B****n
发帖数: 11290 | 1 我幫你用nonlinear regression fit一下
B+A^2/(0.5817A+1.8218B)會更好
至於公式怎麼來的 我認為一種可能是觀察到sqrt(A^2+B^2)-B=A^2/(sqrt(A^2+B^2)+
sqrt(B^2))
然後觀察 (sqrt(A^2+B^2)+sqrt(B^2)) 和 可以被A和B的線性組合逼近 (ie. xA+yB)
這個可以從泰勒展開式來看 超過一次項明顯當A,B很大的時候不合
而(sqrt(A^2+B^2)+sqrt(B^2)) 又可以被A,B線性組合夾擠
我就把型式如同B+A^2/(xA+yB)的函數 和Y=sqrt(A^2+B^2) 做一個nonlinear
regression fit
結果發現當x=0.5817 y=1.8218時比原公式還好一些 只是原公式數字更簡單 也逼近的還
不錯就是了 當然這也可以看出為什麼原公式x=0.6 y=1.8的原因 |
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x********i
发帖数: 905 | 2 1950 Shiing-shen Chern, Differential Geometry of Fiber Bundles.
1970 Shiing-shen Chern, Differential Geometry: Its Past and Its Future.
1978 Shing-Tung Yau, The Role of Partial Differential Equations in
Differential Geometry.
1983 Wu-chung Hsiang, Geometric Applications of Algebraic K-Theory.
1983 Yum-Tong Siu, Some Recent Developments in Complex Differential Geometry.
2002 Sun-Yung Alice Chang and Paul Chien-Ping Yang, Non-linear Partial
Differential Equations in Conformal Geometry.
2002 Yum-To... 阅读全帖 |
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x********i
发帖数: 905 | 3 2015 Abel Prize to Nash and Nirenberg
Wednesday March 25th 2015
John NashThe Norwegian Academy of Sciences and Letters will award the 2015
Abel Prize to John F. Nash Jr. (left), Princeton University, and Louis
Nirenberg (right), Courant Institute, New York University, "for striking and
seminal contributions to the theory of nonlinear partial differential
equations and its applications to geometric analysis." (Photos: Nash: ©
Peter Badge/Typos 1 in coop. with the HLF - all rights reserved 20... 阅读全帖 |
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L*m
发帖数: 235 | 4 近十年JAMS上的华人作者，JAMS上的文章相对更多，搜的没那么仔细，有可能不完全。
大家也看看有没有漏的
2015
Kähler-Einstein metrics on Fano manifolds. I: Approximation of metrics
with cone singularities
Xiuxiong Chen, Simon Donaldson and Song Sun.
Kähler-Einstein metrics on Fano manifolds. II: Limits with cone angle
less than 2π
Xiuxiong Chen, Simon Donaldson and Song Sun.
Kähler-Einstein metrics on Fano manifolds. III: Limits as cone angle
approaches 2π and completion of the main proof
Xiuxiong Chen, Simon Donaldson... 阅读全帖 |
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a******n
发帖数: 98 | 5 I built a structural model for an air vehicle. As it contains tension-only
element, nonlinear analysis need to be applied. I don't know how to
constrain six degrees of freedom in order to remove rigid body motion.
There are some symmetric conditions existing, but I still can not constrain
six degrees of freedom. Someone suggested the "inertial relif" function of
Nastran. Even in Nastran, it sounds like that "inertial relief" is not
working for nonlinear model. (I am not familar with Nastran). Is |
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l***o
发帖数: 7937 | 6 Actually Adina is pretty strong in Fluid-Structure Interaction and is widely
used in FEA of ships and submarines.
Ansys is pretty strong in linear static analysis (in which case only the direct solver is needed to solve the problem), but not robust when it comes to highly nonlinear problems (geometric and material nonlinearities, contact, etc.), often diverging when involving iterative procedures. Tentalizing with the parameters to get a successful run often takes quite a long time. I personally |
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u****d
发帖数: 122 | 7 How do you think the other two mostly used FEA softwares, Nastran and Abaqus?
