⑴ 怎么利用r语言做em算法估计混合双参数指数分布的数值模拟
建议你先看一下这本书:
Modeling Survival Data Using Frailty Models
chap 2. Some Parametric Methods
2.1 Introction . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 Exponential Distribution . . . . . . . . . . . . . . . . . . . 20
2.3 Weibull Distribution . . . . . . . . . . . . . . . . . . . . . 21
2.4 Extreme Value Distributions . . . . . . . . . . . . . . . . 23
2.5 Lognormal . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.6 Gamma . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.7 Loglogistic . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.8 Maximum Likelihood Estimation . . . . . . . . . . . . . 30
2.9 Parametric Regression Models
chap 6. Estimation Methods for Shared Frailty Models
6.1 Introction . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.2 Inference for the Shared Frailty Model . . . . . . . . . . 106
6.3 The EM Algorithm . . . . . . . . . . . . . . . . . . . . . . . 108
6.4 The Gamma Frailty Model . . . . . . . . . . . . . . . . . . . 110
6.5 The Positive Stable Frailty Model . . . . . . . . . . . . . . 111
6.6 The Lognormal Frailty Model . . . . . . . . . . . . . . . . . 113
6.6.1 Application to Seizure Data . . . . . . . . . . . . . . . 113
6.7 Modified EM (MEM) Algorithm for Gamma Frailty Models 114
6.8 Application
然后用最基本的package "survival"
并参考你的模型可能用到的一些functions:
survreg(formula, data, weights, subset,na.action, dist="weibull",....)
survreg.distributions include "weibull", "exponential", "gaussian",
"logistic","lognormal" and "loglogistic"
frailty(x, distribution="gamma", ...)
distribution: either the gamma, gaussian or t distribution may be specified.
frailty.gamma(x, sparse = (nclass > 5), theta, df, eps = 1e-05,
method = c("em","aic", "df", "fixed"),...)
⑵ R语言有没有做CRF或者“命名实体识别”的包
基本上需要rule-based + ML-based 方法。
规则就要根据实际数据来设计了。如果有标注数据，那么我想应该可以EM算法学出一些对齐信息来（word alignment）。
⑶ 急求如何用MATLab实现EM算法
最大期望算法（Expectation Maximization Algorithm，又译期望最大化算法），是一种迭代算法，用于含有隐变量（hidden variable）的概率参数模型的最大似然估计或极大后验概率估计。
实现代码如下：
02 Jul 2015 hui cheng
06 May 2015 Mei Dong
very good job！
12 Nov 2014 Jobaer
please, sir , send me a source code on image segmentation. I want to segement weeds from soil.My email address is [email protected] .
18 Jan 2014 HuangJunFeng HuangJunFeng
16 Dec 2013 widdy
19 Feb 2013 Tong Chu
01 Jan 2013 manas nag
sir
after executing this it is declaring that k is undefined
04 Dec 2012 Jason Rebello
Some people want to know how to view the segmented image. For example suppose you have two classes ie k=2; us the following code to view it
[row col] = size(ima);
final_img = zeros(row,col);
for i=1:row
for j=1:col
if mask(i,j)==1
final_img(i,j)=1;
else
final_img(i,j)=255;
end
end
end
imshow(final_img/255);
This is a naive way of viewing it .. you may have to change somethings if k>2. Anywayz hope it helps. The mask basically stores the segmented image.
16 Nov 2011 surya
great job.i am using the same algorithm in my project for x-ray images.can u please tell how to view the segmented image
Comment only
18 Feb 2010 prashanth
Sir, I am starting my project on the same subject. i was unable to find the algorithm psuedocode for em algorithm. kindly send me one at [email protected]. Also can u just tell me the explanation for the source code..
Comment only
21 Dec 2009 maria
Hi, could you please explain how I can use "mask" to see result of segmentation??
Comment only
17 Mar 2009 Patrick
Greetings Prof., Very nice .. could you please let me know what exactly does the mask variable store ? As what i see it classifies each pixel that falls within each class . Am i correct in that assumption?
Thanks
24 May 2008 darko brajicic
great job!
27 Apr 2008 Bilo Bilo
Thanks
15 Aug 2007 smiled fisher
06 Nov 2006 Karthik Raja T
HI, Greetings,can it for my color image segmentation ?
04 Sep 2006 Mikel Rodriguez
12 Jul 2006 carlos mas
03 May 2006 Mohamed Sami
look when u make a code u must show us the output to see it then u read ur code .. try to explain that with output we can see bye
⑷ matlab实现EM算法
1. EM算法程序：
http://www.mathworks.com/matlabcentral/fileexchange/3713-em-algorithm-for-clustering-emfc-m
2. EM image segmentation：
http://www.mathworks.com/matlabcentral/fileexchange/10956-em-image-segmentation
3. 贝叶斯图像分割程序：(Bayseian image segmentation)
没有找到合适的程序代码 :-(
⑸ 求MATLAB 编写的支持向量机、神经网络、KNN或EM算法有关“数据缺失”的源程序满意最少在加100分。谢谢！！
好像这些算法在数据缺失的情况下是没法进行的吧，只能说改进之后在数据缺失情况下做了相应处理，你说的这些算法都可以在网上找到代码