scholarly journals Inverse estimation of parameters for multidomain flow models in soil columns with different macropore densities

2011 ◽  
Vol 47 (4) ◽  
Author(s):  
Bhavna Arora ◽  
Binayak P. Mohanty ◽  
Jennifer T. McGuire
Keyword(s):  
Estimation Of Parameters ◽  
Soil Columns ◽  
Flow Models ◽  
Inverse Estimation

Calibration of microscopic traffic-flow models using multiple data sources

2010 ◽  
Vol 368 (1928) ◽  
pp. 4497-4517 ◽  
Author(s):  
Serge Hoogendoorn ◽  
Raymond Hoogendoorn
Keyword(s):  
Driving Simulator ◽  
Likelihood Estimation ◽  
Joint Estimation ◽  
Data Sources ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Ratio Test ◽  
Estimation Of Parameters ◽  
Flow Models ◽  
Car Following

Parameter identification of microscopic driving models is a difficult task. This is caused by the fact that parameters—such as reaction time, sensitivity to stimuli, etc.—are generally not directly observable from common traffic data, but also due to the lack of reliable statistical estimation techniques. This contribution puts forward a new approach to identifying parameters of car-following models. One of the main contributions of this article is that the proposed approach allows for joint estimation of parameters using different data sources, including prior information on parameter values (or the valid range of values). This is achieved by generalizing the maximum-likelihood estimation approach proposed by the authors in previous work. The approach allows for statistical analysis of the parameter estimates, including the standard error of the parameter estimates and the correlation of the estimates. Using the likelihood-ratio test, models of different complexity (defined by the number of model parameters) can be cross-compared. A nice property of this test is that it takes into account the number of parameters of a model as well as the performance. To illustrate the workings, the approach is applied to two car-following models using vehicle trajectories of a Dutch freeway collected from a helicopter, in combination with data collected with a driving simulator.

Inverse estimation of parameters in a soil nitrogen turnover model for a beech forest

2001 ◽  
pp. 912-913
Author(s):  
E. Priesack ◽  
S. Gayler ◽  
R. Brumme ◽  
N. Bartsch ◽  
T. Vor
Keyword(s):  
Soil Nitrogen ◽  
Beech Forest ◽  
Estimation Of Parameters ◽  
Turnover Model ◽  
Nitrogen Turnover ◽  
Inverse Estimation

Inverse Estimation of Parameters in a Nitrogen Model Using Field Data

2000 ◽  
Vol 64 (2) ◽  
pp. 533-542 ◽  
Author(s):  
Barbara Schmied ◽  
Karim Abbaspour ◽  
Rainer Schulin
Keyword(s):  
Field Data ◽  
Estimation Of Parameters ◽  
Nitrogen Model ◽  
Inverse Estimation

Avalanche Stratification - Experimental Tests of the “Metastable Wedge” and “Continuous Flow” Models

2000 ◽  
Vol 627 ◽  
Author(s):  
M. E. Swanson ◽  
M. Landreman ◽  
J. Michel ◽  
J. Kakalios
Keyword(s):  
Continuous Flow ◽  
Granular Media ◽  
Experimental Tests ◽  
Coarse Sand ◽  
Angle Of Repose ◽  
Flow Models ◽  
Maximum Angle ◽  
Stratification Effect ◽  
Upward Moving ◽  
Moving Layer

ABSTRACTWhen an initially homogeneous binary mixture of granular media such as fine and coarse sand is poured near the closed edge of a “quasi-two-dimensional” Hele-Shaw cell consisting of two vertical transparent plates held a narrow distance apart, the mixture spontaneously forms alternating segregated layers. Experimental measurements of this stratification effect are reported in order to determine which model, one which suggests that segregation only occurs when the granular material contained within a metastable heap between the critical and maximum angle of repose avalanches down the free surface, or one for which the segregation results from smaller particles becoming trapped in the top surface and being removed from the moving layer during continuous flow. The result reported here indicate that the Metastable Wedge model provides a natural explanation for the initial mixed zone which precedes the formation of the layers, while the Continuous Flow model explains the observed upward moving kink of segregated material for higher granular flux rates, and that both mechansims are necessary in order to understand the observed pairing of segregated layersfor intermediate flow rates and cell separations.

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