[Seisunix] Modeling Covid-19 with Seismic Unix
fasn.ufpa at gmail.com
Sun Apr 5 20:52:40 CEST 2020
Good to know John
Em dom, 5 de abr de 2020 3:39 PM, John Stockwell <john.19071969 at gmail.com>
> I send my good wishes to all of you and I hope that you, your families,
> and your friends are faring well in this difficult time.
> For those who are interested in modeling populations, such as the current
> epidemic, there is a logistic equation solver called
> “verhulst” in the SU package which you may find of interest.
> For example for Covid-19 cases in the US, taking 22 January as day 0 of
> cases in the US and 29 February as day 0 for deaths. Respective
> stepmax= values of 72 for cases and 34 for deaths are both 3 April
> verhulst stepmax=72 h=1 a1=.176 y0=1 a2=1e7 mode=x > calculated_cases.bin
> verhulst stepmax=35 h=1 a1=.268 y0=1 a2=1e6 mode=x > calculated_deaths.bin
> xgraph < calculated_cases.bin n=72 nplot=1 d1=1 &
> xgraph < calculated_deaths.bin n=34 nplot=1 d1=1 &
> The growth rate a1 values are determined empirically from publicly
> available data, in this case from the CDC and from the Worldometer site.
> You will have to make your own estimate of a1 for the data that you are
> Another parameter that is harder to get is an estimate of the carrying
> capacity of the system a2. Here I am assuming a maximum of 1 million cases
> in the US and 100 thousand deaths.
> The number of new cases or deaths per day is measured by the derivative of
> the solutions to the verhulst equation
> verhulst stepmax=72 h=1 a1=.176 y0=1 a2=1e7 mode=y > delta_cases.bin
> verhulst stepmax=35 h=1 a1=.268 y0=1 a2=1e6 mode=y > delta_deaths.bin
> xgraph < delta_cases.bin n=72 nplot=1 d1=1 &
> xgraph < delta_deaths.bin n=34 nplot=1 d1=1 &
> The peak in the change of the population per day occurs when the
> population reaches the exactly half of the carrying capacity of the system.
> Thus, raising the carrying capacity will increase the height of the peak
> and move it out later in time.
> Take care, everyone and stay safe.
> John Stockwell
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