Journal ArticleDOI
Nonlinear Parameter Estimation Using Spreadsheet Software
Jon M. Wraith,Dani Or +1 more
TLDR
A brief discussion of nonlinear least-squares optimization, its application within the context of some commercial spreadsheet software packages, and some of the capabilities of this approach are illustrated using examples from the authors' respective upper division Soil Physics lecture/laboratory courses.Abstract:
Many fundamental processes in the natural and physical sciences exhibit substantial nonlinear relations among the component variables. Instructing students on how to identify parameters in models for such relations based on measured data, and providing a means to illustrate the impacts of specific components on the behavior of nonlinear relationships, is therefore a critical element of university science training. Commercially available spreadsheet software programs offer convenient and effective means for performing nonlinear parameter estimation. Among the advantages of the spreadsheet approach to nonlinear optimization and parameter estimation are its relative ease of use, general applicability, demonstration or reinforcement of least-squares principles, and the ability to interactively alter selected parameter values and immediately view the results via embedded graphics. In this paper we provide a brief discussion of nonlinear least-squares optimization, demonstrate its application within the context of some commercial spreadsheet software packages, and illustrate some of the capabilities of this approach using examples from our respective upper division Soil Physics lecture/laboratory courses. Our experiences indicate that students learn spreadsheet techniques more readily than often specialized mathematical or statistical programs, and that they provide a valuable tool in their future endeavors.read more
Citations
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Journal ArticleDOI
Frequency, electrical conductivity and temperature analysis of a low-cost capacitance soil moisture sensor
Fred Kizito,Colin S. Campbell,Gaylon S. Campbell,Douglas R. Cobos,Brody Teare,Brady P. Carter,Jan W. Hopmans +6 more
TL;DR: In this paper, the authors evaluated the ECH 2 O sensors for measurement of soil moisture content, bulk electrical conductivity (EC b ), and temperature across a range of soils, across a measurement frequency between 5 and 150MHz.
Journal ArticleDOI
Liquid Retention and Interfacial Area in Variably Saturated Porous Media: Upscaling from Single Pore to Sample Scale Model
Dani Or,Markus Tuller +1 more
TL;DR: In this article, a new model for liquid configuration in angular pore space considering both capillary and adsorptive contributions was proposed as an alternative to the conventional bundle of capillaries representation.
Journal ArticleDOI
Parameter estimation of two-fluid capillary pressure–saturation and permeability functions
TL;DR: In this article, an extension of the inverse parameter estimation method to the modified multi-step outflow method for two-fluid (air-water, air-oil and oil-water) flow systems was considered.
Journal ArticleDOI
Standardizing Characterization of Electromagnetic Water Content Sensors: Part 1. Methodology
TL;DR: In this paper, the authors developed a set of standardized performance criteria for measuring soil water content from indirect measurements (e.g., from measured travel time, capacitance, performance).
References
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Journal ArticleDOI
A closed-form equation for predicting the hydraulic conductivity of unsaturated soils
van Genuchten,M. Th. +1 more
TL;DR: Van Genuchten et al. as mentioned in this paper proposed a closed-form analytical expression for predicting the hydraulic conductivity of unsaturated soils based on the Mualem theory, which can be used to predict the unsaturated hydraulic flow and mass transport in unsaturated zone.
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Numerical Recipes, The Art of Scientific Computing
Journal ArticleDOI
The Theory of Infiltration
TL;DR: In this paper, the theory of secrecy and algebraic inference is used for detecting anomalous soil in Soil Science, and the authors propose a method to detect anomalous soils.