  A trend across most areas where simulation-driven development is used is the
ever increasing size and complexity of the systems under consideration, pushing
established methods of modeling and simulation towards their limits. This paper
complements existing surveys on large-scale modeling and simulation of physical
systems by conducting expert surveys. We conducted a two-stage empirical survey
in order to investigate research needs, current challenges as well as promising
modeling and simulation paradigms. Furthermore, we applied the analytic
hierarchy process method to prioritise the strengths and weakness of different
modeling paradigms. The results of this study show that experts consider
acausal modeling techniques to be suitable for modeling large scale systems,
while causal techniques are considered less suitable.
