Lotfali Askar Zadeh (Persian: لطفعلی عسکرزاده born February 4, 1921), better known as Lotfi A. Zadeh, is a mathematician, electrical engineer, computer scientist, and a professor of computer science at the University of California, Berkeley. Zadeh describes himself in an interview with Jeanne Spriter James as an American, mathematically oriented, electrical engineer of Iranian descent, born in Russia!
Life and career
Zadeh was born in Baku, Azerbaijan SSR, to an Iranian Azeri father from Ardabil, Rahim Aleskerzade, who was a journalist on assignment from Iran, and a Russian Jewish mother, Fanya Koriman, who was a pediatrician. When Zadeh was ten years old, his family moved to Iran, his father’s homeland.
Zadeh grew up in Iran, and studied at Alborz High School. After high school, he sat for the national university exams and placed second in the entire country. In 1942, he graduated from the University of Tehran with a degree in electrical engineering (Fanni), and moved to the United States in 1944. He received an MS degree in electrical engineering from MIT in 1946, and a PhD in electrical engineering from Columbia University in 1949.
Zadeh taught for ten years at Columbia University, was promoted to Full Professor in 1957, and has taught at the University of California, Berkeley since 1959. He published his seminal work on fuzzy sets in 1965, in which he detailed the mathematics of fuzzy set theory. In 1973 he proposed his theory of fuzzy logic.
Zadeh is noted to be “quick to shrug off nationalism, insisting there are much deeper issues in life”, and is quoted as stating: “The question really isn’t whether I’m American, Russian, Iranian, Azerbaijani, or anything else. I’ve been shaped by all these people and cultures and I feel quite comfortable among all of them.”Zadeh also notes in the same interview from which the above quote is taken: “Obstinacy and tenacity. Not being afraid to get embroiled in controversy. That’s very much a Turkish tradition. That’s part of my character, too. I can be very stubborn. That’s probably been beneficial for the development of Fuzzy Logic.”
Zadeh is married to Fay Zadeh and has two children, Stella Zadeh and Norman Zadeh.
Because of the importance of the relaxation of Aristotelian logic, which opens up applicability of rational methods to the majority of practical situations without dichotomous truth values, Zadeh is one of the most referenced authors in the fields of applied mathematics and computer science, but – as noted below – his contributions are not limited to fuzzy sets and systems.
Fuzzy sets and systems
The law of the excluded middle states that for all propositions p, either p or ~p must be true, there being no middle true proposition between them. This should not be confused with the principle of bivalence, which states that either p must be true or false.
Jan Łukasiewicz was the first to propose a systematic alternative to the bi-valued logic of Aristotle and described the 3-valued logic, with the third value being Possible. Zadeh, in his theory of fuzzy sets, proposed using a membership function (with a range covering the interval [0,1]) operating on the domain of all possible values. He proposed new operations for the calculus of logic and showed that fuzzy logic was a generalisation of classical and Boolean logic. He also proposed fuzzy numbers as a special case of fuzzy sets, as well as the corresponding rules for consistent mathematical operations (fuzzy arithmetic).
Lotfi Zadeh is also credited, along with John R. Ragazzini, in 1952, with having pioneered the development of the z-transform method in discrete time signal processing and analysis. These methods are now standard in digital signal processing, digital control, and other discrete-time systems used in industry and research. He is an editor of International Journal of Computational Cognition.
Zadeh’s latest work includes computing with words and perceptions. His recent papers include From Search Engines to Question-Answering Systems—The Role of Fuzzy Logic, Progress in Informatics, No. 1, 1-3, 2005; and Toward a Generalized Theory of Uncertainty (GTU)—An Outline, Information Sciences, Elsevier, Vol. 172, 1-40, 2005.
- 1965. Fuzzy sets. Information and Control. 1965; 8: 338–353.
- 1965. “Fuzzy sets and systems”. In: Fox J, editor. System Theory. Brooklyn, NY: Polytechnic Press, 1965: 29–39.
- 1972. “A fuzzy-set-theoretical interpretation of linguistic hedges”. Journal of Cybernetics 1972; 2: 4–34.
- 1973. “Outline of a new approach to the analysis of complex systems and decision processes”. IEEE Trans. Systems, Man and Cybernetics, 1973; 3: 28–44.
- 1974. “Fuzzy logic and its application to approximate reasoning”. In: Information Processing 74, Proc. IFIP Congr. 1974 (3), pp. 591–594.
- 1975. “Fuzzy logic and approximate reasoning”. Synthese, 1975; 30: 407–428.
- 1975. “Calculus of fuzzy restrictions”. In: Zadeh LA, Fu KS, Tanaka K, Shimura M, editors. Fuzzy Sets and their Applications to Cognitive and Decision Processes. New York: Academic Press, 1975: 1–39.
- 1975. “The concept of a linguistic variable and its application to approximate reasoning”, I-III, Information Sciences 8 (1975) 199–251, 301–357; 9 (1976) 43–80.
- 2002. “From computing with numbers to computing with words — from manipulation of measurements to manipulation of perceptions” in International Journal of Applied Math and Computer Science, pp. 307–324, vol. 12, no. 3, 2002.
Awards and honors
In 1994 Zadeh was inducted as a Fellow of the Association for Computing Machinery. He was awarded the IEEE Medal of Honor in 1995 “For pioneering development of fuzzy logic and its many diverse applications.”
Zadeh has a long list of achievements, including an honorary Professorship from the Azerbaijan State Oil Academy (1993), but the awards Zadeh has received since 2003, include:
- Outstanding Contribution Award, Web Intelligence Consortium (WIC), Halifax, Canada, 2003.
- Wall of Fame, Heinz Nixdorf MuseumsForum (HNF), Paderborn, Germany, 2004.
- Civitate Honoris Causa, Budapest Tech Polytechnical Institution, Budapest, Hungary; Sept. 4, 2004.
- Doctor Honoris Causa, Muroran Institute of Technology, Muroran, Japan; Oct. 29, 2004.
- Doctor Honoris Causa, Hong Kong Baptist University, Hong Kong, China; Nov. 9, 2004.
- V. Kaufmann Prize and Gold Medal, International Association for Fuzzy-Set Management and Economy (SIGEF), Barcelona, Spain, Nov. 15, 2004.
- Foreign member of the Polish Academy of Sciences, 2005.
- Nicolaus Copernicus Medal of the Polish Academy of Sciences, 2005.
- J. Keith Brimacombe IPMM Award in recognition of his development of fuzzy set theory and fuzzy logic, 2005.
- Doctor Honoris Causa, Universidad Politécnica de Madrid, Madrid, Spain; Jan. 29, 2007.
- Richard E. Bellman Control Heritage Award
- Doctor Honoris Causa, Ryerson University, Toronto, Ontario, Canada; June 10, 2008.
Zadeh’s most recent recognition comes from The Franklin Institute in Philadelphia. Lotfi Zadeh received the2009 Benjamin Franklin Medal in Electrical Engineering for inventing and developing the field of “fuzzy logic,” in which a system applies a quantitative assessment to inherently ambiguous ideas, thus providing a new paradigm to improve artificial intelligence and automated control systems.