The acoustic scattering matrix for a cylinder whose cross sectional boundar
y deviates from a circle is determined by using a boundary perturbation met
hod. It is shown how to obtain the scattering matrix approximation up to a
desired order, for a scatterer with a given impedance. The limits of hard a
nd soft scatterers are included as special cases. In addition, the first-or
der scattering matrix is used to solve an optimization problem, i.e., that
of finding the shape of the scatterer which yields a reflected field closes
t to a given field in a least-squares sense. (C) 1999 Elsevier Science B.V.
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