Helicopter-borne frequency-domain electromagnetic (HEM) surveys are used extensively for mineral and groundwater exploration and a number of environmental investigations. To have a meaningful interpretation of the measured multi- frequency HEM data, in addition to the resistivity maps which are provided in each frequency or for some particular depth levels, it is a necessity ...

This paper considers the inversion of ill-posed linear operators. To regularise the problem the solution is enforced to lie in a non-convex subset. Theoretical properties for the stable inversion are derived and an iterative algorithm akin to the projected Landweber algorithm is studied. This work extends recent progress made on the efficient inversion of finite dimensional linear systems under...

Stochastic seismic inversion is a family of inversion algorithms in which the inverse solution was carried out using geostatistical simulation. In this work, a new 3D stochastic seismic inversion was developed in the MATLAB programming software. The proposed inversion algorithm is an iterative procedure that uses the principle of cross-over genetic algorithms as the global optimization techniqu...

Most previous studies utilized a log-linear regression model to invert multi-spectral images into bathymetric data. Based on the Levenberg-Marquardt optimization algorithm, we developed an automated method for calibrating the parameters for a non-linear inversion model. Our method has been successfully applied to an IKONOS multispectral image. We compared depth data derived from our model to th...

We investigate the formal expressivity properties of linear transductions, the class of transductions generated by linear transduction grammars, linear inversion transduction grammars and preterminalized linear inversion transduction grammars. While empirical results such as those in previous work are of course an ultimate test of modeling adequacy for machine translation applications, it is eq...

Full waveform inversion (FWI) is an appealing seismic data-fitting procedure for the derivation of highresolution quantitative models of the subsurface at various scales. Full modelling and inversion of viscoelastic waves from multiple seismic sources allow for the recovering of different physical parameters, although they remain computationally challenging tasks. An efficient massively paralle...

One of the most challenging problems in electromagnetic (EM) geophysical methods is developing fast and stable methods of EM modeling and inversion for 3-D inhomo­ geneous geoelectrical structures. In this paper I present an overview of the research conducted by the Consortium for Electromagnetic Modeling and Inversion (CEMI) at the University of Utah on developing fast forward mod­ eling and i...