Determination of point wave sources by pointwise observations: stability and reconstruction
Gottfried Bruckner; Masahiro Yamamoto; Gottfried Bruckner; Dedicated to the memory of Professor Dr Siegfried Prößdorf.; Masahiro Yamamoto; Dedicated to the memory of Professor Dr Siegfried Prößdorf.
Журнал:
Inverse Problems
Дата:
2000-06-01
Аннотация:
We consider a wave equation with point source terms where λ∈C<sup>1</sup>[0,T] is a known function such that λ(0)0, α<sub>k</sub>∈, δ(·-x<sub>k</sub>) is the Dirac delta function at x<sub>k</sub>, 1≤k≤N. We discuss the inverse problem of determining point sources {N,α<sub>1</sub>,...,α<sub>N</sub>,x<sub>1</sub>,...,x<sub>N</sub>} or {x<sub>1</sub>,...,x<sub>N</sub>} from observation data u(η,t), 0<t<T with given η∈(0,1) and T>0. We prove uniqueness and stability in determining point sources in terms of the norm in H<sup>1</sup>(0,T) of observations. The uniqueness result requires that η is an irrational number and T≥1, and our stability result needs further a priori (but reasonable) information of unknown {x<sub>1</sub>,...,x<sub>N</sub>}. Moreover, we establish two schemes for reconstructing {x<sub>1</sub>,...,x<sub>N</sub>} which are stable against errors in L<sup>2</sup>(0,T).
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