Abstract
The paper presents a computational oriented overview on the order re-
duction problem for passive (positive real) linear systems. The numerical dificulties
associated with the standard order reduction procedure, which involves the stabilizing
solutions of two Riccati equations, are discussed. Some new approximate methods
are proposed, which are specic to the discrete time setting, but may be easily ex-
tended to cope with continuous time models by using a simple bilinear transformation.
Numerical results conclude the presentation.
