Yu-Chi Ho

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This article is about the Chinese-American mathematician.

For the writer and mayor of St Paul, see Laurence C. Hodgson.
Yu-Chi "Larry" Ho

Born March 1, 1934 (1934-03-01) (age 74)
Shanghai, China
Residence United States
Nationality American (1961-present)
Chinese (1934-1961)
Fields Applied mathematics
Control theory
Institutions Harvard University
Alma mater Harvard University
Massachusetts Institute of Technology
Doctoral advisor Arthur E. Bryson, Jr.
Kumpati S. Narendra
Notable awards Richard E. Bellman Control Heritage Award
Rufus Oldenburger Medal

Yu-Chi "Larry" Ho (Chinese: 何毓琦) (born March 1, 1934 in Shanghai, China) is a renowned Chinese-American mathematician, control theorist, and a professor at the School of Engineering and Applied Sciences, Harvard University.

He is well-known as the co-author of Applied Optimal Control, the top referenced work on the subject of optimal control,[1] as well as a pioneer in various other fields such as differential games, pattern recognition, and discrete event dynamic systems.

Contents

[edit] Biography

[edit] Education

Yu-Chi Ho was born on March 1, 1934 in Shanghai, China and came to the United States at the age of 15 in 1949. After finishing the last year of high school in 1950, Ho was accepted to the Massachusetts Institute of Technology where he received a S.B. in Electrical Engineering in the summer of 1953, at the age of 19. Ho later reported that his initial interests were in mechanical engineering, due to a childhood experience repairing an European ornamental clock without any previous knowledge of its mechanisms. His application to MIT mechanical engineering, however, was routed to the electrical engineering department by mistake, and Ho decided to stay in the department.[2] Ho continued his graduate studies at MIT, receiving a S.M. degree in Electrical Engineering in 1955.

After working for Bendix Aviation for three years, Ho moved to Harvard University in 1958 where he completed a Ph.D. in Applied Mathematics in 1961. His thesis A Study Optimal Control of Dynamic Systems was advised by Arthur E. Bryson, Jr. and Kumpati S. Narendra.

[edit] Career

After finishing his Ph.D. in the spring of 1961, Yu-Chi Ho left for a summer job in California, skipping the graduation ceremony.[3] Ho returned to Harvard in the fall of 1961 for a teaching appointment, receiving tenure in 1965,[4] and remained in the School of Engineering and Applied Sciences until his retirement in 2001. At Harvard, Ho held the title of Gordon McKay Professor of Systems Engineering, Emeritus, as well as the T. Jefferson Coolidge Chair of Applied Mathematics, Emeritus. He was also the visiting professor to the Cockrell Family Regent's Chair in Engineering at the University of Texas, Austin in 1989. In 2001, Ho retired from teaching duties at Harvard after 40 years of service and became a Research Professor. He was appointed (part time) the Chair Professor and Chief Scientist at the Center for Intelligent and Networked Systems (CFINS), Department of Automation, Tsinghua University. In his career, he has supervised 50 Ph.D. students at Harvard and 5 students at Tsinghua.

Ho has an Erdös number of 3: Yu-Chi Ho - Simson Baron - István Joó - Paul Erdös.

[edit] Professional activities

Yu-Chi Ho is a member of the U.S. National Academy of Engineering and a foreign member of the Chinese Academy of Engineering and the Chinese Academy of Sciences. He is also an IEEE Life Fellow and an INFORMS Inaugural Fellow, and a Distinguished Member of the IEEE Control Systems Society. In addition to services on various governmental and industrial panels, and professional society administrative bodies, he was the program chairman for the IEEE Conference on Decision and Control 1972, the general chairman of the IEEE Robotics and Automation Conference 1987, and President of the IEEE Robotics & Automation Society in 1988. Ho co-founded Network Dynamics, Inc., a software firm specializing in industrial automation. He is on the editorial boards of several international journals and is the editor-in-chief of the international Journal on Discrete Event Dynamic Systems.

[edit] Community service

Yu-Chi Ho was the founder and the first chair of the annual United Asian American Dinner of Massachusetts. He also served as the Chairman of the Board of Greater Boston Chinese Cultural Association from 1995 to 1998, the President of the New England Chapter of the Organization of Chinese Americans from 1982 to 1985, a board member of the Mass Endowment for Humanities from 1985 to 1989, and a founding member and member of the steering committee of the 80-20 Initiative, a national political movement for Asian Americans.

[edit] Honors and Awards

Yi-Chi Ho accepting the American Automatic Control Council Richard E. Bellman Control Heritage Award in 1999.
Yi-Chi Ho accepting the American Automatic Control Council Richard E. Bellman Control Heritage Award in 1999.

[edit] Personal life

Ho became a naturalized citizen of the United States in 1961. He proposed to his wife Sophia on Valentine's Day, 1959,[5] and they have three children, Adrian, Christine and Lara, born in 1961, 1963, and 1973,[6] two of which received Ph.D. degrees.[3] They currently reside in Lexington, Massachusetts. Since April 25, 2007, Ho blogs on ScienceNet.cn, a science blog network sponsored by the Chinese Academy of Engineering and the Academy of Sciences.[7]

[edit] Work

[edit] Control theory and optimization

Yu-Chi Ho's research in control theory began when he was a graduate student at MIT. His first paper published in 1955, titled time-domain compensation for closed-loop systems by a delay line method, presented a new approach to the synthesis and analysis of closed-loop systems in the time domain.[8] Following his meeting with Rudolf E. Kalman at the first American Control Conference in 1960,[9] Ho began a lifelong collaboration with Kalman which formed what is now known as the modern control theory. The widely used classical control theory at the time focused on analysis in the frequency domain using Laplace and Fourier transforms, and the techniques proposed by Kalman, the time-domain based state space models, were not widely accepted. With Kalman, Ho showed that the state space representation provides a convenient and compact way to model and analyze dynamical systems with multiple inputs and outputs which would otherwise take multiple Laplace transforms to encode, and it can be extended into nonlinear systems. Seminar papers in area includes controllability of linear dynamic systems,[10] an in-depth investigation of the theory of controllability proposed by Kalman in 1961 (then known as the Kalman-Bertram condition).