widely
direct solver is needed to solve the problem), but not robust when it comes
to highly nonlinear problems (geometric and material nonlinearities, contact
, etc.), often diverging when involving iterative procedures. Tentalizing
with the parameters to get a successful run often takes quite a long time. I
personally never used Ansys before, but I saw a former colleague of mine (
who then had muitiple-year experien |
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k*********g
发帖数: 791 | 8 nonlinear很难吗？？？
如果是transient问题，反正要time marching；
nonlinearity一般能轻松搞定；
学固体力学的一群狗死们整天把自己lock在一个狗死大房子里，从来不跟物理学家、数
学家、流体力学家们讨论讨论，所以技术能力特别低；
低到连个navier方程的张量形式也写不端正；
一个那么简单的东西被他们写得那么复杂； |
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h****g
发帖数: 74 | 9 如题，如果你想找有限元的工作，请发简历到h****************[email protected]
我会forward你的简历，要求如下(可以适当放宽）：
Highly Desired:
• Requires an accredited engineering MS or PhD degree (typically
Mechanical) or equivalent industrial experience and good working knowledge
of numerical simulation software tools including structural analysis, but
not limited to.
• Incumbents have usually gained 2 to 5 years of industry experiences
or gained Ph.D in the area of nonlinear structural analysis area.
• The person should hav... 阅读全帖 |
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s*****r
发帖数: 261 | 10 Abstract:
Various model-based control methods are currently used in control of
piezoelectric tubes, others such as internal model control and model
predictive control are anticipated to be employed soon. All these control
systems are designed based on black box models. However, systematic black
box modeling of piezoelectric tubes has been overlooked in the literature to
a large extent or has been presented in a too brief and faulty way. In this
article, a novel structure of artificial neural net... 阅读全帖 |
|
s****1
发帖数: 425 | 11 书基本都是全新，里面也没有笔迹。大部分是原子分子光学方面的书，有感兴趣的同学
发信给我，可以提供详情。廉价处理
1,Atom Optics, Pierre Meystre
2,Physics of atoms and molecules, B.H. Bransden and C.J. Joachain
3,Quantum optics, Marlan O.Scully and M. Suhail Zubairy
4,Nonlinear optics, Robert W. Boyd
5,Elements of quantum optics, Pierre Meystre and Murray Sargent
6,Spectra of Diatomic molecules (Molecular spectra and molecular structure )
Gerhard herzberg
7,The principles of nonlinear optics, Y.R. Shen
8,Laser spectroscopy, W. Demtroder
9,The theory of ... 阅读全帖 |
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p*****n
发帖数: 26 | 12 As far as I know, you can use nonlinear equations like quadratic equations
to fit your data from LCMSMS. It is said that it is quite normal the
standard curve shows nonlinear property if your concentration range is large
. Softwares like Xcalibur LCQuan from ThermoQuest can be used. |
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R*j
发帖数: 248 | 13 I guess my question is: For those samples whose concentrations are beyond
the "Linear range" of standard curve in LC/MS/MS, can I dilute them to
linear range before analysis. Since linear curve makes more sense to most
people.
Apparently, another way is to establish a nonlinear standard curve which
covers the samples with high concentration.
Do you happen to know whether FDA agrees with nonlinear standard curve (e.g.
, quadratic equation)?
you |
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b****r
发帖数: 2555 | 14 First, are you sure of your laser output? Is the laser output itself
stable enough? OPA is based on nonlinear effect, so 10% fluctuation in
laser pulse may lead to 100% fluctuation of your OPA output.
Second, what is your output wavelenth? 1550 nm is always more stable
than 1200 nm output, because of the nonlinear crystal used.
Third, what OPA you are using? OPA from Newport is not as good as
a former soviet union company (EKSPLA or something).
Last, alignment and protection. Even air flow has e |
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l*****1
发帖数: 137 | 15 Interfacial Nonlinear Laser Spectroscopy and Dynamics Post-doctoral
Opportunity
(with apologies for cross-posting)
A position is available in the vibrational spectroscopy and dynamics of
molecular species at liquid interfaces, in particular related to Acid-Base
Equilibria at Mineral-Water Interfaces. There are also opportunities to
contribute to the development of novel infrared sources for nonlinear
spectroscopy.
