Unit 5 - Week 6 (Concept Review)

Pixar is a company that creates a huge amount of images, audio recordings, and videos, and they need to decide what compression algorithms to use on all those files.

When would Pixar most likely use lossless compression?

• When saving the rendered 3D images that will become the film.

• When saving images of the characters for the film website.

• When saving the videos of film trailers for uploading to YouTube.

• When saving audio clips to embed in stuffed animals, like Buzz Lightyear's "To Infinity and Beyond!"

Consider these two files:

- A still screenshot of the Apple homepage

- A 5-second video of the same Apple homepage

Is it possible for the video to take up less space than the image?

• Yes, but only if there is no movement in the video recording of the Apple home page

• Yes, but only if the video is saved in the Quicktime .mov file format.

• Yes, if the video is compressed with a lossy compression algorithm.

• No, the video will always take up more space than the image.

Tom is recording an album of songs using a digital audio recording application, and he wants the recordings to be high quality.

Which advice will best help him to achieve his goal?

• He should save the audio using a lossless compression algorithm.

• He should save the audio using a lossy compression algorithm at high quality setting.

• He should save the file using an open standard.

• He should add metadata to the file with the title, artist, and genre.

• He should save the file on a USB drive, not his internal hard drive.

Tags

NGSS.MS-PS4-3

GIMP is an open-source photo-editing application that gives you a variety of ways to manipulate photos.

Which of the following operations could be considered "lossless"?

• Crop: Trims the sides of the image.

• Grayscale: Converts the photo to black & white (256 shades of grey).

• Invert: Inverts all the pixel colors and brightness values (i.e. black pixels become white pixels).

A mapping company is creating a program that can predict the traffic on routes and estimate the delay from the traffic. The program takes an input of 5 routes and outputs the delay for each route.

The program has two phases:

- Setup: Loads historical traffic data for the geographic region.

- Simulation: Predicts the traffic and estimates the delay of 5 routes.

The initial setup phase takes 10 minutes. The simulation phase takes 5 minutes per route, which amounts to 25 minutes total for the 5 routes. The program takes 35 minutes total.

The company would like to improve the program's efficiency by parallelizing the simulation operations.

What is true about the potential efficiency gains?

• The version with parallelized simulation operations will always take less time than the sequential version, even if the company runs the software on a computer that cannot do parallel computing.

• A version with parallelized simulation operations could take a total time of less than 10 minutes (including setup and simulation).

• Even if it's run on a powerful computer, a version with parallelized simulation operations would still take at least 15 minutes.

• Once the simulation operations are parallelized, the entire simulation phase will never take longer than 5 minutes.

Which of these situations is most analogous to parallel computing?

• In a relay race, a team of multiple people each run one segment of the race. Cumulatively, they complete the race, but each person can run for a shorter period of time and focus their energy on that segment.

• On a football team, each player position focuses on different parts of the field (e.g. goalkeeper, quarterback, halfback). Each player picks the position that caters to their strengths, so that their team can most effectively move the ball down the field.

• When multiple people work on a jigsaw puzzle, they can each work on a different part of the puzzle. Once each person has put together a significant area of the puzzle, they can merge the areas and see the completed puzzle.

• People can be pen pals with other people all over the globe. Each person sends letters to however many pen pals they would like, and it's up to the recipient if they would like to send a letter back.

Rebecca is developing a program that simulates the effect of rising ocean levels on the world's largest cities.

When she ran her first version of the program on a computer in her research lab, the computer took 75 minutes to complete the simulation. To improve the performance, she parallelized the simulation, computing the effects on each city in parallel. When she ran the parallelized program on the same computer, it took an average of 15 minutes to complete.

What is the speedup of the parallel solution?

• 15

• 1/5

• 60

• 5

Tags

NGSS.HS-ETS1-4

Darius is creating a program that can simulate a bridge under different extreme weather conditions and calculate the probability of collapse.

The pseudocode that describes the program is attached.

Darius decides to change the program so that the computer can run each loop iteration in parallel.

Assuming that he runs the program on a computer that can run 6 tasks in parallel, how long will the parallelized solution take?

• 3 minutes

• 7 minutes

• 5 minutes

• 13 minutes

• 10 minutes

Tags

NGSS.MS-ETS1-4

32 teams qualified for the 2014 World Cup. If the names of the teams were arranged in sorted order (an array), how many items in the array would binary search have to examine to find the location of a particular team in the array, in the worst case?

• At most, 32

• At most, 1

• At most, 6

• At most, 16

2^____ = 32?

• 32

• 1

• 5

• 16