Fir stly\, I will talk about the situation when bounda ry conditions are given on many plates and the ass ociated Wiener-Hopf equation. The Wiener-Hopf meth od can be considered as a Riemann-Hilbert method w ith added analytisity information allowing for ful l power of complex analysis methods to be exploite d. I will explain the difficulties involved when m atrix Wiener-Hopf equations are solved. I will des cribe how recent advances in computation of ration al approximations and orthogonal polynomials can b e used. The corresponding canonical acoustics sca ttering problems will be considered.

This is j oint work with Matthew J. Priddin and Lorna J. Ayt on.

Secondly\, I will talk about how speci al functions called Mathieu function can be used t o solve Helmholz equation with boundary conditions given on a plate. This allows to produce a fast and stable code for challenging conditions like va rying elasticity and porosity on a plate. This is joint work with Matthew J. Colbrook. LOCATION:Seminar Room 1\, Newton Institute CONTACT:INI IT END:VEVENT END:VCALENDAR