Cyber-Physical Systems (CPS) have started to emerge as a consequence of the general trend toward the integration of beforehand isolated systems into large-scale federations of distributed systems comprising software and physical entities. Moreover, each system as part of such a federation is autonomous in the sense that it is developed, operated, evolved, and governed independently from the other systems. However, they all interact with each other in a dynamic and open world, which causes individual systems to dynamically join or leave the federation over time, the federation architecture to dynamically vary, and emergent behavior of the overall federation.
An example for such a CPS is a large-scale federation of autonomous robots as shown in the figure above. In contrast to our CPS lab, in which three robots are available, this project should consider large-scale federations with hundreds or even thousands of robots. Though the robots may act autonomously and therefore independently from each other, they may also interact to jointly perform a task such as collaboratively exploring an unknown territory. Thereby, the robot may sense their environment, store important information in a context model and share that information with other autonomous robots in the system. This is illustrated in the figure by links connecting individual robots such that the whole federation can be described by a graph with robots as nodes and interactions between robots as links between the nodes.
This requires scalable means to test and validate such systems through simulation that makes use of the graph structure of such federations. For instance, while an individual autonomous robot can be rather easily simulated in isolation, the federation behavior that emerges when thousands of robots collaborate can only be effectively simulated with a scalable solution.