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全部话题 - 话题: distribution
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m**********d
发帖数: 137
1
来自主题: Biology版 - 关于cell cycle distribution analysis
我在用一个作用于G1/S checkpoint的药物处理细胞,现在需要用FACS看一下cell
cycle distribution。向前辈们请教一下,这种情况需要synchronize我的细胞吗,或
者什么情况下需要做synchronization? 非常感谢
m******5
发帖数: 1383
2
来自主题: Biology版 - Nuclear actin distribution
I happened to be reading a review article published 1 year ago talking about
that actin play a very important role inside cell nuclear, by recruting
Nuclearsome remodeling complex or stablizing pre-mRNA.
But there isn't any NLS harbored on actin, and it has been proved that actin
can not migrate into cell nuclear on their own. So, how come a little
amount of actin leaking into cell nuclear can have so significant function?
On the other hand, did anyone ffind that different isoforms of actin have... 阅读全帖
a*****n
发帖数: 2835
3
来自主题: Biology版 - how to measure cell size distribution
请教版上有没有朋友做过细胞直径分布测量实验的,cell size distribution.
研究TSC-mTOR signaling 的经常要测量细胞直径,有人用流式细胞仪,也有不少用
cell counter的。
我最近做了几次,用的是cell counter,得到的细胞直径分布图一般都是不规则的曲线
,而文章里面的一般是类似正态分布曲线图
请问有这方面经验的版友,这个实验有什么关键的注意事项?
附图1是截取一篇cell文章里的结果
附图2是我自己的一个结果
多谢!
V*f
发帖数: 171
4
来自主题: Biology版 - how to measure cell size distribution
use 20- 100 times more cells, then you will have a normal distribution
w*****g
发帖数: 47
5
来自主题: Computation版 - Multivariate Normal Distribution
How to make draws which follow multivariate normal distribution? used the
subroutine to decompose the covariance matrix into cholesky factor. but can
not guarantee the matrix is positive definite. is all covariance matrix
positive definite?
o***a
发帖数: 724
6
【 以下文字转载自 Mathematics 讨论区 】
发信人: olama (Obama), 信区: Mathematics
标 题: 有啥好的normal distribution random variable的C代码?
发信站: BBS 未名空间站 (Sun May 17 02:19:12 2009), 站内
大家能推荐一个好的么
3x
t*****e
发帖数: 224
7
☆─────────────────────────────────────☆
fyyzy (雪的童话) 于 (Tue May 8 01:59:45 2007) 提到:
两个 assets, risk free 资产的return R>0 和一个risky asset Z (其return 是
state-contingent,只有两个equally likely states),riskly asset Z return 分别
是A, B, 满足A>R>B,只有一个investor with strictly increasing and risk
averse utility function U(.),她可以买risky和riskless资产,w是weight on
risky asset。
Fix B,consider a new asset with the same distribtution of returns as Z
except that A increases. Does the new asset distribution necessarily
s*******y
发帖数: 558
8
We are pleased to announce the availability of a bibliography on
Distributed Data Mining. The current version contains 246 entries.
It can be downloaded from the following site:
http://www.csee.umbc.edu/~hillol/DDMBIB/
The site also provides an interface to submit bibliographic
information for relevant papers.
Department of CSEE
University of Maryland Baltimore County
o***a
发帖数: 724
9
【 以下文字转载自 Mathematics 讨论区 】
发信人: olama (Obama), 信区: Mathematics
标 题: 有啥好的normal distribution random variable的C代码?
发信站: BBS 未名空间站 (Sun May 17 02:19:12 2009), 站内
大家能推荐一个好的么
3x
m***i
发帖数: 86
10
We need 2-4 researchers to review papers on content distribution networks
for a prestigious international conference. If you are interested, please
drop me a line on mitbbs account with a brief description of your background
. Thanks.
s******a
发帖数: 184
11
在 matlab 里如何simulate 符合下面这样的hierarchical distribution 的data:
X|P ~ binomial(P)
P ~ beta(\alpha, \beta)
c*****t
发帖数: 198
12
【 以下文字转载自 Biology 讨论区 】
发信人: compact (support), 信区: Biology
标 题: how to measure the spatial distribution of amino acids, like lysine
发信站: BBS 未名空间站 (Tue Jul 1 13:42:59 2008)
other than C14 isotope measurement. Thank you.
s********5
发帖数: 24
13
本人博士毕业,工作三年。求审稿机会。
擅长方向:
Water distribution system modeling, GIS, geodatabase, asset management,
water main breaks, capital improvement planning, water demand modeling and
forecasting, time series analysis, genetic algorithm, optimal sensor
placement, real-time modeling and energy optimization, contamination
scenario analysis, visualization
可以提供简历。请站内信联系。
谢谢!
c*******i
发帖数: 951
v****k
发帖数: 229
15
NO.
suppose g(x) is a function, and x follows some distribution f(x), then
E[g(x)] exists if the integral \int{g(x)f(x)}dx absolutely converges,
i.e. \int{|g(x)|f(x)dx} for your example, suppose x follows N(\mu,\sigma^2) you can check the
integral \int{(1/|x|)f(x)} diverges.
DK
发帖数: 194
16
来自主题: Mathematics版 - A question on T distribution
For student t distribution,
what is the formula to find t when the degree of freedom and probability is
known?
d****y
发帖数: 53
17
来自主题: Mathematics版 - A question on T distribution
well...as usual, no closed form expression for the inverse CDF of t
distribution. Use x=tinv(p,nu) in Matlab, speed is not bad.
s******y
发帖数: 289
18
来自主题: Mathematics版 - A question on T distribution
http://en.wikipedia.org/wiki/Student's_t-distribution
or any basic stat book, you can find the pdf of T
f******k
发帖数: 297
19
来自主题: Mathematics版 - 请教:limit distribution
search for stable Levy distribution...
e****c
发帖数: 183
20
standard normal distribution 的CDF 和pdf,F(x) 和f(x), 限定x<0, 有什么关系吗
?比如我想知道两者相除,F(x)/f(x), 有最大值、最小值吗?谢谢。
r***r
发帖数: 123
21
BlackKnife,
Thanks for your expertise.
I know very little about statistics. Don't even know what is gamma distribution
. Would you please give me some formula or agrithom to calculate gamma
inverse. I couldn't find any.
We currently use Excel/SAS to get around of this. My boss want do it in the
Oracle.
Thanks once again!

