Changes between Version 6 and Version 7 of project/project/subproj/wps51


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Timestamp:
May 18, 2022 9:20:13 AM (7 months ago)
Author:
westbrink
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  • project/project/subproj/wps51

    v6 v7  
    3434=== Progress so far:
    3535||
    36 The progress made so far includes the selection of appropriate methods and first applications.
    37 Several input parameters are varied simultaneously as part of the uncertainty analysis. Since this leads to a number of model runs which increases exponentially with the number of input parameters, it is useful to filter out those parameters that do not make a significant contribution to the uncertainty of the output. This is done using the Morris method. It requires a number of model runs that is linear in the number of inputs and is based on the idea that the difference between results with only one different input factor is a measure of how sensitive the result is to variation of that input factor.
     36The progress made so far includes the selection of appropriate methods and the finished application of the Morris-Method. In addition, initial simulations to investigate the influence of input parameter uncertainties on those of the output parameters were conducted.
     37
     38Several input parameters are varied simultaneously as part of the uncertainty analysis. Since this leads to a number of model runs that increase exponentially with the number of input parameters, it is useful to filter out those parameters that do not make a significant contribution to the uncertainty of the output. This is done using the Morris method. It requires a number of model runs that is linear in the number of inputs and is based on the idea that the difference between results with only one different input factor is a measure of how sensitive the result is to variation of that input factor.
    3839A number r of trajectories of sampling points is constructed in the parameter space, where two following points differ in only one input factor. This is used to calculate r measures for each input factor. The mean µ and the mean of the absolute measures µ* can be used to rank the input factors in order of importance for the uncertainty of the output.
    3940Additionally, the Bayesian approach will be used to estimate the allowed uncertainty in the input parameters to ensure the desired accuracy of the results.
    4041A prior probability distribution, which contains information on the input data, is updated with a so-called likelihood, the probability of obtaining a desired output with a wanted spread given some specific input. This leads to a posterior distribution that provides information about the variance of the input parameters given desired properties of the model outputs. 
    4142
    42 The Morris method was used for different setups, whereby model areas with horizontally homogeneous properties or individual obstacles were initially considered. The ‘land surface model’ and the ‘radiation model’ were used for horizontally homogeneous natural and urban surfaces, and the ‘vegetation_pars’ or ‘pavement_pars’ and the ‘soil_pars’ were varied. Using the ‘plant canopy model’, a horizontally homogeneous plant canopy was considered and the influence of its height, its LAD-profile and the canopy drag coefficient on the stationary wind profile was examined. Setups with single obstacles included a single building with varying dimensions or a single tree varying in height, crown height to width ratio, LAI, crown and trunk diameter and canopy drag coefficient.
     43The Morris method was used for different setups, whereby model areas with horizontally homogeneous properties or individual obstacles were initially considered. The ‘land surface model’ and the ‘radiation model’ were used for horizontally homogeneous natural and urban surfaces, and the ‘vegetation_pars’ or ‘pavement_pars’ and the ‘soil_pars’ were varied. Using the ‘plant canopy model’, a horizontally homogeneous plant canopy was considered and the influence of its height, its LAD-profile and the canopy drag coefficient on the stationary wind profile were examined. Setups with single obstacles included a single building with varying dimensions or a single tree varying in height, crown height to width ratio, LAI, crown and trunk diameter, and canopy drag coefficient.
    4344
    4445In addition to these simple setups, the influence of green and blue elements in an urban area should be investigated in order to be able to adjust the accuracy and effort involved in data collection in urban areas accordingly. A grid sensitivity study has already been carried out for such a setup. The simulation of diurnal cycles and the uncertainty and sensitivity analysis will follow.
     
    6970'''Lindauer:''' Dynamische Sensitivitätsanalysemethoden energetischer Wohngebäudequartierssimulationen, 2017.
    7071
    71 '''Saltelli et al.:''' Sensitivity Analysis in Praxtice, 2004.
     72'''Saltelli et al.:''' Sensitivity Analysis in Practice, 2004.
    7273
    7374'''Soong-Oh Han:''' Varianzbasierte Sensitivitätsanalyse als Beitrag zur Bewertung der Zuverlässigkeit adaptronischer Struktursysteme, 2011.
                                                                                                                                                                                                                                                                                                                                                                               
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