scholarly journals Stochastic Process-Based Inversion of Electromagnetic Data for Hydrocarbon Resistivity Estimation in Seabed Logging

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 935
Author(s):  
Muhammad Naeim Mohd Aris ◽  
Hanita Daud ◽  
Khairul Arifin Mohd Noh ◽  
Sarat Chandra Dass
Keyword(s):  
Stochastic Process ◽  
Computer Simulation ◽  
Finite Element ◽  
Confidence Interval ◽  
Loss Function ◽  
Gradient Descent ◽  
Absolute Error ◽  
Forward Modeling ◽  
Electromagnetic Data ◽  
Simulation Input

This work proposes a stochastic process-based inversion to estimate hydrocarbon resistivity based on multifrequency electromagnetic (EM) data. Currently, mesh-based algorithms are used for processing the EM responses which cause high time-consuming and unable to quantify uncertainty. Gaussian process (GP) is utilized as the alternative forward modeling approach to evaluate the EM profiles with uncertainty quantification. For the optimization, gradient descent is used to find the optimum by minimizing its loss function. The prior EM profiles are evaluated using finite element (FE) through computer simulation technology (CST) software. For validation purposes, mean squared deviation and its root between EM profiles evaluated by the GP and FE at the unobserved resistivities are computed. Time taken for the GP and CST to evaluate the EM profiles is compared, and absolute error between the estimate and its simulation input is also computed. All the resulting deviations were significantly small, and the GP took lesser time to evaluate the EM profiles compared to the software. The observational datasets also lied within the 95% confidence interval (CI) where the resistivity inputs were estimated by the proposed inversion. This indicates the stochastic process-based inversion can effectively estimate the hydrocarbon resistivity in the seabed logging.

scholarly journals Estimation of the Reliability of a Stress–Strength System from Poisson Half Logistic Distribution

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1307
Author(s):  
Isyaku Muhammad ◽  
Xingang Wang ◽  
Changyou Li ◽  
Mingming Yan ◽  
Miaoxin Chang
Keyword(s):  
Confidence Interval ◽  
Loss Function ◽  
Credible Interval ◽  
Absolute Error ◽  
Asymptotic Distributions ◽  
Logistic Distribution ◽  
Bayes Estimators ◽  
Posterior Density ◽  
Error Loss ◽  
Highest Posterior Density

This paper discussed the estimation of stress-strength reliability parameter R=P(Y<X) based on complete samples when the stress-strength are two independent Poisson half logistic random variables (PHLD). We have addressed the estimation of R in the general case and when the scale parameter is common. The classical and Bayesian estimation (BE) techniques of R are studied. The maximum likelihood estimator (MLE) and its asymptotic distributions are obtained; an approximate asymptotic confidence interval of R is computed using the asymptotic distribution. The non-parametric percentile bootstrap and student’s bootstrap confidence interval of R are discussed. The Bayes estimators of R are computed using a gamma prior and discussed under various loss functions such as the square error loss function (SEL), absolute error loss function (AEL), linear exponential error loss function (LINEX), generalized entropy error loss function (GEL) and maximum a posteriori (MAP). The Metropolis–Hastings algorithm is used to estimate the posterior distributions of the estimators of R. The highest posterior density (HPD) credible interval is constructed based on the SEL. Monte Carlo simulations are used to numerically analyze the performance of the MLE and Bayes estimators, the results were quite satisfactory based on their mean square error (MSE) and confidence interval. Finally, we used two real data studies to demonstrate the performance of the proposed estimation techniques in practice and to illustrate how PHLD is a good candidate in reliability studies.

Computer simulation of optical radiation scattering by aerosol media

2020 ◽  
Vol 86 (8) ◽  
pp. 43-48
Author(s):  
V. V. Semenov
Keyword(s):  
Finite Element Method ◽  
Computer Simulation ◽  
Finite Element ◽  
Optical Radiation ◽  
Light Transmission ◽  
Initial Conditions ◽  
Practical Significance ◽  
The Finite Element Method ◽  
Dispersed Medium ◽  
Element Method

Development of the technologies simulating optical processes in an arbitrary dispersed medium is one of the important directions in the field of optical instrumentation and can provide computer simulation of the processes instead of using expensive equipment in physical experiments. The goal of the study is simulation of scattering of optical radiation by aerosol media using the finite element method to show a practical significance of the results of virtual experiments. We used the following initial conditions of the model: radius of a spherical particle of distilled water is 1 μm, wavelength of the incident optical radiation is 0.6328 μm, air is a medium surrounding the particle. An algorithm for implementation of the model by the finite element method is proposed. A subprogram has been developed which automates a virtual experiment for a group of particles to form their random arrangement in the model and possibility of changing their geometric shape and size within predetermined intervals. Model dependences of the radiation intensity on the scattering angle for single particle and groups of particles are presented. Simulation of the light transmission through a dispersed medium provides development of a given photosensor design and determination of the minimum number of photodetectors when measuring the parameters of the medium under study via analysis of the indicatrix of scattering by a group of particles.

High-resolution electroencephalographic forward modeling in traumatic brain injury using the finite element method

2013 ◽  
Author(s):  
S.Y. Matthew Goh ◽  
Andrei Irimia ◽  
Carinna M. Torgerson ◽  
Ron Kikinis ◽  
Paul M. Vespa ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Traumatic Brain Injury ◽  
Finite Element ◽  
Brain Injury ◽  
High Resolution ◽  
Forward Modeling ◽  
The Finite Element Method ◽  
Element Method

scholarly journals Finite Element Prediction for the Internal Stresses of (Ti,Al)N Coatings

2016 ◽  
Vol 61 (1) ◽  
pp. 149-152 ◽  
Author(s):  
L.W. Żukowska ◽  
A. Śliwa ◽  
J. Mikuła ◽  
M. Bonek ◽  
W. Kwaśny ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Computer Simulation ◽  
Finite Element ◽  
Experimental Studies ◽  
Single Layer ◽  
Internal Stresses ◽  
Pvd Coatings ◽  
Properties Of Coatings ◽  
Gradient Coatings ◽  
Element Method

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.

Research on 3D Finite-element Forward Modeling for Frequency-Domain Airborne EM Using Octree mesh

2021 ◽  
Author(s):  
X. Han ◽  
C. Yin ◽  
Y. Su ◽  
B. Zhang ◽  
Y. Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Frequency Domain ◽  
Forward Modeling ◽  
3D Finite Element ◽  
Airborne Em ◽  
Octree Mesh

Computer simulation of metalforming processes (Elastic-plastic finite element analysis of forging)

1982 ◽  
Vol 4 (1) ◽  
pp. 20-25 ◽  
Author(s):  
P Hartley ◽  
C.E.N Sturgess ◽  
G.W Rowe
Keyword(s):  
Finite Element Analysis ◽  
Computer Simulation ◽  
Finite Element ◽  
Element Analysis ◽  
Elastic Plastic

Finite-element time-domain modeling of electromagnetic data in general dispersive medium using adaptive Padé series

2017 ◽  
Vol 109 ◽  
pp. 194-205 ◽  
Author(s):  
Hongzhu Cai ◽  
Xiangyun Hu ◽  
Bin Xiong ◽  
Michael S. Zhdanov
Keyword(s):  
Finite Element ◽  
Time Domain ◽  
Dispersive Medium ◽  
Domain Modeling ◽  
Electromagnetic Data ◽  
Time Domain Modeling
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