| Kohichi SAKANIWA |
Throughout his career, Dr. Sakaniwa has played a central role in the development of science by spearheading research in the fields of communication theory, signal theory, signal processing algorithms and error correction coding, all of which constitute the foundation of information communication theory. His main achievements can be summarized as follows:
(1) Contributions to the design of communication equalizers: During his doctorate course when digitization of communication systems began to be studied, Dr. Sakaniwa undertook research on transversal equalizers, which were important elements in digital communication systems, and proposed and established a new design method for equalizers. After he became a faculty member, he proposed new configurations and equalizing algorithms for communication adaptive equalizers, educated young researchers, and was responsible for a number of important research breakthroughs.
(2) Contributions to the basics of signal theory and communication theory: As a faculty member, he began to study signal theory and communication theory, and worked on the sampling theorem, which is fundamental to digital communication systems. In particular, he pointed out that conventional sampling theory-based signal restoration requires in principle an indefinite delay, and showed that a restoration formula using only the samples of the past semi-infinite interval can be derived if sampling is carried out in intervals shorter than the Nyquist interval. This groundbreaking finding has made it possible to handle digital communication systems on a more rigorously theoretical basis than before, and provided a new fund of knowledge for the design of interpolation filters and predictive coding, thereby making a great contribution to the development of this field. In addition, at the time when facsimile communication began to spread, he showed how a facsimile signal that had been distorted as it traveled through a band-limited communication line could be restored to its original form. He thus elucidated the principles for transmission limits and the methods for restoring facsimile signals.
(3) Contributions to the theory and configuration of error correction codes: In 1989, as a visiting researcher of the Ministry of Education in Southwestern Louisiana University, he began research on error correction coding, which is the basic technology supporting information and communication systems. He made significant contributions to the establishment and development of this area of research by opening up new fields of endeavor in error correction coding, such as the coding of real numbers and on the ring of integers, algebraic-geometric coding, and low-density parity check (LDPC) coding, and by training young researchers.
(4) Contributions to education and society: He helped in the development of outstanding young researchers through his educational and research activities at the university. He has also played a key role in the communications administration policy and the stability of the communications business in Japan by serving in a number of government and industry advisory bodies, including his time as chair of the Telecommunications Dispute Settlement Commission, Ministry of Internal Affairs and Communications. He was president of the Society of Information Theory and Its Applications. Within the IEICE, he held important posts, such as president of the Engineering Sciences Society, chair of the Tokyo Section, director of general affairs, and director of publications.
As mentioned above, Dr. Sakaniwa has made major contributions to the development of the electronics, information and communication fields and to the revitalization of Japan through his research activities in the IEICE, other engineering societies both in Japan and abroad, and in the university and through his activities in telecommunications administration. We are convinced that he truly deserves to be a recipient of the Distinguished Achievement and Contributions Award.
