نتایج جستجو برای: expectationmaximization

تعداد نتایج: 273  

Journal: :EURASIP J. Image and Video Processing 2009
Xiaotao Zou Bir Bhanu Amit K. Roy-Chowdhury

A multilayered camera network architecture with nodes as entry/exit points, cameras, and clusters of cameras at different layers is proposed. Unlike existing methods that used discrete events or appearance information to infer the network topology at a single level, this paper integrates face recognition that provides robustness to appearance changes and better models the time-varying traffic p...

2012
Kurt Hornik Bettina Grün

Finite mixtures of von Mises-Fisher distributions allow to apply model-based clustering methods to data which is of standardized length, i.e., all data points lie on the unit sphere. The R package movMF contains functionality to draw samples from finite mixtures of von Mises-Fisher distributions and to fit these models using the expectation-maximization algorithm for maximum likelihood estimati...

1994
Yaxin Zhang Michael D. Alder Roberto Togneri

tive way to improve the performance of recognizers. This paper describe a speaker-independent isolated word recognition system which uses a well known technique, the combination of vector quantization with hidden Markov modeling. The conventional vector quantization algorithm is substituted by a statistical clustering algorithm, the ExpectationMaximization algorithm, in this system. Based on th...

2017
Rongda Zhu Lingxiao Wang ChengXiang Zhai Quanquan Gu

We propose a generic stochastic expectationmaximization (EM) algorithm for the estimation of high-dimensional latent variable models. At the core of our algorithm is a novel semi-stochastic variance-reduced gradient designed for the Qfunction in the EM algorithm. Under a mild condition on the initialization, our algorithm is guaranteed to attain a linear convergence rate to the unknown paramete...

2013
Francisco A.A. Souza Rui Araújo Francisco A. A. Souza

This paper addresses the problem of online quality prediction in processes with multiple operating modes. The paper proposes a new method called mixture of partial least squares regression (Mix-PLS), where the solution of the mixture of experts regression is performed using the partial least squares (PLS) algorithm. The PLS is used to tune the model experts and the gate parameters. The solution...

2012
Stéphane GOUTTE

In this paper we discuss the calibration issues of regime switching models built on mean-reverting and local volatility processes combined with two Markov regime switching processes. In fact, the volatility structure of this model depends on a first exogenous Markov chain whereas the drift structure depends on a conditional Markov chain with respect to the first one. The structure is also assum...

2004
Meir Feder Josko A. Catipovic

One of the main obstacles to reliable underwater acoustic communications is the relatively complex and unstable behavior of the ocean channel. The channel equalization method, that can estimate and track this complex and rapidly varying ocean response, may lead to reliable data communications at high rates which utilize fully the available bandwidth. Unfortunately, standardized equalization tec...

2004
Jeffrey A. Fessler

This paper describes rapidly converging algorithms for computing attenuation maps from Poisson transmission measurements using penalized-likelihood objective functions. We demonstrate that an under-relaxed cyclic coordinate-ascent algorithm converges faster than the convex algorithm of Lange [l], which in turn converges faster than the expectationmaximization (EM) algorithm for transmission tom...

2003
Yunxin Zhao Xiaobo Zhou K. Palaniappan

Novel statistical modeling and training techniques are proposed for improving classification accuracy of land cover data acquired by LandSat Thermatic Mapper (TM). The proposed modeling techniques consist of joint modeling of spectral feature distributions among neighboring pixels and partial modeling of spectral correlations across TM sensor bands with a set of semi-tied covariance matrices in...

2006
Jingyi Zhang Li Chin Khor Wai Lok Woo Satnam Singh Dlay

A novel learning algorithm for blind source separation of postnonlinear convolutive mixtures with non-stationary sources is proposed in this paper. The proposed mixture model characterizes both convolutive mixture and post-nonlinear distortions of the sources. A novel iterative technique based on Maximum Likelihood (ML) approach is developed where the ExpectationMaximization (EM) algorithm is g...

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