Abstract
Most of the critical aspects for secure and dependable systems, such as safety, integrity, availability, are related to uncertainty. Literature proposes many approaches to deal with uncertainty, mainly in the area of risk management and safety and reliability engineering. However, what is still missing is a clear understanding of the nature of uncertainty that very often has produced mistreatments in the design. In this paper, we propose a conceptual model for uncertainty that can be used to deal with systems’ qualities such as security and dependability. Particularly, we will consider the relation between uncertainty risk and how risk affects quality attributes of the system. We use a case study in Air Traffic Management to illustrate our approach.