Abstract for:Uncertainty in nonlinear relationships

One central characteristic of complex systems is the existence of nonlinear relationships among many variables of interest. The importance of nonlinearity is often recognized but can only be examined in detail, in the context of how it influences system behavior, with computer simulation. Even when well-formulated nonlinear relationships are used in dynamic modeling, uncertainty in the assumed shape (function form) and values may exists. In order to develop rigorous formulations it is necessary to recognize the uncertainty in the nonlinear relationship and explore the possible impact of such uncertainty in system behavior. Sensitivity analysis, assuming deterministic probabilities, is generally recommended and used for this task. In this paper, we explore some implications of using deterministic probability to explore uncertainty in the formulation of nonlinear relationships and contrast these with the use of imprecise probability functions as a way of conducting such analysis.