scholarly journals Least Squares Estimation of Hydraulic Conductivity From Field Data

1995 ◽  
Author(s):  
K. R. Bailey ◽  
B. G. Fitzpatrick ◽  
M. A. Jeffris
Keyword(s):  
Parameter Estimation ◽  
Hydraulic Conductivity ◽  
Least Squares ◽  
Air Force ◽  
Field Data ◽  
Flow Equation ◽  
Groundwater Model ◽  
Flow Parameters ◽  
Air Force Base

Abstract In this paper, we present some numerical results of the determination of flow parameters in a groundwater model. The data used in this parameter estimation is from the MADE experiments conducted on Columbus Air Force Base. Our results are based on least squares cost functional with a finite difference scheme used to solve the flow equation.

Powell’s method-based nonlinear least-squares data fitting for the Mittag-Leffler relaxation function

2015 ◽  
Vol 22 (5) ◽  
pp. 1058-1067
Author(s):  
Changqing Fang ◽  
Huiyu Sun ◽  
Jianping Gu
Keyword(s):  
Parameter Estimation ◽  
Least Squares ◽  
Relaxation Function ◽  
Nonlinear Least Squares ◽  
Data Fitting ◽  
Direct Search ◽  
Search Method ◽  
Direct Search Method ◽  
Viscoelastic Models

The Mittag-Leffler relaxation function, [Formula: see text], with [Formula: see text], plays an important role in the fractional viscoelastic models. The Mittag-Leffler function is an infinite series whose analytic derivatives are unexplored, thus a direct search method based on Powell’s method is introduced to solve the minimization problem of nonlinear least-squares data fitting for Mittag-Leffler relaxation function in this paper. A simple and effective method is provided for the determination of the initial values and an acceleration strategy is proposed for this direct search method. Numerical results show this direct search method is efficient in the parameter estimation of the Mittag-Leffler relaxation function. Furthermore, the acceleration strategy proves to be conducive to improving the computational efficiency of this direct search method.

scholarly journals Automatic calibration of the groundwater simulation model with high parameter dimensionality using sequential uncertainty fitting approach

2020 ◽  
Vol 20 (8) ◽  
pp. 3487-3501
Author(s):  
Fariborz Masoumi ◽  
Saeid Najjar-Ghabel ◽  
Akbar Safarzadeh ◽  
Behnam Sadaghat
Keyword(s):  
Hydraulic Conductivity ◽  
Simulation Model ◽  
Pso Algorithm ◽  
Unconfined Aquifer ◽  
Flow Equation ◽  
Specific Yield ◽  
Automatic Calibration ◽  
Groundwater Model ◽  
Total Uncertainty ◽  
Groundwater Simulation

Abstract Calibration of the groundwater simulation model is one of the main challenges in the modeling process. In addition, hydrogeological complexities and the lack of field data in terms of time and space lead to uncertainty in the model. Therefore, the present study linked the groundwater simulation model (MODFLOW) and sequential uncertainty fitting approach (SUFI-2) to the uncertainty-based automatic calibration of the Ardabil groundwater model located in northwestern Iran. Hydraulic conductivity, specific yield, recharge rate, the hydraulic conductivity of the riverbed material, and the boundary conductance of the aquifer were considered as the uncertain parameters. Furthermore, the Newton solution method for the unconfined aquifer was used for solving the groundwater flow equation. A Normalized Total Uncertainty Index was defined to evaluate the performance of the SUFI-2 algorithm. According to the MODFLOW-SUFI-2 calibration findings, 60% of observational data was bracketed by a 95% confidence interval, on average. The Ardabil groundwater model was also calibrated with the PSO algorithm. In comparison with SUFI-2, although this method resulted in good coverage of the solution, it obtained irrational values for most parameters since they only aimed to match observational and computational values. Eventually, SUFI-2 showed a small number of simulation runs compared with the PSO algorithm.