The Borguet group has received a grant from the American Chemical Society
Petro |
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m********8
发帖数: 123 | 16 although i ever studied extensively wave mechanics in solids & fluids, such
as acoustics which is nonlinear but non dispersive and water wave which is
nonlinear & dispersive consequently much more mathematically complicated
than electromagnetic waves, at this point of time i am deeply obsessed by
how light propogates and by things such as how to calcultate the force
exerted by photons;
while the wave mechanics i have come across is more involved in math and
forbidably difficult to solve analytic |
|
y***n
发帖数: 28 | 17 Physical Chemistry Postdoc Research Opportunity at Boston University
Xin Chen’s research group, newly-founded at Boston University, Department
of Chemistry in 2011, is seeking a postdoctoral researcher (or a visiting
scholar) with experience in ultrafast laser spectroscopy and nonlinear
optics. His/her major responsibility would be to set up and carry
experiments using a board-band vibrational sum-frequency spectrometer and
imaging system. Candidates experienced in nonlinear v... 阅读全帖 |
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e*******n
发帖数: 4912 | 18 101. 1917年，日本数学家挂谷宗一（Kakeya，S(1886-1947)）提出
一个问题：一位武士上厕所时遭到袭击，他只有一根短棒，为了
挡住射击，短棒应旋转360度（支点可以变化），但厕所很小，
问短棒最少要扫过多大面积？
这个问题引起当时很多人的兴趣，如1925年Birkhoff在他
写的The origin, nature, and influence of relativity
一书中提到“近几年日本数学家挂谷宗一提出的问题，是同样令
人感兴趣的问题”
1928年，苏联数学家Besicovitch，Abram Samoilovitch
（1891-1970）解决了这个问题，答案是可以任意小，1960s
Besicovitch在美国数学会就挂谷问题专门做了期科普电影，
有意思的是中间他打了个喷嚏，Besicovitch觉得很不雅，
坚持要求在录像中把这个镜头剪掉，于是现在人们看到的是
镜头突然转向一边，然后是一声闷响....
102. William James seemed to have what seemed vitally important
ideas in d... 阅读全帖 |
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s****1
发帖数: 425 | 19 有些书全新，其它书里面也没有笔迹。有感兴趣的同学发信给我，可以提供详情。廉价
处理
1,Atom Optics, Pierre Meystre
2,Physics of atoms and molecules, B.H. Bransden and C.J. Joachain
3,Quantum optics, Marlan O.Scully and M. Suhail Zubairy
4,Nonlinear optics, Robert W. Boyd
5,Elements of quantum optics, Pierre Meystre and Murray Sargent
6,Spectra of Diatomic molecules (Molecular spectra and molecular structure )
Gerhard herzberg
7,The principles of nonlinear optics, Y.R. Shen
8,Laser spectroscopy, W. Demtroder
9,The theory of atomix structu... 阅读全帖 |
|
发帖数: 1 | 20 Optics and Photonics Symposium in Nankai University（OPS-NKU2017）
Date: 2017-07-04
Optics and Photonics Symposium in Nankai University 2017 (OPS-NKU2017) will
be held from Oct. 20 to Oct. 22, 2017 in Nankai University, Tianjin, China.
This conference is sponsored and organized by the Key Laboratory of Weak
Light Nonlinear Photonics, Ministry of Education and School of Physics of
Nankai University. The symposium will invite world-renowned scientists,
engineers and technicians, and young talents ... 阅读全帖 |
|
k*******d
发帖数: 1340 | 21 Nonlinear的话这本也不错：
Nonlinear Programming
by Dimitri P. Bertsekas |
|
y****d
发帖数: 432 | 22 ★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
前面说明：
需要的童鞋请到我的签名档的博客查找！谢谢！发E-mail太累了！
觉得有价值的话可以顶一下，以便更多的人看到！谢谢！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
详细介绍
1. Advanced Calculus with Applications in Statistics
2.A History of Probability and Statistics and Their Applications before 1750
3.Markov Decision Processes: Discrete Stochastic Dynamic Programming
4.Probability and Statistical Inference
5.Continuous Univariate Distributions, Vol. 1
6.Continuous Univariate Distributions, Vol. 2
7.The Theory of Measures and Integratio... 阅读全帖 |
