How to apply Genetic Algorithm solver to do parameter estimation for ODE based model?

조회 수: 2 (최근 30일)
I have a ODE based model and a set of experimental data for my project. There are seven parameters (Constant) inside the model need to do parameter estimation through Genetic Algorithm solver. My fitness function/Objective function will be sum of quadratic difference between simulated and experimental result.
pm(..) is the parameter I need to do estimation to best fit my curve. The function cgtase_cont is the mathematical model used. I tried to use GA solver to run it but it always appeared "Optimization running. Error running optimization. Too many output arguments.". Function square_error_ga is my objective function.
Using GA to solve this problem is the requirement of the project. Thanks in advance!
----------------------------------------------------------------------
Function cgtase_cont code:
function dx = cgtase_cont(t,x,ux,Ks,K1,H,KI,Kox,Ag,Ea,R,Ad,Ed,dH,dS,dCp,Temp0,rol,N,Di,V,Vs,...
K2,Kd,Ysx,mx,Clx,qO2,YH,Ah,Cp,U,uxp,I,Ki,K,D,Tempj)
dx = zeros(6,1);
%state variables
u = (ux*x(2))/((Ks+x(2))*(1+K1/H+H/K2)*(x(2)+KI+(x(2)^2)/Ks)*(Kox+1.4e-3))*(Ag*exp(-Ea/(R*x(4)))-Ad*exp(-Ed/(R*x(4))));
dGTS = dH-x(4)*dS+dCp*(x(4)-Temp0-x(4)*log(x(4)/Temp0));
Pg = 0.4*6*rol*N^3*Di^5;
Kla = 0.0195*((Pg/V)^0.55)*((Vs)^0.64)*(1+2.12*x(1)+0.2*x(1)^2)^-0.25;
Kn = 111.3*exp(-((x(4)-313.3)/7.42)^2);
%models
dx(1) = (u-Kd)*x(1);
dx(2) = (u/Ysx+mx)*(-x(1));
dx(3) = (Kla*(Clx-x(3))-qO2*x(1));
dx(4) = ((u*x(1))/(YH*rol*Cp)-(U*Ah)/(V*rol*Cp)*(x(4)-Tempj));
dx(5) = ((uxp*I)/(I+Ki)*u*x(1)-K*x(5));
dx(6) = (D*exp(-dGTS/(R*x(4))))*x(5)-Kn*x(6);
------------------------------------------------------------
Function square_error_ga code:
function error = squared_error_ga(data_time, data_points, fn_time, fn_points)
% Intepolate the fit to match the time points of the data
fn_values = interp1(fn_time, fn_points, data_time);
% Square the error values and sum them up
error = sum((fn_values - data_points).^2);
--------------------------------------------------------
Function ga_error code:
function error = ga_error(pm)
%Estimated Parameter set
Ks = pm(1); %half saturation constant (g/l) pm(1)
Ki = pm(2); %saturation constant for inducer (g/l) pm(2)
Ag=10^pm(3); %Ag = 10^7.9; %Arrhenius constant for growth pm(3)
Ad=10^pm(4); %Ad = 10^10; %Arrhenius constant for death pm(4)
KI= pm(5); %inhibition constant due to excessive subtrate (g/l)pm(5)
mx = pm(6); %cell maintenance coefficient on substrate pm(6)
Ysx = pm(7); %yield coefficient (g/g)pm(7)
D = pm(8); %preexponential factor (per h) pm(8)
Kox = pm(9); %oxygen limitation constant (g/l) pm(9)
%Actual Constant
%Ks = 7.5; %half saturation constant (g/l)
%Ki = 0.001; %saturation constant for inducer (g/l)
%Ag = 10^7.9; %Arrhenius constant for growth
%Ad = 10^10; %Arrhenius constant for death
%KI= 0.001; %inhibition constant due to excessive subtrate (g/l)
%mx = 0.003; %cell maintenance coefficient
%Ysx = 0.0105; %yield coefficient (g/g)
%D = 1.65*10^14; %preexponential factor (per h)
%Kox = 7.104*10^-7; %oxygen limitation constant (g/l
ux = 0.1027; %maximum specific growth rate (per h)
K1 = 7.05*10^-10; %constant (Molar)
K2 = 6.86*10^-8; %constant (Molar)
H = 10^(-7.1); %ion hydrogen concentration (M)
Ea = 10000; %activation energy for growth (cal/mol)
Ed = 80000; %activation energy for death (cal/mol)
R = 1.987; %gas constant (cal/mol K)
uxp = 0.5872; %maximum specific production rate (per h)
I = 0.162; %inducer concentration (g/l)
K = 0.0625; %protein degradation rate
dH = 9.4*10^3; %change in enthalpy (cal/mol)
dS = -0.01*10^3; %change in entropy (cal/mol)
dCp = -0.32*10^3; %change in the heat capacity of the protein between fold and unfold state
Temp0 = 295; %reference temperature (K)
rol = 998.23; %density medium (g/l)
Di = 46*10^-3; %impeller diameter (m), Rushton
V = 1.5; %volume culture (l)
Vs = 1.1372; %oxygen superficial velocity (m/s)
Clx = 7*10^-3; %saturated DO concentration (g/l)
qO2 = 384*10^-3; %specific uptake rate of oxygen (g/g h)
U = 3.6482*10^4; %overall heat transfer coefficient (cal/h m2 K)
Ah = 0.606; %contacted surface area (m2)
YH = 0.42*10^-3; %1/YH is metabolic heat evolved per g biomass (g/cal)
Cp = 1; %heat capacity of medium (cal/ g K)
N = 10/3; %agitation speed (rev/s)
Kd = 0.02; %specific death rate (per h)
Tempj=293;
%-------------------------------------------
ode45(@(t,x)cgtase_cont(t,x,ux,Ks,K1,H,KI,Kox,Ag,Ea,R,Ad,Ed,dH,dS,dCp,Temp0,rol,N,Di,V,Vs,...
K2,Kd,Ysx,mx,Clx,qO2,YH,Ah,Cp,U,uxp,I,Ki,K,D,Tempj), ...
[0 60], [0.12 50 1.4e-3 310 0 0]);
error = squared_error_ga([0 4 8 12 16 20 24 28 32 36 40 44 48] , ...
[0 0 0.7586 1.2944 4.9136 6.9158 10.3277...
10.0373 10.8607 12.9424 12.6819 11.7554 10.6795], ...
t, ...
y(:,6));
------------------------------------------------------
The graph of my project is something like:
%
  댓글 수: 2
Joker
Joker 2019년 3월 14일
Hello, Bendo! have you address this problem. i have the same question.
Jan
Jan 2019년 3월 14일
@Joker: Really exactly the same question? In the original question, the output of ode45 was not caught, so I cannot guess, why the code runs at all. As far as I can see, the GA-part has not been posted and the error message was shown partially only. So please be so kind and open a new thread providing the required details to help you.

댓글을 달려면 로그인하십시오.

답변 (0개)

카테고리

Help CenterFile Exchange에서 Genetic Algorithm에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by