[QSAR] add correction layer to neural network

[List for Members of Cheminformatics and QSAR Society]

Hi Ines,

You should not get a systematic error.  Something must be wrong.  Did you use a bias on the network.  If not, that may explain a systematic error. Check J Med Chem for details on Bayesian neural nets.


-----Original Message-----
From:	qsar_society-bounces at ccl.net on behalf of List for Members of Cheminformatics and QSAR Society
Sent:	Mon 5/26/2008 21:48
To:	List for Members of Cheminformatics and QSAR Society
Cc:	
Subject:	Re: [QSAR] add correction layer to neural network

Hi, 
I have a three layered feed forward network with back propagation scheme. my inputs neurons are the descriptors while my output neuron is the drug activity. 
I am using the early stopping method methods in which I have a validation set to detect the over-fitting behaviour.
I notice that there is a systematic error in the predicted activities and I think of adding a correction layer in the network to fix this systematic error but I do not know how to do it. M experience with ANN in matlab is small. 
Thanks in advance. 
Best regards, 
Ines


----- Original Message ----
From: List for Members of Cheminformatics and QSAR Society <qsar_society at ccl.net>
To: qsar_society at ccl.net
Sent: Saturday, May 24, 2008 2:45:41
Subject: Re: [QSAR] add correction layer to neural network

Hi Ines,

Do you mean a hidden layer?  What network architecture do you want?  Have you tried Bayesian regularization to prevent overtraining and overfitting?

    -----Original Message----- 
    From: qsar_society-bounces at ccl.net on behalf of List for Members of Cheminformatics and QSAR Society 
    Sent: Fri 5/23/2008 09:32 
    To: qsar at qsar.org 
    Cc: 
    Subject: [QSAR] add correction layer to neural network
    
    

    Dear all,
    How can I add a correction layer to neural network in MATLAB software?
    Any help would be greatly appreciated.
    Thanks in advance
    Best wishes
    Inas
    
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