科学网—何毓琦的留言板

[239]许培扬 2020-12-26 08:30

遥祝何院士合家圣诞快乐，平安健康幸福！北京许培扬陈东福合家

我的回复(2020-12-26 13:35)：Wish your family the best of 2021!

[238]严春来 2020-10-20 16:58

何老师，您好！我是攀枝花学院图书馆的老师，也是泰国国王理工大学的一名博士研究生，目前正在进行虚拟学术社区科研合作与成果转化方面的研究，故发此问卷，恳请您拨冗填写以下问卷。本问卷实行匿名制，所有数据只用于统计分析，请放心填写。
链接如下：https://www.wjx.cn/hj/qh3wrjpt3ky6ksetxvlw.aspx
如果您对相关研究感兴趣，可以给我留言或者邮箱：wingvestige@163.com
再次感谢您的填写和支持！

[237]fmjzjn 2020-6-17 08:21

尊敬的何教授，向您学习，向您致敬！

我的回复(2020-6-17 08:38)：Thank you for your kind words.

[236]魏焱明 2020-5-2 10:25

FYI:
Do it home to save life from drowning of coronavirus
http://blog.sciencenet.cn/blog-2339914-1231208.html

[235]魏焱明 2020-4-30 10:11

FYI:
My free invention of space sterilizer to kill coronavirus
http://blog.sciencenet.cn/blog-2339914-1230862.html

[234]王一君 2019-12-21 16:19

何老师，您好！本人是华中师范大学情报学在读硕士，目前正在进行虚拟学术社区系统有序度方面的研究，故发此问卷，恳请您拨冗填写以下问卷。本问卷实行匿名制，所有数据只用于统计分析，请放心填写。
链接如下：https://www.wjx.cn/hj/bi2jnusxz0e6lq1vdku84g.aspx
如果您对相关研究感兴趣，可以给我留言或者邮箱：1083634082@qq.com
再次感谢您的填写和支持！

[233]许培扬 2019-5-10 07:00

问候何院士祝您合家身体健康生活愉快！欢迎您们全家来浙江诸暨老家玩。北京许培扬

我的回复(2019-5-10 19:24)：Many thanks, you too.

[232]于灏 2018-8-25 07:56

Dear Professor He, I am so sorry to disturb you again. The last message has some mistake in format. Thus I send message again. Please forgive me. I am studying the optimal control recently. But there is a concept about conjugate point confused me. Fortunately, this concept is mentioned in your paper--“J.V. Breakwel and Ho Yu-Chi, “On the conjugate point condition for the control problem,” International Journal of Engineering Science,vol.2, issue. 6, pp. 565-579, Mar. 1965.\". However, I can not find the manuscript from the Internet. Could you please send me a copy of the manuscript? ?I would be very grateful. My e-mail address is Betty_Guoli@163.com. Best regards.

我的回复(2018-8-26 01:52)：Thank you for your interest. However, 45+years ago there were no Internet and/or electronic copies of paper. Thus, the best you can do is to write to the publisher and find out what library archive their journals. BTW, as I recall my conjugate point condition can be reinterpreted as the Riccati equation of the problem has finite escape time. Hope this helps. Good luck

[231]于灏 2018-8-25 07:50

Dear Professor He, It is so sorry to disturb you. I am studying the optimal control recently. But there is a concept about conjugate point confused me. Fortunately, this concept is mentioned in your paper--“J.V. Breakwel and Ho Yu-Chi, “On the conjugate point condition for the control problem,” International Journal of Engineering Science,vol.2, issue. 6, pp. 565-579, Mar. 1965.\". However, I can not find the manuscript from the Internet. Could you please send a copy of the manuscript to me ? ?I would be very grateful. My e-mail address is Betty_ty_Guoli@163.com. Be. Best regards.

我的回复(2018-8-26 04:56)：Unfortunately after 40+ years, I no longer have a copy of the paper nor was electronic copy available then.

[230]高一环 2018-5-25 18:00

Dear Professor He, I used to follow your blog since ten years ago. It was like a window to look out, to imagine what it would be to do research in the U.S. I went to Brown University as a visiting scholar last year. Now when I read your former blogs again, I find so many familiar things. I am writing to say thank you. Thanks for keep writing blogs here. Thanks for providing so many new things to Chinese young researchers including me. Best regards.

我的回复(2018-5-25 18:13)：Comment like yours makes my day. Thank you.

[229]张萌秋 2018-5-20 13:37

Dear teacher, Hello, I am editor of WeChat public account platform (ID:penetratingview current user 1.60 million yen). Can we reprint "He Xiaoqi: A university professor living in the United States" article is very good, I hope to get The teacher's authorization, we will indicate the author and source, I wish the teacher is good, hope for recovery.

我的回复(2018-5-21 04:51)：Sure you can.

[228]程宗明 2017-9-14 06:57

A Small friendly correction: You can aim for the best, say Tsinghua or Baida. These two university have: should be "two universities have. Great assay! Best wishes!

