Yu-Chi "Larry" Ho (; born March 1, 1934) is a
Chinese-American
Chinese Americans are Americans of Han Chinese ancestry. Chinese Americans constitute a subgroup of East Asian Americans which also constitute a subgroup of Asian Americans. Many Chinese Americans along with their ancestors trace lineage from m ...
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
,
control theorist
Control may refer to:
Basic meanings Economics and business
* Control (management), an element of management
* Control, an element of management accounting
* Comptroller (or controller), a senior financial officer in an organization
* Controlling ...
, and a
professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...
at the
School of Engineering and Applied Sciences,
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...
.
He is the co-author of ''Applied Optimal Control'',
and an influential researcher in
differential game In game theory, differential games are a group of problems related to the modeling and analysis of conflict in the context of a dynamical system. More specifically, a state variable or variables evolve over time according to a differential equatio ...
s,
pattern recognition
Pattern recognition is the automated recognition of patterns and regularities in data. It has applications in statistical data analysis, signal processing, image analysis, information retrieval, bioinformatics, data compression, computer graphi ...
, and
discrete event dynamic system In control engineering, a discrete-event dynamic system (DEDS) is a discrete-state, event-driven system of which the state evolution depends entirely on the occurrence of asynchronous discrete events over time. Although similar to continuous-variab ...
s.
Ho was elected a member of the
National Academy of Engineering
The National Academy of Engineering (NAE) is an American nonprofit, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy ...
in 1987 for pioneering and sustained contributions to applied optimization, control, and systems engineering theory and application.
Biography
Education
Yu-Chi Ho was born on March 1, 1934, in
Shanghai
Shanghai (; , , Standard Mandarin pronunciation: ) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flow ...
, China, and left home at the age of 15 in 1949 to complete his high school education in Hong Kong. In 1950, Ho was accepted to the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
and came to the U.S., where he received a
B.S.
A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years.
The first university to admit a student to the degree of Bachelor of Science was the University ...
in
electrical engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
in the summer of 1953, at the age of 19. Ho later reported that his initial interests were in
mechanical engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, and ...
, due to a childhood experience repairing a 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. Ho continued his graduate studies at MIT, receiving a
M.S.
A Master of Science ( la, Magisterii Scientiae; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree in the field of science awarded by universities in many countries or a person holding such a degree. In contrast to ...
degree in
electrical engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
in 1955.
After working for
Bendix Aviation
Bendix Corporation is an American manufacturing and engineering company which, during various times in its existence, made automotive brake shoes and systems, vacuum tubes, aircraft brakes, aeronautical hydraulics and electric power systems, av ...
for three years, Ho moved to
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...
in 1958, where he completed a
Ph.D.
A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...
in
applied mathematics
Applied mathematics is the application of mathematical methods by different fields such as physics, engineering, medicine, biology, finance, business, computer science, and industry. Thus, applied mathematics is a combination of mathematical s ...
in 1961. His thesis ''A Study Optimal Control of Dynamic Systems'' was advised by
Arthur E. Bryson, Jr.
Arthur Earl Bryson Jr. (born October 7, 1925) is the Paul Pigott Professor of Engineering Emeritus at Stanford University and the "father of modern optimal control theory". With Henry J. Kelley, he also pioneered an early version of the backpr ...
and
Kumpati S. Narendra
Kumpati S. Narendra is an American control theorist, who currently holds the Harold W. Cheel Professorship of Electrical Engineering at Yale University. He received the Richard E. Bellman Control Heritage Award in 2003. He is noted "for pioneer ...
.
Career
After finishing his Ph.D. in the spring of 1961, Yu-Chi Ho returned to Harvard in the fall of 1961 for a teaching appointment, receiving tenure in 1965, 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
The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...
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
Tsinghua University (; abbr. THU) is a national public research university in Beijing, China. The university is funded by the Ministry of Education.
The university is a member of the C9 League, Double First Class University Plan, Projec ...
