# [R] D-optimum design - optimization model in R

Bert Gunter bgunter@4567 @ending from gm@il@com
Tue Dec 4 15:16:36 CET 2018

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Bert Gunter

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On Tue, Dec 4, 2018 at 3:29 AM Thanh Tran <masternhattt using gmail.com> wrote:

> Dear all,
>
>
>
> I'm trying to use the D-optimum design. In my data, the response is KIC,
> and 4 factors are AC, AV, T, and Temp. A typical second-degree response
> modeling is as follows:
>
>
>
>
> > mod <-
>
> lm(KIC~AC+I(AC^2)+AV+I(AV^2)+T+I(T^2)+Temp+I(Temp^2)+AC:AV+AC:T+AC:Temp+AV:T+AV:Temp+T:Temp,
>
> + data = data)
>
>
>
> The result of the model:
>
>
>
> KIC = 4.85 – 2.9AC +0.151 AV + 0.1094T
>
>           + 0.0091Temp + 0.324 AC^2-0.0156V^2
>
>           - 10.00106T^2 - 0.0009Temp^2 + 0.0071AC´AV
>
>           - 0.00087AC´T -0.00083AC´Temp – 0.0018AV´T
>
>          +0.0015AV´Temp – 0.000374 AV ´ T
>
>
>
> Based on the above response modelling, I want to determine levels of the
> AC, AV, T, and Temp to have the Maximum value of KIC. The result running in
> Minitab as is shown in Figure 1. In R, I try to compute an D-optimum design
> with the following codes:
>
>
>
> > attach(data)
>
> > F.trig <- F.cube
>
> > F.trip <-
>
> F.cube(KIC~AC+I(AC^2)+AV+I(AV^2)+T+I(T^2)+Temp+I(Temp^2)+AC:AV+AC:T+AC:Temp+AV:T+AV:Temp+T:Temp,
>
> + c(4,4,30,5), # Smalesst values of AC,AV,T, and Temp
>
> + c(5,7,50,25), # Highest values of AC,AV,T, and Temp
>
> + c(3,3,3,3)) # Numbers of levels ofAC,AV,T, and Temp
>
> > res.trip.D <- od.AA(F.trip,1,alg = "doom", crit = "D",
>
> + graph =1:7, t.max = 4)
>
>
>
> I have the result as shown in Figure 2 but I cannot find out the optimum
> design as shown in Figure 1 using Minitab.
>
>
>
> If anyone has any experience about what would be the reason for error or
> how I can solve it? I really appreciate your support and help.
>
>
>
> Best regards,
>
> Nhat Tran
>
>
>
> Ps: I also added a CSV file for practicing R.
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