Jacob Ziv, codeveloper of the Lempel-Ziv knowledge 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 principle and knowledge 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 method, enabling good knowledge reconstruction. With lossless algorithms, as an IEEE Spectrum article defined in 2021, “bits disappear, making the info file dramatically smaller and thus simpler to retailer and transmit,” however in contrast to lossy compression strategies resembling those used with JPEG and MP3 information, the bits “reappear on command.”
The Lempel-Ziv knowledge compression algorithm, which paved the best way for GIF, PNG, and ZIP information, was designated an IEEE Milestone in 2004.
Ziv’s scientific contributions “modified perpetually the best way 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.”
Info and communication principle pioneer
Born in Israel, Ziv obtained 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 centered on communications methods.
He was chosen in 1959 as considered one of a handful of researchers from Israel’s protection lab to check 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 Info Idea describing the Ziv-Zakai sure, a way 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 courses 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 knowledge 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 unintentionally flipped.
Jacob Ziv [left] and Abraham Lempel revealed algorithms for lossless knowledge compression in 1977 and 1978, each within the IEEE Transactions on Info Idea. The strategies, which turned 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 knowledge compression. Ziv instructed IEEE Spectrum that he and Lempel had been the “good match” for the mission: “I knew all about info principle and statistics, and Abraham was well-equipped in Boolean algebra and laptop science.”
In 1977, whereas Ziv was on sabbatical at Bell Labs, he and Lempel revealed a paper within the IEEE Transactions on Info Idea, “A Common Algorithm for Sequential Knowledge Compression.” The algorithm they described was quicker and extra environment friendly than Huffman coding, which was the lossless knowledge compression commonplace on the time. Ziv and Lempel’s algorithm turned referred to as LZ77.
The brand new algorithm labored on any form of knowledge and didn’t require preprocessing. It wanted to take just one move at a picture file with a purpose to compress it.
That significantly 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 next yr, the 2 researchers issued a refined model, LZ78.
The 2 algorithms, also called LZ1 and LZ2, paved the best way for the Unix compression applications of the early Eighties in addition to the WinZip and Gzip compression applications within the early Nineties. They’re used at present in GIF, TIFF and different picture codecs.
A long-lasting legacy
Ziv garnered a number of awards for his pioneering contributions to knowledge compression. Along with the 2021 IEEE Medal of Honor, he obtained an IEEE Info Idea SocietyGolden Jubilee Award for Technological Innovation in 1998.
He was awarded a 2017 EMET Prize (referred to as Israel’s Nobel Prize), an Affiliation for Computing EquipmentKanellakis Award in 1997, and a 1995 Marconi Prize.
Ziv’s curiosity in schooling led him to alternatives past the Technion. He chaired the Israeli Council for Larger 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 applications and tasks in science, expertise, engineering, and arithmetic.
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