Critical infrastructure dependencies 1-0-1

Most of our critical infrastructures consist of complex systems-of-systems that provide services or products. The coupling mechanism between the chained systems in such complex systems of systems is dependencies. Dependencies may propagate cascading failures. Most studies on dependencies in infrastructures are based on either an economic model or on a graph model. These regard dependencies mostly as an available or unavailable commodity. In this paper we describe a model view on dependencies showing why dependencies in reality are far more complex than some of the models suggest. At the same time, we will present on-going work on how often serious cascading effects between various critical infrastructures occur based upon an empirical analysis of collected data.