In the last five years, several complex systems have been investigated in nonlinear systems theory and have had a huge impact on the scientist research. Due to their complexities in the design, analysis, and control, innovative ideas, novel models, and techniques are still expected in the future in these expanding areas.

This special issue is intended to present and discuss advanced topics and their complexity in the nonlinear systems theory. It is expected that novel complex models, their bifurcation analysis, and their related control techniques will be established. Among others, applications in medical and biosciences disciplines are especially encouraged to be submitted to this special issue to present their related latest developments.

Potential topics include but are not limited to the following:

• Mathematical modeling and analysis in medicine (hormone regulation, immune response, epidemiology, tumor growth, HIV infection, etc.)
• Mathematical modeling and chaos analysis in biosciences (population dynamics, ecological system, cell kinetics, etc.)
• Bifurcation analysis of spatiotemporal or delayed chaotic dynamical systems
• Design, analysis, and implementation of new hyperchaotic systems
• Bifurcation analysis and control of fractional-order complex systems
• Advanced control and synchronization schemas of new hyperchaotic systems