  We associate the existence of short-lived compact radio sources with the
intermittent activity of the central engine caused by a radiation pressure
instability within an accretion disk. Such objects may constitute a numerous
sub-class of Giga-Hertz Peaked Spectrum sources, in accordance with the
population studies of radio-loud active galaxies, as well as detailed
investigations of their radio morphologies. We perform the model computations
assuming the viscosity parametrization as proportional to a geometrical mean of
the total and gas pressure. The implied timescales are consistent with the
observed ages of the sources. The duration of an active phase for a moderate
accretion rate is short enough (< 10^3-10^4 years) that the ejecta are confined
within the host galaxy and thus these sources cannot evolve into large size
radio galaxies unless they are close to the Eddington limit.
