sim.pointSource: Simulate Point-Source Epidemics

Description

Simulation of epidemics which were introduced by point sources. The basis of this programme is a combination of a Hidden Markov Model (to get random timepoints for outbreaks) and a simple model (compare sim.seasonalNoise) to simulate the baseline.

Usage

sim.pointSource(p = 0.99, r = 0.01, length = 400, A = 1, 
        alpha = 1, beta = 0, phi = 0, frequency = 1, state = NULL, K)

Arguments

probability to get a new outbreak at time i if there was one at time i-1, default 0.99.

probability to get no new outbreak at time i if there was none at time i-1, default 0.01.

length

number of weeks to model, default 400. length is ignored if state is given. In this case the length of state is used.

amplitude (range of sinus), default = 1.

alpha

parameter to move along the y-axis (negative values not allowed) with alpha > = A, default = 1.

beta

regression coefficient, default = 0.

phi

factor to create seasonal moves (moves the curve along the x-axis), default = 0.

frequency

factor to determine the oscillation-frequency, default = 1.

state

use a state chain to define the status at this timepoint (outbreak or not). If not given a Markov chain is generated by the programme, default NULL.

additional weigth for an outbreak which influences the distribution parameter mu, default = 0.

Value

disProga object disProg (disease progress) including a list of the observed, the state chain and nearly all input parameters.

encoding

latin1

Examples

Run this code

# Plotting of simulated data
    disProgObj <- sim.pointSource(p = 0.99, r = 0.5, length = 208,
                                    A = 1, alpha = 1, beta = 0, phi = 0,
                                    frequency = 1, state = NULL, K = 2)
    # plot the simulated disease with the defined outbreaks
    plot(disProgObj)

    state <- rep(c(0,0,0,0,0,0,0,0,1,1), 20)
    disProgObj <- sim.pointSource(state = state, K = 1.2)
    plot(disProgObj)