A sensitivity analysis of DC resistivity prospecting on finite, homogeneous blocks and columns

Geophysics ◽  
2007 ◽  
Vol 72 (6) ◽  
pp. F237-F247 ◽  
Author(s):  
Qi You Zhou
Keyword(s):  
Sensitivity Analysis ◽  
Electric Potential ◽  
Finite Size ◽  
Sensitivity Matrix ◽  
Subsurface Hydrology ◽  
Block Boundary ◽  
Scheme Design ◽  
Vertical Arrays ◽  
Analytic Expressions ◽  
Resistivity Inversion

Besides field applications to geophysical prospecting and subsurface hydrology, electrical resistivity tomography can be applied to finite-scale blocks in the laboratory to characterize the resistivity structure of the blocks and to monitor internal physical and chemical processes. This requires a fast and accurate calculation of the sensitivity matrix to perform a successful resistivity inversion for such blocks. However, the complex geometric shape and boundary and the finite size of the block limit the application of field-suitable sensitivity calculation methods to these blocks. As blocks and finite columns are often used in the laboratory experiments, this paper develops practical analytic expressions, based on the method of image charges, for the sensitivity matrix for these two types of homogenous bodies. The corresponding formulae for the electric potential distribution and theelectrode array coefficient are also presented. As a result of the theory, the effects of placing limits on the sum index in the electric-potential calculation can be analyzed, and a comparison of the theoretical and the numerically simulated electric potential is shown. The results demonstrate the correctness of the theory and indicate that even the addition of only one set of mirror current sources greatly reduces the effects of the block boundary on the electric-potential calculation. Finally, several interesting sensitivity distributions for cross-surface arrays on blocks, and for circular and vertical arrays on columns, are given. Although the formulae developed here are only valid for homogeneous blocks and columns, and an element of relatively small volume is required to permit a good approximation to the sensitivity, the theory is useful in the verification of numerically simulated results, in sensitivity-analysis for optimum probing-scheme design, and in successful resistivity inversion calculation for finite bodies.

scholarly journals 3D DC Resistivity Inversion with Topography Based on Regularized Conjugate Gradient Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jian-ke Qiang ◽  
Xue Han ◽  
Shi-kun Dai
Keyword(s):  
Conjugate Gradient Method ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Electric Potential ◽  
Weighting Function ◽  
Dc Resistivity ◽  
Sensitivity Matrix ◽  
Synthetic Model ◽  
Model Study ◽  
Resistivity Inversion

During the past decades, we observed a strong interest in 3D DC resistivity inversion and imaging with complex topography. In this paper, we implemented 3D DC resistivity inversion based on regularized conjugate gradient method with FEM. The Fréchet derivative is assembled with the electric potential in order to speed up the inversion process based on the reciprocity theorem. In this study, we also analyzed the sensitivity of the electric potential on the earth’s surface to the conductivity in each cell underground and introduced an optimized weighting function to produce new sensitivity matrix. The synthetic model study shows that this optimized weighting function is helpful to improve the resolution of deep anomaly. By incorporating topography into inversion, the artificial anomaly which is actually caused by topography can be eliminated. As a result, this algorithm potentially can be applied to process the DC resistivity data collected in mountain area. Our synthetic model study also shows that the convergence and computation speed are very stable and fast.

Study on Structure Sensitivity Analysis Using ANSYS PDS

2011 ◽  
Vol 243-249 ◽  
pp. 1830-1834
Author(s):  
Ke Ke Peng
Keyword(s):  
Sensitivity Analysis ◽  
Structure Sensitivity ◽  
Design System ◽  
Complex Structures ◽  
Probabilistic Design ◽  
Sensitivity Matrix ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Sensitive Factor ◽  
Incremental Form

As to sensitivity analysis, based on traditional sensitive factor definition and concept of reliability vector, two kinds of sensitivity problems are putted forward in this paper. And factor sensitivity matrix is defined. As far as large and complex structures are concerned, factor sensitivity matrix of incremental form is given. Furthermore, sensitivity surface is putted forward. ANSYS PDS（ANSYS Probabilistic Design System）can solve the above two kinds of sensitivity problems efficiently. The example bridge is a CFST arch bridge with 83.6 meter-span, which operated for 10 years. The analysis result shows that the definitions enhance the maneuverability of sensitivity analysis, and ANSYS PDS is practical.

scholarly journals Fully Graph Sensitivity Solution of the Switched Circuits by Two-graph

