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全部话题 - 话题: poisson
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c*****e
发帖数: 59
1
因为需要向图像里添加Poisson noise,
平均值比较大,大概1E6,
先有的c++ Poisson noise的程序,如Boost,
精度有限,只能应付700以内的平均值
请问大牛们如何解决这个问题,
能有一个平均值幅度比较大的Poisson随机数generator,
谢谢~~
s*********e
发帖数: 1051
2
来自主题: Statistics版 - zero-truncated poisson是啥意思?
in a standard poisson, zero outcome has nonzero probability.
the zero-truncated poisson is a standard poisson with zero probability of
zero outcome.
l******1
发帖数: 292
3
在sas 里面,poisson regression model里面,response variable可以是binary吗?
我用了proc genmod option/dist/poisson,不是很清楚如果dependent variable是
binary (0,1)可以用/poisson还是用别的选项?菜鸟,等大虾指点!
x******r
发帖数: 367
4
来自主题: Computation版 - solve Poisson equation numerically
Thanks.
Are there any simple Poisson equations that have the analytical solution?
I just download some programs to solve Poisson equations.
But I have no data to verify that the program is correct.
j****j
发帖数: 270
5
Hi all,
I am looking for the Radon-Nikodym derivative when both Brownian Motion and
Poisson Process present? For example, when the Bt and Nt are independent, we
have a Radon-Nikodym derivative which is the product of the RN derivative
of the Brownian Motion part and the RN derivative of the Poisson Process
Part. But what if they are not independent?
S******r
发帖数: 11
6
【 以下文字转载自 Statistics 讨论区 】
发信人: Superior (瘦歪歪~苏必列尔湖的夏天), 信区: Statistics
标 题: 如何test两个Poisson分布的mean difference? 急
发信站: BBS 未名空间站 (Thu Oct 8 22:39:22 2009, 美东)
现在知道两年内某事件发生了50次,紧接下来的两个月发生了6次,假设两段时间内都
服从poisson分布,请问如何test whether the intensity difference between the
two time period is significant?
多谢。我的想法是用normal distribution来近似,但是好像有sample size的问题。请
问大家用上面观察到的数据如何进行test? 具体就是(1)如何做近似test (用CLT?) (
2)如何做基于精确distribution的mean test?
多谢!
v*******g
发帖数: 334
7
来自主题: Statistics版 - 求助:Power analysis for poisson regression?
我的 Model 是
Proc Genmod ;
class X Y ;
model count=A B X Y /dist=poisson link=log scale=D;
A B 是 continuous variables , A 是我想 test 的 variable , B X Y 是
covariates
it looks proc power or proc glmpower don't couple with poisson model.
h**l
发帖数: 4883
8
来自主题: Statistics版 - Poisson and Binomial
I am trying to compare the academic performance of 2 groups of students. the
dependent variable is the “number of passes on assessments”. The students
take a varied number of assessments ranging anywhere from 5 to 12. I think
it's a binomial distribution. But would Poisson regression work? What are
the essential differences between Poisson and Binomial? Are they equivalent
in this case?
s*********e
发帖数: 1051
9
来自主题: Statistics版 - Poisson and Binomial
do you mean "negative binomial" ^_^?
standard Poisson definitely won't work, since your outcomes range from 5 to
12. however, truncated poisson might.
x*******i
发帖数: 1791
10
来自主题: Statistics版 - Poisson and Binomial
multimomial. 我也认为是。
the number of passed in some fix number of total test.
不是poisson。 poisson没有上线。
z******a
发帖数: 3
11
If your response follows Poisson distribution, you may use poisson
regression. If your response is Binomial, you may consider using Proc GIMMIX
and using the proper Link function.
m****r
发帖数: 237
12
这个问题不是很明确。。不过看你的意思应该是在test if the data follows a poiss
on distribution or not.
Chisq-test can be used to test whether a random variable is from some specif
ied distribution, for instance, poisson in your case.
