[R] Neural Network
javad bayat
jbayat67 at yahoo.com
Sat Jan 24 07:41:09 CET 2015
Dear Charles;
I think my variables are dependent. For e.g. the concentration of Phosphorus, Nitrogen, Silica and etc. have effect on the present of Chlorophyll a and the concentration of Chlorophyll a can make the Eutrophication in lake along with other algeas.
So I think they are dependent variables.
Regards.
--------------------------------------------
On Thu, 1/22/15, Charles Determan Jr <deter088 at umn.edu> wrote:
Subject: Re: [R] Neural Network
roject.org>
Date: Thursday, January 22, 2015, 4:41 PM
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
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
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.
______________________________________________
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--
Dr. Charles Determan, PhD
Integrated Biosciences
--
Dr. Charles Determan, PhD
Integrated Biosciences
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