何毓琦的个人博客分享 http://blog.sciencenet.cn/u/何毓琦 哈佛(1961-2001) 清华(2001-date)

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Education of a Control Engineer. 精选

已有 12036 次阅读 2015-7-16 22:24 |系统分类:教学心得

 

 

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26 years ago when I received the highest award of the IEEEControl System Society, The Control Engineering and Science Field Award,  I gave the following acceptance speech. Re-reading it more than  two decades later, I still feel the same way. I post it here to share  with Science Net readers.

 

 

EDUCATION OF A CONTROL ENGINEER

-LESSONS I HAVE LEARNED-

 

Remarks by

Y.C.Ho

On accepting the IEEE Control Engineering and Science  Field Award at the 28th  Conference on  Decision andcontrol

December 14,1989 Tampa,Florida

 

 

It is the tradition on this occasion for the recipient to say something  about the history and the future of the field which is represented by this award. The six illustrious previous recipients of this award before me have very thoroughly reviewed the  history of our Society and the award. I doubt that I have anything  useful to add or subtract. As for the future, I am always reminded of the story about Professor Howard Aileen,the father  of modem digital computers. I spent half of my professional  life in the laboratory that bears his name. In 1948, Time  Magazine  did  a cover article about the onset of the computer age and interviewed Professor Aiken. He had just finished building the Mark IV series of computers (note1).The reporter wanted to know how many of  these Mark IV computers would eventually be needed  by the world.  Aiken thought about it and replied "Oh, maybe ten". So much for  predicting future. Now this leaves me only with personal reminiscences. Of course, I could talk about how Kalman, Narendra, and I got together and wrote the controllability  paper, or let you guess who wrote what part in the book  Applied Optimal Control. But that is the same as foisting your  home vacation slides on your dinner guests.  What is interesting and memorable to me personally is not necessarily  suitable material for public consumption.

 

Instead let me share some of the lessons I learned  in the past   29 years (1960-1989) with you. They may be of interest  particularly to young engineers in the audience who are just starting out in the business.In this connection I am reminded of last year's bestseller"All I really need to know I learned in  Kindergarten " (note 2). While that may very well be true,  I am a much slower learner. Looking back, I did not even begin learning useful lessons until the senior year in college and I am  still learning to this date.

 

At one time in the 50's at MIT's EE department, the gospel  was that there were only two   books any electrical engineer needed to know.Symthe's "Static and DynamicElectricity" for the physically oriented and Bode's  "Feedback Amplifier Design"  for the mathematicians. In my senior year I registered for a course on high gain lowdrift DCamplifier design. I don't know how many of you in this  room still remember the 400 cps chopper-stabilized DC vacuum  tube feedback amplifiers.  Designing those things is enough to drive one mad with frustration. Thinking  that reading Bode  would be beneficial, I tried without any success to understand  the  book even  thoughit was extremely well written.  Then and there, I learned the gap between theory and  practice.  At any given time, the most sophisticated theory  always has very little to do with the most advanced applications.

My second lesson began when I went to work in industry for  the Bendix  Aviation  Corp. At the time I had Brown and Campbell, and Newton,Gould & Kaiser (note 3)  under my belt.I was all set to design  servomechanisms. Instead , I was told to learn all about digital computers because my boss (note4) needed me to design logical circuits for numerical control. I knew nothing  about digital computers, switching theory, transistors and  magnetic cores. But I found out what a good education  prepares you to do. It teaches you how to think for yourself and learn on your own. What I  learned and did in12 months (four patents resulted)  were a lot more than several courses put together.

 

My 3rd lesson began when I came back to Harvard- I learned the wonders and magic of applying mathematics in engineering.  This essentially determined my work for the rest of my professional life. The works that influenced me included the early preprints of Kalman who was happy to sent them to anyone who asked for them, a draft copy of "adaptive control - a guided tour" by Bellman lent to me by my classmate, S. Dreyfus who  was then programming for Bellman. I was also fortunate to  be in the class the first time Bill Root taught  Davenport & Root in book form. As the classic 50's song says, those were the days!

 

The early 60's gave me my fourth lesson- The limitation of  mathematics in engineering. I owe this to the tutelage of Arthur E. Bryson, Jr. and Lotfi Zadeh. Some physicists take the  position that  it is not physics if it cannot be tested and validated.I came to appreciate that it is not engineering if it cannot be put into practice and that an"exercise left to the reader" is often the difference between success and failure of an engineering  endeavor. Of course, this is a two edged sword. What is "intuitively obvious" to an engineer may require months of hard work  by a mathematician to prove or, even more importantly, to disprove.

The following assertions and beliefs I hold dear to my heart:

a.  Good ideas often come from real problems. Necessity IS  the mother ofinvention.

b.  Good ideas are often conceptually simple once thoroughly understood. One should take the position that it is possible to explain anything to anybody in any amount of allotted time at the level they can omprehend.

c.   If you make a sincere commitment to work on a real problem rather than a commitment to use a particular technique,something good and interesting always comes out of it in the end.

d. You can learn anything in six months to suit your  purpose. What looks formidable at a distance becomes far less so once you get into it. Thus, by all means dive into  new fields. It is far easier to pick up loose nuggets  lying on the surface than to dig deep into a mine worked out by someelse.

 

My personal experiences whether they were with differential games, (the result of studying proportional navigation law and  dog fight ,1966), team decision analysis (understanding the question who knows what when, and the second guessing paradox, 1970), incentive control (from time-of-day electricity pricing,  1979), or PA and DEDS (from a real  manufacturing problem,1977) certainly reinforce these beliefs.

