Abraham Lempel ( he, אברהם למפל, born 10 February 1936) is an Israeli

computer scientist A computer scientist is a person who is trained in the academic study of computer science. Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus (a ...

and one of the fathers of the LZ family of

lossless data compression Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...

Biography

Lempel was born on 10 February 1936 in

Lwów Lviv ( uk, Львів) is the largest city in Western Ukraine, western Ukraine, and the List of cities in Ukraine, seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is o ...

, Poland (now

Lviv Lviv ( uk, Львів) is the largest city in Western Ukraine, western Ukraine, and the List of cities in Ukraine, seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is o ...

, Ukraine). He studied at Technion - Israel Institute of Technology, and received a B.Sc. in 1963, M.Sc. in 1965, and

D.Sc. Doctor of Science ( la, links=no, Scientiae Doctor), usually abbreviated Sc.D., D.Sc., S.D., or D.S., is an academic research degree awarded in a number of countries throughout the world. In some countries, "Doctor of Science" is the degree used f ...

in 1967. Since 1977 he has held the title of full professor. Lempel is now a professor emeritus in Technion. His historically important works start with the presentation of the LZ77 algorithm in a paper entitled "A Universal Algorithm for Sequential Data Compression" in the '' IEEE Transactions on Information Theory'' (May 1977), co-authored by

Jacob Ziv Jacob Ziv ( he, יעקב זיו; born 1931) is an Israeli electrical engineer who, along with Abraham Lempel, developed the LZ family of lossless data compression algorithms. Biography Ziv was born in Tiberias, British mandate Palestine, on 27 ...

. He is the recipient of the 1998 Golden Jubilee Award for Technological Innovation from the

IEEE Information Theory Society The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

; and the 2007

IEEE Richard W. Hamming Medal The IEEE Richard W. Hamming Medal is presented annually to up to three persons, for outstanding achievements in information sciences, information systems and information technology. The recipients receive a gold medal, together with a replica ...

, for "pioneering work in data compression, especially the Lempel-Ziv algorithm". Lempel founded HP Labs—Israel in 1994, and served as its director until October 2007.

Works

The

LZ77 and LZ78 LZ77 and LZ78 are the two lossless data compression algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978. They are also known as LZ1 and LZ2 respectively. These two algorithms form the basis for many variations including ...

algorithms authored by Lempel and

have led to a number of derivative works, including the

Lempel–Ziv–Welch Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempe ...

algorithm, used in the GIF image format, and the Lempel-Ziv-Markov chain algorithm, used in the

7-Zip 7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999. 7-Zip has its own archive format called 7z, ...

and xz compressors. The algorithms have also been used as originally published in formats such as DEFLATE, used in the PNG image format.

Bibliography

References

External links

Abraham Lempel – GHN: IEEE Global History Network
*
Technion: Computer Science Department: Prof. Abraham Lempel
* * {{DEFAULTSORT:Lempel, Abraham 1936 births Living people Israeli computer scientists Modern cryptographers Israeli information theorists Technion – Israel Institute of Technology faculty Jewish scientists Scientists from Lviv Israeli Jews Polish emigrants to Israel

Biography

Works

Bibliography

See also

References

External links