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The Applications of Fuzzy Logic in Japan

Lotfi Zadeh developed Fuzzy Logic in 1964 and published its explanantion in 1965. Fuzzy Logic does not mean imprecise logic; it means the logic of fuzzy sets. The concept of a fuzzy set is a brilliant generalization of the mathematics of regular sets. Zadeh is an electrical engineer so he conceived of fuzzy sets as having practical applications, rather than as pure mathematics. For some of the purely mathematical aspects of the topic, see the mathemetics of fuzzy sets.

In the early 1970's C.B. Brown and his cohorts were trying to find applications of fuzzy logic to structural analysis.

The first major application came in 1974 when S. Assilian and E. Mamdani in the United Kingdom developed a controller for a steam engine. Their initial efforts at creating a contoller were unsatisfactory because the adaptive system was taking too long to establish an equilibrium. To speed up the adaption time Assilian and Mamdani tried creating some rules based upon linguistics. These worked so well that a whole new line of research was opened up.

The first industrial application of fuzzy logic was developed in Denmark in 1976 and implemented six years later in 1982. In 1977 Dubois applied the fuzzy set concept to traffic conditions.

It was not until the late 1970's that Japanese research began to develop the applications of fuzzy logic. As in many matters in Japan there was a Kanto and a Kansai version of this effort. Kanto means the Tokyo area and Kansai the Osaka area. At Tokyo University H. Shibata and T. Terano led this research. In Osaka K. Asai and K. Tanaka were the leaders. As elsewhere in the world there was a tendency for people who knew nothing of the topic except its name to dismiss it as trivial and unimportant.

In about 1979 Seiji Yasunobu at Hitachi started trying to develop a system for the operation of the subway trains of Sendai. In 1987 this system was in operation in the Sendai subways.

In 1985 Fuji Electrical offered commercially a contol mechanism based upon fuzzy logic.

The successes that Japanese companies were achieving with fuzzy logic prompted the Japanese government agency MITI (Ministry of International Trade and Industry) to set up in 1988 a major collaborative reseach project called the Laboratory for International Fuzzy Engineering Research (LIFE). This was a major effort program involving 50 companies in a six year, $5 billion program.

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