Your p-value here is between 0.5 and 0.9, you can't reject your null hypothe
sis, which is the data follows poisson distribution. That's how you get your
result.
There is a theorem behind this. You can google for chi-square test for it. O
ne of the application of Chi-square test
x********u
发帖数: 64
13
这2个是一样的么?
还是有什么区别
好像log-linear model,是用proc genmod,dist=poisson
模型是
log (E(y))=ax
而poisson regression呢?
w********r
发帖数: 14958
14
来自主题: ComputerGraphics版 - Poisson disk distribution (转载)
【 以下文字转载自 CS 讨论区 】
发信人: withourcar (注意不是老id"没有车"), 信区: CS
标 题: Poisson disk distribution
发信站: BBS 未名空间站 (Wed Nov 27 11:43:25 2013, 美东)
请问有人了解这方面数学分析的文章吗?
关于dispersion, variance, distribution方面的结论。 谢谢
n*****3
发帖数: 1584
15
your library have the uniform random generator right?
it is easy transfer to get poisson random #,
check numeric receipt or some other reference
c*****e
发帖数: 59
16
多谢你的建议,
gsl可以正确的产生平均值比较大的Poisson随机数~
再就是,除了gsl,还有什么c++ libraries经常用呢?
r**u
发帖数: 1567
17
http://www.agner.org/random/
We used this library to simulate the appearance of transient fault on the
processor, which follows poisson distribution.
n**h
发帖数: 2
18
【 以下文字转载自 Science 讨论区,原文如下 】
发信人: NaOH (氢氧化钠), 信区: Science
标 题: 急问!poisson's PDE analytical solution!
发信站: Unknown Space - 未名空间 (Wed Jun 9 19:23:30 2004) WWW-POST
2-D,正方形,边界条件为constant (0)
方程右边是常数。
我就想知道那里能找到这个方程analytical solution。自己古迹是没能力解决了,时间
太紧了,不可能从头补习,谢谢!
h***o
发帖数: 539
19
a constant can be expanded by sin(n\pi y). and I suppose
the constant at the right hand side of poisson equation has nothing to
do with boundary conditions.
x*****u
发帖数: 3419
20

如果是laplace,用分离变量可解,如果是poisson,一般不行吧。
如果能找到Greenberg的Foundation of Applied Mathematics,看p552有例题。
x******r
发帖数: 367
21
来自主题: Computation版 - solve Poisson equation numerically
Are there any softwares that can solve Poisson equation numerically
directly,matlab, mathematica or others?
I mean that it will give you the result without writing code by yourself?
w****h
发帖数: 212
22
Poisson/Markov ON-OFF的Traffic是不是属于Gaussian分布的?
能否就用Gaussian概率分布表达式描述这些traffic?
zu
发帖数: 49
23
KS是测量连续分布的,检测离散型分布如Poisson用Chi-sq。比较好,
S+和R应该比较相似,解决特殊问题相对SAS和SPSS要方便些,可以自己编写程序,适合搞
统计学的专业人士。
SAS和SPSS相对S+比较好操作,也更好掌握,侧重实际应用。
j****j
发帖数: 270
24
say by changing of measure, you can get rid of the drift of the brown motion
, and you can change the intensity of the poisson process, ...
j****j
发帖数: 270
25
You sure it talks about change-of-measure when BM and Poisson are not
independent? Thanks!
H****j
发帖数: 21
26
想找点习题练练手,有解答便于查对。poisson process, markov chain 之类的应用题。
书或者什么其他资料都行。主要是加强一下sense,并不要很多复杂的数学计算.
盼回复!
多谢先!
x**7
发帖数: 239
27
来自主题: Quant版 - Poisson distribution question
楼上正解,Poisson的interarrival time 是 exponential, exponential is
memoryless。 所以 无论是什么时候到达车站 expectation == 10 min for No.2 Bus
n***e
发帖数: 13
28
来自主题: Quant版 - Poisson distribution question
这个问题好像一开始的假设应该明确:
如果假设平均等待时间是10分钟,那应该是poisson,所以等待时间是10分钟。
如果假设等待时间是uniform(0,10),那就应该是用conditional probability解。

Bus
n*******m
发帖数: 101
29
来自主题: Statistics版 - Poisson and Binomial
how about poisson for rate?
