S Programming
Statistical Models in S
| Hi-index | 0.00 |
Based on measles case data from pediatricians in Lower Saxony, a simulation study was conducted in order to reproduce the current vaccination-disease relationship and afrerwards predict the impact of different vaccination strategies. The programs were written in S-Plus and make use of the language's array processing facilities. The process of infection was modeled by means of an age-structured compartmental model. The main data structure is a two dimensional array, representing the complete population, partitioned according to age cohorts and the compartments, which represent the stages of infection. The flow of individuals through the compartments is modeled weekly and performed by means of array operations. The number of new infections in each age cohort is simulated as a Poisson random variable, depending on the number of infectious individuals of any age and the transmission probability between ages. The transmission coefficients are organized in a matrix enabling the transmission process to be computed by matrix multiplication.