stant. The next stage is governed by the hyperbolic decision function EFTA00624245 23.6 Dynamics of STI and LTI Propagation 99 tanh (shape (s — FocusBotmdary)) -I- 1 9 (s) 2 The entire updating sequence is obtained by the composition (go f) (s), whose derivative is then (s. of) sech2 (f (s)) • shape