Selection of processing parameters for solving the 3D inverse problem of gravity exploration by the discrete Fourier transform method in GIS INTEGRO

2021 ◽  
pp. 47-52
Author(s):  
Nadezhda Pimanova ◽  
Viktor Spiridonov
Keyword(s):  
Inverse Problem ◽  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
A Priori ◽  
Processing Parameters ◽  
Effective Density ◽  
Transform Method ◽  
Optimal Values ◽  
Priori Information ◽  
Selection Of

In GIS INTEGRO, a program using the discrete Fourier transform is created to solve the 3D inverse problem of gravimetry. The result of its work is a 3D distribution of the effective density. The program allows to use an extended parametrization of the form: fα,β(r,x) = f(r,zα)|z|–β. By changing the parameters α — "depth multiplier" — and β — "exponent at z"— one can obtain various equivalent distributions of effective densities and choose the most appropriate one based on a priori information. The experience of solving the 3D inverse problem by this method with different set values of these parameters allowed us to recommend the optimal values. As a criterion for choosing a solution from a variety of possible solutions, it is proposed to use a comparison of them with the data of seismic studies of the DDS and the CCP.

Innovative Approach to Information Search by Example of a Patent Analysis of an Important Substitution Plan

2020 ◽  
pp. 143-157
Author(s):  
Maria A. Milkova
Keyword(s):  
Information Search ◽  
Topic Modeling ◽  
Cognitive Biases ◽  
A Priori ◽  
Import Substitution ◽  
Innovative Approach ◽  
Iterative Search ◽  
Comprehensive Picture ◽  
Priori Information ◽  
Selection Of

Nowadays the process of information accumulation is so rapid that the concept of the usual iterative search requires revision. Being in the world of oversaturated information in order to comprehensively cover and analyze the problem under study, it is necessary to make high demands on the search methods. An innovative approach to search should flexibly take into account the large amount of already accumulated knowledge and a priori requirements for results. The results, in turn, should immediately provide a roadmap of the direction being studied with the possibility of as much detail as possible. The approach to search based on topic modeling, the so-called topic search, allows you to take into account all these requirements and thereby streamline the nature of working with information, increase the efficiency of knowledge production, avoid cognitive biases in the perception of information, which is important both on micro and macro level. In order to demonstrate an example of applying topic search, the article considers the task of analyzing an import substitution program based on patent data. The program includes plans for 22 industries and contains more than 1,500 products and technologies for the proposed import substitution. The use of patent search based on topic modeling allows to search immediately by the blocks of a priori information – terms of industrial plans for import substitution and at the output get a selection of relevant documents for each of the industries. This approach allows not only to provide a comprehensive picture of the effectiveness of the program as a whole, but also to visually obtain more detailed information about which groups of products and technologies have been patented.

scholarly journals The Neuroelectromagnetic Inverse Problem and the Zero Dipole Localization Error

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Rolando Grave de Peralta ◽  
Olaf Hauk ◽  
Sara L. Gonzalez
Keyword(s):  
Inverse Problem ◽  
Unique Solution ◽  
A Priori ◽  
Inverse Solution ◽  
Localization Error ◽  
A Priori Information ◽  
Dipole Localization ◽  
Inverse Solutions ◽  
Priori Information ◽  
Additional Constraints

A tomography of neural sources could be constructed from EEG/MEG recordings once the neuroelectromagnetic inverse problem (NIP) is solved. Unfortunately the NIP lacks a unique solution and therefore additional constraints are needed to achieve uniqueness. Researchers are then confronted with the dilemma of choosing one solution on the basis of the advantages publicized by their authors. This study aims to help researchers to better guide their choices by clarifying what is hidden behind inverse solutions oversold by their apparently optimal properties to localize single sources. Here, we introduce an inverse solution (ANA) attaining perfect localization of single sources to illustrate how spurious sources emerge and destroy the reconstruction of simultaneously active sources. Although ANA is probably the simplest and robust alternative for data generated by a single dominant source plus noise, the main contribution of this manuscript is to show that zero localization error of single sources is a trivial and largely uninformative property unable to predict the performance of an inverse solution in presence of simultaneously active sources. We recommend as the most logical strategy for solving the NIP the incorporation of sound additional a priori information about neural generators that supplements the information contained in the data.

Generalized positivity constraint on magnetic equivalent layers

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. J99-J110
Author(s):  
André L. A. Reis ◽  
Vanderlei C. Oliveira Jr. ◽  
Valéria C. F. Barbosa
Keyword(s):  
Inverse Problem ◽  
Magnetic Moment ◽  
A Priori ◽  
Synthetic Data ◽  
Total Field ◽  
Magnetization Direction ◽  
Moment Distribution ◽  
Equivalent Sources ◽  
Priori Information ◽  
Equivalent Layer