Together with his student Robert Lee at MIT, the paper A Bayesian approach to problems in stochastic estimation and control formulated a general class of stochastic estimation and control problems from a Bayesian Decision-Theoretic viewpoint.[11]

[edit] Pattern recognition

After joining the faculty of Harvard University, Ho developed the Ho-Kashyap rule in pattern recognition with his first Ph.D. student, Rangasami L. Kashyap.[12][13]

[edit] Game theory

He then turned his attention to game theory, and published in 1965 the landmark paper Differential Games and Optimal Pursuit-Evation Strategies,[14] proving the optimality of a proportional guidance scheme. His paper Nonzero Sum Differential Games[15] opened the way for general game-theoretic studies in systems and control.

[edit] Discrete event dynamic systems

Since the 1970s, Ho focused on research in discrete event dynamic systems, making significant contributions in perturbation analysis and ordinal optimization, including the book Perturbation Analysis of Discrete Event Dynamic Systems, a primary reference in perturbation analysis.[16]

[edit] Publications

[edit] Books

  • Bryson, A.E.; Ho, Y.C. (1975). Applied optimal control. Washington, DC: Hemisphere. ISBN 0891162283. 
  • Ho, Y.C.; Cao, X.R. (1991). Discrete Event Dynamic Systems and Perturbation Analysis. Kiuwer Aca-demic Publishers, Boston. ISBN 0891162283. 
  • Ho, Y.C.; Zhao, Q.C, Jia, Q.S. (2007). Ordinal Optimization: Soft Optimization for Hard Problems. Berlin: Springer. ISBN 0387372326. 

[edit] About Yu-Chi Ho's work

[edit] References

  1. ^ Bryson, A.E.; Ho, Y.C. (1975). Applied optimal control. Washington, DC: Hemisphere. 
  2. ^ On Research and Education (#11) Changing Research Direction and Field of Endeavor
  3. ^ a b Yu-Chi Ho (2007-05-25). An American Graduation. Retrieved on 2008-05-20.
  4. ^ Harvard Celebrates the launching of the School of Engineering and Applied Sciences September 20, 2007
  5. ^ Yu-Chi Ho (2008-02-12). A Valentine Day Tribute to My Wife. Retrieved on 2008-05-20.
  6. ^ The Family Automobile Trip and vacation in the US
  7. ^ http://www.sciencenet.cn/blog/何毓琦.htm
  8. ^ Ho, Y.C. (1955). "Time-domain compensation for closed-loop systems by a delay line method". 
  9. ^ On Research #10 - some specific advice to Chinese Ph.D students
  10. ^ Kalman, R.E.; Ho, Y.C.; Narendra, K.S. (1963). "Controllability of linear dynamical systems". Contributions to Differential Equations 1 (2): 189-213. 
  11. ^ Ho, Y.; Lee, R. (1964). "A Bayesian approach to problems in stochastic estimation and control". Automatic Control, IEEE Transactions on 9 (4): 333-339. 
  12. ^ Ho, Y.C.; Kashyap, R.L. (1965). "An algorithm for linear inequalities and its applications" (abstract). IEEE Trans. Elec. Comp 14 (5): 683-688. doi:10.1109/PGEC.1965.264206. 
  13. ^ Ho, Y.C.; Kashyap, R.L. (1966). "A Class of Iterative Procedures for Linear Inequalities". SIAM Journal on Control 4: 112. 
  14. ^ Ho, Y.; Bryson, A.; Baron, S. (1965). "Differential games and optimal pursuit-evasion strategies" (abstract). Automatic Control, IEEE Transactions on 10 (4): 385-389. doi:10.1109/TAC.1965.1098197. 
  15. ^ Starr, A.W.; Ho, Y.C. (1969). "Nonzero-sum differential games". Journal of Optimization Theory and Applications 3 (3): 184-206. doi:10.1007/BF00929443. 
  16. ^ Ho, Y.C.; Cao, X.R. (1991). "Discrete Event Dynamic Systems and Perturbation Analysis". Kiuwer Aca-demic Publishers, Boston. 

[edit] External links

v • d • e
Richard E. Bellman Control Heritage Award
1979–2000

Hendrik Wade Bode (1979) · Nathaniel B. Nichols (1980) · Charles Stark Draper (1981) · Irving Lefkowitz (1982) · John V. Breakwell (1983) · Richard E. Bellman (1984) · Harold Chestnut (1985) · John Zaborszky (1986) · John C. Lozier (1987) · Walter R. Evans (1988) · Roger W. Brockett (1989) · Arthur E. Bryson, Jr. (1990) · John G. Truxal (1991) · Rutherford Aris (1992) · Eliahu I. Jury (1993) · Jose B. Cruz, Jr. (1994) · Michael Athans (1995) · Elmer G. Gilbert (1996) · Rudolf E. Kalman (1997) · Lotfi Asker Zadeh (1998) · Yu-Chi Ho (1999) · W. Harmon Ray (2000)
Complete roster: 1979–2000 · 2001–present
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