Remembering Data Compression Pioneer Jacob Ziv

Jacob Ziv, codeveloper of the Lempel-Ziv information compression algorithm, died on 26 March on the age of 91.

The IEEE Life Fellow was awarded the 2021 IEEE Medal of Honor “for fundamental contributions to information theory and data compression technology, and for distinguished research leadership.”

Ziv, {an electrical} engineering professor on the Technion—the Israel Institute of Technology, in Haifa—and his colleague Abraham Lempel perfected the lossless compression approach, enabling good information reconstruction. With lossless algorithms, as an IEEE Spectrum article defined in 2021, “bits disappear, making the data file dramatically smaller and thus easier to store and transmit,” however not like lossy compression strategies comparable to those used with JPEG and MP3 recordsdata, the bits “reappear on command.”

The Lempel-Ziv information compression algorithm, which paved the way in which for GIF, PNG, and ZIP recordsdata, was designated an IEEE Milestone in 2004.

Ziv’s scientific contributions “changed forever the way we store, process, and transfer information,” the Technion’s president, physicist Uri Sivan, wrote in a tribute to Ziv. “He was an inspiration to all of us—a beacon of scientific excellence [and] a symbol of science’s great potential to ignite technological revolutions that affect all of mankind.”

Information and communication principle pioneer

Born in Israel, Ziv acquired bachelor’s and grasp’s levels in electrical engineering from the Technion in 1954 and 1957. He started his profession in 1955 as a analysis engineer with the Israeli Ministry of Defense, the place his work targeted on communications methods.

He was chosen in 1959 as one among a handful of researchers from Israel’s protection lab to check overseas. He moved to the United States to attend MIT, the place he earned a Ph.D. in electrical engineering in 1962. While at MIT, he held a part-time job as a analysis engineer within the utilized science division at U.S. protection contractor Melpar, in Watertown, Mass. After a yr, he moved again to Israel and rejoined the Ministry of Defense as head of its communications division.

He returned to the United States in 1968 to work at Bell Telephone Laboratories, in Murray Hill, N.J. The following yr, he and Moshe Zakai printed a paper in IEEE Transactions in Information Theory describing the Ziv-Zakai sure, a technique to find out whether or not a processor is getting essentially the most correct info attainable from a given sign.

Ziv relocated to Israel in 1970, this time to affix the Technion as a professor {of electrical} engineering. He served as dean of the EE college from 1974 to 1976 and vice chairman of educational affairs from 1978 to 1982. He taught lessons on the institute all through his profession, punctuated by three analysis sabbaticals within the info analysis division at Bell Labs.

At the Technion and at Bell, Ziv performed analysis in information compression, info principle, and statistical communications. He made a number of contributions to the speculation of error-correcting codes and an encoding scheme that transmits messages as binary numbers in order that they are often recovered even when some bits are by accident flipped.

Jacob Ziv [left] and Abraham Lempel printed algorithms for lossless information compression in 1977 and 1978, each within the IEEE Transactions on Information Theory. The strategies, which grew to become referred to as LZ77 and LZ78, are nonetheless in use.Jacob Ziv/Technion

Lempel-Ziv compression algorithms

It was in his early days on the Technion that Ziv met Lempel, a pc scientist who shared his curiosity in enhancing lossless information compression. Ziv advised IEEE Spectrum that he and Lempel had been the “perfect match” for the undertaking: “I knew all about information theory and statistics, and Abraham was well-equipped in Boolean algebra and computer science.”

In 1977, whereas Ziv was on sabbatical at Bell Labs, he and Lempel printed a paper within the IEEE Transactions on Information Theory, “A Universal Algorithm for Sequential Data Compression.” The algorithm they described was quicker and extra environment friendly than Huffman coding, which was the lossless information compression customary on the time. Ziv and Lempel’s algorithm grew to become referred to as LZ77.

The new algorithm labored on any type of information and didn’t require preprocessing. It wanted to take just one go at a picture file so as to compress it.

That enormously diminished the time it took to investigate and compress a knowledge file by searching for distinctive sequences of bits whereas concurrently compressing the info, utilizing tips that could check with beforehand seen sequences. The following yr, the 2 researchers issued a refined model, LZ78.

The two algorithms, often known as LZ1 and LZ2, paved the way in which for the Unix compression applications of the early Eighties in addition to the WinZip and Gzip compression applications within the early Nineties. They are used right this moment in GIF, TIFF and different picture codecs.

A long-lasting legacy

Ziv garnered a number of awards for his pioneering contributions to information compression. In addition to the 2021 IEEE Medal of Honor, he acquired an IEEE Information Theory SocietyGolden Jubilee Award for Technological Innovation in 1998.

He was awarded a 2017 EMET Prize (referred to as Israel’s Nobel Prize), an Association for Computing MachineryKanellakis Award in 1997, and a 1995 Marconi Prize.

Ziv’s curiosity in training led him to alternatives past the Technion. He chaired the Israeli Council for Higher Education planning and grants committee from 1985 to 1991, for instance. An Israel Academy of Sciences and Humanities member from 1981 till his dying, he served as its president from 1995 to 2004.

In 1997 he established the Israeli National Infrastructure Forum for Research and Development to advertise applications and tasks in science, know-how, engineering, and arithmetic.