|
l******i
发帖数: 1404 | 23 楼主说的无条件稳定可能也没错，只是应该指的针对某一种方程吧。
就我所知，
对于nonlinear elastodyamics方程，
所有不是fully implicit method都不是unconditional stability的。
即使fully implicit method里面绝大部分放在nonlinear elastodyamics也不会稳定。
A-stable就更不可能了。 |
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h******5
发帖数: 58 | 24 c++零基础，但工作需要，也得顶着头皮上，看了点tutorial就开始program了。
最近要解决一个问题是用一些sample来fit normal distribution 算出最小二乘方下的
normal distribution 的parameters。easypeasy 吧？但是我就是不会做。。。找了
个GSL的library，但里面貌似搞的过于复杂，apply到我的project 上compile不出来。
不知道是什么原因。版上有没有人做过同样的东西？可否分享一下。如果能分享那一小
部分的code或者网上能找到的code，那就感激不尽啦。（实在基础太差，不是一点就能
点通的。。。）
我之前用的是一下的example，可惜太笨了不会用，也没有100%明白他再搞什么东西。
https://www.gnu.org/software/gsl/manual/html_node/Example-programs-for-
Nonlinear-Least_002dSquares-Fitting.html#Example-programs-for-Nonlinear-
Least_002d... 阅读全帖 |
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b*******t
发帖数: 297 | 25 大家好，
真心求教过来人给一些知道，非常感谢！
个人的情况是：一般State学校的在读PhD，地球科学类，现在是第四年开始，现在的研
究主要是用开源的并行模型模拟一些大尺度的物理现象，前两年用机器学习的方法做过
一些物理现象的分类和预报（已发表）。本科国内非名校数学系毕业。PhD期间上过一
些本校数学系的课程，例如：Numerical Analysis, Nonlinear Equations and
Unconstrained Optimization, Nonlinear Dynamics and Chaos, Parallel Computing
等，准备再上个Stochastic Different Equation。
个人打算是明年毕业，自己专业找工作基本只能是Postdoc，所以想尝试一下Quant类的
工作。不知道像我这种情况难度大不大？最近也在版上和网上考古了一下，得到的基本
信息如下：
1）有很多物理、数学、计算机的PhD在做Quant
2) Quant也分好几种，有的做模型开发，有的做模型运行
3）貌似大部分工作需要C++
4）找了一些转行的入门书籍，比如Optio... 阅读全帖 |
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L*******t
发帖数: 2385 | 26 本质上是MLE的estimation。或者换成Bayesian都行。
noise可以是很大一类分布。
然而效果depend on data和很多因素。
很简单的线性代数告诉我们如果你选择的factors构成了你的Y variable取值空间的一
组基
的话，那么线性关系是成立的。其他条件和情况你自己可以分析。。
如果从Taylor expansion的角度上来说，你是在把 Y = F(X)做泰勒展开然后取线性项
。效果是取决于函数F的性质的。如果F highly nonlinear，那么线性逼近没什么意义
了。
所以nonlinearity全部在noisy里面。
最新的技术是可以考虑model uncertainty的linear regression。作者的numerics表明
如果确实model有regime的话，用sublinear expectation linear regression效果会好
非常多。
所以用Linear regression要慎重啊。 |
|
L*******t
发帖数: 2385 | 27 Adrian, Crump, Vogt 2016
"Nonlinearity and Flight to Safety in the Risk-Return Trade-Off for Stocks
and Bonds"
无论是里面提到的nonlinearity，predictive regression 还是用VIX做factors，我都
很喜欢。
不知道大家怎么看。。 |
|
f*****g
发帖数: 260 | 28 你是只对statistical DOE 感兴趣呢，还是其他的DOE, 比如nonlinear DOE methods (
e.g., genetic algorithm）？
如果是前者，有许多软件的帮助文件都有这方面的介绍并可以网上下载。比如design
expert, JMP(belong to SAS）。只是，这些软件关于原理方面的解释不会全面。所以
，想了解具体的理论，就只有看些统计方面的书了。
如果是nonlinear DOE，那么就只有找这方面的论文或软件了。具体还得看你是只局限于会用这些DOE方法，还是你准备开发些新方法，让别人将来能用你的方法了。 |
|
d******e
发帖数: 7844 | 29 大师啊，凭什么不可以假设Continuity和Smoothness？
大师啊，这么多人在使用Linear Model，你为什么不去质疑Linearity的Assumption啊？
Nonlinear Model随处可见，可哪个人说Nonlinear Model颠覆传统的Linear Model了？
姑且认为你提出的Model是正确的（实在是没办法，你写的那个玩艺，作为人类基本是
没人看得懂了），你无非也就是解决了一个连续性不成立的情况而已。而你说的连续性
或者平滑性不成立的例子你又能举出多少？ |
|
y****d
发帖数: 432 | 30 ★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
前面说明：
需要的童鞋请到我的签名档的博客查找！谢谢！发E-mail太累了！
觉得有价值的话可以顶一下，以便更多的人看到！谢谢！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
详细介绍
1. Advanced Calculus with Applications in Statistics
2.A History of Probability and Statistics and Their Applications before 1750
3.Markov Decision Processes: Discrete Stochastic Dynamic Programming
4.Probability and Statistical Inference
5.Continuous Univariate Distributions, Vol. 1
6.Continuous Univariate Distributions, Vol. 2
7.The Theory of Measures and Integratio... 阅读全帖 |
|
A*******s
发帖数: 3942 | 31 theoretically pure nonlinearity cannot be captured by linear model, say y=
sin(x). however in reality, 1) such case rarely happens; 2) if there are
many variables, it is not necessary to introduce nonlinearity.
