UNIT 01 - Digital Information

LEARNING GOALS -- At the conclusion of this unit, I will be able to :

    1. show how a computer stores information as binary 'bits'. The AP says:

      • Number bases, including binary and decimal, are used to represent data.

      • Binary (base 2) uses only combinations 0's and 1's

      • Decimal (base 10) uses only combinations of the digits 0 – 9.

      • As with decimal, a digit’s position determines its numeric value.

      • The place value of each position is determined by the base raised to the power of the position.

    2. demonstrate ability to convert binary values to decimal and from decimal to binary

    3. demonstrate ability to convert hex values to decimal and back Removed by AP although you should understand how hex is easier for humans to use rather than binary

    4. demonstrate how images and other complex information are represented in a computer

    5. explain how we reduce the size of digital information and the tradeoffs that are involved. The AP Says:

      • Lossy data compression algorithms reduce the number of bits stored or transmitted in a digital file by removing data.. Lossless compression algorithms do not.

      • Lossless compression algorithms are used in situations where quality or ability to reconstruct the original is critical.

      • Lossy compression algorithms are used when transmission time or bandwidth considerations are most important..

    6. collaborate with a peer to find a solution to a text compression problem using the Text Compression Widget (lossless compression scheme).

    7. explain some factors that make compression challenging

    8. describe the purpose and rationale for lossless and lossy compression

    9. explain how images are encoded with pixel data

    10. describe a pixel as an element of a digital image.

    11. encode a B&W image in binary representing both the pixel data (intensity) and metadata (width, height).

    12. create the necessary metadata to represent the width and height of a digital image, using a computational tool

    13. explain why image width and height are metadata for a digital image.

    14. use the Pixelation Tool to encode small color images with varying bits-per-pixel settings

    15. explain the color encoding scheme for digital images.

    16. use the Pixelation Tool to encode an image of the student’s design.

    17. explain the benefits of using hexadecimal numbers for representing long streams of bits.

    18. Compare & Contrast copyright with open source software

    19. Compare & Contrast copyright with Creative Commons Copyright

TERMS & CONCEPTS:

Term Description
Abstraction The difference between what we as human beings do when interacting with hardware of software and what the software/hardware actually does
Bandwidth the largest possible number of bits that can flow into a computer (that is what you pay your ISP for. It isn't *necessarily* the exact number of bits that make it into your computer however)
Bit-rate the actual number of bits moving through the wire or through the air to your computer
Buffering the process where a steady/minimum number of bits is made available to your computer. Allows for an inconsistent input of bits
Copyright Any sort of intellectual property is automatically copyrighted when you finish doing it. The harder part might be in proving that it is yours.
Creative Commons Copyright

A specific type of copyright allowing creators (like us!) to assign certain types of rights - can change/can't change etc...
Hexadecimal A base-16 number system that uses sixteen distinct symbols 0-9 and A-F to represent numbers from 0 to 15
Heuristic a problem solving approach (algorithm) to find a satisfactory solution where finding an optimal or exact solution is impractical or impossibly
Header File information required for a software program to 'setup' a file but does not contain the actual data that makes up the file.
Image a type of data used for graphics or pictures
Innovation A new approach to improve or replace an existing item, idea, object etc...
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
Metadata data that describes other data. For example, a digital image my include metadata that describe the size of the image, number of colors, or resolution
Open Source A type of software that is (almost?) always expected to be free and available to use and edit
Overflow Error odometer
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
Roundoff Error 1/3

Little Bo Peep Has Lost Her Sheep

and Radar Cannot Find Them

They'll all (face to face)

Meet in parallel Space

Preceding Their Leaders Behind them