“…These are models involving stochastic volatility or, more in general, stochastic state space models. For example models of this type are used in the study of clutter in signal processing, of wave propagation in random acoustic or electromagnetic media, of noise in telecommunications, of biomedical systems in medicine, as well as in the study of other models in mathematical finance (see, for example, [9,11,13,14] and the reference therein).…”