Interactions issues in risk analysis of complex systems

This communication considers the problem of modeling the mechanism of risk analysis (assessment and management) of a network of complex systems. One of main attributes of complexity is interactions ; indeed, interactions between systems in a network have the effect of propagating and even amplifying effects of local disturbances. Two types of interactions are commonly encountered : the influence that can be described by an acyclic hierarchical relationships graph of the interacting systems and the interdependence for which the graphical representation of relationships allows loops (see [4, 5, 6]). As stated in [3] concerning projects management, "every project involves risks and every project needs to have a management strategy for dealing with threats and opportunities represented by each risk" ; this assertion can apply to almost any human activity (that is a complex system) as uncertainty is inherent to it. Risk analysis of human activities becomes therefore an important issue that must be addressed with appropriate scientific tools and methods (see [5] for more details and mathematical tools used to this end). Today, an ever-increasing number of professionals and managers in industry, government, and academia are devoting a larger portion of their time and resources to the task of improving their approach to, and understanding of, risk-based decision making [4]. Integration of risk factor in decision making or risk informed decision making is receiving a great attention by researchers and decision makers in many socieconomic domains [4]. But to address correctly important risks, decision makers must consider discriminating or categorizing them ; this process consists basically in assigning them to predefined classes or categories that is nominaly classifiying them [5]. Steps in risk analysis process are described in sections below.