The expectation-maximization maximum-likelihood (EM-ML) algorithm for image reconstruction in positron emission tomography (PET) essentially solves a large linear system of equations. In this paper, we study computational aspects of a recently developed preprocessing scheme for focusing the attentio
ML Estimation of the MultivariatetDistribution and the EM Algorithm
โ Scribed by Chuanhai Liu
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 325 KB
- Volume
- 63
- Category
- Article
- ISSN
- 0047-259X
No coin nor oath required. For personal study only.
โฆ Synopsis
Maximum likelihood estimation of the multivariate t distribution, especially with unknown degrees of freedom, has been an interesting topic in the development of the EM algorithm. After a brief review of the EM algorithm and its application to finding the maximum likelihood estimates of the parameters of the t distribution, this paper provides new versions of the ECME algorithm for maximum likelihood estimation of the multivariate t distribution from data with possibly missing values. The results show that the new versions of the ECME algorithm converge faster than the previous procedures. Most important, the idea of this new implementation is quite general and useful for the development of the EM algorithm. Comparisons of different methods based on two datasets are presented.
๐ SIMILAR VOLUMES
The EM algorithm is used for many applications, including the Boltzmann machine, stochastic Perceptron, and HMM. This algorithm gives an iterating procedure for calculating the MLE of stochastic models which have hidden random variables. It is simple, but the convergence is slow. We also have the Fi