自己
其他
新月
g****t
发帖数: 31659
22
gamma 分布的公式网上一查就能看到。
里头就gamma函数是个积分,别的都是加减乘除。
gamma函数那个积分的计算有专有的算法,
不过需要花时间看文献。numerical receipts啥的
应该有现成的代码。
如果你不想查文献,gamma函数按它的级数极限定义
算算看能不能满足你得计算速度要求。

distribution
the
B**W
发帖数: 2273
23
来自主题: Mathematics版 - Bidirectional Von Mises Distribution (转载)
【 以下文字转载自 Statistics 讨论区 】
发信人: BenW (Ben), 信区: Statistics
标 题: Bidirectional Von Mises Distribution
发信站: BBS 未名空间站 (Thu Jun 18 11:00:46 2009, 美东)
Can anybody help me on its estimation?
Best is ready-to-use code or program in R, Matlab, or other popular software.
Thanks.
s**l
发帖数: 869
24
目前能想到的就是
1.用photoshop测量
2.打印出来图片,直接在图片上测量
大家一般是怎么做的呢?
有没有什么软件specific用来统计length distribution的阿?能减轻些工作量也是好
的。谢谢!
E**E
发帖数: 103
25
author = "Itzykson, C. and Pearson, R. B. and Zuber, J. B.",
title = "{DISTRIBUTION OF ZEROS IN ISING AND GAUGE MODELS}",
journal = "Nucl. Phys.",
volume = "B220",
year = "1983",
pages = "415",
SLACcitation = "%%CITATION = NUPHA,B220,415;%%"
you can try to follow the link below:
http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=715403493&_sort=d&_acct=C000020939&_version=1&_urlVersion=0&_userid=440026&md5=
c*****t
发帖数: 198
26
【 以下文字转载自 Biology 讨论区 】
发信人: compact (support), 信区: Biology
标 题: how to measure the spatial distribution of amino acids, like lysine
发信站: BBS 未名空间站 (Tue Jul 1 13:42:59 2008)
other than C14 isotope measurement. Thank you.
b***k
发帖数: 2673
27
☆─────────────────────────────────────☆
sbtim (15#) 于 (Wed Sep 5 10:41:11 2007) 提到:
因为一个有限的采样数据中存在outlier,
为了得到更为可靠的distribution的location, scale估计值,
想采用bootstrap方法,
只是不确定这样产生的simulation samples, 会
不会使得估计出的statistics (mean, median, variation, quantiles)
与初始sample得到的statistics估计值有很大偏差?
请大家不吝赐教。
多谢了先。
☆─────────────────────────────────────☆
arnaud (Prrrrrf) 于 (Wed Sep 5 11:18:51 2007) 提到:
bootstrap方法要在现有样本基础上重新抽样,这个resampling过程有很多研究,根据数
据特征,可以分别采用传统bootstrap(iid),moving blocks boot(depe
i****e
发帖数: 78
28
以前扫过一眼这方面的PAPER,这个方法好像是不是需要
market option price做基础,然后得到distribution。
我现在的难题其实是没有market option price quotes,
只有历史数据。
s*********e
发帖数: 1051
29
来自主题: Quant版 - distribution of perl in winXP
which distribution would you recommend? i am thinking of perl in cygwin. Is
it a good choice?
Thank you so much for your insight!
o***a
发帖数: 724
30
【 以下文字转载自 Mathematics 讨论区 】
发信人: olama (Obama), 信区: Mathematics
标 题: 有啥好的normal distribution random variable的C代码?
发信站: BBS 未名空间站 (Sun May 17 02:19:12 2009), 站内
大家能推荐一个好的么
3x
I***e
发帖数: 1136
31
Correlation with cauchy distribution isn't well defined: cauchy dist'n doesn
't have even first moment.
d*******1
发帖数: 293
32
yes, it has no variance. How about beta distribution?
x**p
发帖数: 105
33
Is there a way to back out from market instruments the joint stock price
distribution under risk-neutral measure for two stocks at a future time t?
r*******y
发帖数: 290
34
来自主题: Quant版 - 如何求implied distribution
use call options for all strikes
then f(s)=exp(-rt)d^2 (call)/dK^2

