What is the meaning for InputDelays and FeedbackDelays in Neural Network time series prediction?

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Xiangming 2013-10-29

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评论： Greg Heath 2014-5-21

Hi all,

I'm a littile confused about the meaning of InputDelays and FeedbackDelays in NN time series prediction. Actually, in the example of NARX prediction, InputDelays=1:2, FeedbackDelays=1:2, I wonder how to determine these two values and what these values extactly mean? Any suggestion is highly appreciated.

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Answer 1

Greg Heath 2013-10-30

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y(t) = f(x(t-id:t-1),y(t-fd:t-1);

Good input feedback delays can be obtained by finding the significant delays of the input-target cross correlation function.

Good output feedback delays can be obtained by finding the significant delays of the target autocorrelation function.

I have posted several examples in the NEWSGROUP and ANSWERS.

Searching the two word phrase significant delay seems a good place to start.

Hope this helps.

Greg

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Greg Heath 2013-10-31

在 MATLAB Online 中打开

Regularization via the mse option or trainbr can be used to mitigate the fact that there are more unknown weights than equations. I think it is most used for smaller data sets whose data division subsets would not be sufficiently large for reliable design and estimation of performance on unseen non-training data.

If you wish to make a few comparison designs, please use MATLAB data

help nndatasets

so that we can compare results.