W**********E
发帖数: 242
30
来自主题: Statistics版 - Poisson and Binomial
我想你是不是可以用POISSON模型,但用不同的OFFSET(parameter is not just lamda
but lamd/offset)。 Y/OUTCOME就是错误的次数,OFFSET 就是总共经历过的测试。打
个比方,Y=5, OFFSET=5=>5次测试内发生5次错误的概率; Y=5, OFFSET=10=>10次测试
内发生5次错误的概率;Y=1, OFFSET=12=>12次测试内发生1次错误的概率。
b*******g
发帖数: 513
31
来自主题: Statistics版 - zero-truncated poisson是啥意思?
虽然我猜就是一个自变量除去0的truncated poisson分布。但还是不太确定。感觉有些
东西不能从字面上联想。知道的同学,麻烦告诉一声,多谢!
S******r
发帖数: 11
32
现在知道两年内某事件发生了50次,紧接下来的两个月发生了6次,假设两段时间内都
服从poisson分布,请问如何test whether the intensity difference between the
two time period is significant?
多谢。我的想法是用normal distribution来近似,但是好像有sample size的问题。请
问大家用上面观察到的数据如何进行test? 具体就是(1)如何做近似test (用CLT?) (
2)如何做基于精确distribution的mean test?
多谢!
z*****n
发帖数: 95
33
y = min (x1, x2,..,xn) 的概率分布,where x1, ..., xn is Poisson distribution

多谢大侠们
s*r
发帖数: 2757
34
why not just proc logistic
how can a 0/1 binary variable be poisson? only when 0 is the majority and
there is very few 1 and it is unlikely to observe 2. in this case, the
iteration will have problems
i*****r
发帖数: 24
35
看到个问题,已知degree of freedom N-1,
和 (kai) x^2,查表得,x^2 falls between 0.9 and 0.5,
conclusion data set is Poisson distribution.
不是统计专业的,不懂为什么,请给点建议。谢谢。
i*****r
发帖数: 24
36
thanks for replying. the question is this, i explained it wrongly, yesterda
y.
" A series of 25 measurements on a radioactive sample provides a mean of 950
and value of 17,526 for sum(xi-r)^2(for i=1 to N), Do the data follow norma
l distribution?"
Ans: use formula, chi^2=18.5. look at table p between 0.9 to
0.5. so is Poisson Distribution.
s********e
发帖数: 68
37
来自主题: Statistics版 - stata 里用poisson regression的一个问题
请问在stata里面,做一个简单的poisson regression, 如何做goodness of fit test
来检验
adequency of the model。
stata output好像没有给出这个output。
谢谢各位
l*********s
发帖数: 5409
38
poisson regression with all categorical covariates are usually termed as log
-linear model
L*********u
发帖数: 104
39
来自主题: Statistics版 - test if poisson or not in SAS
请统计牛人们帮我解一道题:
The data are summarized below for 150 fields examined.
Here, xi denotes the number of cell clumps per field and ni, denotes the
frequency of occurrence of fields of each cell clump count.
xi 0 1 2 3 4 5 6 >=7
ni 6 23 29 31 27 13 8 13
Write a SAS program to perform a chi-square goodness-of-fit at α = .05
to test the hypothesis that the observed counts were drawn from a Poisson
probability distribution.
用proc freq 作chi-square test的话 testp怎么确定?
S********a
发帖数: 359
40
正在做generalized linear mixed model with Poisson distribution, 目前理解是用proc glimmix procedure in SAS or lmer in R, 谁能给推荐一下这方面的书,最好有例子的,谢谢
t**********y
发帖数: 374
41
来自主题: Statistics版 - poisson transformation
最近看到两种transformation 常用poisson distribution 做例子:
log transformation
variance stabilizing transformation
想问下他们适用于那些情况,有什么区别?