我的回复(2017-9-14 09:01)：Thanks. Some old Chinese language habit ( gender, polarity, et al) still slips through even after more than half a century of living and breathing English.

[227]许培扬 2017-9-13 10:25

何院士您好。得知您和您夫人在北京，我们特别高兴，我们去看望您们。我的手机13901205407 请您告诉我们在哪里相聚？

[226]赵明旺 2017-7-25 21:16

I have sent the email to your mail box in Harvard Univ, ho@seas.harvard.edu, in morning. Please receive the email form the mail box. Thank you.

我的回复(2017-7-26 19:29)：BTW, please ignore my last comment. It wad sent by mistake.

我的回复(2017-7-26 05:11)：Many thanks. But please read the first sentence of anyone of my blogs first.

我的回复(2017-7-25 22:27)：I have just replied.

[225]赵明旺 2017-7-25 07:09

Dear Prof. Ho,

I am glad to read your message on sciencenet and thank you very much for your help.

Based on the definitions of the controllable region of the input-constrained systems[1], I propose a computing method on the volume of the region and a proportional relation theorem between the volume of the region and the size of the solution space of the control laws in the controller designing is proposed and proven. According to the theorem, the bigger the volume is, the bigger the size of the solution space, and then the better the performance of the closed-loop control systems designed by the conventional control methods are. So, I think, the volume of the region is a good measure on the control ability and efficiency of the input variables to the state space and, after deeply understanding on that, the better works on the application of the volume to the system analysis and control design can be developed and expected. My two questions are as follows.

1. Whether the same or similar works have been done after 1960's? In the control ability studying, some conclusions promoting the ability has been proposed in the earlier works, such as, the distribution of the eigenvalues of the system matrix A must be uniform, the angel between the eigenvectors and the vectors of the input matrix B must tend to be orthogonal, and so on. But, as a synthetical measure on the control ability, I doesn't find the same or similar works and the theorem on the relation between the volume of the controllable region and the solution space of the control laws maybe proposed firstly.

2. If my works on the control ability are with some innovation, how to name the new measure? Considered the relation to the solution space of the control laws, whether the new measure can be named as 'controllable abundance'?

Your are a key pioneer on the state controllability and your comments and suggestions are very important to me. Thank you for help.

Best regards.

Mingwang Zhao

Wuhan University of Science and Technology

July 25, 2017

References

[1] Hu, T., Lin, Z., & Qiu, L. (2002). An explicit description of the null controllable regions of linear systems with saturating actuators. Systems & Control Letters, 47, 65-78.

[224]赵明旺 2017-7-22 12:19

I am glad to read your message on sciencenet and thank you very much for your help. An email about my questions has been sent to your email box in Harvard Univ.

[223]赵明旺 2017-7-22 07:14

Prof. Ho, 我从读硕士开始一直学习您的最优控制、离散时间摄动分析等方面著作和文章，受益匪浅。现有一问题请教。对线性离散和连续系统，通过已有的定义能控域（即所有能控状态构成的几何体）的工作，我建立了计算任意N步（或有限时间T、无限时间等）能控域在n维空间的体积的方法，用此体积作为控制能力的一个测度，并证明这个体积与控制设计中控制律(control law)的解空间大小的正比关系。因此这个体积大，即控制设计的解空间大，设计控制器就可能达到更好的性能。我想把这个能控域的体积命名controllable abundance(控制丰富性或充裕性)，并进一步研究其在系统分析和控制中的应用。但由于能控性方面工作是上个世纪60年代的工作，许多文献查找不易。您是能控性工作的重要的开拓者，不知您能否告诉我是否已经有类似或相关工作？这个工作该如何进一步发展下去？打扰了，谢谢! 学生：赵明旺

我的回复(2017-7-22 09:13)：I have difficulty reading technical Chinese. Please write to me in English via an e- mail with your questions. I'll see if I can help

[222]LairdUnlimited 2017-6-13 06:36

http://blog.sciencenet.cn/blog-3226978-1060427.html Prof. Ho, I am starting to follow 45th POTUS cabinet as well as 115th US Congressional hearings closely... cheers!

我的回复(2017-6-14 02:18)：Our current president seems to have no sense of shame. he tells a lie; he knows that it is a lie; he also knows that you know it is a lie; yet he goes on telling it.

[221]魏焱明 2017-6-6 01:42

you may be interested in this article:
创新发明--可用于直升机的蹬伞式或百叶窗板式推进桨
http://blog.sciencenet.cn/blog-2339914-1058615.html
Also some papers may interest you in this full collection.
http://vixra.org/author/yanming_wei

我的回复(2017-6-6 01:54)：Thank you for the references.

[220]LairdUnlimited 2017-4-15 23:01

I like American's traditional woman's college...https://en.wikipedia.org/wiki/Women%27s_colleges_in_the_United_States

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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何毓琦

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)