Question 1

In a ___ data compression method, the received data is an exact copy of the original message.&#10;A) lossless&#10;B) lossy&#10;C) JPEG&#10;D) MPEG

Accepted Answer

In a lossless data compression method, the received data is an exact copy of the original message. This means that there is no loss of information during the compression process. Choices C and D are specific file formats for image and video compression, and choice B refers to a type of compression where some data is intentionally removed in order to achieve a smaller file size.

Question 2

___ is a lossy compression method for pictures and graphics, whereas ___ is a lossy compression method for video.&#10;A) DCT, MPEG&#10;B) MPEG, JPEG&#10;C) JPEG, MPEG&#10;D) JPEG, DCT

Accepted Answer

JPEG is a lossy compression method for pictures and graphics, whereas MPEG is a lossy compression method for video. Option A is incorrect because DCT is a compression technique used in both JPEG and MPEG. Option B is incorrect because MPEG is a compression method for video, not JPEG. Option D is incorrect because DCT is a compression technique, not a compression method.

Question 3

___ encoding is a lossless data compression method.&#10;A) Only Huffman&#10;B) Only Run-length&#10;C) Only LZ&#10;D) Huffman, run-length, or LZ

Accepted Answer

Huffman, run-length, and LZ are all lossless data compression methods. Each method has its own strengths and weaknesses, so the best choice will depend on the specific data being compressed. It is often a good idea to try all three methods and compare the results to see which one produces the best compression ratio for the given data.

Question 4

In ___ encoding, PPPPPPPPPPPPPPP can be replaced by P15.&#10;A) Huffman&#10;B) run-length&#10;C) LZ&#10;D) MPEG

Accepted Answer

In run-length encoding, repeated characters are replaced with a count of the number of repetitions, so PPPPPPPPPPPPPPP can be replaced by P15. This method of compression is often used for image data, where there are many runs of identical pixels. Huffman encoding is a form of variable-length coding, LZ compression is a form of dictionary coding, and MPEG is a standard for video compression.

Question 5

In JPEG encoding, the ___ process breaks the original picture into smaller blocks and assigns a value to each pixel in a block.&#10;A) blocking&#10;B) DCT&#10;C) quantization&#10;D) vectorization

Accepted Answer

The blocking process in JPEG encoding involves dividing the original image into smaller, more manageable blocks (usually 8x8 pixels), where each pixel within these blocks is then assigned a specific value. This step is crucial for the subsequent stages of JPEG compression, such as the Discrete Cosine Transform (DCT) and quantization, to be more effective.

Question 6

In ___ encoding, the more frequently occurring characters have shorter codes than the less frequently occurring characters.&#10;A) Huffman&#10;B) run-length&#10;C) LZ&#10;D) JPEG

Accepted Answer

Huffman encoding uses variable-length codes to represent characters, with the more frequently occurring characters having shorter codes. This makes the encoding more efficient than fixed-length encodings, as it minimizes the total number of bits required to represent the data.

Question 7

The last step in JPEG, ___, removes redundancies.&#10;A) blocking&#10;B) quantization&#10;C) compression&#10;D) vectorization

Accepted Answer

The last step in the JPEG image compression process is compression, which specifically aims to remove redundancies and reduce the file size. Quantization, which occurs before compression, reduces the precision of the image's components to make the image easier to compress. Blocking and vectorization are not steps in the JPEG compression process.

Question 8

LZ encoding requires ___.&#10;A) only a dictionary&#10;B) only a buffer&#10;C) only an algorithm&#10;D) a dictionary, a buffer, and an algorithm

Accepted Answer

LZ encoding requires a dictionary, which stores a list of previously encountered patterns or sequences, a buffer, which is used to temporarily store the input data, and an algorithm, which uses the dictionary and buffer to compress the data. Therefore, all three components are necessary for LZ encoding.

Question 9

A string of one hundred 0s is replaced by two markers, a 0, and the number 100. This is ___.&#10;A) run-length encoding&#10;B) Morse coding&#10;C) Huffman encoding&#10;D) Lempel Ziv encoding

Accepted Answer

This scenario describes run-length encoding, a data compression technique that replaces repetitive patterns with markers indicating the pattern repetition. In this case, the 100 zeros are replaced by a marker indicating the number of zeros present.

Question 10

___ is an example of lossy compression.&#10;E) Huffman encoding&#10;F) Lempel Ziv encoding&#10;G) Run-length encoding h. JPEG

Accepted Answer

JPEG is a widely used lossy compression technique for digital images. It uses a combination of techniques, including color subsampling and discrete cosine transform, to achieve high compression rates. However, some information is lost during compression, resulting in a lower quality image compared to the original.

Question 11

Data is compressed using a dictionary with indexes to strings. This is __________ .&#10;A) Huffman encoding&#10;B) Lempel Ziv encoding&#10;C) Morse coding&#10;D) lossy coding

Accepted Answer

The answer of Data is compressed using a dictionary with...

Question 12

JPEG encoding involves ___, a process that reveals the redundancies in a block.&#10;A) blocking&#10;B) the discrete cosine transform&#10;C) quantization&#10;D) vectorization

Accepted Answer

The answer of JPEG encoding involves ___, a process that...

Question 13

___ data compression method, the received data need not be an exact copy of the original message.&#10;A) Only in MP3&#10;B) Only in JPEG&#10;C) Only in MPEG&#10;D) In MP3, JPEG, or MPEG

Accepted Answer

The answer of ___ data compression method, the received data...

Deck 15: Data Compression