1/30/2017

Modelling irregular and multimodal tree diameter distributions by FMM

Today, I read the paper 'Modelling irregular and multimodal tree diameter distributions by FMM'. It introduced an application of FMM to realistic problems. I think it is really helpful for my research. I sketched the logic of this whole method.

Summary:
There are a few steps to apply FMM to modelling irregular and multimodal tree diameter distributions:
1. select database as samples
2. select regular distributions
the upper one is Weibull distribution and the other is gamma distribution.
The finite mixture dnesity functions consisting of two or three Weibull distributions and two or three gamma distributions can be written as
the upper one is k=2 and the other is k=3.
3. use multistart method (MM) to choose initial parameter values (weights and components)
4. estimate the parameters of the mixture model using MLE
5. apply MLE by using EM algorithm with a Newton-type (NT) method to optimize the parameters
6. evaluate the fitting results by p value of chi-square test, bias and RMSE

I think they could be applied to my research.

Tomorrow, I will try to find corresponding codes in Matlab to realize the logic. There are many related packages in Matlab and I think I can find them in Matlab.

4 comments:

  1. looks good. Ensure that the distribution used by you for purposes of fitting has the same feature as the NMR T2 distribution.

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  2. there are several error minimization tools in MATLAB... Yifu can guide you ...

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    Replies
    1. Thank you so much for your advice. I will ask Yifu for help if I have some problems.

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