Remembering Information 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 basic contributions to info idea and information compression expertise, and for distinguished analysis management.”

Ziv, {an electrical} engineering professor on the Technion—the Israel Institute of Know-how, in Haifa—and his colleague Abraham Lempel perfected the lossless compression approach, enabling excellent information reconstruction. With lossless algorithms, as an IEEE Spectrum article defined in 2021, “bits disappear, making the information file dramatically smaller and thus simpler to retailer and transmit,” however in contrast to lossy compression methods equivalent to those used with JPEG and MP3 information, the bits “reappear on command.”

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

Ziv’s scientific contributions “modified without end the way in which we retailer, course of, and switch info,” 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 logo of science’s nice potential to ignite technological revolutions that have an effect on all of mankind.”

Data and communication idea 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 Protection, the place his work targeted on communications techniques.

He was chosen in 1959 as certainly one of a handful of researchers from Israel’s protection lab to review overseas. He moved to america to attend MIT, the place he earned a Ph.D. in electrical engineering in 1962. Whereas 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 Protection as head of its communications division.

He returned to america in 1968 to work at Bell Phone Laboratories, in Murray Hill, N.J. The next yr, he and Moshe Zakai revealed a paper in IEEE Transactions in Data Idea describing the Ziv-Zakai certain, a technique to find out whether or not a processor is getting essentially the most correct info potential from a given sign.

Ziv relocated to Israel in 1970, this time to hitch the Technion as a professor {of electrical} engineering. He served as dean of the EE school 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.

On the Technion and at Bell, Ziv carried out analysis in information compression, info idea, and statistical communications. He made a number of contributions to the idea 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 revealed algorithms for lossless information compression in 1977 and 1978, each within the IEEE Transactions on Data Idea. The strategies, which turned often known 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 have been the “excellent match” for the mission: “I knew all about info idea and statistics, and Abraham was well-equipped in Boolean algebra and pc science.”

In 1977, whereas Ziv was on sabbatical at Bell Labs, he and Lempel revealed a paper within the IEEE Transactions on Data Idea, “A Common Algorithm for Sequential Information Compression.” The algorithm they described was quicker and extra environment friendly than Huffman coding, which was the lossless information compression normal on the time. Ziv and Lempel’s algorithm turned often known as LZ77.

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

That enormously decreased the time it took to research and compress an information file by on the lookout for distinctive sequences of bits whereas concurrently compressing the information, utilizing tips to consult with beforehand seen sequences. The next yr, the 2 researchers issued a refined model, LZ78.

The 2 algorithms, also referred to as LZ1 and LZ2, paved the way in which for the Unix compression packages of the early Nineteen Eighties in addition to the WinZip and Gzip compression packages within the early Nineteen Nineties. They’re used at the moment in GIF, TIFF and different picture codecs.

An enduring legacy

Ziv garnered a number of awards for his pioneering contributions to information compression. Along with the 2021 IEEE Medal of Honor, he acquired an IEEE Data Idea SocietyGolden Jubilee Award for Technological Innovation in 1998.

He was awarded a 2017 EMET Prize (often known as Israel’s Nobel Prize), an Affiliation for Computing EquipmentKanellakis 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 Greater Schooling planning and grants committee from 1985 to 1991, for instance. An Israel Academy of Sciences and Humanities member from 1981 till his demise, he served as its president from 1995 to 2004.

In 1997 he established the Israeli Nationwide Infrastructure Discussion board for Analysis and Growth to advertise packages and tasks in science, expertise, engineering, and arithmetic.