The approximate string matching problem consists in finding all locations at which a pattern p of length m matches a substring of a text t of length n, after a finite number of given edit operations. In this paper,we investigate such a problemwhen the edit operations are translocations of adjacent factors of equal length and inversions of factors. In particular, we first present anO(nmmax(α, β)...

This article deals with the efficient (approximate) inversion of finite element stiffness matrices of general second-order elliptic operators with L∞-coefficients. It will be shown that the inverse stiffness matrix can be approximated by hierarchical matrices (H-matrices). Furthermore, numerical results will demonstrate that it is possible to compute an approximate inverse with almost linear co...

Inversions are a class of chromosomal mutations, widely regarded as one of the major mechanisms for reorganizing the genome. In this paper we present a new algorithm for the approximate string matching problem allowing for non-overlapping inversions which runs in O(nm) worst-case time and O(m2) space, for a character sequence of size n and pattern of size m. This improves upon a previous O(nm2)...

We consider a Bayesian model for doing lithology–fluid prediction from prestack (amplitude versus offset) seismic data. Related to the Bayesian model, we look at two inversion algorithms. The first algorithm simulates from the posterior distribution with no approximations, but the algorithm is quite computer demanding. The second inversion algorithm introduces an approximation in the likelihood...

The problem of image reconstruction in thermoacoustic tomography requires inversion of a generalized Radon transform, which integrates the unknown function over circles in 2D or spheres in 3D. The paper investigates implementation of the recently discovered backprojection type inversion formulas for the case of spherical acquisition in 3D. A numerical simulation of the data acquisition with sub...

Five numerical phantoms were developed to investigate the accuracy of approximate inversion schemes in the reconstruction of oxygen saturation in photoacoustic imaging. In particular, two types of inversion are considered: Type I, an inversion that assumes fluence is unchanged between illumination wavelengths, and Type II, a method that assumes known background absorption and scattering coeffic...

We deal with an inverse problem of simultaneously identifying the space-dependent diffusion coefficient and the source magnitude in the time fractional diffusion equation from viewpoint of numerics. Such simultaneous inversion problem is often of severe ill-posedness as compared with that of determining a single coefficient function. The forward problem is solved by employing an implicit finite...