(color online) Fitness value curves and output of system for four chaotic maps with sawtooth signal. Panels (a) and (b) are fitness value curve and output of Logistic chaotic system with sawtooth signal. Panels (c) and (d) are fitness value curve and output of nonlinear Chebyshev chaotic system with sawtooth signal. Panels (d) and (f) are fitness value curve and output of nonlinear Tent chaotic system with sawtooth signal. Panels (g) and (h) are fitness value curve and output of nonlinear Cubic chaotic system with sawtooth signal, respectively.