Using models and abstraction to extend and unify systems

Systems engineering is in a transition period. The existence of `systems of systems´ and other complex systems has raised issues that challenge traditional methods of systems engineering. This paper describes selected high level aspects of a comprehensive systems engineering method called model oriented systems engineering (MOSE) that is intended to address the full scope of both traditional and complex systems. The method supports similarities as well as differences of these system types. The modeling approach regards both scientific theories and engineering artifacts, such as concepts of operations, requirements specs, and architecture descriptions, as models of systems. The paper describes relations between models and systems, including the conceptualization of a model as a region of systems