Abstract
In previous work, we proposed modeling and simulation of UML activities in Parallel DEVS. With respect to parallelism, either one of the following statements holds true about the semantics of activities in order to attain a valid execution. A time base, regardless of its granularity, shall be explicitly defined in order to account for parallelism in a simulation environment with sequential execution. Or, the environment shall be physically parallel in multiple processes. We examine the former by dissecting into some of its properties that are related to control constructs within activity modeling in the viewpoint of Parallel DEVS formalism.