3+4+Supplementum/2012 - Společnost pro pojivové tkáně

where r is a parameter. The velocity of
number of infected persons (derivation) is
proportional of number of persons endangered
by grippe minus number of infected
persons, in mathematic formulation:
Infect´ = r.State – a.Infect, (2)
Where a is parameter.
The equation (1) a (2) is the differential
equation system with initial conditions:
State = n, Infect = 1.
The simulation program consists of
Block1, calculated the right side of (1), (2)
in universal time point:
Block1: derState = -r.State.Infect; derInfect
= r.State-a.Infect;
The main program set initial conditions
to values State, Infect, the parameter values,
the scheduling of calculation according
to block1 and integration of differential
equations:
schedule(start time, blok1, continuous,…);
integr(1, derState, State,…);
integr(1,derInfect, Infect,…);
where integrate vector has unit length.
The graphic output can be schedule by
statement
graph(State,…); graph(Infect,…);
The simulation system is called by statement:
wait(time of end simulation,…).
226
Model of hospital beds occupancy
The example of discrete simulation
model will be performed. The model
structure will be changed in finite time
points only. Let’s the hospital has n
departments. The free beds are infill step
by step. If all beds are occupied then the
queue are created of patients waiting for
cure at home. The model will show a course
of bed occupation at real hospital. The
task is to calculate average queue length
and perceptual bed occupation. The convenient
bed number can be determined by
simulation experiments.
Each hospital department has the
record:
n number of beds,
i number of occupied beds,
patient pointer to the patient data
structure with the first bed starting,
queue pointer to the patient queue
structure with the last patient at
queue starting,
utilizing bed utilizing,
d queue length of patient waiting
on cure,
daverage average queue length,
tbed last time of bed occupation changing,
tqueue last time of queue length changing.
The list of hospital departments are at
fig. 1. Each record has the pointer to the
next record.
depbeg Department 1 Department 2
fig. 1. Hospital departments list.
LOCOMOTOR SYSTEM vol. 19, 2012, No. 3+4