UML & SysML modelling languages

This article deals with a recurring question in use case modelling: given a use case that’s automatically triggered by the system clock or timer, what actor should be used? To illustrate the options given in this article, I’ve chosen the example of a system that processes new card transactions on a daily basis, aim of the use case “Process customer transactions”.

In this context, it is common use to define as the primary actor the system’s clock or timer, since this actor triggers the use case. Is it the only approach or are there alternatives? This article deals with this subject through 3 alternatives.