Expressing Environment Assumptions and Real-time Requirements for a Distributed Embedded System with Shared Variables

In a distributed embedded system, it is often necessary to share variables among its computing nodes to allow the distribution of control algorithms. It is therefore necessary to include a component in each node that provides the service of variable sharing. For that type of component, this paper discusses how to create a Colored Petri Nets (CPN) model that formally expresses the following elements in a clearly separated structure: (1) assumptions about the behavior of the environment of the component, (2) real-time requirements for the component, and (3) a possible solution in terms of an algorithm for the component. The CPN model can be used to validate the environment assumptions and the requirements. The validation is performed by execution of the model during which traces of events and states are automatically generated and evaluated against the requirements.