Critical infrastructures (CIs) are large scale systems that are essential for the smooth and reliable operation of everyday activities in modern societies. To understand the operation characteristics of CIs, as well as the behavior of interdependencies between different CIs, we usually use modeling and simulation methodologies. In this work we propose an interdependent CI modeling methodology based on hybrid systems.
We adopt open hybrid automata to model the constituent components of different critical infrastructures, including any dependencies that may exist between them. Then, using open hybrid automata composition properties, we can compose different CI component models together, creating a single hybrid automaton model that represents interdependent CIs. Finally, simulating the composition model we can generate sample paths that show how component faults can cascade and/or escalate between CIs.