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- Akio Utsugi, Toru Kumagai
- Neural Computation
- 2001

For Bayesian inference on the mixture of factor analyzers, natural conjugate priors on the parameters are introduced, and then a Gibbs sampler that generates parameter samples following the posterior is constructed. In addition, a deterministic estimation algorithm is derived by taking modes instead of samples from the conditional posteriors used in the… (More)

- Akio Utsugi
- Neural Computation
- 1997

The self-organizing map (SOM) algorithm for finite data is derived as an approximate MAP estimation algorithm for a Gaussian mixture model with a Gaussian smoothing prior, which is equivalent to a generalized deformable model (GDM). For this model, objective criteria for selecting hyperparameters are obtained on the basis of empirical Bayesian estimation… (More)

- A Utsugi
- 1997

A topology-selection method for self-organizing maps (SOMs) based on empirical Bayesian inference is presented. This method is natural extension of the hyperparameter-selection method presented earlier, in which the SOM algorithm is regarded as an estimation algorithm for a Gaussian mixture model with a Gaussian smoothing prior on the centroid parameters,… (More)

- Akio Utsugi
- Neural Processing Letters
- 2001

In this paper the ensemble of independent factor analyzers (EIFA) is proposed. This new statistical model assumes that each data point is generated by the sum of outputs of independently activated factor analyzers. A maximum likelihood (ML) estimation algorithm for the parameter is derived using a Monte Carlo EM algorithm with a Gibbs sampler. The EIFA… (More)

- Akio Utsugi
- Neural Computation
- 1998

In the statistical approach for self-organizing maps (SOMs), learning is regarded as an estimation algorithm for a Gaussian mixture model with a Gaussian smoothing prior on the centroid parameters. The values of the hyperparameters and the topological structure are selected on the basis of a statistical principle. However, since the component selection… (More)

- Akio Utsugi
- Neural Processing Letters
- 2000

Generative topographic mapping (GTM) is a statistical model to extract a hidden smooth manifold from data, like the self-organizing map (SOM). Although a deterministic search algorithm for the hyperparameters regulating the smoothness of the manifold has been proposed previously, it is based on approximations that are valid only on abundant data. Thus, it… (More)

- Toru Kumagai, Akio Utsugi
- Neurocomputing
- 2004

We proposed to cluster a set of magnetoencephalogram (MEG) records using mixture of factor analyzers to remove those outlying records that were contaminated with artifacts. We showed the e4ectiveness of the proposed clustering approach by applying it to visual and auditory evoked MEG data. c © 2004 Elsevier B.V. All rights reserved.

- Akio Utsugi, Motoyuki Akamatsu
- IFAC HMS
- 2007

- Akio Utsugi, Masatoshi Ishikawa
- Systems and Computers in Japan
- 1991

- Akio Utsugi
- Neurocomputing
- 2002

A generalized ICA model allowing overcomplete bases and additive noises in the observables is applied to natural image data. It is well known that such a model produces independent components that resemble simple cells in primary visual cortex or Gabor functions. We adopt a variable-sparsity density on each independent component, given by the mixture of a… (More)