Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great eff...

This paper proposes robust algorithms to perform deconvolution and inversion of the heat equation starting from 1D and 2D discrete noised data. The solutions are provided as splines that minimize some parameterized quadratic functionals. Parameters choice determines the trade-off between the regularity of the solution and the approximation of the initial data. The solutions are derived in an ex...

This paper deals with the iterative solution of large sparse symmetric positive definite systems. We investigate preconditioning techniques of the two-level type that are based on a block factorization of the system matrix. Whereas the basic scheme assumes an exact inversion of the submatrix related to the first block of unknowns, we analyze the effect of using an approximate inverse instead. W...

The focus of our study is lithology/fluid inversion with spatial coupling from prestack seismic amplitude variation with offset AVO data and well observations. The inversion is defined in a Bayesian setting where the complete solution is the posterior model. The prior model for the lithology/fluid LF characteristics is defined as a profile Markov randomfield model with lateral continuity. Each ...

We present a top-down approach to the study of the dynamics of icosahedral virus capsids, in which each protein is approximated by a point mass. Although this represents a rather crude coarse-graining, we argue that it highlights several generic features of vibrational spectra which have been overlooked so far. We furthermore discuss the consequences of approximate inversion symmetry as well as...

Several inverse problems exist in the atmospheric sciences that are computationally costly when using traditional gradient based methods. Unfortunately, many standard evolutionary algorithms do not perform well on these problems. This paper investigates why the temperature inversion problem is so difficult for heuristic search. We show that algorithms imposing smoothness constraints find more c...

The title mol-ecule, C(25)H(22)F(6)N(2)O(3), adopts an open conformation whereby the quinoline and carboxyl-ate ester groups are orientated in opposite directions but to the same side of the piperidine ring so that the mol-ecule has an approximate U-shape. The piperidine ring adopts a distorted boat conformation. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate ...

Approximate higher order polynomial inversion of the top-hat filter is developed with which the turbulent stress tensor in Large-Eddy Simulation can be consistently represented using the filtered field. Generalized (mixed) similarity models are proposed which improved the agreement with the kinetic energy transfer to small scales. These similarity models are analyzed for random periodic signals...

I approximate the inverse Hessian (L′L)−1, where L is a Born modeling operator and L′ is the corresponding adjoint RTM operator, with non-stationary matching filters. These non-stationary filters can be seen as a low-rank approximation of the true inverse Hessian. For 3D least-squares imaging, I use these matching filters to precondition the inversion of prestack seismic data and observe a sign...