one of the main steps within the geoid computation methodology without applying the stokes formula is downward continuation of the harmonic residual observables from the surface of the earth down to the surface of the reference ellipsoid. this downward continuation is done via the abel-poisson integral and its derivatives. this integral in which the unknowns, i.e. harmonic residual potential va...

Potential field data are of great significance to the study geological characteristics. Downward continuation potential converts from a high plane low plane. Since this method is mathematically an inverse problem solution, it unstable. The Tikhonov regularization strategy effective means downward field. However, achieving high-precision requirements in stage precise geophysical exploration stil...

Internal multiples have long been recognized as a problem in seismic imaging. Some theoretical developments have been made to attenuate them, but there is no 3D theory as yet that is valid for a wide range of velocity models. The goal of this paper is to present such a theory. Through the development of this theory we show that, unless certain simplifying assumptions are made about the velocity...

the aim of this paper is to minimize output phase noise for the pure signal synthesis in the frequency synthesizers. for this purpose, first, an exact mathematical model of phase locked loop (pll) based frequency synthesizer is described and analyzed. then, an exact closed-form formula in terms of synthesizer bandwidth and total output phase noise is extracted. based on this formula, the phase ...

noise exposure is one of the main problems in petroleum industry. petroleum in dustry is a strategic industry in iran with large number of workers whom are exposed to different noise sources. identification and evaluation of this noise sources and reducing excessive noises are big issues in petroleum industry from point of occupational health. this descriptive-analytic study was performed in th...

Seismic data are commonly modeled by a high-frequency single scattering approximation. This amounts to a linearization in the medium coefficient about a smooth background. The discontinuities are contained in the medium perturbation. The wave solutions in the background medium admit a geometrical optics representation. Here we describe the wave propagation in the background medium by a one-way ...