16 Questions
What is the basic idea behind Lempel Ziv Encoding?
Creating a dictionary of strings for communication and substituting previously-encountered strings with their index in the dictionary.
Who developed the Lempel–Ziv–Welch (LZW) universal lossless data compression algorithm?
Abraham Lempel, Jacob Ziv, and Terry Welch
What is the purpose of building an indexed dictionary in the Lempel Ziv Compression algorithm?
To facilitate substitution of previously-encountered strings with their index in the dictionary during compression.
Which phase of Lempel Ziv Compression involves extracting the smallest substring that cannot be found in the remaining uncompressed string?
Compressing a string of symbols
Which widely used file compression utility was based on the Lempel–Ziv–Welch (LZW) algorithm?
Unix file compression utility compress
In what year was the Lempel–Ziv–Welch (LZW) algorithm published?
1984
What is the basic idea behind Lempel Ziv Compression?
Storing the substring in a dictionary and assigning it an index value
What is the inverse process of Lempel Ziv Compression?
Lempel Ziv Decompression
Which statement is true about universal coding schemes like LZW?
They do not require advance knowledge about the data
What happens in the LZW encoding algorithm when P + C is already in the dictionary table?
P is updated to P + C
In the LZW compression example, what is added to the dictionary table after processing 'BABAABAAA'?
'BA' and 'AB'
What is the output after processing 'BABAABAAA' using LZW compression?
'66 65 256 65 66 257 66 65 256 65 65 257 258 257 259 260'
What does the LZW decompression process involve?
Translating each code from the compressed file through the code table to find characters it represents
What happens if 'P + C' is not in the dictionary table in the LZW encoding algorithm?
'P + C' is added to the dictionary table
What kind of coding scheme does LZW represent?
Universal coding scheme
In Lempel Ziv Compression, what does 'Insert the index and the last character of the substring into the compressed string' mean?
'Index and last character are added to the end of the compressed string'
Learn about Lempel-Ziv encoding, a dictionary-based data compression technique developed by Abraham Lempel and Jacob Ziv. This lecture covers the evolution of LZ-77 coding to LZ-78 and its universal lossless data compression variant Lempel-Ziv-Welch (LZW).
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