dv |
|
s********p
发帖数: 637 | 32 yes, you are right, that is why I mentioned "数据本身可以找到其他可替代的相
关的变量", basically accords with 2) you said
Also, even "heoretically pure nonlinearity cannot be captured by linear model", if we know the exact nonlinearity (basically impossible) or we have a large set of function to fit, transformation still very helpful. |
|
r********n
发帖数: 7441 | 33 不明白，为啥非要搞分段线性，直接 nonlinear regression 就可以了
第一， linear regression model 只是一种简化手段，是目前技术条件能够做到
的最成熟的，真实统计相关关系一般都不是 linear 的
第二，如果非要分段，每个分段点自己也是个随机变量，它的分布是否对称？如果不对
称的话，你用回归就不对了（假设normal）
第三，nonlinear least squares 的结果应该更加可靠(robust),而且有现成算法 |
|
s*********e
发帖数: 1051 | 34 below was posted on my blog before and hope it helpful.
/************************************************
* ARMA - GARCH ESTIMATION USING PROC MODEL *
************************************************/
data garch;
lu = 0;
lh = 0;
ly = 0;
do i = 1 to 1000;
h = 0.3 + 0.4 * lu ** 2 + 0.5 * lh;
u = sqrt(h) * rannor(1);
y = 1 + 0.6 * (ly - 1) + u - 0.7 * lu;
lu = u;
lh = h;
ly = y;
output;
end;
run;
proc model data = garch;
parms ar1 ma1 mu;
y = mu + ar1 ... 阅读全帖 |
|
f*******c
发帖数: 56 | 35 Please contact Professor Wang directly if you are an statistical expert in
the fields mentioned below.
************************************************************************
Dear Colleague,
I would like to cordially invite you to consider contributing your expertise
to a forthcoming book entitled Encyclopedia of Business Analytics and
Optimization. As Editor, I am actively searching for quality material that
would be of interest to our audience. This is a wonderful opportunity since
contribut... 阅读全帖 |
|
h***x
发帖数: 586 | 36 Some nonlinear transformations such as log, sqrt ...
and the binning mentioned by LS. If your dependent variable is category, and
predictor is continues, group the variable into 10 or 20 bins, calculate
response rate in each bin. Combine adjacent bins with same response rate.
This method works better than nonlinear transformation, but has its own
problems.
Both methods can be automated easily... |
|
A*******s
发帖数: 3942 | 37 my 2 cents--GAM might be the best choice for nonlinear modeling in business
for a few reasons, say
can use cross validation to govern the trace of the penalization matrix and
avoid overfitting, which is a big concern of nonlinear modeling;
easy to illustrate the marginal effect of each variable, which is not
available in MARS and CART.
Additive assumption make some ad-hoc tasks much easier. say convenient
missing imputation (may not theoretically sound tho), "neutralizing" one
variable, etc... |
|
A*******s
发帖数: 3942 | 38 我的两分钱--这是个面试必问的问题，我觉得答好不容易，答得全面了面试官还会容易
confused...
