Unit 1 Digital Information

Creative Commons

Copyright for creative work

Open Source

refers exclusively to software. Anyone can use or modify the source code.

Open Access

set of principles and a range of practices through which research outputs are distributed online, free of cost or other access barriers.

Binary

0 and 1's

Describe how the process of sampling, RGB pixels, and binary sequences work together to display a digital color image.

Each pixel will have a certain amount of red, green, and blue. For black and white images we had one bit per pixel. The 0 was for black and 1 was white. For the color images we started off with 3 bits per pixel. The three colors were represented by one bit each. For example, 100 would be red, 010 is green, and 001 would be blue. Digital images use 24 bits. Each color is represented by 8 bits. 8 bits for red, 8 bits for green, and 8 bits for blue.

How is a Creative Commons license different from a regular copyright?

It allows your work to be shared as you like. You can pick how you want your work shared or used.

An author is preparing to send their book to a publisher as an email attachment. The file on their computer is 1000 bytes. When they attach the file to their email, it shows as 750 bytes. The author gets very upset because they are concerned that part of their book has been deleted by the email address. If you could talk to this author, how would you explain what is happening to their book?

Just because the file is smaller doesn't mean that information is lost - it just means the email automatically compressed the data.

What is the difference between open access and open source.

Open source refers to exclusively to software. It means that the source code for that software is openly available, thus allowing for modification, and that the software may be redistributed freely. (As a side note, the related term "free software" refers to the users' freedom to copy, run, distribute, and modify software, rather than meaning free of cost. While open access refers to unrestricted public access, usually in the context of research.

Abstraction

Reducing information and detail to focus on essential characteristics.

Data Compression

Reducing the amount of space needed to store a piece of data

Bit

Smallest digit in a computer in binary. A 0 or a 1.

Roundoff Error

occurs when an exact value cannot be made with available place values

Lossy Compression

A process for reducing the number of bits needed to represent something in which some information is lost or thrown away. This process is not reversible.

Byte

8 bits

Digital Data

A discrete representation of data

Sampling

A process for creating a digital representation of analog data by measuring the analog data at regular intervals called samples.

Overflow Error

Beyond the limits of data

What are the similarities and differences between the binary and decimal systems?

Both systems use symbols to represent values. Decimal has 10 symbols (0-9) while binary has 2 symbols (0 and 1). Digits in decimal represents powers of 10 where binary is powers of 2.

Lossless Compression

Data that can later be reconstructed

Analog Data

Data with values that change continuously, or smoothly, over time. Some examples of analog data include music, colors of a painting, or position of a sprinter during a race.

Which of the following would result in a better digital approximation of an analog black and white image?

Decreasing the size of each sample square, thus increasing the number of samples taken.

Your computer science teacher asks you to sample a black and white image that is 4" x 6". How would you sample the image to provide a good digital approximation using the pixelation widget? What sample size would you use? How would your decision affect the digital representation?

Discuss how you would break down the image for each square. Justify your answer.

How many bits would be needed to count all of the students in class today?

Enough bits to count 36

What is the difference between overflow and round off?

For overflow, if the number is too large it might reset the pattern or truncate the numbers. For round off, the numbers get rounded up or down if there are repeating numbers that go beyond the amount of data.

int

In computer science, an integer is a datum of integral data type, a data type that represents some range of mathematical integers. Integral data types may be of different sizes and may or may not be allowed to contain negative values. Integers are commonly represented in a computer as a group of binary digits

How would you explain a number system to someone who had never seen numbers before?

Number systems are symbols used in our everyday lives to make sense of our world.

Multiple Choice: Analog vs. Digital Which statement about analog and digital images is true?

Sampling an analog image more frequently produces a digital image with a better representation.

You've been given a new cell phone with a 2 gigabyte data plan. You plan to use your phone for text messages, images, video, and music. Which of these categories are best compressed using lossless compression? Which of these categories are best compressed using lossy compression? Why?

Text can use lossless since it is small in size. Video should be lossy because of the large file sizes. Image and audio can be either depending on the size.

Assume your friend just sent you 32 bits of pixel data (just the 0s and 1s for black and white pixels) that were encoded after sampling an image. Choose the two statements that are true.

The correct width and height must be input into the pixelation widget to produce the image. The fact that only 32 bits were used to represent the image indicates relatively large sample squares were used. The digital image may vary from the analog image significantly.

What is the most important quality of lossless compression?

The data is transformed to usually make it smaller. It can always be reconstructed back to the original.

As a reminder, in the warm-up we saw the this scenario: Imagine you were using some of our pixelation tools to create an image and you posted it online for your friends to see - but, a week later you find out someone took that image and put it on a T-shirt that they're selling for $10 each. Now that we understand Copyright, what would need to change in order for the scenario from the warm-up to be okay?

The images is slightly edited The tshirt sites you as the image author The tshirt creator reaches out to you as the creator asking permission to use the image

"The binary pattern 01000001 represents the number 65." Write a brief response explaining whether you believe this statement is always true

The letter "A" is represented by 65. This binary does represent 65 but can be used to represent other things.

Decimal

The number that binary represents

Modern car odometers can record up to a million miles driven. What happens to the odometer reading when a car drives beyond its maximum reading?

The odometer turns over to zero after it has reached its maximum capacity. This is an overflow error.

When using bits to represent fractions of a number, can you create all possible fractions? Why or why not?

There are values that cannot be represented

Each time we add another bit, what happens to the amount of numbers we can make?

We can make twice as many numbers. Two bits can have four combinations, three bits can have eight... 00, 01, 10, 11 - 2 bits - 4 combinations 000, 001, 011, 111, 110, 100, 010, 101 - 3 bits - 8 combinations 4 bits = 16 combinations....

intelluctual property

creations of the mind, such as inventions; literary and artistic works; designs; and symbols, names and images used in commerce.