Additive and multiplicative noises acting simultaneously on Ermakov-Ray-Reid systems

"We investigate numerically the effect of additive and multiplicative noises on parametric oscillator systems of Ermakov-Ray-Reid type whenboth noises act simultaneously. We find that the main perturbation effects on the dynamical invariant of these systems are produced by theadditive noise. Different from the separate action of the multiplicative noise when the dynamical invariant of these systems is robust, we alsofind a weak effect that can be attributed to the multiplicative noise."