text说的都没错，但是需要了解为什么这么说的前提，以及实际面对的data和model的
性质。比如说“with multicollinearity, model's estimates are still unbiased
but have higher variance.” 这话自然没错，但是unbiased estimates的前提是你的
model没有mis-specification，或者mis-specification没有大的影响。如果real
model有10个variable但你只包括了9个，有bias。如果real model是nonlinear的但你
搞了个linear的，有bias。而且real model很可能是由一堆latent variables'
nonlinear functions组成的，在这种情况下，即使你把所有能观察到的variable都加
进去，也不能把所有的latent variables和他们的functional forms都包括到，m... 阅读全帖 |
|
y****d
发帖数: 432 | 39 ****************************************************************************
1）这些资料我以前也分享过，但是因为一些原因我的google博客被关闭了，我就不能
维护下载链接了。现在重新整理出来，免费分享给需要的人。
2）这些资料整理在www.svipbook.com不用担心，都是免费下载的。
3）如果大家需要在人大经济论坛下载任何文件，可以跟帖，我在有时间的情况下给你
下载下来然后传到你能下载的网盘比如dropbox or mediafire
4）如果您认为对您有帮助，请转载这个帖子。谢谢
****************************************************************************
★【1】牛人整理的统计学资料
list
1. AdvancedCalculus with Applications in Statistics
2.A History of Probability and Statistics and Their Applications... 阅读全帖 |
|
f**d
发帖数: 768 | 40 http://theory.people.com.cn/GB/40538/3132387.html
10年前，中国一百多名顶尖级科学家，耗时4年，预测了21世纪的100道科学难题。
其中很多课题已经成为国家973，985的重点攻关课题。
这是中国科学家第一次向全世界发布自己对未来的看法。
其中19个难题涉及神经科学
49.脑神经系统动力学
Dynamics of the Nervous systems in Brain
50.生命、人的思维、意识、目的等的物理学基础
The Physical Bases of Life, Thinking, Consciousness and Intention
54.脑的计算模型能带我们走多远
How far can the Computational Model of Brain Bring Us?
56.未来的认知神经科学能否给意识以新的解释
If the Future Cognitive Neuroscience Give Us New Explanation of
Consciousness
59.脑的选择性自适应
The Selective... 阅读全帖 |
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S*********g
发帖数: 24893 | 41 【 以下文字转载自 StephenKing 俱乐部 】
发信人: StephenKing (金博士), 信区: StephenKing
标 题: 不系安全带，John Nash今天车祸死了
发信站: BBS 未名空间站 (Sun May 24 11:17:59 2015, 美东)
John Forbes Nash, Jr.
Born June 13, 1928
Bluefield, West Virginia, U.S.
Died May 23, 2015 (aged 86) [1]
Residence United States
Nationality American
Fields
Mathematics
Economics
Institutions
Massachusetts Institute of Technology
Princeton University
Alma mater
Princeton University
Carnegie Institute of Te... 阅读全帖 |
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c*********t
发帖数: 1861 | 42 把return 替换成regression，这个摘要还有得一救。。。
Abstract：Nonlinearity model parameter return is difficulty , which need
certain mathematics basis. It is easy and accurate that nonlinearity return
with MATLAB regression analysis toolbox, a penetrating fitting curve can be
given directly.
摘 要 非线性模型参数回归难度大，需要一定的数学基础，用MATLAB 回归分析工具箱
可直接非线性回归，计算简单准确，并能给出直观的拟合曲线图。 |
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y***y
发帖数: 198 | 43 ☆─────────────────────────────────────☆
nde (nonlinear differential equation) 于 (Wed Jul 16 13:19:58 2008) 提到:
转一个：
http://blog.sina.com.cn/s/blog_44544ace010005gj.html
中国历史上每一次分裂和战乱都直接导致大量人口消灭和伴随的巨大物质财富的毁灭，
三国时期是更是中国人口的一个低谷。资料库中，我们了解到公元157年东汉人口达五
千六
百多万，大动乱后公元260－28O年，魏、蜀、吴三国人口可能总数才七百六十余万，不及
原来的七分之一。但也有人认为三国时人口虽然锐减，但应该不会低于1000万，因为有很
多“部曲”是不计入官方人口统计的。
史书公认仅曹操破徐州一次坑杀江淮难民就达数万口，竟至"江淮间空尽，人民相食"。
192年，董卓部将李隺、郭汜攻破长安，"时三辅民尚数十万户，隺等放兵劫略，攻剽城邑
，人民饥困，二年间相啖食略尽"。两年间数十万户人聚居的繁华地区竟然所剩无几，
一片
荒凉。少帝刘协逃出长安后，住处是以 |
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y***y
发帖数: 198 | 44 ☆─────────────────────────────────────☆