After almost 3 decades, I am still learning.This is the greatest joy of an academic career.You never stop or want to stop learning. Looking back, I realize "I am a lucky guy" (note 5)  .Without   the love and total supportof my parents, family,  and particularly, my wife of 30 years , I surely would not be here tonight.The many good friends, colleagues, and my 37  former Ph.D.students in the field have all taught me much more than I taught them. Above all,on occasions when I became lazy or sloppy, they were the ones who kept me honest. My whole  career is essentially spent working for one institution  which represents the best example of American  private higher education; I thank Harvard University for the standard she inspires and the freedom she gives to young faculty members.  But in this holiday season of   thanksgiving and  particularly in such an eventful year in world affairs as this, one entity symbolizes all the good things I am  thankful for. It is old fashioned and may be chauvinistic to  say this in such an international setting, but I say it  with sincerity and all the gratitude  that only an immigrant is privileged to feel about his adopted country -  "Thank you, the United States  of America, for the freedom and opportunities you give to your citizens". Good evening and happy holidays.

 

 

Reference notes

1. which had less memory than one of those $500 TI  programmable calculators nowadays carried around by high  school students.

2. Robert Flughum,Random House1988.

3.Two best known control texts at that time.

4.Dr. E. Calvin Johnsonof the describing function fame.

5. Phrase made popularby the comedian, SteveMartin.




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该博文允许注册用户评论 请点击登录 评论 (18 个评论)

IP: 123.116.97.*   回复 | 赞 +1 [9]刘立   2020-3-9 07:01
好文,学习了
回复  待有空,拟将这篇科研生涯经验谈,翻译成中文。可否授权中文翻译?
2020-3-9 11:321 楼(回复楼主) 赞 +1 | 回复
IP: 116.1.59.*   回复 | 赞 +1 [8]suoyouluntan   2015-7-18 23:34
一直感觉何先生的英文博文,相比其它的英文文章来说更容易阅读和理解,词汇和语言风格都有点像中国人写的英文文章,有一种一读了就体会到是中国人写的英文的感觉。   是因为何先生是华人出身?  是因为何先生刻意照顾中文读者(应该也不是,因为这种颁奖会明显是在国外且听众应该多是老外)?

这到底是什么原因呢?其他科学网读者有没有这种感觉呢?
回复  I think you are reading more into my speech than there is.
2015-7-20 06:501 楼(回复楼主) 赞 +1 | 回复
IP: 108.213.68.*   回复 | 赞 +1 [7]ahmen   2015-7-17 23:47
My impression is that very few professors in China have real experience with industry. In the old days, there weren't many domestic high tech industry to speak of. I hope this situation changes in the coming years.

Chairman Mao tried to do something about it in the 70's, but wasn't successful. But I can see the wisdom in his thinking, even though I am not his fan at all.
回复  To a lesser degree, what you said is true even among US professors. I never regretted the three years I spent in industry.
2015-7-18 04:251 楼(回复楼主) 赞 +1 | 回复
IP: 132.183.13.*   回复 | 赞 +1 [6]邵鹏   2015-7-17 22:02
This is really insightful - I believe these are not only restricted to engineer education, thanks for sharing and this made my day.
回复  Thanks for the encouragement.
2015-7-18 04:221 楼(回复楼主) 赞 +1 | 回复
IP: 117.28.251.*   回复 | 赞 +1 [5]雷蕴奇   2015-7-17 21:01
Cannot help to read the speech for 3 times. I belive that I will read it again, surely, also I hope that my students can understand what Prof. Ho means in his speech too, gradually. Thank you, Prof. Ho!
回复  Thanks for the. Feedback. Your words are my reward for writing.
2015-7-18 04:231 楼(回复楼主) 赞 +1 | 回复
IP: 111.1.127.*   回复 | 赞 +1 [4]朱志亮   2015-7-17 19:42
“my 37  former Ph.D.students in the field have all taught me much more than I taught them” 谦卑的人
IP: 192.51.147.*   回复 | 赞 +1 [3]张明武   2015-7-17 17:13
读了以后,从您的成功经历我有以下几个启示。

一,学习。终生的学习,不断的进步。
二,实践。用学习到的知识来解决工程问题。从解决实际问题出发引导学习。从学习到实践再到学习,在人生之路上不断追求;从中获取成功和快乐。
三,与优秀的人在一起。这些人,可能是同学,老师或者同事。可以与这些人交流中学到东西。能满足提供这样的群落条件的,是一个好的大学,或者好的公司。
四,感恩的心。自己是幸运的,是满载着别人的帮助与支持。

这句话对我也很有冲击
"...it is not engineering if it cannot be put into practice and that an"exercise left to the reader" is often the difference between success and failure of an engineering  endeavor..."

非常感谢您的分享。
回复  Thank you for the kind words and for your excellent Chinese summary.
2015-7-17 19:181 楼(回复楼主) 赞 +1 | 回复
IP: 119.145.137.*   回复 | 赞 +1 [2]孟凡   2015-7-17 16:45
best memeories, u have been a legend in this field
回复  Thanks.
2015-7-17 19:181 楼(回复楼主) 赞 +1 | 回复
IP: 106.39.150.*   回复 | 赞 +1 [1]谢力   2015-7-16 23:17
写的非常好。为什么何先生离开工业界到哈佛读博士呢?或许您在以前的博文给出过答案,祝好
回复  After 4.5 years of MIT working very hard to get my BS and MS, I was tired of study, still very young (20.5 years old) and needed money. so I took a full time  industrial job that lasted three years. but I always wanted to get a ph.d degree so I returned to graduate study in 1958.
2015-7-17 00:041 楼(回复楼主) 赞 +1 | 回复
回复  Thanks.
2015-7-17 19:552 楼(回复楼主) 赞 +1 | 回复

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