. In his career, he has supervised 50 Ph.D. students at Harvard and 3 students at Tsinghua.
Professional activities
Yu-Chi Ho is a member of the U.S.
National Academy of Engineering
The National Academy of Engineering (NAE) is an American nonprofit, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy ...
and a foreign member of the
Chinese Academy of Engineering
The Chinese Academy of Engineering (CAE, ) is the national academy of the People's Republic of China for engineering. It was established in 1994 and is an institution of the State Council of China. The CAE and the Chinese Academy of Sciences ...
and the
Chinese Academy of Sciences
The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republi ...
. He is also an
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
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
Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...
. He is on the editorial boards of several international journals and is the founding editor-in-chief of the international Journal on Discrete Event Dynamic Systems.
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.
Honors and awards
![Yu-Chi Ho Bellman Award](https://upload.wikimedia.org/wikipedia/commons/a/a5/Yu-Chi_Ho_Bellman_Award.jpg)
*
Guggenheim Fellowship (1970)
*
IEEE Control Systems Science and Engineering Award
The IEEE Control Systems Award is a Institute of Electrical and Electronics Engineers#Technical field awards, technical field award given to an individual by the Institute of Electrical and Electronics Engineers (IEEE) "for outstanding contributio ...
(1989)
* Chiang Technology Achievement Award (1993)
*
Richard E. Bellman Control Heritage Award The Richard E. Bellman Control Heritage Award is an annual award (since 1979) given by the American Automatic Control Council (AACC) for achievements in control theory, named after the applied mathematician Richard E. Bellman. The award is given fo ...
from the
American Automatic Control Council
The American Automatic Control Council (AACC) is an organization founded in 1957 for research in control theory. AACC is a member of the International Federation of Automatic Control (IFAC) and is an association of the control systems divisions of ...
(1999)
*
Rufus Oldenburger Medal
The Rufus Oldenburger Medal is an award given by the American Society of Mechanical Engineers recognizing significant contributions and outstanding achievements in the field of automatic control. It was established in 1968 in the honor of Rufus O ...
from the
American Society of Mechanical Engineers (1999)
* 2002 class of
Fellow
A fellow is a concept whose exact meaning depends on context.
In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements.
Within the context of higher education ...
s of the
Institute for Operations Research and the Management Sciences
The Institute for Operations Research and the Management Sciences (INFORMS) is an international society for practitioners in the fields of operations research (O.R.), management science, and analytics. It was established in 1995 with the merger of ...
* Isaacs Award from the
International Society of Dynamic Games
The International Society of Dynamic Games (ISDG) is an international non-profit, professional organization for the advancement of the theory of dynamic games.
History
The ISDG was founded on August 9, 1990 in Helsinki, Finland, at the site of ...
(2004)
* Member, US
National Academy of Engineering
The National Academy of Engineering (NAE) is an American nonprofit, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy ...
* Foreign member,
China Academy of Engineering
* Foreign member,
China Academy of Sciences
Personal life
Ho became a naturalized citizen of the United States in 1961. He and his wife Sophia have three children and six grand children. They currently reside in
Lexington, Massachusetts
Lexington is a suburban town in Middlesex County, Massachusetts, United States. It is 10 miles (16 km) from Downtown Boston. The population was 34,454 as of the 2020 census. The area was originally inhabited by Native Americans, and was firs ...
. 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.
[http://www.sciencenet.cn/blog/何毓琦.htm ]
Work
Control theory and optimization
Yu-Chi Ho's research in control theory began when he was a graduate student at MIT. His 1955 paper ''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
Time domain refers to the analysis of mathematical functions, physical signals or time series of economic or environmental data, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the cas ...
.
Ho collaborated with
Rudolf E. Kálmán
Rudolf Emil Kálmán (May 19, 1930 – July 2, 2016) was a Hungarian Americans, Hungarian-American electrical engineer, mathematician, and inventor. He is most noted for his co-invention and development of the Kalman filter, a mathematical algo ...
