the helicopter-borne electromagnetic (hem) frequency-domain exploration method is an airborne electromagnetic (aem) technique that is widely used for vast and rough areas for resistivity imaging. the vast amount of digitized data flowing from the hem method requires an efficient and accurate inversion algorithm. generally, the inverse modelling of hem data in the first step requires a precise a...

the stolt (f-k) migration algorithm is a direct (i.e. non-recursive) fourier-domain technique based on a change of variables (or equivalently, a mapping) that converts the input spectrum to the output spectrum. the algorithm is simple and efficient but limited to constant velocity. a v(z)(f-k) migration method, capable of very high accuracy for vertical variations of velocity, can be formulated...

A theoretical relation is presented between the seismological Fourier amplitude spectrumand the mean squared value of the elastic response, which is defined by Gaussian distribution. Byshifting a general process to its mean value, spectrum of the mean squared value of the displacementis computed from the Fourier amplitude spectrum and the real part of the relative displacementtransfer function ...

The frequency-dependent characteristics of microstrip planar circuits have been previously analyzed using several full-wave approaches. All those methods directly give characteristic of the circuits frequency by frequency. Computation time becomes important if these planar circuits have to be studied over a very large bandwidth. The transmission line matrix (TLM) method presented in this paper ...

purpose: comparison of the results of visual evoked potential (vep) in time domain and frequency domain between multiple sclerosis (ms) suspected patients and normal indivisuals. method: eleven ms suspected patients with normal visual findings and 20 normal individuals were tested by vep. results were compared between two groups. results: the time domain results showed no significant difference...