Model Concept: Kesten Process

A Kesten Process is mathematical description of the evolution of some variable X(t) over time such that its value at time=t+1 is given as X(t+1) = aX(t) + b. Importantly, a and b are random variables with positive means (typically, the mean value of a is less than 1) resulting in nontrivial, intermittent behavior of the variable X(t). {Sornette D (1998) Physica A 250:295-314}