Nonlinear theories Dynamics 40 Mathematical models 23 Chaotic behavior in systems 22 Mathematical optimization 20 Mathematics 18 Control theory 14 Mathematical physics 11 Differentiable dynamical systems 10 Data processing 9 Nonlinear systems 9 Time-series analysis 9 System analysis 8 Computational complexity 7 Engineering mathematics 6 Regression analysis 6 Automatic control 5 Congresses 5 Coupled problems (Complex systems) 5 Image processing 5 Neural networks (Computer science) 5 Stochastic processes 5 Structural analysis (Engineering) 5 Cellular automata 4 Convex functions 4 Differential equations, Nonlinear 4 PID controllers 4 Solitons 4 System identification 4 Systems engineering 4