Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct, nonlinear inversion algorithm for hyperbolic problems via
  projection-based model reduction   We estimate the wave speed in the acoustic wave equation from boundary
measurements by constructing a reduced-order model (ROM) matching discrete
time-domain data. The state-variable representation of the ROM can be
equivalently viewed as a Galerkin projection onto the Krylov subspace spanned
by the snapshots of the time-domain solution. The success of our algorithm
hinges on the data-driven Gram--Schmidt orthogonalization of the snapshots that
suppresses multiple reflections and can be viewed as a discrete form of the
Marchenko--Gel'fand--Levitan--Krein algorithm. In particular, the
orthogonalized snapshots are localized functions, the (squared) norms of which
are essentially weighted averages of the wave speed. The centers of mass of the
squared orthogonalized snapshots provide us with the grid on which we
reconstruct the velocity. This grid is weakly dependent on the wave speed in
traveltime coordinates, so the grid points may be approximated by the centers
of mass of the analogous set of squared orthogonalized snapshots generated by a
known reference velocity. We present results of inversion experiments for one-
and two-dimensional synthetic models.

18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th