  Objectives: Simulate the transmission process of COVID-19 in a cruise ship,
and then to judge how many infections there will be in the 3711 people in the
"Diamond Princess" and analyze measures that could have prevented mass
transmission.
  Methods: Based on the crowd flow model, the virus transmission rule between
pedestrians is established, to simulate the spread of the virus caused by the
close contact during pedestrians' daily activities on the cruise ship.
  Measurements and main results: Three types of simulation scenarios are
designed, the Basic scenario focus on the process of virus transmission caused
by a virus carrier and the effect of the personal protective measure against
the virus. The condition that the original virus carriers had disembarked
halfway and more and more people strengthen self-protection are considered in
the Self-protection scenario, which would comparatively accord with the actual
situation of "Diamond princess" cruise. Control scenario are set to simulate
the effect of taking recommended or mandatory measures on virus transmission
  Conclusions: There are 850~1009 persons (with large probability) who have
been infected with COVID-19 during the voyage of "Diamond Princess". The crowd
infection percentage would be controlled effectively if the recommended or
mandatory measures can be taken immediately during the alert phase of COVID-19
outbreaks.

Physics and Society;Computers and Society