Paul M. Geffert analyses the interplay of noise and time delay in non-excitable nonlinear
systems and the modulation of stochastic effects. In particular the author studies coherence
resonance which is a constructive effect of noise that occurs in nonlinear systems and
demonstrates that it can be modulated by time-delayed feedback. Analytical methods for the
investigation of stochastic delay differential equations are developed. Noise or random
perturbations and time delay are two phenomena which arise in many fields of physics chemistry
or biology just to mention a few examples. The investigated model is a generic Hopf normal
form so that these methods and results can be transferred to many different areas of science.
