TUAT Kuroda Lab.
Stochastic modelling of human mobility and viral transmission (Ver 0.0)
Total Population (N) 100 Total number of people in the system
Grid-Size (M) 50 Total number of sites on the Grid
Detection Rate (DR) Detection during the SP
Detection Rate Assymptotic (DR2) Detection during the AP
Transmission Rate (TR) Probability of viral transmission during SP
Assymptotic Period (AS) Nb of step where patients are assymptotic
Symptomatic Period (SP) Nb of step where patients are symptotic
Maximum Mobility (m) Maximum number of sites that a person can travel during each step when no mobility restriction is applied
lockdown timing (fraction of total population) Percentage of detected patient at which the lockdown is enforced
Restrained mobility (mR) Maximum number of sites that a person can travel during each step during the lockdown
Mobility restriction period Number of steps during which lockdown is imposed.

After several weeks of "lockdown" as the sole answer to the COVID-19 pandemic, many countries are restarting their economic and social activities. However, balancing the
re-opening of society against non-medical measures needed for minimizing interpersonal contacts requires a careful assessment of the risks of infection as a function of the
confinement relaxation strategies. Here, we present a stochastic model that examines this problem. In our model, people are allowed to move between discrete positions on a
one-dimensional grid with viral infection possible when two people are collocated at the same site. Our model features three sets of adjustable parameters, which characterize (i)
viral transmission, (ii) viral detection, and (iii) degree of personal mobility, and as such, it is able to provide a qualitative assessment of the potential for second-wave infection
outbreaks based on the timing, extent, and pattern of the lockdown relaxation.

Note to the users:

  1. The simulation is performed using random values generated using Python's rand function. New random values are generated for each run of simulations, meaning that
    the results will change from one run to the next. The users should average the results over multiple runs of simulation (with the same entry values) in order to obtain
    reliable averaged values.
  2. The calculation time can vary from a few seconds to several minutes depending on the parameter used essentially depending on the grid number (M), person's number(N),
    and their ratio (=population density=N/M). In order not to overload our server, we set maximum values for N and M of 2000, and the program will stop when calculation
    time reaches 3 minutes.

References : Ando, Matsuzawa et al., Stochastic Modelling of the effects of human mobility and viral transmission characters during the relaxation of COVID-19 lockdown restrictions

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