qed (天下唯我) 于 (Sun Jul 20 17:02:19 2008) 提到:
最后连国家机器里最暴力的军队都没战斗力了
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nde (nonlinear differential equation) 于 (Sun Jul 20 17:20:56 2008) 提到:
可是腐败的根源还是在于官员的权力是根据他对于皇帝忠诚而决定的，而不是由人民赋
予的。
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haohaohao99 (haole) 于 (Sun Jul 20 17:35:26 2008) 提到:
然
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qed (天下唯我) 于 (Sun Jul 20 17:49:46 2008) 提到:
民主政府一样可以腐败
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y***y
发帖数: 198 | 45 ☆─────────────────────────────────────☆
Corinthian (这也会过去) 于 (Sun Jul 20 17:08:54 2008) 提到:
愤青比腐败分子更有害
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nde (nonlinear differential equation) 于 (Sun Jul 20 17:18:51 2008) 提到:
梁山好汉算愤青么？
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qed (天下唯我) 于 (Sun Jul 20 17:50:48 2008) 提到:
你自己该是愤青吧
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kzeng (寱语·尚能饭否？) 于 (Sun Jul 20 18:11:44 2008) 提到:
我正想说，哈哈
你自己该是愤青吧
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Corinthian ( |
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y***y
发帖数: 198 | 46 ☆─────────────────────────────────────☆
qbz (暂无) 于 (Sun Jul 20 12:57:19 2008) 提到:
在国内的本科历史毕业生找什么工作？
如果在美国读个历史博士的话，能找什么工作？
本人本科专业是理科，可是并不感兴趣。我一直很喜欢读历史
可是不知道读历史书和真正的做历史研究是不是非常不同？
另外，历史专业毕业之后能找什么工作？
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Bod (Bod) 于 (Sun Jul 20 13:10:54 2008) 提到:
我也好奇
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changjiang (待富者) 于 (Sun Jul 20 15:40:34 2008) 提到:
可以做惠普ceo之类的。
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nde (nonlinear differential equation) 于 (Sun Jul 20 1 |
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g******t
发帖数: 18158 | 47 买名牌的潮女们不可能选出潮女当权管事的，最后上台都是职业政治家（又叫政客），
通过他们管理国家。另外不仅仅是数人头决定的，大公司大财团和媒体在选举中也起重
要作用。当然你可以说那样显示了民主的虚伪性。但是从另一个角度看，独裁就是拳头
最大的那个人按照他的意愿随手划条线，其他人赚了赔了看自己运气。民主就是给个人
，团体不同的weight，最后整出一条 weighted nonlinear smooth curve，方方面面
都照顾点，当然不可能每个人都满意。每个个人，团体有多少weight，用什么方法来
fit the curve，各个国家各个时代都不一样，大家为了自己的利益要吵啊。但是在大
多数情况下，总比拳头最大的那个人随手划的线好一点。 |
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b****r
发帖数: 2555 | 48 ☆─────────────────────────────────────☆
didadida (滴滴嗒嗒) 于 (Sun Nov 20 19:46:56 2011, 美东) 提到:
资源丰富，人口相对较少
靠天吃饭，可以随便挥霍
比如北欧的那些国家，比如澳大利亚
其实，这类环境即便是专制，也会过得不错，例如沙特阿拉伯
对于其他国家，民主自由的结果就是最终破产，比如西欧南欧正在这条破产路上大踏步
前进，日本经济上也是裹足不前了好几年，美国正在欧巴马带领下踏上欧洲的道路
一人一票就是个joke
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xiaoju (可爱的龙猫) 于 (Sun Nov 20 20:33:15 2011, 美东) 提到:
伊拉克，利比亚发来贺电。
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deedee2009 (deedee) 于 (Sun Nov 20 21:48:08 2011, 美东) 提到:
自由民主适合于铁杆警察特务控制的国家
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h***i
发帖数: 89031 | 49 现在deep learning 已经很多地方跟人类学习差不多了
下一步的leangring model,解决nonlinear dynamic problem， 机器的学习能力，就要
超过人脑的学习能力
未来世界的秩序，只能靠君臣父子 |
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j****n
发帖数: 7636 | 50 下面是wiki里的第一句。最后的变化当然可以是很大的。
简单说数学里讲这个函数是有界的，他就说这个函数值总是很小。 这不是有误导之嫌吗？
In chaos theory, the butterfly effect is the sensitive dependence on initial
conditions; where a small change at one place in a nonlinear system can
result in large differences to a later state. |
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