i have problem in ANN

i tried to model an ANN model to predict the behavior of concrete due to sulfate attack but the model cannot predict in out of inputs range.

for instance, i trained the network to predict the concrete behavior at different ages like 10, 100, 500, 1000, and 2000 days. the model can predict the propertie at any time between 10 and 2000 days, but it has a large error at predicting the properties at 20000 days.

Answer 1

[Greg Heath]

This is not exceptional.

NNets are good interpolators but very poor extrapolators.

The basic assumption is that training data has, approximately, the same statistical characteristics as the general population.

Hope this helps.

Thank you for formally accepting my answer.

Greg

[Ali]

thank you for this helpful answer, but how can i extrapolate some results for the previous mentioned example. which method can i use?

[Greg Heath]

There is no sure way.

You might be able to recognize a particular functional behavior via plots.

However, don't bet the mortgage on guaranteed success.

Greg