a tiny square or dot that contains a single point of color of a larger image.
RGB: the RGB color model uses varying intensities of (R)ed, (G)reen, and (B)lue light are added together in to reproduce a broad array of colors.

Lossless Compression: a data compression algorithm that allows the original data to be perfectly reconstructed from the compressed data.
Lossy Compression: (or irreversible compression) a data compression method that uses inexact approximations, discarding some data to represent the content. Most commonly seen in image formats like .jpg.

Abstraction: a simplified representation of something more complex. Abstractions allow you to hide details to help you manage complexity, focus on relevant concepts, and reason about problems at a higher level.

Aggregation: a computation in which rows from a data set are grouped together and used to compute a single value of more significant meaning or measurement. Common aggregations include: Average, Count, Sum, Max, Median, etc.
Pivot Table: in most spreadsheet software it is the name of the tool used to create summary tables.
Summary Table: a table that shows the results of aggregations performed on data from a larger data set, hence a "summary" of larger data. Spreadsheet software typically calls them "pivot tables".