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 <deter...@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 <deter...@umn.edu> wrote: Subject: Re: [R] Neural Network Cc: "r-help@r-project.org" <r-help@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@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@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help 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 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