, a pioneer of
modern control theory. Before Kálmán, time series analysis and
classical control theory
Classical control theory is a branch of control theory that deals with the behavior of dynamical systems with inputs, and how their behavior is modified by feedback, using the Laplace transform as a basic tool to model such systems.
The usual obj ...
studied the
frequency domain
In physics, electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency, rather than time. Put simply, a time-domain graph shows how a s ...
, using
harmonic analysis, especially
Laplace and
Fourier transform
A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, ...
s. Kálmán developed the study of the
time domain
Time domain refers to the analysis of mathematical functions, physical signals or time series of economic or environmental data, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the cas ...
using
state-space models. Joining Kálmán, 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; further, the state-space representation can be extended into
nonlinear systems
In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other ...
. Their paper ''controllability of linear dynamic systems'',
developed the theory of
controllability Controllability is an important property of a control system, and the controllability property plays a crucial role in many control problems, such as stabilization of unstable systems by feedback, or optimal control.
Controllability and observabi ...
(then known as the "Kalman-Bertram condition").
Together with Ho's 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.
Pattern recognition
After joining the faculty of Harvard University, Ho developed the
Ho-Kashyap rule in
pattern recognition
Pattern recognition is the automated recognition of patterns and regularities in data. It has applications in statistical data analysis, signal processing, image analysis, information retrieval, bioinformatics, data compression, computer graphi ...
with his first Ph.D. student,
Rangasami L. Kashyap.
Game theory
Turning his attention to
game theory
Game theory is the study of mathematical models of strategic interactions among rational agents. Myerson, Roger B. (1991). ''Game Theory: Analysis of Conflict,'' Harvard University Press, p.&nbs1 Chapter-preview links, ppvii–xi It has appli ...
, Ho in 1965 published the paper ''Differential Games and Optimal Pursuit-Evasion Strategies'',
that proved the optimality of a proportional guidance scheme. His paper ''Nonzero Sum Differential Games''
was an influential game-theoretic study in systems and control, following earlier work by
Samuel Karlin
Samuel Karlin (June 8, 1924 – December 18, 2007) was an American mathematician at Stanford University in the late 20th century.
Biography
Karlin was born in Janów, Poland and immigrated to Chicago as a child. Raised in an Orthodox Jewish hous ...
, for example.
Discrete event dynamic systems
Since the 1970s, Ho focused on research in
discrete event dynamic system In control engineering, a discrete-event dynamic system (DEDS) is a discrete-state, event-driven system of which the state evolution depends entirely on the occurrence of asynchronous discrete events over time. Although similar to continuous-variab ...
s, making contributions in
perturbation analysis
In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...
and
ordinal optimization
Mathematical optimization (alternatively spelled ''optimisation'') or mathematical programming is the selection of a best element, with regard to some criterion, from some set of available alternatives. It is generally divided into two subfi ...
, including the book ''Perturbation Analysis of Discrete Event Dynamic Systems''.
and the book "Ordinal Optimization - Soft Optimization for Hard Problems" (Springer 2007)
Publications
Books
*
*
*
About Yu-Chi Ho's work
*
References
External links
Home Page at Harvard UniversityMathematics Genealogy Project profile*
Sciencenet.cn BlogBiography of Yu-Chi Hofrom the Institute for Operations Research and the Management Sciences
{{DEFAULTSORT:Ho, Yu-Chi
1934 births
Living people
Scientists from Shanghai
Control theorists
Chinese emigrants to the United States
Richard E. Bellman Control Heritage Award recipients
Nanyang Model High School alumni
Harvard University alumni
John A. Paulson School of Engineering and Applied Sciences faculty
MIT School of Engineering alumni
Members of the United States National Academy of Engineering
Foreign members of the Chinese Academy of Sciences
Foreign members of the Chinese Academy of Engineering
Fellows of the Institute for Operations Research and the Management Sciences
Bendix Corporation people