From Complicated to Complex Uncertainties in System of Systems

In this discussion paper we demonstrate the catastrophic failure property of complex system of systems by simulation and an uncertainty propagation technique. Complex uncertainty cannot manifest in complicated systems that structurally lack significant circular causal dependencies. The applicability of flexibility engineering as a technique of not only harnessing but also exploiting uncertainty in system of systems is questioned and discussed for systems under complex uncertainties. Given the rapid and unintuitive uncertainty propagation in complex systems, and the impossibility of backward propagation to determine the sources of complex uncertainty, we note that flexibility engineering must be rethought and reframed for system of systems; simply because exercising new options can 1) unintentionally and dramatically increase the structural complexity, exposing the system more dangerously to possibility of a sudden global failure, and 2) be deployed in inappropriate situations and conditions that do not necessarily lead to added value promised by deployment of adaptive solutions.