
236 Feedback Control in Systems Biology
7.6 Exploiting time-varying models
Linear time-invariant models will no t always be able to effectively capture
the dynamics of highly nonlinear biomolecular networks. For example, many
biomolecular regulatory networks produce limit cycle dyna mics, e.g. circadian
rhythms, [37], cAMP oscillations in aggregating Dictyostelium discoideum
cells, [38], or Ca
2+
oscillations, [39]. Since such robust oscillatory dynam-
ics cannot be produced by purely linear time-invariant systems, it is unlikely
that the underlying network will be accur ately identified using linear time-
invariant models. As discussed previously, how