Find automatically data of interest

Question

Daniele Sonaglioni 2022-10-25

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1834993-find-automatically-data-of-interest

评论： dpb 2022-10-25

Hello everyone,

I havew a question about how to improve my code.

I have a time-Temperature profile that is a bit noisy: my goal is to automatically find the heating, cooling and isotheramal portions by only looking at the first derivative of the temperature with respect to the time. Unluckily, the code is not perfect but I don't know how to improve it: can anyone help me?

Attached you can fine the test data and the code I use together with the subroutines.

close all
clear
tic
load 'conv_ageing_atm5_m60p80_01to2048s_bif_74165.txt'
conv_ageing_atm5_m60p80_01to2048s_bif_74165;
t=conv_ageing_atm5_m60p80_01to2048s_bif_74165(1:end,2);
T=conv_ageing_atm5_m60p80_01to2048s_bif_74165(1:end,3);
Cp=conv_ageing_atm5_m60p80_01to2048s_bif_74165(1:end,4);
time=conv_ageing_atm5_m60p80_01to2048s_bif_74165(1:end,5);
un=[1:1:length(T)];
ratew=(gradient(T)./gradient(time));
rate=smoothdata(ratew,'movmedian',30);
rate=nearest(rate);
flag=zeros(length(T),1);
for i=1:length(T)
   if rate(i)>0;
       flag(i)=1;
   else if rate(i)==0;
           flag(i)=0;
       else if rate(i)<0;
               flag(i)=-1;
           end
       end
   end    
end
[y]=remove_outliers(flag);
figure(1)
plot(un,flag,'o')
hold on
plot(un,y,'ro')
[Aw,Bw,Cw]=group_data(y);%Aw=heating/Bw=isother/Cw=cooling
[Vw]=organize_vector(Aw);%heating
[Uw]=organize_vector(Bw);%isotherm
[Ww]=organize_vector(Cw);%cooling
formatSpec = 'You have %d heating scans\n';
fprintf(formatSpec,length(Vw))
formatSpec2 = 'You have %d isotherms\n';
fprintf(formatSpec2,length(Uw))
formatSpec3 = 'You have %d cooling scans\n';
fprintf(formatSpec3,length(Ww))
toc

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Daniele Sonaglioni 2022-10-25

Dear @Jan,

when I wrote "the code is not perfect" I was referring to the fact that it detects some heating and/or cooling and/or isotherm segments that do not exist.

On the data that I have attached, there are 14 heating segments, 40 isotherms and 25 cooling but the code finds more heating and isotherm scans.

By increasing the smoothing window I can solve the problem but I was wondering if there is an alternative way to solve the problem.

dpb 2022-10-25

Might want to look at findchangepts in Signal Processing TB...

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Answer 1

Jan 2022-10-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1834993-find-automatically-data-of-interest#answer_1083213

在 MATLAB Online 中打开

Some methods are "ugly":

load 'conv_ageing_atm5_m60p80_01to2048s_bif_74165.txt'

Loading data directly into the workspace creates variables dynamically. This impedes Matlab's JIT acceleration and the debugging. Prefer to load data into a specific variable:

Data = load('conv_ageing_atm5_m60p80_01to2048s_bif_74165.txt');

This line is a waste of time only:

conv_ageing_atm5_m60p80_01to2048s_bif_74165;

Use a less painful name for variables. Hiding important information in the name of variables is a programming anti-pattern:

value = Data.conv_ageing_atm5_m60p80_01to2048s_bif_74165;

Use ":" instead of "1:end", because it is faster:

% Replace: t = conv_ageing_atm5_m60p80_01to2048s_bif_74165(1:end,2); by
t = value(:, 2);

Replace the code:

flag=zeros(length(T),1);
for i=1:length(T)
   if rate(i)>0;
       flag(i)=1;
   else if rate(i)==0;
           flag(i)=0;
       else if rate(i)<0;
               flag(i)=-1;
           end
       end
   end    
end