2021 ◽  
Vol 20 ◽  
pp. 252-256
Author(s):  
Bohumil Brtník
Keyword(s):  
Sensitivity Analysis ◽  
Design Variable ◽  
Electronic Circuit ◽  
Switched Capacitors ◽  
Sensitivity Matrix ◽  
Matrix Methods ◽  
Graph Method ◽  
Switched Current ◽  
General Parameter ◽  
Switched Circuits

The most general parameter of the electronic circuit is its sensitivity. Sensitivity analysis helps circuit designers to determine boundaries to predict the variations that a particular design variable will generate in a target specifications, if it differs from what is previously assumed. There are two basic methods for calculating the sensitivity: matrix methods and graph methods. The method described in this article is based on a graph, that contains separate input ad output nodes for each phase. This makes it possible to determine the transmission sensitivity even between partial switching phases. The described fully-graph method is suitable for switched current circuits and switched capacitors circuits, too

scholarly journals Steric Effects on Electroosmotic Nano-Thrusters under High Zeta Potentials

Mathematics ◽  
2021 ◽  
Vol 9 (24) ◽  
pp. 3222
Author(s):  
Jiaxuan Zheng ◽  
Siyi An ◽  
Yongjun Jian
Keyword(s):  
Electric Potential ◽  
Steric Effect ◽  
Specific Impulse ◽  
Fluid Motion ◽  
Finite Size ◽  
Numerical Algorithms ◽  
Ionic Species ◽  
Double Layers ◽  
Power Ratio ◽  
Zeta Potentials

Here, space electroosmotic thrusters in a rigid nanochannel with high wall zeta potentials are investigated numerically, for the first time, considering the effect of finite size of the ionic species. The effect, which is called a steric effect, is often neglected in research about micro/nano thrusters. However, it has vital influences on the electric potential and flow velocity in electric double layers, so that the thruster performances generated by the fluid motion are further affected. These performances, including thrust, specific impulse, thruster efficiency, and the thrust-to-power ratio, are described by using numerical algorithms, after obtaining the electric potential and velocity distributions under high wall zeta potentials ranging from −25.7 mV to −128.5 mV. As expected, the zeta potential can promote the development of thruster performances so as to satisfy the requirement of space missions. Moreover, for real situation with consideration of the steric effect, the thruster thrust and efficiency significantly decrease to 5–30 micro Newtons and 80–90%, respectively, but the thrust-to-power ratio is opposite, and expends a short specific impulse of about 50–110 s.

Sensitivity Analysis and Optimization of Undamped Rotor Critical Speeds to Supports Stiffness

2002 ◽  
Vol 124 (2) ◽  
pp. 296-301 ◽  
Author(s):  
Shyh-Chin Huang ◽  
Chin-Ann Lin
Keyword(s):  
Sensitivity Analysis ◽  
Solution Process ◽  
Optimal Solution ◽  
Frequency Equation ◽  
Sensitivity Matrix ◽  
Variable Metric ◽  
Critical Speeds ◽  
Rotor Design ◽  
Receptance Method ◽  
Variable Metric Method

This paper introduced a new approach that employed the assumed-modes method and the receptance method, to the sensitivity analysis and the optimization of rotor-bearing systems. First, the frequency equation in terms of receptances was derived. The natural frequencies and the critical speeds for a typical rotor system were then illustrated. Beginning with the receptance equation, the authors, for the first time, derived a sensitivity matrix and employed it into an optimization process. The topographical method in conjunction with the variable metric method followed for the optimal solution. In the solution process, the sensitivity matrix provided important information for search direction. Examples of critical speeds adjustment via supports change in an optimal sense were illustrated. Numerical results showed that the approach was very efficient and the solutions were very accurate. This approach, in addition, provided such valuable information as which supports dominated specific critical speeds. The developed approach proved to be very helpful to rotor engineers in both rotor modification and rotor design.

Locating Scheme Analysis for Robust Assembly and Fixture Design

1999 ◽  
Author(s):  
Rikard Söderberg ◽  
Johan S. Carlson
Keyword(s):  
Sensitivity Analysis ◽  
Monte Carlo Simulation ◽  
Control Process ◽  
Fixture Design ◽  
Variation Analysis ◽  
Scheme Design ◽  
Embodiment Design ◽  
The Matrix ◽  
Early Design Stages ◽  
Scheme Analysis

Abstract This paper highlights the importance of robust locating scheme design and proposes methods and tools for components and assembly robustness design and evaluation. The way datums and locators affect the entire variation control process, from early design stages to inspection of the final product, is discussed, and a structured work plan for incorporating robust locating scheme design into embodiment design is proposed. Methods and tools for locating scheme analysis are developed and presented Sensitivity analysis and variation analysis are exemplified and discussed using a small assembly case. A comparision of Monte Carlo simulation versus the “matrix method” is made for variation analysis.

