نتایج جستجو برای: inversion problems

تعداد نتایج: 625529  

2011
Yanfei Wang Y. Wang

We consider numerical solution methods for seismic impedance inversion problems in this paper. The inversion process is ill-posed. To tackle the ill-posedness of the problem and take the sparsity of the reflectivity function into consideration, an l1 norm regularization model is established. In computation, a nonmonotone gradient descent method based on Rayleigh quotient for solving the minimiz...

The aim of seismic inversion is mapping all of the subsurface structures from seismic data. Due to the band-limited nature of the seismic data, it is difficult to find a unique solution for seismic inversion. Deterministic methods of seismic inversion are based on try and error techniques and provide a smooth map of elastic properties, while stochastic methods produce high-resolution maps of el...

Journal: :SIAM Journal on Optimization 2008
Maria B. Chiarolla Ulrich G. Haussmann

Utility functions of several variables are ubiquitous in economics. Their maximization requires inversion of the gradient map. Using convex analysis tools, we provide a representation of an extension of this inverse that accounts for possible constraints. To solve economic equilibrium problems, the utility functions of the agents are frequently aggregated into a representative (agent’s) utility...

1993
Magnus Sandell Anders Grennberg

One important parameter for an ultrasonic transducer is the echo it yields from a pointlike reflector. It can be measured directly but there are however certain problems connected with this. We propose an alternative method to calculate the echo from a pointlike reflector by measuring the echoes from sliding halfplanes. Using a tomographic way of reasoning, we can calculate the point echoes fro...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان 1390

during natural gas processing, water in natural gas may cause to hydrates formation in pipelines which may lead to serious damages to process equipments. given the problems raised by present of water in natural gas, glycol solvent uses to remove water.in contact of glycol with gas always an amount of btex and voc absorb along with water, which on glycol recovery process, these substances separa...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
meisam torab mostaedi parissa khadiv parsi mohammad ali moosavian

an experimental study of the phase inversion behavior of liquid-liquid dispersion has been conducted in a spray extraction column for systems of toluene / water, n-hexane/water, ccl4/water, toluene /water + glycerol (25 % wt), toluene + ccl4 (25 % wt) / water and toluene / acetic acid (5 % wt)/water. the effects of physical properties, mass transfer and column geometry on phase inversion have b...

2000
F. Boschetti L. Moresi

Inversion algorithms employ numerical evaluation of the mismatch between model and data to guide the search for minima in parameter spaces. In an alternative approach, the numerical evaluation of data misfit can be replaced by subjective judgement of the solution quality. This widens the class of problems that can be treated within the framework of formal inverse theory, in particular including...

Journal: :Remote Sensing 2017
Raffaele Persico Giovanni Ludeno Francesco Soldovieri Alberic De Coster Sébastien Lambot

Linear inverse scattering problems can be solved by regularized inversion of a matrix, whose calculation and inversion may require significant computing resources, in particular, a significant amount of RAM memory. This effort is dependent on the extent of the investigation domain, which drives a large amount of data to be gathered and a large number of unknowns to be looked for, when this doma...

Journal: :Frontiers in Earth Science 2023

Acoustic impedance (AI) inversion is widely used in geophysics and reservoir prediction. But the traditional method cannot fully exploit sparse characteristics of geological attributes. There are problems with multiplicity low resolution. To solve this problem, a data-driven acoustic reweighted L1 norm constraints (DRL1) proposed. In process, local cross-correlation analysis introduced to above...

Journal: :IJCOPI 2012
Kusum Deep Hadush Mebrahtu Adane

In this paper a variant of partially mapped crossover (VPMX) is designed using cut point positions and is tested for its performance with the existing partially mapped crossover (PMX).In order to test the performance ,two mutation operators are used. These mutation operators are inverted displacement and inversion mutations. Partially mapped crossover (PMX) with inversion and with inverted disp...

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