Hi,

My experience with the SIR model (not SEIR) is that the estimated parameters are very sensitive to the initial condition of the Infected pool. Hence, this initial condition should be also considered as a parameter to be identified. However, the main problem (at least with France data) is that fitting Infected and Recovered (cured or dead people) together gives not satisfactory results.

My two cents...

S.

Le 30/04/2020 à 18:44, Chin Luh Tan a écrit :
Just notice that this email was stuck due to the image attached was too large, and notice the new post by Claus with the SEIR model from Matlab, perhaps Scilabers could make the model more realistic together.

CL

============ Forwarded message ============
From: Chin Luh Tan <chinluh....@bytecode-asia.com <mailto:chinluh....@bytecode-asia.com>> To: "Users mailing list for Scilab"<users@lists.scilab.org <mailto:users@lists.scilab.org>>
Date: Thu, 30 Apr 2020 00:03:46 +0800
Subject: Re: [Scilab-users] Corona modelling
============ Forwarded message ============

    Hi,

    I just modified Stephane's nice GUI to make it able to load the
    real world data from internet so that we could overlapped the data
    to the SIR model to study the effect of locked-down, and the
    meaning of the coefficients.

    From some reading from the internet, the "Susceptible" population
    is kind of like difficult to determined, and some suggested to use
    "current cases" as "optimum model" assuming the condition is
    recovering. As or the "optional model", the "total population" is
    being used.

    While "beta" is the transmission coefficient, "gamma" the recovery
    factor, can anyone explained more details, perhaps in layman term,
    how to relate these  parameters to one country condition, such as
    the relationship between gamma with the number of days (what days
    is it referring to), beta "actual meaning" in layman term, and
    perhaps link with some "technical term" the newspaper always seen
    on papers?

    I attached the GUI, which will load 3 sets of data from Johns
    Hopkins Github,
    
(https://github.com/CSSEGISandData/COVID-19/tree/master/csse_covid_19_data/csse_covid_19_time_series
    
<https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/github.com/CSSEGISandData/COVID-19/tree/master/csse_covid_19_data/csse_covid_19_time_series>)
    which could be download using following 3 lines directly from the
    Scilab:


    --> fn =
    
getURL('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_deaths_global.csv
    
<https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_deaths_global.csv>')
    --> fn =
    
getURL('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_global.csv
    
<https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_global.csv>')
    --> fn =
    
getURL('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_recovered_global.csv
    
<https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_recovered_global.csv>')

    and run the GUI as attached.




    rgds,
    CL


    ---- On Mon, 30 Mar 2020 14:13:40 +0800 *Stéphane Mottelet
    <stephane.motte...@utc.fr <mailto:stephane.motte...@utc.fr>>*
    wrote ----




        Hello Heinz,

        Here is an interactive version (made for my children last
        week...) :

        /// Confinement COVID-19 !/
        /// Stephane MOTTELET, UTC/
        /// Tue Mar 24 08:55:03 CET 2020/
        /// /
        function  *dydt*=_sir_(*t*, *y*, *bet*, *gam*, *N*)
             *dydt*=[-*bet*/*N***y*(1)**y*(2)
*bet*/*N***y*(1)**y*(2)-*gam***y*(2) *gam***y*(2)];
        endfunction

        function  _draw_(*bet*, *gam*)
             t=0:1:360;
             N=6e7;
             if  exists("gcbo")  &&  is_handle_valid(gcbo)
                 sb  =  gcbo;
                 if  sb.tag=="beta"
                     *bet*=sb.value;
                     *gam*=findobj("gamma").value
                 else
                     *gam*=sb.value;
                     *bet*=findobj("beta").value
                 end
                 y=ode('stiff',[N-1;1;0],0,t,list(_sir_,*bet*,*gam*,N));
                 curves  =  findobj("curves");
                 curves.children(1).data(:,2)=y(3,:);
                 curves.children(2).data(:,2)=y(2,:);
                 curves.children(3).data(:,2)=y(1,:);
             else
                 y=ode('stiff',[N-1;1;0],0,t,list(_sir_,*bet*,*gam*,N));
                 scf(0)
                 clf
                 plot(t,y)
                 gce().tag="curves";
                 gce().children.thickness=2;
                 legend("Susceptible","Infected","Recovered",-1)
sb1 = uicontrol("style","slider",...
                 "units","normalized",...
                 "Position",  [0.85,0.2,0.05,0.48],...
                 "BackgroundColor",  [1,1,1],...
                 "Callback_Type",12,...
                 "sliderstep",[1/1000,1/10],...
                 "min",0.15,"max",0.3,"value",*bet*,...
                 "Callback","draw","tag","beta");
uicontrol("style","text",...
                 "string","$\beta$",...
                 "units","normalized",...
                 "Position",  [0.85,0.125,0.05,0.08],...
                 "BackgroundColor",  [1,1,1],...
"HorizontalAlignment","center"); sb1 = uicontrol("style","slider",...
                 "units","normalized",...
                 "Position",  [0.90,0.2,0.05,0.48],...
                 "BackgroundColor",  [1,1,1],...
                 "Callback_Type",12,...
                 "sliderstep",[1/1000,1/10],...
                 "min",0,"max",1/15,"value",*gam*,...
                 "Callback","draw","tag","gamma");

                 uicontrol("style","text",...
                 "string","$\gamma$",...
                 "units","normalized",...
                 "Position",  [0.9,0.125,0.05,0.08],...
                 "BackgroundColor",  [1,1,1],...
"HorizontalAlignment","center");
             end
        end

        clf

        _draw_(0.3,1/15)

        Le 30/03/2020 à 02:14, Heinz Nabielek a écrit :

            Colleagues:

            is there an straightforward Scilab approach for solving the three 
coupled nonlinear differential equations of first order given by the Standard 
Model of Epidemics?


            S= number Susceptible:              S'=-aSI
            I=  number Infected:                I'=aSI - bI
            R= number Recovered:                R'=bI
            whereby 'a' is the transmission coefficient, 'b' the recovery 
factor (after Reed-Frost 1928).
            Initial values for S, I, R are available.

            Thank you
            Heinz
            _______________________________________________
            users mailing list
            users@lists.scilab.org  <mailto:users@lists.scilab.org>
            
https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users
  
<https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users>

-- Stéphane Mottelet
        Ingénieur de recherche
        EA 4297 Transformations Intégrées de la Matière Renouvelable
        Département Génie des Procédés Industriels
        Sorbonne Universités - Université de Technologie de Compiègne
        CS 60319, 60203 Compiègne cedex
        Tel : +33(0)344234688
        http://www.utc.fr/~mottelet  
<https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/www.utc.fr/~mottelet>

        _______________________________________________
        users mailing list
        users@lists.scilab.org <mailto:users@lists.scilab.org>
        http://lists.scilab.org/mailman/listinfo/users
        
<https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users>





_______________________________________________
users mailing list
users@lists.scilab.org
https://antispam.utc.fr/proxy/1/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/lists.scilab.org/mailman/listinfo/users

--
Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
http://www.utc.fr/~mottelet

_______________________________________________
users mailing list
users@lists.scilab.org
http://lists.scilab.org/mailman/listinfo/users

Reply via email to