[R] Neural Network

[Charles Determan Jr]

Javad,

First, please make sure to hit 'reply all' so that these messages go to the
R help list so others (many far more skilled than I) may possibly chime in.

The problem here is that you appear to have no dependent variable (i.e. no
eutrophication variable).  Without it, there is no way to a typical
'supervised' analysis.  Given that this is likely a regression type problem
(I assume eutrophication would be continous) I'm not quite sure
'supervised' is the correct description but it furthers my point that you
need a dependent variable for any neuralnet algorithm I am aware of.  As
such, if you don't have a dependent variable then you will need to look at
unsupervised methods such as PCA.  Other users may have other suggestions.

Regards,
Charles

On Wed, Jan 21, 2015 at 11:36 PM, javad bayat <jbayat67 at yahoo.com> wrote:

> Dear Charles;
> Many thanks for your attention. what I want to know is: How can I predict
> the Eutrophication by these parameters in the future?
> These variables are the most important variables that control the Eutro.
> in lakes.
> Let me break it to two parts.
> 1) How can I predict these variables by NN?
> 2) Is it possible to predict the Eutro. by these variables?
>
>
> Many thanks for your help.
>  Regards,
>
>
>
>
>
>
>
> --------------------------------------------
> On Wed, 1/21/15, Charles Determan Jr <deter088 at umn.edu> wrote:
>
>  Subject: Re: [R] Neural Network
>  To: "javad bayat" <jbayat67 at yahoo.com>
>  Cc: "r-help at r-project.org" <r-help at r-project.org>
>  Date: Wednesday, January 21, 2015, 9:10 PM
>
>  Javad,
>  You
>  question is a little too broad to be answered
>  definitively.  Also, this is not a code writing service.
>  You should make a meaningful attempt and we are here to help
>  when you get stuck.
>  1.
>  If you want to know if you can do neural nets, the answer is
>  yes.  The three packages most commonly used (that I know
>  of) are 'neuralnet', 'nnet' and
>  'RSNNS'.  You should look in to these package
>  documentation for how to use them.  There are also many
>  examples online if you simply google them.
>  2. You question is unclear, are you
>  wanting to predict all the variables (e.g. phosphorus, Total
>  N, etc.) or do you have some metric for eutrophication?
>  What exactly is the model supposed to predict?
>  3. If you want to know if a
>  neuralnet is appropriate, that is more of a statistical
>  question.  It depends more on the question you want to
>  answer.  Given your temporal data, you may want to look in
>  to mixed effects models (e.g nlme, lme4) as another
>  potential approach.
>  Regards,
>  On Tue, Jan 20, 2015 at
>  11:35 PM, javad bayat via R-help <r-help at r-project.org>
>  wrote:
>  Dear
>  all;
>
>  I am the new user of R. I want to simulation or prediction
>  the Eutrophication of a lake. I have weekly data(almost for
>  two years) for Total phosphorus, Total N, pH, Chlorophyll a,
>  Alkalinity, Silica.
>
>  Can I predict the Eutrophication by Neural Network in R?
>
>  How can I simulation the Eutrophication by these
>  parameter?
>
>  please help me to write the codes.
>
>  many thanks.
>
>
>
>  ______________________________________________
>
>  R-help at r-project.org
>  mailing list -- To UNSUBSCRIBE and more, see
>
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>
>  PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
>
>  and provide commented, minimal, self-contained, reproducible
>  code.
>
>
>
>
>  --
>  Dr. Charles Determan, PhD
>  Integrated Biosciences
>
>
>


-- 
Dr. Charles Determan, PhD
Integrated Biosciences

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