  We address the issue of how to identify the equations of a largely unknown
chaotic system from knowledge about its state evolution. The technique can be
applied to the estimation of parameters that drift slowly with time. To
accomplish this, we propose an adaptive strategy that aims at synchronizing the
unknown real system with another system whose parameters are adaptively evolved
to converge on those of the real one. Our proposed strategy is tested to
identify the equations of the Lorenz and the Rossler systems. We also consider
the effects of measurement noise and of deviation of our fitting model from
consistency with the true dynamics.
