Emergent Disservices in Interdependent Systems and System-of-Systems

The assessment and the evaluation of the risk exposure to failures and cyber attacks, is nowadays - in times of pervasive ICT applications - a much required task. However, in some cases, and especially when evaluating an ICT infrastructure (which can be logically and geographically sparse and which can provide services to other systems), the evaluation of system risk is not sufficient. In fact in this context, a failure judged negligible for the life of a system may have not negligible effect on another system which is in someway in relation with the former one. In this paper, we present a formal approach based on the concept of system of system allowing to represent the interdependencies existing among a group of collaborating systems. Moreover we show how such an approach can be integrated in a risk assessment methodology in order to obtain a system of system risk assessment framework.