多谢!
G********n
发帖数: 615
42
Xiang Tang awarded the 2010 Andre Lichnerowicz Prize
September 2010
About the André Lichnerowicz prize in Poisson geometry
The André Lichnerowicz prize was established in 2008 to be awarded for
notable contributions to Poisson geometry. The prize is to be awarded every
two years at the International Conference on Poisson Geometry in Mathematics
and Physics" to researchers who had completed their doctorates at most
eight years before the year of the Conference.
The prize was named in memory of An... 阅读全帖
b***y
发帖数: 14281
43
来自主题: Military版 - 方励之的学术成就全记录
既然有人争论方的学术水平,就上网搜了一下。应该说这个水平对于一个junior
faculty来说可以算是很牛B了,但是对于老方这种senior的已经搞了一辈子的人来说,
就只能算so so。不要说是院士,离aps fellow的级别也还差了不少。引用率最高的一
篇文章还是95年到了arizona之后跟老外合作的,被引118次,这也是方唯一一篇被引用
上百次的文章。可见方励之89之前确实没有做出过什么重要的工作,他的名声和地位绝
对是靠政治得来的,当然其中部分的也是80年在中国搞科普所得,必须承认科普工作也是
有重要的社会意义的。
(BTW,有人说你这个搜索未必完整。不错,确实不能保证100%毫无遗漏。但是我
用的search engine is THE search engine everybody in this community uses today.
So, if any article is not found by this search engine, sadly, it simply doesn't matter,
because no one would ever n... 阅读全帖
k*z
发帖数: 4704
44
来自主题: Statistics版 - 牛牛 Xie Liang关于 Erlang C的Model应用
http://saslist.com/blog/2012/07/13/sas-functions-for-computing-
http://listserv.uga.edu/cgi-bin/wa?A2=ind1210c&L=sas-l&F=&S=&P=
SAS functions for computing parameters in Erlang-C model
Call center management is both Arts and Sciences. While driving moral and
setting up strategies is more about Arts, staffing and servicing level
configuration based on call load is in the domain of Sciences.
The science part of call center management is based on Queueing Theory,
which studies "the Phenomena of sta... 阅读全帖
s**u
发帖数: 9035
45
发信人: matrice (matrice), 信区: Physics
标 题: 拙作“杨振宁先生与复旦大学物理系教师的座谈”zz
发信站: BBS 未名空间站 (Mon Aug 22 22:23:35 2011, 美东)
http://blog.sciencenet.cn/home.php?mod=space&uid=4395&do=blog&i
拙作“杨振宁先生与复旦大学物理系教师的座谈”
已有 302 次阅读 2011-8-22 13:24 |个人分类:生活点滴|系统分类:科研笔记|关键词:
复旦大学 杨振宁 杂志发表 物理系 文章
最近在物理杂志发表的“杨振宁先生与复旦大学物理系教师的座谈”是以本人为作者的
文章。它基于杨先生与复旦大学物理系教师的对话。将它转变为一篇文章是一个创作过
程。每一个词、每一个标点都倾注了我们的心血。由于不必细说的种种方面,本文的成
文花费了我们大量的精力。本人学习研读过杨先生很多著作,与杨先生交往多年,也对
物理学史有所熟悉,但为在本文中保持和传达杨先生的风格仍然付出了大量心血。希望
本文能很好地表达杨先生的风格。
我们也很感谢物理杂志的合作。
... 阅读全帖
o**a
发帖数: 76
46
来自主题: Mathematics版 - 问一道调和函数的题目
用Poisson公式可以证明(见最后),但这道题在Ahlfors书上出现在Poisson公式之前,
大家有没有什么好办法?
