  In this paper Gaussian models of retarded and accelerated anomalous diffusion
are considered. Stochastic differential equations of fractional order driven by
single or multiple fractional Gaussian noise terms are introduced to describe
retarding and accelerating subdiffusion and superdiffusion. Short and long time
asymptotic limits of the mean squared displacement of the stochastic processes
associated with the solutions of these equations are studied. Specific cases of
these equations are shown to provide possible descriptions of retarding or
accelerating anomalous diffusion.
