Use of adjusted time parameters in system dynamics models

The errors caused by the use of Euler integration in system dynamics models may be reduced by the application of Richardson's extrapolation to the results of simulations using two or more different values of DT. Thus, it is possible to obtain accurate results using substantially less computational effort than would otherwise be necessary. Here it is shown how the computational effort required may be reduced still further by deliberately modelling using time parameters (such as smoothing and delay times) that differ from those of the actual system being modelled. Alternative methods for calculating adjusted time parameters in terms of the system time parameters and the value of DT are presented.