证明(Poisson公式):
由于
\int_{|z|=r} u(r*exp(i\theta)) d\theta = alpha * log(r) + beta
而 u有界,所以alpha=0
定义u(0)=beta, 则u在|z|<\rou连续,并且满足平均值公式
从而满足极大和极小值原理
根据|z|=r上的u的值以及Poisson公式我们可以得到一个|z|<=r上的调和函数v
u-v在|z|<=r满足极大和极小值原理,而在边界上是0,从而恒等于0
从而u在z=0也调和。
m*****e
发帖数: 1506
47
http://blog.sciencenet.cn/home.php?mod=space&uid=4395&do=blog&i
拙作“杨振宁先生与复旦大学物理系教师的座谈”
已有 302 次阅读 2011-8-22 13:24 |个人分类:生活点滴|系统分类:科研笔记|关键词:
复旦大学 杨振宁 杂志发表 物理系 文章
最近在物理杂志发表的“杨振宁先生与复旦大学物理系教师的座谈”是以本人为作者的
文章。它基于杨先生与复旦大学物理系教师的对话。将它转变为一篇文章是一个创作过
程。每一个词、每一个标点都倾注了我们的心血。由于不必细说的种种方面,本文的成
文花费了我们大量的精力。本人学习研读过杨先生很多著作,与杨先生交往多年,也对
物理学史有所熟悉,但为在本文中保持和传达杨先生的风格仍然付出了大量心血。希望
本文能很好地表达杨先生的风格。
我们也很感谢物理杂志的合作。
施郁 (复旦大学物理系教授)
2011.8.22.
附原文如下。这里是html文件的唯一源,转载请注明。
【发表为:施郁,戴越,《物理》8卷(2011年)8期,491-499,特约专稿。本文是学
术文章,使用本文时请注意引用规... 阅读全帖
h******i
发帖数: 661
48
你们学校ap能发这么多paper?
1989
Cosmological implications of quasar-galaxy associations, L.Z.Fang, Y.Q.Chu
and X.F. Zhu, Mod. Phys. Lett., 4, 887.
Geometrical optics in an inhomogeneous universe, L.Z.Fang and X.P.Wu,
Chinese Phys. Lett., 6, 233.
Quasar clustering and its cosmological implication, L.Z.Fang, Inter. J. Mod.
Phys. A4, 3477.
L'Osservatorio astronomico di Pechino: la sua storia, il presente, L.Z.Fang,
Scienza e Tecnica, Annuario della EST 88/89 404.
Overview on the frontier of high energy astr... 阅读全帖
b***y
发帖数: 14281
49
来自主题: Military版 - 方励之的学术成就全记录
No. The search include his early works up to 1978. Here is the same list
sorted by year.
1) The Influence of Gravitation on the Vacuum State.
By Li-Zhi Fang.
Acta Phys. Sinica 27 ( 1978) 181-18.
2) THE STRUCTURE AND STABILITY OF THE ABNORMAL NEUTRON STAR.
By Li-Zhi Fang, Qin-Yue Qu, Zhen-Ru Wang, Tan Lu, Liao-Fu Luo.
Sci.Sin.22:187-198,1979.
3) Some Recent Developments in Astrophysics. (Talk).
By Li-Zhi Fang, A. Qadir, R. Ruffini.
In *Nathiagali 1980, Proceedings, Physics and Contemporary Needs... 阅读全帖
S******8
发帖数: 24594
50
老方到美国后发的文章列表,你自己看吧:
1990
174. Biased clustering in a universe with hot dark matter and a cosmic
string, L.Z.Fang, S.P.Xiang and L.Yan, Astr. & Astrophys. 233, 1.
175. Periodicity of redshift distribution in a T-3 universe, L.Z.Fang, Astr.
& Astrophys. 239, 24.
176. An upper limit to quasar's peculiar velocity, L.Z.Fang, Y.Q.Chu, X.F.
Zhu and L.F. Wang, Inter. J. Mod. Phys., 5, 2993.
177. Quasar pair and quasar's peculiar velocity, L.Z.Fang, Developments in
general relativity, astrophysics and qu... 阅读全帖
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