The EM algorithm is the standard tool for maximum likelihood estimation in finite mixturemodels. Its most important drawbacks are the slow convergence, the need for a suitable stopping criterion and the choice of the...
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The EM algorithm is the standard tool for maximum likelihood estimation in finite mixturemodels. Its most important drawbacks are the slow convergence, the need for a suitable stopping criterion and the choice of the initial values. In this paper, we focus on the issue of selecting initial values for the EM algorithm in mixture poisson regression models. A new strategy, aiming at overcoming limitations of other approaches, is proposed and a simulation study comparing its performance with two alternative strategies is carried out. In models with overlapped components and/or not similar mixing proportions, the new strategy has proven to provide more accurate parameter estimates and to require a fewer number of iterations until the EM algorithm convergence saving computing time.
In this work, we propose to compare two algorithms to compute maximum likelihood estimates for the parameters of a mixturepoissonregression model: the EM algorithm and the Stochastic EM algorithm. The comparison of ...
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In this work, we propose to compare two algorithms to compute maximum likelihood estimates for the parameters of a mixturepoissonregression model: the EM algorithm and the Stochastic EM algorithm. The comparison of the two procedures was done through a simulation study of the performance of these approaches on simulated data sets and real data sets. Simulation results show that the choice of the approach depends essentially on the overlap of the regression lines. In the real data case, we show that the Stochastic EM algorithm resulted in model estimates that best fit the regression model.
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