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Suppose a musician wants a guitar
string that has a certain specific
sound. This specification can be
translated into eigenvalue locations
in the complex plane: persistent
tones correspond to eigenvalues
near the imaginary axis; highly
damped tones give eigenvalues farther
in the left half of the complex
plane. Can we design a string that
has the desired response?
In this talk, we investigate the
construction of a spatially-varying
damping coefficient that induces
a wave operator having specified
eigenvalues. This problem is distinguished
from the more familiar inverse Sturm-Liouville
problem by the fact that the operator
in question in non-self-adjoint.
Still, many of the same theoretical
devices, based on eigenvalue asymptotics,
prove useful. The constructed damping
functions are even about the midpoint
and should vary mildly about their
mean. Numerical results, in the
absence and presence of noise, demonstrate
the efficacy of this technique.
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