Future dependent events, as shown by the example of SLAM

Random events in discrete simulation models are classified in ordinary and future dependent events. An event occurring between to and T is classified as an ordinary event, if the probability distribution for the realization in time is known at time to. If changes of the system after time to can affect the probability distribution of an event, it is called a future dependent event. To show the difference we give two examples. In contrary to ordinary events future dependent events are not well supported by the currently most used languages like GPSS, SIMULA, SIMSCRIPT and SLAM. In taking SLAM as an example, we are going to demonstrate, how to adapt a simulation language to be able to handle future dependent events with as slight an effort as possible.