distribution
s******a
发帖数: 184
35
针对一个随机数据有一个已知的采样集,估算这个数据的probability distribution
一般用那些方法?
s******a
发帖数: 184
36
假入需要用MCMC模拟一个非常复杂的分布,如何选择proposal distribution 呢?
s******a
发帖数: 184
37
在 matlab 里如何simulate 符合下面这样的hierarchical distribution 的data:
X|P ~ binomial(P)
P ~ beta(\alpha, \beta)
S***w
发帖数: 1014
38
来自主题: Quant版 - Poisson distribution question
不是expotenial distribution 吧

一个车站,有两路车经过(1,2路)。1路车每5分钟一班,2路每10分钟。你刚到车站
看到有一辆车刚开走,但是你没看到是几路。问题:下一辆2路到达要经过的时间的
expectation
答案是10分钟吗?因为exponential no memory, so no matter when you arrive the
bus station, the average waiting time is 10 min
t*****j
发帖数: 1105
39
来自主题: Quant版 - Poisson distribution question
应该是25/6 分钟吧。和exponential distribution没关系。
t*****j
发帖数: 1105
40
来自主题: Quant版 - Poisson distribution question
你说的是对的。昏倒,我也是按你这个思路算的。1路车2/3概率,2路车1/3概率。
貌似我是弄的uniform distribution,貌似也不对,或者就是貌似我算的是任
意下一班车?不记得了。
谢谢nykee mm了!
p***n
发帖数: 27
41
本人对spherical and elliptical distribution的含义和用处不是很理解,学的云里雾里。这里有高手详细指点一下吗?用简单的语言平铺直叙吧。数学公式等的我都懂,wiki我也看了,不用重复。多谢了
M*********l
发帖数: 214
42
Portfolio optimization under elliptical distributions?

里雾里。这里有高手详细指点一下吗?用简单的语言平铺直叙吧。数学公式等的我都懂
,wiki我也看了,不用重复。多谢了
s*****g
发帖数: 77
43
来自主题: Quant版 - distribution of St=integal <0>W_sd_s?
请教大牛:
如果St= integal of W_sd_s from 0 to t, what is the distribution of St?
面试官英语太难听懂了,勉强明白这个意思。
S****h
发帖数: 558
44
Let us say X~N(0,a), Y~N(0,b), and correlation of them is \rho. Is the
joint-distribution of (X,Y) joint normal? I
feels that it is not true, but cannot come up with a quick example. Can
anyone give me one? Thanks.
s***e
发帖数: 267
45
Shiloh,
If X and Y are jointly normal, here is one easy way to solve your problem:
Define Z1=X-Y and Z2=2X+Y then they are jointly normal as well. So you write
down their joint Normal mean and variance. The conditional distribution of
normal is still normal, and here you only need the mean. Its formula is not
hard to derive, and you can easily google its answer.
d********t
发帖数: 9628
46
把其中一个a*X+b,把另一个c*Y+d,新的distributions的correlation还是rho吗?
谢谢!
l**********r
发帖数: 12
47
how to calculate the distribution of the time of reaching minimum of a
Brownian Motion Bt? 0<=t<=1
I guess that its pdf looks like
- symmetric around 1/2
- higher at 0, 1 and lower at 1/2
y***s
发帖数: 23
48
As B_t and -B_t have the same distribution, it's
enough to consider the max.
Pr(max B_t > a)=Pr(min B_t > a)=exp(-2a^2).
Take derivative to get the pdf.
reference
3.3' in
http://projecteuclid.org/DPubS/Repository/1.0/Disseminate?view=
k*******d
发帖数: 1340
49
My understanding is argmin{Bt, t in [0,1]} is the argument t, so we are
asked to find the distribution of t_min where B(t_min) is the mininum of B(t
) when t in [0,1]. It seems to me you are finding the pdf of the minimum
value.
S**********3
发帖数: 188
50
来自主题: Quant版 - log return distribution 选择
NIG (Normal Inverse Gaussian), has fatter tail than normal distribution.
Monte Carlo simulation works.
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