نتایج جستجو برای: em algorithm

تعداد نتایج: 1052416  

Journal: :CoRR 2014
Atanu Kumar Ghosh Arnab Chakraborty

Conventional approaches of sampling signals follow the celebrated theorem of Nyquist and Shannon. Compressive sampling, introduced by Donoho, Romberg and Tao, is a new paradigm that goes against the conventional methods in data acquisition and provides a way of recovering signals using fewer samples than the traditional methods use. Here we suggest an alternative way of reconstructing the origi...

2014
Zhihua Zhang

In statistics, an expectationmaximization (EM) algorithm is an iterative method for finding maximum likelihood or maximum a posteriori (MAP) estimates of parameters in statistical models, where the model depends on unobserved latent variables. The EM iteration alternates between performing an expectation (E) step, which creates a function for the expectation of the log-likelihood evaluated usin...

2005
Charles Byrne

The EM algorithm is not a single algorithm, but a template for the construction of iterative algorithms. While it is always presented in stochastic language, relying on conditional expectations to obtain a method for estimating parameters in statistics, the essence of the EM algorithm is not stochastic. The conventional formulation of the EM algorithm given in many texts and papers on the subje...

1998
Nir Friedman

In recent years there has been a flurry of works on learning Bayesian networks from data. One of the hard problems in this area is how to effectively learn the structure of a belief network from incomplete data—that is, in the presence of missing values or hidden variables. In a recent paper, I introduced an algorithm called Structural EM that combines the standard Expectation Maximization (EM)...

1998
Lucas Parra Harrison H. Barrett

| Using a theory of list-mode Maximum Likelihood (ML) source reconstruction presented recently by Bar-rett et al. 1], this paper formulates a corresponding Expectation Maximization (EM) algorithm, as well as a method for estimating noise properties at the ML estimate. List-mode ML is of interest in cases where the dimensionality of the measurement space impedes a binning of the measurement data...

2008
Xian-Bin Wen Hua Zhang Ze-Tao Jiang

A valid unsupervised and multiscale segmentation of synthetic aperture radar(SAR) imagery is proposed by a combination GA-EM of the Expectation Maximization(EM) algorith with the genetic algorithm (GA). The mixture multiscale autoregressive(MMAR) model is introduced to characterize and exploit the scale-to-scale statisticalvariations and statistical variations in the same scale in SAR imagery d...

2004
Yu lin-Sen Zhang Tian-Wen

Finite normal mixture model-based image segmentation techniques can produce robust segmentation results. But the EM algorithm used for learning mixture parameters is very sensitive to initialization. Estimating the number of components and the optimal model parameters inevitably brings a heavy computation burden. In the view of boosting learning, the paper gives a weighted EM algorithm, which i...

1998
CHUANHAI LIU DONALD B. RUBIN YING M A N WU Y. N. WU

The EM algorithm and its extensions are popular tools for modal estimation but are often criticised for their slow convergence. We propose a new method that can often make EM much faster. The intuitive idea is to use a 'covariance adjustment' to correct the analysis of the M step, capitalising on extra information captured in the imputed complete data. The way we accomplish this is by parameter...

2004
Wojtek Kowalczyk Nikos A. Vlassis

We propose a gossip-based distributed algorithm for Gaussian mixture learning, Newscast EM. The algorithm operates on network topologies where each node observes a local quantity and can communicate with other nodes in an arbitrary point-to-point fashion. The main difference between Newscast EM and the standard EM algorithm is that the M-step in our case is implemented in a decentralized manner...

Journal: :ژورنال بین المللی پژوهش عملیاتی 0
a. kourank beheshti s.r. hejazi s.h. mirmohammadi

this paper addresses the vehicle routing problem with delivery time cost. this problem aims to find a set of routes of minimal total costs including the travelling cost and delivery time cost, starting and ending at the depot, in such a way that each customer is visited by one vehicle given the capacity of the vehicle to satisfy a specific demand. in this research, a hybrid metaheuristic approa...

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