Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Software » comp.soft-sys.matlab

Topic: RBFNN
Replies: 4   Last Post: Dec 7, 2012 3:14 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Greg Heath

Posts: 5,953
Registered: 12/7/04
Re: RBFNN
Posted: Dec 6, 2012 7:12 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

"dean86" wrote in message <k9klgr$lss$1@newscl01ah.mathworks.com>...
> "Greg Heath" <heath@alumni.brown.edu> wrote in message <k9jc90$905$1@newscl01ah.mathworks.com>...
> > "dean86" wrote in message <k9id39$82r$1@newscl01ah.mathworks.com>...
> > > Hi all,
> > > I have the following problem:
> > > 777 input from some different sensors, I have to do a PCA and then a RBF to predict the number of analytes.

> >
> > What type of sensors? Unfortunately the trace that I have doesn't specify the type of sensors, it says just "Different kind of sensors".

>
> > How many measurement vectors for NN input? N = 343? Yes
>
> > How many dimensions in each input vector? I = 777 ? Yes
>
> > Regression or classification ? I'm sorry but actually I just know that I have to use the scores of the PCA to train a radial basis function neural network to predict concentration of the analytes. I'm sorry but once again the web is the only resource that I have to learn this topic.
>
> > What is the output ?
> > How many dimensions in each output vector? O = ?
> >

> > > Could you help me to understand the correct way to do the RBF, to use the command 'newrb', but above all, how to understand the results?
> >
> > > First thing that I do is to load the data, then I have this matrix 777x343, so I do the transpose and I start to do the mean-centring and then the PCA on this matrix and I obtain the scores (343x4) and the loadings (777x4). Now I have to use this scores to do this RBF, so I obtain the transpose of the scores matrix (4x343) and now, should I use the newrb with this last matrix and the original data matrix (777x343)?
> > >

> > What is the criterion for input dimensionality reduction why 777==> 4? This makes no sense to me. Because when I use the PCA I can clearly see from the plot that I can keep just 4 variables.
> >
> > All NEWRB needs are input and output matrices and a reasonable value for the MSE goal and a range of candidate spread values.
> >
> > For regression standarize both input and target matrices. For c-class classification, standardize the input matrix but use one of c (=O) binary coding for the output matrix.
> >
> > Use MSEgoal = 0.01*mean(var(t',1)) % yields R^2 >= 0.99
> >
> > Obtain multiple designs from a loop over spread values. I usually start with a coarse search spread = 2^(i-1), i = 1,2,... Then refine the search if needed.
> >
> > Old posts:
> >
> > 5 threads for heath newrb overfitting overtraining
> >
> > Neural Networks Question
> > Newrb with k-means training
> > *RBFNN Design using MATLAB's NEWRB
> > Retrain the created neural network
> > *Training Feed Forward Neural Networks
> >
> > 3 threads for heath newrb overfitting -overtraining
> >
> > Question Regarding RBF?
> > Neural Network -- Incremental Training
> > train rfb newrb
> >
> > 2 threads for heath newrb -overfitting overtraining
> > See "*" above


What is the size of your output target matrix?

Greg

Greg


Date Subject Author
12/3/12
Read RBFNN
dean86
12/3/12
Read Re: RBFNN
Greg Heath
12/4/12
Read Re: RBFNN
dean86
12/6/12
Read Re: RBFNN
Greg Heath
12/7/12
Read Re: RBFNN
dean86

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.