Standard approaches to time-delay embedding will often fail to provide
an embedding that is useful for many common applications. This happen
s in particular when there are multiple timescales in the dynamics. We
present a modified procedure, non-uniform embedding, which overcomes
such problems in many cases. For more complex nonlinear dynamics we in
troduce variable embedding, where, in a suitable sense, the embedding
changes with the state of the system. We show how to implement these p
rocedures by combining embedding and modeling into a single procedure
with a single optimization goal. (C) 1998 Elsevier Science B.V.