Direct and Inverse Problems for a Fourth Order Anomalous Diffusion Model

2020 ◽  
Vol 399 ◽  
pp. 55-64
Author(s):  
Jader Lugon Junior ◽  
Luiz Bevilacqua ◽  
Antônio José da Silva Neto
Keyword(s):  
Inverse Problem ◽  
Sensitivity Analysis ◽  
Diffusion Model ◽  
Fourth Order ◽  
Anomalous Diffusion ◽  
Equation Model ◽  
Order Equation ◽  
Sigmoid Function ◽  
Sensitivity Matrix ◽  
Fractional Equations

The second order equation (also known as Fick’s equation) is derived from a classical well-known theory, but it is not enough to model all applications of interest. Recently, fractional equations and higher order equations began to receive more attention, demanding increased research efforts. They are used to simulate the diffusion process in many important applications in sciences, such as chemistry, heat and mass transfer, biology and ecology. In this work, the sensitivity analysis is performed for a recently developed anomalous diffusion model in order to evaluate the possibility of estimating a set of parameters that are part of the fourth order equation model, including the parameters representing the variation of the fraction of particles that are allowed to diffuse using a sigmoid function. Finally, after the sensitivity analysis the Inverse Problem approach is used to estimate viable parameters that are necessary for simulation in the cases considered. The differential equation was approximated using the Finite Difference Method, and that solution was implemented in the RStudio platform. The Sensitivity Matrix was calculated and the Inverse Problem was solved using the same RStudio platform, and the Simulated Annealing Method.

scholarly journals VISUALISASI POTENSIAL LISTRIK DI ANTARA DUA PLAT SEJAJAR BERHINGGA DENGAN PROGRAM KOMPUTER BERBASIS MATLAB

2018 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Eviliony Eviliony ◽  
Erwin Erwin ◽  
Antonius Surbakti
Keyword(s):  
Computer Program ◽  
Laplace Equation ◽  
Electric Potential ◽  
Input Data ◽  
Finite Size ◽  
Two Dimensional ◽  
Parallel Plates ◽  
Main Program ◽  
Contour Graph ◽  
Plate Width

The calculation of electric potential between two parallel plates with finite size is difficult work, visualization of the issue comprehensively is needed. In this paper, visualization of electric potential between two parallel plates with finite size has been done by developing a MATLAB based computer program. The electric potential was calculated by solving two dimensional Laplace equation. There are two parts of the program that have been developed, the menu program and the main program. The menu program was provided to store the input data required in the calculation. While, the main program served toperform calculations and visualization of the electric potential. The visualization of the electric potential was shown in the mesh and contour graph. The results showed that the program is applicable for various sizes of plates, and the electric potential in each position can be calculated and visualized. However, the computer programs has some limitations, such as for perfoming calculations of electric potential. For plate width ( ) of  m, distance of plates ( ) of  m, and initial potential ( )of  Volt, the electric potential in coordinate (20,0.5) is not defined (NaN).

A Sensitivity Analysis Method for Transient Stability Assessment Feature Selection

2013 ◽  
Vol 448-453 ◽  
pp. 2447-2454
Author(s):  
De Quan Yao ◽  
Shuai Zhao ◽  
Hong Jie Jia ◽  
Hao Liang
Keyword(s):  
Sensitivity Analysis ◽  
New England ◽  
Transient Stability ◽  
Test System ◽  
Impact Factors ◽  
Features Selection ◽  
Stability Assessment ◽  
Analysis Method ◽  
Sensitivity Matrix ◽  
Sensitivity Analysis Method

Input features selection is the premise of transient stability assessment base on neural network method. This paper adopts sensitivity analysis method to calculate the sensitivity-matrix of input features. And on this basis it defines important indexes and impact factors. Based on the gap information of impact factors, it selects the optimal subset of input features, which helps to decrease the redundant information and reduce the dimension of input features. This approach can improve the efficiency and accuracy of transient stability assessment effectively. The results of New England test system demonstrate the validity of the approach.

The partial realization theory of finite size two-dimensional arrays

1981 ◽  
Vol 64 (10) ◽  
pp. 1-8
Author(s):  
Tsuyoshi Matsuo ◽  
Yasumichi Hasegawa ◽  
Yoshikuni Okada
Keyword(s):  
Finite Size ◽  
Two Dimensional ◽  
Realization Theory
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