Mekanisme Dan Proteksi Jaminan Nasabah Pada Gadai Informal

Liquidity ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 103-109
Author(s):  
Yuri Nanda Larasati ◽  
Jafril Khalil
Keyword(s):  
Qualitative Research ◽  
Research Methods ◽  
Financial Services ◽  
Field Data ◽  
Qualitative Research Methods ◽  
Research Field ◽  
Consumer Society ◽  
Library Research ◽  
The Cost

Regulation of the financial services authority (OJK) No. 31/POJK.05/2016 on Venture had arranged that the financial services agency on the basis of the law of pledge is in coaching and supervision OJK. Yet the existence of laws – invitation to Governing Enterprise pawn shops causing business activities conducted by the above parties are not yet regulated. The condition is feared could cause harm to the consumer society. The purpose of this research is to know the procedures, mechanisms, protection of goods and guarantee the consumer on an informal pledge financing, methods of determination of the cost of maintenance of the goods and the goods of the execution mechanism of the pledge as well as protection for the collateral items are viewed from the side of the consumer by looking at laws-invitations and Sharia. To find out whether the pledge have gotten permission from OJK. This research uses qualitative research methods with the study of library research, field data and simulations. The approach used in this study is the empirical juridical approach. Elaboration upon the results is discussed further in this article.

THE REALIZATION OF THE ITERATIVE METHOD OF THE LEAST SQUARES FOR THE ESTIMATION OF STATIC OBJECT PARAMETERS IN MATLAB ENVIRONMENT

2017 ◽  
pp. 28-36
Author(s):  
Galina Vasil’evna Troshina ◽  
Alexander Aleksandrovich Voevoda
Keyword(s):  
Parameter Estimation ◽  
Iterative Method ◽  
Least Squares ◽  
Input Signal ◽  
Layer Structure ◽  
Estimation Procedure ◽  
Parameter Estimation Procedure ◽  
Noise Simulation ◽  
Static Object ◽  
Object Parameters

It was suggested to use the system model working in real time for an iterative method of the parameter estimation. It gives the chance to select a suitable input signal, and also to carry out the setup of the object parameters. The object modeling for a case when the system isn't affected by the measurement noises, and also for a case when an object is under the gaussian noise was executed in the MatLab environment. The superposition of two meanders with different periods and single amplitude is used as an input signal. The model represents the three-layer structure in the MatLab environment. On the most upper layer there are units corresponding to the simulation of an input signal, directly the object, the unit of the noise simulation and the unit for the parameter estimation. The second and the third layers correspond to the simulation of the iterative method of the least squares. The diagrams of the input and the output signals in the absence of noise and in the presence of noise are shown. The results of parameter estimation of a static object are given. According to the results of modeling, the algorithm works well even in the presence of significant measurement noise. To verify the correctness of the work of an algorithm the auxiliary computations have been performed and the diagrams of the gain behavior amount which is used in the parameter estimation procedure have been constructed. The entry conditions which are necessary for the work of an iterative method of the least squares are specified. The understanding of this algorithm functioning principles is a basis for its subsequent use for the parameter estimation of the multi-channel dynamic objects.

An Augmented Iteratively Re-weighted and Refined Least Squares Method for lp Minimization Problem in Inverse Modeling of Potential Field Magnetic Data

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Maysam Abedi
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Least Squares ◽  
Minimization Problem ◽  
Potential Field ◽  
Field Data ◽  
Least Squares Method ◽  
Porphyry Copper ◽  
Magnetic Data ◽  
Magnetic Field Data

The presented work examines application of an Augmented Iteratively Re-weighted and Refined Least Squares method (AIRRLS) to construct a 3D magnetic susceptibility property from potential field magnetic anomalies. This algorithm replaces an lp minimization problem by a sequence of weighted linear systems in which the retrieved magnetic susceptibility model is successively converged to an optimum solution, while the regularization parameter is the stopping iteration numbers. To avoid the natural tendency of causative magnetic sources to concentrate at shallow depth, a prior depth weighting function is incorporated in the original formulation of the objective function. The speed of lp minimization problem is increased by inserting a pre-conditioner conjugate gradient method (PCCG) to solve the central system of equation in cases of large scale magnetic field data. It is assumed that there is no remanent magnetization since this study focuses on inversion of a geological structure with low magnetic susceptibility property. The method is applied on a multi-source noise-corrupted synthetic magnetic field data to demonstrate its suitability for 3D inversion, and then is applied to a real data pertaining to a geologically plausible porphyry copper unit.  The real case study located in  Semnan province of  Iran  consists  of  an arc-shaped  porphyry  andesite  covered  by  sedimentary  units  which  may  have  potential  of  mineral  occurrences, especially  porphyry copper. It is demonstrated that such structure extends down at depth, and consequently exploratory drilling is highly recommended for acquiring more pieces of information about its potential for ore-bearing mineralization.

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