Wester-Ebbinghaus, MatthiasMoldt, DanielAdameit, SimonEngels, GregorKaragiannis, DimitrisMayr, Heinrich C.2019-01-172019-01-172010978-3-88579-255-0https://dl.gi.de/handle/20.500.12116/19712Modern software systems are frequently characterized as systems of systems. Agentorientation as a software engineering paradigm exhibits a high degree of qualification for addressing many of the accompanying challenges. However, systems of systems demand for means of hierarchical/recursive decomposition that are not inherently rooted in the agent-oriented paradigm. We present a model that still relies on the actor metaphor, but shifts the focus to collective agency. We propose a universal model of a system unit that both embeds system actors and is itself embedded as a collective system actor in surrounding system units. Consequently, we can apply our model of a system unit at arbitrary levels of a system of systems and compose the overall system by means of nested actor hierarchies. (High Level) Petri nets as our modeling technique supply precise operational semantics for the functioning of these kind of systems. In addition, we offer abstraction mechanisms that allow for rather high-level or low-level views and smooth transitions between them.enText/Conference Paper1617-5468