CSP - U2C1Assessment Review

Under which of the following conditions is it most beneficial to use a heuristic approach to solve a problem?

• When the problem can be solved in a reasonable time and an approximate solution is acceptable.
• When the problem can be solved in a reasonable time that an exact solution is needed.
• When the problem cannot be solved in a reasonalbe time and an approximate solution is acceptable.
• When the problem cannot be solved in a reasonable time an exact solution is needed.

The colors of the pixels in a digital image often represented by red, gren, and blue values between 0 and 255 (an RGB triplet). A photographer is manipulating a digital image to lighten it because all of the RGB values in the image are less than 100, making it very dark. He does this by adding 20 to the R, G, and B values of each pixel, then overwriting the original image. What type of transformation is the photographer using on the digital image.

• Lossless transformation
• Lossy transformation
• Multiband transformation
• Chrome Sampling transformation

Which of the following is a true statement about data compression?

• Data compression is only useful for files being transmitted over the Internet.
• Regardless of the compression technique used, once a data file is compressed, it cannot be restored to its original state.
• Sending a compressed version of a file ensures that the contents of the file cannot be intercepted by an unauthorized user.
• There are trade-offs involved in choosing a compression technique for storing and transmitting data.

A video-streaming Web site uses 32-bit intergers to count the number of times each video has been played. In anticipation of some videos being played more times than can be represented with 32 bits, the Web site is planning to change to 64-bit integers for the counter. Which of the following describes the result of using 64-bit integers instead of 32-bit integers?

• 2 times as many values can be represented. 
• 32 times as many values can be represented.
• 2^32 times as many values can be represented.
• 32^2 times as many values can be represented.

Select the answer that lists the units of bytes in ascending order (from the smallest to largest).

• gigabyte, megabyte, terebyte
• megabyte, terabyte, kilobyte
• gigabyte, terabyte, megabyte
• kilobyte, gigabyte, terabyte

An artist makes an RGB raster image in which each pixel color is encoded with 12-bits --- 4 bits each for red, green, and blue. Which of the following correctly shows the hexadecimal value for Red as a 12-bit representation?

• FOO
• OOF
• FFOO
• FFOOOO

A compression scheme for long strings of bits called run-length encoding is described as follows:
Rather than record each 0 and 1 individually, instead record "runs" of bits by storing the number of consecutive 1s and 0s that appear.
Since it's binary, any run of 0s must be followed by a run of 1s (even if the run is only 1-bit long) and vice versa. Thus, you can store a list of small numbers that represents the alternating runs of 0s and 1s. (Look at the example on the board)

To uncompress the data back into its original binary state, you simply reverse the process. This technique is an example of what type of compression?

• Lossy compression
• Lossless compression
• Fast Fourier Transform compression
• Tailored compression

A raw digital sound file samples a sound wave at some interval and measures the height of the wave at each point. Thus, raw sound is recorded as a list of numbers.

In very broad terms the MP3 audio compression algorithm identifies frequencies and volume levels - low and high - that are outside the range of human hearing and removes the data representing these frequencies from the original. This technique results in a smaller audio file that sounds exactly the same to the human ear.

This technique is an example of what type of compression?

• Lossy compression
• Lossless compression
• Fast Fourier Transform compression
• Tailored compression

Approximately how much bigger (how many more bytes) is a megabyte than a kilobyte?

• 1,000 times bigger
• 100,000 times bigger
• 1,000,000 times bigger
• 1,000,000,000 times bigger

The image show on the board is an encoding for a black and white pixel image. The first two bytes of the data (circled in red) are used to encode the width and height of the image.

What is the best term for this type of "data about the data"?

• megadata
• superdata
• metadata
• predata