In the following dissemination of a virus has been simulated following a few simple rules. Because these rules are so simple, the results obtained should not be valued too much. Even so, several phenomena can be illustrated reasonably well.
A number of inhabitants are assigned to each of the pixels of a bitmap (here it will be 4, such that a pixel corresponds more or less to a home with four residents). The pixel is coloured red if one or more residents are contaminated. A pixel can take on shades of yellow if the number of ill persons of a pixel exceeds the number of inhabitants at the start of the simulation (guests). Immunised persons are indicated in hues of blue.
Per iteration (= ~ a video image) the program calculates the number of persons contaminated by their next neighbours as well as how far (how many pixels) an inhabitant has travelled (if he is allowed to at least). All parameters (i.e. the probability of transmission, de mean durations of contagiousness and immunity, the probability of death of a patient, the fraction of mobile persons and their mean mobility) are considered to be Poisson-distributed (see the figure below). Every decision taken by the program is determined by throwing dice (in other words: it takes a random sample of the Poisson distribution).
A Possion distribution with a mean of 10
The three graphs to the left of the three videos below, which correspond to three scenarios, indicate how the total numbers of contagious, immunised and deceased persons in the entire bitmap evolve during the run of the iterations.
Uncontrolled dissemination. This video is better viewed full screen. | ||
Air traffic and public transport are stopped. This video is better viewed full screen. | ||
People may not leave their houses. This video is better viewed full screen. |
Repeated recurrence of contagion. This video is better viewed full screen. |
Chaotic dissemination. This video is better viewed full screen. |
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"Viral Whisper" is a soundtrack that has been created by moving sound-windows over the PC's desktop. For a detailed description see the "Best of Windows" page. The video underneath accompanies the track. This video is better viewed full screen. |