The standard reverse-time migration (RTM) algorithm is usually described as zero-lag correlation of the backprojected data with the source wavefield. The data are back-projected by a finite-difference algorithm, where each trace acts as a source-time history of a point source at the geophone location. This is a simple and easily understood migration method, but appears inflexible to improvement...

We give an elementary, self-contained, and purely combinatorial proof of the Rayleigh monotonicity property of graphs. Consider a (linear, resistive) electrical network – this is a connected graph G = (V,E) and a set of positive real numbers y = {ye : e ∈ E} indexed by E. In this paper we allow graphs to have loops and/or multiple edges. The value of ye is interpreted as the electrical conducta...

The paper discusses the Nonlinear Dirac Equation with Kerr-type nonlinearity (i.e., $\psi^{p-2}\psi$) on noncompact metric graphs a finite number of edges, in case Kirchhoff-type vertex conditions. Precisely, we prove local well-posedness for associated Cauchy problem operator domain and, infinite $N$-star graphs, existence standing waves bifurcating from trivial solution at $\omega=mc^2$, any ...

In this paper, we consider the existence of positive solutions to the following p Kirchhoff-type system ⎧⎪⎨⎪⎪⎩ −M (∫ Ω |∇u|pdx ) Δpu = g(x)|u|q−2u+ α α+β |u|α−2u|v|β , x ∈Ω, −M (∫ Ω |∇u|pdx ) Δpv = h(x)|v|q−2v+ β α+β |u|α |v|β−2v, x ∈Ω, u = v = 0, x ∈ ∂Ω, where Ω is a bounded domain in RN , M(s) = a + bsk , Δpu = div(|∇u|p−2∇u) is the p Laplacian operator, α > 1 , β > 1 , 1 < p < q < α +β < p∗ ...

We apply iterative resolution estimation to least-squares Kirchhoff migration. Resolution plots reveal low illumination areas on seismic images and provide information about image uncertainties.

Estimating the relative importance of vertices and edges is a fundamental issue in the analysis of complex networks, and has found vast applications in various aspects, such as social networks, power grids, and biological networks. Most previous work focuses on metrics of vertex importance and methods for identifying powerful vertices, while related work for edges is much lesser, especially for...

the k-th semi total point graph of a graph g, , ‎is a graph‎ obtained from g by adding k vertices corresponding to each edge and‎ connecting them to the endpoints of edge considered‎. ‎in this paper‎, a formula for laplacian polynomial of in terms of‎ characteristic and laplacian polynomials of g is computed‎, ‎where is a connected regular graph‎.the kirchhoff index of is also computed‎.

We analyze the singular spectrum of selfadjoint operators which arise from pasting a finite number of boundary relations with a standard interface condition. A model example for this situation is a Schrödinger operator on a star-shaped graph with continuity and Kirchhoff conditions at the interior vertex. We compute the multiplicity of the singular spectrum in terms of the spectral measures of ...

Let G be a connected graph of order n with Laplacian eigenvalues μ1 ≥ μ2 ≥ . . .≥ μn−1 > μn = 0. The Kirchhoff index of G is defined as Kf = Kf(G) = n∑n−1 k=1 1/μk. In this paper. we give lower and upper bounds on Kf of graphs in terms on n, number of edges, maximum degree, and number of spanning trees. Moreover, we present lower and upper bounds on the Nordhaus–Gaddum-type result for the Kirch...

In this paper, we introduce a notion of generalized states from an EQ-algebra E1 to another EQ-algebra E2, which is a generalization of internal states (or state operators) on an EQ-algebra E. Also we give a type of special generalized state from an EQ-algebra E1 to E1, called generalized internal states (or GI-state). Then we give some examples and basic properties of generalized (internal) st...