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Estimation

The first goal of this research was to compare the accurracy of Bayesian learning forecast against other neural network and regression models. We use Azoff's NN benchmarks [1], the results of an implementation of backpropagation in MUME [4], the Multivariate Adaptive Regression Splines method [3] and compare them with the results obtained using Neal's implementation of Bayesian learning [7].

Table 1 shows the result for the Mackey Glass series without noise and Table 2 for the series with 20% of noise added to the targets.

   table132
Table 1: Performances in Mackey Glass series. a-stp: Hertz rules adaptive steepest descent with weight update per pattern. shann: is the Shanno varian of conjugate gradients with inexact line search. BFGS: is the quasi-Newton method with inexact line search.

The error ARV is the average relative variance:

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where the tex2html_wrap_inline505 is the standard deviation of each set. The normalization implies that if the estimated mean of the data is used as predictor, ARV=1 is obtained.

  table147
Table 2: Performances in Mackey Glass series with 20% noise in the targets 

In the case of Bayes the mean ARV for 200 Markov Chain Monte Carlo states is shown.



Rafael A. Calvo
Fri Apr 18 12:26:35 GMT+1000 1997