Dispersive Rayleigh wave attenuation using inverse-dispersion method

Attenuation Correction in SPECT during Image Reconstruction using an Inverse Monte Carlo Method: A Simulation Study

Introduction: The main goal of SPECT imaging is to determine activity distribution inside the organs of the body. However, due to photon attenuation, it is almost impossible to do a quantitative study. In this paper, we suggest a mathematical relationship between activity distribution and its corresponding projections using a transfer matrix. Monte Carlo simulation was used to find a precise tr...

Inverse, Shifted Inverse, and Rayleigh Quotient Iteration as Newton's Method

Two-norm normalized inverse, shifted inverse, and Rayleigh quotient iteration are well-known algorithms for approximating an eigenvector of a symmetric matrix. In this work we establish rigorously that each one of these three algorithms can be viewed as a standard form of Newton’s method from the nonlinear programming literature, followed by the normalization. This equivalence adds considerable...

Dispersive Wave Analysis – Method and Applications

A technique for estimating the dispersion characteristics of propagating waves as measured by an array is detailed. The technique consists of bandpass filtering the data through a filterbank and then processing the filtered waveforms non-dispersively. The results can show the dispersion of the entire time series or be parsed in time to analyze the dispersion characteristics of any section of th...

Rayleigh-wave dispersion reveals crust-mantle decoupling beneath eastern Tibet

The Tibetan Plateau results from the collision of the Indian and Eurasian Plates during the Cenozoic, which produced at least 2,000 km of convergence. Its tectonics is dominated by an eastward extrusion of crustal material that has been explained by models implying either a mechanical decoupling between the crust and the lithosphere, or lithospheric deformation. Discriminating between these end...

Rayleigh Wave Dispersion Curve Inversion: Occam Versus the L1-Norm