It is known from the potential theory that a continuous and planar layer of dipoles can exactly reproduce the total-field anomaly produced by arbitrary 3D sources. We have proven the existence of an equivalent layer having an all-positive magnetic-moment distribution for the case in which the magnetization direction of this layer is the same as that of the true sources, regardless of whether the magnetization of the true sources is purely induced or not. By using this generalized positivity constraint, we have developed a new iterative method for estimating the total magnetization direction of 3D magnetic sources based on the equivalent-layer technique. Our method does not impose a priori information about the shape or the depth of the sources, does not require regularly spaced data, and presumes that the sources have a uniform magnetization direction. At each iteration, our method performs two steps. The first step solves a constrained linear inverse problem to estimate a positive magnetic-moment distribution over a discrete equivalent layer of dipoles. We consider that the equivalent sources are located on a plane and have a uniform and fixed magnetization direction. In the second step, we use the estimated magnetic-moment distribution and solve a nonlinear inverse problem for estimating a new magnetization direction for the dipoles. The algorithm stops when the equivalent layer yields a total-field anomaly that fits the observed data. Tests with synthetic data simulating different geologic scenarios show that the final estimated magnetization direction is close to the true one. We apply our method to field data from the Goiás alkaline province, over the Montes Claros complex, in the center of Brazil. The results suggest the presence of intrusions with remarkable remanent magnetization, in agreement with the current literature for this region.

ALGORITHM FOR SELECTION OF LAUNCH ELEMENTS IN THE PRESENCE OF A PRIORI INFORMATION ABOUT ITS COMPOSITION AND STRUCTURE

2018 ◽  
pp. 114-119
Author(s):  
O. I. Nemykin
Keyword(s):  
Decision Making ◽  
Loss Function ◽  
Selection Process ◽  
A Priori ◽  
Measurement Information ◽  
A Priori Information ◽  
Space Objects ◽  
Alternative Hypotheses ◽  
Priori Information ◽  
Selection Of

Traditional methods of the theory of statistical solutions are developed for cases of making single-valued two-alternative or multialternative solutions about the class of an object. Assuming the possibility of ambiguous multi-alternative (in the case of solving the problem of selection of space objects of three-alternative) decisions on the classification of of space objects at the stages of the selection process, a modification of the traditional statistical decision making algorithm is required. Such a modification of the algorithm can be carried out by appropriate selection of the loss function. In the framework of the Bayes approach, an additive loss function is proposed, the structure of which takes into account a priori information on the structure and composition of launch elements in relation to the classes «Launch vehicle» and «spacecraft». The algorithm of decision making is synthesized under the conditions of a priori certainty regarding the probabilistic description of the analyzed situation. It is shown that the problem of verifying three-alternative hypotheses can be reduced to an independent verification of three two-alternative hypotheses, which makes it possible to take particular solutions in the solution process and use a different set of the signs of selection for the formation of solutions for individual classes of space objects. The peculiarities of the implementation of the selection algorithm are discussed in the presence of a priori information and measurement information on starts of a limited volume. The synthesized Bayesian decision making algorithm has the properties necessary to solve the problem of selection of space objects at launch in real conditions in the presence of measuring information specified in the form of a training sample. Its architecture allows to form unambiguous and ambiguous decisions about each space object in the launch.

Application of discrete Fourier transform to inverse heat conduction problem regularization

2018 ◽  
Vol 28 (1) ◽  
pp. 239-253 ◽  
Author(s):  
Andrzej Frąckowiak ◽  
Michał Ciałkowski
Keyword(s):  
Inverse Problem ◽  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Heat Conduction Problem ◽  
Outer Boundary ◽  
Turbine Blades ◽  
Stable Solution ◽  
Inverse Heat Conduction Problem ◽  
Content Type ◽  
Cooling Channels

Purpose This paper aims to present the Cauchy problem for the Laplace’s equation for profiles of gas turbine blades with one and three cooling channels. The distribution of heat transfer coefficient and temperature on the outer boundary of the blade are known. On this basis, the temperature on inner surfaces of the blade (the walls of cooling channels) is determined. Design/methodology/approach Such posed inverse problem was solved using the finite element method in the domain of the discrete Fourier transform (DFT). Findings Calculations indicate that the regularization in the domain of the DFT enables obtaining a stable solution to the inverse problem. In the example under consideration, problems with reconstruction constant temperature, assumed on the outer boundary of the blade, in the vicinity of the trailing and leading edges occurred. Originality/value The application of DFT in connection with regularization is an original achievement presented in this study.

A Belief-Based Approach for Adaptive Image Processing

1997 ◽  
Vol 11 (03) ◽  
pp. 359-392 ◽  
Author(s):  
Vittorio Murino ◽  
Gian Luca Foresti ◽  
Carlo S. Regazzoni
Keyword(s):  
Image Processing ◽  
A Priori ◽  
Evaluation Criteria ◽  
Processing System ◽  
Processing Parameters ◽  
Adaptive Image Processing ◽  
Digitally Controlled ◽  
A Chain ◽  
Priori Information ◽  
Stochastic Optimization Algorithm

This paper proposes a new approach to the problem of intelligently regulating image-processing parameters of a distributed network. The proposed approach is based on two-step probabilistic process: (a) belief updating, which consists in computing a functional cost at each node of the network and, (b) belief maximization, which depends on maximizing this functional cost by using a stochastic optimization algorithm. The architecture of an image processing system, consisting of three modules connected in a chain-like structure, is presented as an example showing the capabilities of the proposed approach. Each module is provided with a priori information about the set of parameters that manage a particular data transformation, and with evaluation criteria to judge data quality and to decide on the parameters to be adjusted. Experimental results obtained by using a digitally controlled camera and lens objective, are presented to show the validity of the proposed approach.

Sign in / Sign up

Export Citation Format

Share Document