  In citation networks, the activity of papers usually decreases with age and
dormant papers may be discovered and become fashionable again. To model this
phenomenon, a competition mechanism is suggested which incorporates two
factors: vigorousness and dormancy. Based on this idea, a citation network
model is proposed, in which a node has two discrete stage: vigorous and
dormant. Vigorous nodes can be deactivated and dormant nodes may be activated
and become vigorous. The evolution of the network couples addition of new nodes
and state transitions of old ones. Both analytical calculation and numerical
simulation show that the degree distribution of nodes in generated networks
displays a good right-skewed behavior. Particularly, scale-free networks are
obtained as the deactivated vertex is target selected and exponential networks
are realized for the random-selected case. Moreover, the measurement of four
real-world citation networks achieves a good agreement with the stochastic
model.
