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A gentle tutorial of the em algorithm and its application to parameter estimation for Gaussian mixture and hidden Markov models

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TLDR
In this paper, the authors describe the EM algorithm for finding the parameters of a mixture of Gaussian densities and a hidden Markov model (HMM) for both discrete and Gaussian mixture observation models.
Abstract
We describe the maximum-likelihood parameter estimation problem and how the ExpectationMaximization (EM) algorithm can be used for its solution. We first describe the abstract form of the EM algorithm as it is often given in the literature. We then develop the EM parameter estimation procedure for two applications: 1) finding the parameters of a mixture of Gaussian densities, and 2) finding the parameters of a hidden Markov model (HMM) (i.e., the Baum-Welch algorithm) for both discrete and Gaussian mixture observation models. We derive the update equations in fairly explicit detail but we do not prove any convergence properties. We try to emphasize intuition rather than mathematical rigor.

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References
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Regression with Input-dependent Noise: A Gaussian Process Treatment

TL;DR: This paper shows that prior uncertainty about the parameters controlling both processes can be handled and that the posterior distribution of the noise rate can be sampled from using Markov chain Monte Carlo methods and gives a posterior noise variance that well-approximates the true variance.
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Level-crossing problems for random processes

TL;DR: A survey of known results on certain aspects of the level-crossing properties of random processes is presented and provides a basis for further study in the area.
Book

Continuous Univariate Distributions, Volume 2

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Tangent Prop - A formalism for specifying selected invariances in an adaptive network

TL;DR: A scheme is implemented that allows a network to learn the derivative of its outputs with respect to distortion operators of their choosing, which not only reduces the learning time and the amount of training data, but also provides a powerful language for specifying what generalizations the authors wish the network to perform.
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Radon-Nikodym Derivatives of Gaussian Measures

TL;DR: In this paper, the Radom-Nikodym derivative of the Radon-Niels (R-N) derivative of a Gaussian measure is derived for the case of the Gaussian process W(T + 1) - W(t).