On nonlinear system modeling using principal dynamic modes

The concept of principal dynamic modes was recently proposed as a means to expand a nonlinear system's dynamics into modal components that are quadratic in the system inputs. The most significant system modes may be extracted from this decomposition. This approach has been utilized to analyze nonlinear biological systems. Here, principal dynamic modes are interpreted as a means to approximate nonlinear systems as linear combinations of Wiener systems. The principal dynamic mode method is modified to better achieve this goal, while also enabling a more appropriate simplification when the system is linear.