Revision of the calculation of apparent velocities in relativistic beaming model.

The currently accepted and widely used formula for calculation of apparent transverse velocities of plasmons or shocks in frame of relativistic beaming model was deduced under assumption that the core itself is fixed in a rest frame with respect to the observer. It is reasonable to re-evaluate the correction of the formula and to try to find a revised one in a more general frame. The feasibility and necessity of the revision are discussed in this paper on the basis of general recognition of the radio source structure.