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Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

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Here, Outp = 1/(1+e -Netp )<br />

Netp = ∑r Wrp.Outr<br />

where the index r corresponds to neurons in the hidden layer m.<br />

Outr = 1/(1+e -Net r )<br />

Netr = ∑i Wir.Outi<br />

where wir are the weights connected to neuron r from its preceding layer.<br />

Now, for the output layer with sigmoid type non-linearity we have<br />

∂E/∂Wpq<br />

= (∂E/∂Outq) (∂Outq/∂Netq) (∂Netq/∂Wpq)<br />

= -(tq – Outq) Outq (1- Outq) Outp<br />

= - { (tq – Outq) Outq (1- Outq)} Outp<br />

= -δq. Outp (say).<br />

The readers may now compare this result with that given in fig. 14.6, where<br />

this is written as δq,k Outp,j.<br />

Wsp<br />

Now, we compute the updating rule for Wsp:<br />

Hidden layer m<br />

Hidden layer( m-1)<br />

Wpq<br />

Output layer<br />

Fig. B.1: Defining the weights in a feed-forward<br />

topology of neurons.

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