Abraham Lempel
Encyclopedia
Abraham Lempel is an Israel
i computer scientist
and one of the fathers of the LZ family
of lossless data compression
algorithm
s.
Lempel was born on 10 February 1936 in Lwów
, Poland
(now Lviv
, Ukraine
). He studied at Technion - Israel Institute of Technology
, and received a B.Sc.
in 1963, M.Sc.
in 1965, and D.Sc.
in 1967. Since 1977 he has held the title of full professor. He 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
.
He is the recipient of the 1998 Golden Jubilee Award for Technological Innovation from the IEEE Information Theory Society
; and the 2007 IEEE Richard W. Hamming Medal, 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.
algorithms authored by Lempel and Jacob Ziv
have led to a number of derivative works, including the Lempel–Ziv–Welch algorithm, used in the GIF image format, and the Lempel-Ziv-Markov chain algorithm, used in the 7-Zip
and xz
compressors. The algorithms have also been used as originally published in formats such as DEFLATE
, used in the PNG image format.
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
i computer scientist
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
and one of the fathers of the LZ family
LZ77 and LZ78
LZ77 and LZ78 are the names for 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 most of the LZ variations including LZW, LZSS, LZMA and...
of lossless data compression
Lossless data compression
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange...
algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
s.
Lempel was born on 10 February 1936 in Lwów
Lviv
Lviv is a city in western Ukraine. The city is regarded as one of the main cultural centres of today's Ukraine and historically has also been a major Polish and Jewish cultural center, as Poles and Jews were the two main ethnicities of the city until the outbreak of World War II and the following...
, Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
(now Lviv
Lviv
Lviv is a city in western Ukraine. The city is regarded as one of the main cultural centres of today's Ukraine and historically has also been a major Polish and Jewish cultural center, as Poles and Jews were the two main ethnicities of the city until the outbreak of World War II and the following...
, Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
). He studied at Technion - Israel Institute of Technology
Technion - Israel Institute of Technology
The Technion – Israel Institute of Technology is a research-intensive institute of technology in Haifa, Israel. Originally called the Technikum, it was founded in 1912...
, and received a B.Sc.
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...
in 1963, M.Sc.
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...
in 1965, and D.Sc.
Doctor of Science
Doctor of Science , usually abbreviated Sc.D., D.Sc., S.D. or Dr.Sc., is an academic research degree awarded in a number of countries throughout the world. In some countries Doctor of Science is the name used for the standard doctorate in the sciences, elsewhere the Sc.D...
in 1967. Since 1977 he has held the title of full professor. He is now a professor emeritus in Technion.
His historically important works start with the presentation of the LZ77 algorithm
LZ77 and LZ78
LZ77 and LZ78 are the names for 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 most of the LZ variations including LZW, LZSS, LZMA and...
in a paper entitled "A Universal Algorithm for Sequential Data Compression" in the IEEE Transactions on Information Theory
IEEE Transactions on Information Theory
The IEEE Transactions on Information Theory is a scientific journal published by the Institute of Electrical and Electronic Engineers...
(May 1977), co-authored by Jacob Ziv
Jacob Ziv
Jacob Ziv is an Israeli computer scientist who, along with Abraham Lempel, developed the LZ family of lossless data compression algorithms.-Biography:...
.
He is the recipient of the 1998 Golden Jubilee Award for Technological Innovation from the IEEE Information Theory Society
IEEE Information Theory Society
The IEEE Information Theory Society , formerly the IEEE Information Theory Group, is a professional society of the Institute of Electrical and Electronics Engineers focused on several aspects of information: its processing, transmission, storage, and usage; and the "foundations of the...
; and the 2007 IEEE Richard W. Hamming Medal, for "pioneering work in data compression, especially the Lempel-Ziv algorithm".
Lempel founded HP Labs—Israel
HP Labs
HP Labs is the exploratory and advanced research group for Hewlett-Packard. The lab has some 600 researchersin seven locations throughout the world....
in 1994, and served as its director until October 2007.
Works
The LZ77 and LZ78LZ77 and LZ78
LZ77 and LZ78 are the names for 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 most of the LZ variations including LZW, LZSS, LZMA and...
algorithms authored by Lempel and Jacob Ziv
Jacob Ziv
Jacob Ziv is an Israeli computer scientist who, along with Abraham Lempel, developed the LZ family of lossless data compression algorithms.-Biography:...
have led to a number of derivative works, including the Lempel–Ziv–Welch algorithm, used in the GIF image format, and the Lempel-Ziv-Markov chain algorithm, used in the 7-Zip
7-Zip
7-Zip is an open source file archiver. 7-Zip operates with the 7z archive format, but can read and write several other archive formats. The program can be used from a command line interface, graphical user interface, or with Microsoft Windows shell integration. 7-Zip began in 1999 and is actively...
and xz
Xz
xz is a lossless data compression file format incorporating the LZMA2 compression algorithm. Like gzip and bzip2, concatenation is supported to compress multiple files, but the convention is to bundle a file that is an archive itself, such as those created by the tar or cpio Unix...
compressors. The algorithms have also been used as originally published in formats such as DEFLATE
DEFLATE
Deflate is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. It was originally defined by Phil Katz for version 2 of his PKZIP archiving tool and was later specified in RFC 1951....
, used in the PNG image format.