JIMMY K. OMURA (1940-2024)

BY DARIUSH DIVSALAR

JIMMY KAZUHIRO OMURA was born on Sept. 8, 1940, in Campbell, California, and passed away at age 83 on Aug. 29, 2024, in San Francisco. A renowned electrical engineer and information theorist, he made foundational contributions to information theory, channel codes, spread-spectrum communication systems, and cryptography.

Jim earned his B.S. (1962) and M.S. (1963) degrees from MIT, followed by a Ph.D. (1966) from Stanford University, all in electrical engineering. Spending 15 years as a professor of electrical and computer engineering at UCLA from 1969-84, he was recognized as an outstanding lecturer. His notable achievements included designing several spread-spectrum communication systems and co-developing the Massey-Omura cryptosystem with James Massey (NAE 1991). Alongside Andrew Viterbi (NAE 1978), he co-authored the seminal textbook Principles of Digital Communication and Coding (Dover Publications, 1979). During the 1980s, he was a consultant at the Jet Propulsion Laboratory and contributed to the “Spread Spectrum Communications” series with Marvin Simon, Robert Scholtz (NAE 2009), and Barry Levitt. Over the course of his career, Jim published more than 100 technical papers.

As an esteemed member of the IEEE Information Theory Society and the IEEE Communications Society, Jim was elevated to IEEE fellow status in 1981 for contributions to information and communications theory as applied to communications systems design.

He dedicated his time to the IEEE Information Theory Society (ITS), serving as chairman of the “San Francisco Section,” secretary, and a member of the Board of Governors. From 1973 to 1975, he also served as editor of the IEEE ITS Newsletter.

Jim’s Ph.D. advisor at Stanford, Thomas Kailath (NAE 1984), remained a close friend throughout his life. After his undergraduate years at MIT, Jim wanted to return to California. While he was considering enrolling at UC Berkeley, Harry L. Van Trees (NAE 2015) suggested he apply to study with Thomas Kailath at Stanford. Upon his enrollment at Stanford, Jim and Tom quickly found a shared interest in advanced mathematics, particularly analysis and operator theory. Having been exposed to Bellman’s dynamic programming theory, Jim soon applied those concepts to new results in control theory. Several years later, as an assistant professor at UCLA, he demonstrated that the well-known Viterbi algorithm could also be interpreted as an application of dynamic programming. While Jim was away at UCLA, he and Tom maintained their professional and personal ties, which were greatly strengthened after Jim returned to the Bay Area. Reflecting on their relationship, Tom remarked, “Jim was not just a student; he became a lifelong friend and collaborator. I will always cherish the many technical and social events at Stanford and San Francisco at which we spent long hours discussing both work and life.”

After receiving his Ph.D., Jim spent approximately one year in Southeast Asia after being offered a position with a U.S. government agency. After returning to the U.S., he applied for a faculty position in the System Sciences Division of UCLA’s School of Engineering and Applied Science. Jim participated in an interview conducted by Andrew Viterbi, among other faculty, and ultimately joined UCLA as an assistant professor. Viterbi recalled their close collaboration, particularly in co-authoring Principles of Digital Communication and Coding, a graduate textbook, as well as their paper “Trellis encoding of memoryless discrete-time sources with a fidelity criterion,” published in IEEE Transactions on Information Theory. Viterbi reflected that “both of these were highlights of our academic careers.”

After moving on from academia to pursue diverse entrepreneurial activities incorporating applications of their research, Jim and Andy stayed in touch for decades, visiting one another in San Francisco and San Diego. Their close friendship continued for 50 years, well into their retirements.

Jim co-founded the data security company Cylink Corporation in Sunnyvale, California, in 1984, where he and his team developed the first commercial 1024-bit public key encryption chip, securing large-scale commercial data networks. Cylink went public in 1996 and was later acquired by SafeNet in 2003. During this time, Martin Hellman (NAE 2002) of Stanford University frequently exchanged ideas on cryptography with Jim. Reflecting on Jim’s impact, Marty shared: “Jim was not only a brilliant mind in cryptography but also a great friend. Jim’s insights always pushed the boundaries of what was possible, not only in cryptography, but also in communications more generally. For example, Jim and Dave Forney (NAE 1983) independently realized that Viterbi decoding was optimal and that it could be applied to intersymbol interference — which is just a convolutional code over the reals instead of over GF(2). I totally missed both results, but Jim saw them as ‘obvious.’ I remember him saying that once you understood dynamic programming, the optimality followed immediately. His enthusiasm and creativity were infectious, and his passing is a great loss to both the field and to those of us who knew him.”

From 2002 to 2011, Jim served as the technology strategist for the Gordon and Betty Moore Foundation. In 2013 he co-founded dataFascia Corporation to develop an IT system for the healthcare market.

While at UCLA, Jim advised numerous Ph.D. students, including Dariush Divsalar (NAE 2024) and Ramin Sadr, both of whom kept in touch with Jim through visits and email exchanges. Dariush shared these memories of Jim: “Since I enrolled at UCLA in fall 1973, Jim taught me the fundamentals of information and communication theory and eventually guided me through the Ph.D. program. His support over the years was an intangible and critical component of all my success in my career. Jim’s guidance went far beyond academics; he shaped the way I approached challenges and inspired me to pursue excellence.”

Ramin echoed this sentiment: “Jim was far more than a professor to us over the years; he was a profound source of inspiration, a dedicated mentor, and a true friend. We experienced countless memorable moments together, from my days at UCLA as a Ph.D. student to the early days at Cylink and beyond. Jim consistently offered guidance and shared his remarkable insights throughout my career. His strength and resilience shone through in every facet of his life, including his courageous fight against cancer.”

Jim’s wife, Susan Muroshige, informed Ramin and Dariush of Jim’s passing, which took place on Aug. 30, 2024. She shared: “Unfortunately, the type of lymphoma he had was very difficult to eradicate, and it reappeared after several types of treatments. In July he got covid which infected his lungs and was the cause of his death.”

As a university professor, corporate leader, and consultant, Jim has been responsible for the theoretical underpinning and application of several benchmark technologies for communications systems and data networks during his career. In 2005, he received the IEEE Alexander Graham Bell Medal “for contributions to the theory of communication systems and the commercial applications of spread-spectrum radios and public key cryptography.” He was elected to the National Academy of Engineering in 1997 for his work in spread-spectrum communications and data encryption, and he was inducted into the Silicon Valley Engineering Hall of Fame in 2009.

Jim’s legacy is remembered fondly by many. His co-author, Robert Scholtz of the University of Southern California, described him as a wonderful friend and colleague. Izhak Rubin of UCLA shared memories of working closely with Jim, whose office was right next door, noting that he was not only a brilliant engineer and scientist but also a kind and caring person. Leonard Kleinrock (NAE 1980) of UCLA commented, “Jim Omura had a remarkable career … (as) evidenced (by) the other giants with whom he interacted, e.g., Viterbi, Massey, Forney, Hellman, Kailath, etc., all of whom were either my MIT classmates, or UCLA colleagues.”

Jim is survived by his wife, Susan; son Daniel and his wife, Xiaoqing; daughter Dawn Galperin and her husband, Hernan; grandchildren Kai Omura, Rei Omura, Natalia Galperin, and Dylan Galperin; sisters Akiko Kubo and June Crow; brother George; sister-in-law Claire Omura; and seven nieces and nephews.