Zunächst wird eine generelle Erklärung vonProtesten (die für nicht-autoritäre und autoritäreRegime gilt) vorgestellt. Diese wird amBeispiel der Proteste in der DDR-Diktatur inLeipzig 1989/1990 illustriert. Sodann werdendie einzelnen Schritte der Durchführungeines empirischen Projekts über dieUrsachen der entscheidenden Proteste imOktober 1989 dargestellt. Weiter wird überErgebnisse des Projekts berichtet. Hierzugehört, dass sich eine historische “Tatsache”– nämlich die Teilnehmer:innenzahlvon 70.000 am 9. Oktober 1989 – als falscherweist.

The technical and processual interconnection among critical infrastructures (CIs) has drastically increased over the last decade, amplified by the ongoing digitalization in this sector. With the application of Industrial Control Systems (ICS) and Supervisory Control and Data Acquisition (SCADA) systems, CIs have evolved into highly complex ecosystems, becoming more and more dependent on each other. In such ecosystems, an incident happening within one infrastructure is no longer limited to this infrastructure alone but can have wide-ranging effects on dependent CIs as well as the society as a whole. The cascading effects of such incidents show that it is nowadays no longer sufficient to analyze and assess risks from the perspective of one organization alone. In this talk, we will take a closer look at these interdependencies within and among CIs and how to capture them in a structured way. Further, we will discuss a modelling and simulation approach that is able to describe on an abstract level, how much a critical entity (either a technical component or an entire infrastructure) is affected by an incident. This approach will set the basis for describing how the effects can propagate through the network of interdependent critical systems and infrastructures and for assessing the overall consequences of an incident as part of CI risk management.