02 Fakultät Bau- und Umweltingenieurwissenschaften

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Publication Type: search.filters.UBSTyp.Abschlussarbeit (Master)Subject: search.filters.subject.624

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Now showing 1 - 6 of 6
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    Automated calibration for numerical models of riverflow
    (2016) Fernández, Betsaida
    Calibration of numerical models is fundamental since the beginning of all types of hydro system modeling, to approximate the parameters that can mimic the overall system behavior. Thus, an assessment of different deterministic and stochastic optimization methods is undertaken to compare their robustness, computational feasibility, and global search capacity. Also, the uncertainty of the most suitable methods is analyzed. These optimization methods minimize the objective function that comprises synthetic measurements and simulated data. Synthetic measurement data replace the observed data set to guarantee an existing parameter solution. The input data for the objective function derivate from a hydro-morphological dynamics numerical model which represents an 180-degree bend channel. The hydro- morphological numerical model shows a high level of ill-posedness in the mathematical problem. The minimization of the objective function by different candidate methods for optimization indicates a failure in some of the gradient-based methods as Newton Conjugated and BFGS. Others reveal partial convergence, such as Nelder-Mead, Polak und Ribieri, L-BFGS-B, Truncated Newton Conjugated, and Trust-Region Newton Conjugated Gradient. Further ones indicate parameter solutions that range outside the physical limits, such as Levenberg-Marquardt and LeastSquareRoot. Moreover, there is a significant computational demand for genetic optimization methods, such as Differential Evolution and Basin-Hopping, as well as for Brute Force methods. The Deterministic Sequential Least Square Programming and the scholastic Bayes Inference theory methods present the optimal optimization results.
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    Green infrastructure planning in developing countries; developing green concept in Kurdistan region-Iraq
    (2011) Mohamed, Sawsan
    Under the shadow of ‘Climate Change’ and ‘Global Warming’ effects and within the arising interest to sustainable development, this document presents the long-term framework for sustainable development, protecting the natural and historic environment and adapting cities to climate change through Green Infrastructure Planning (GIP). At the national level, the effect of climate change is overheating, with a more frequent sand storm, and major problem of water sacristy and drought. The Case Study Area is particularly vulnerable to, temperature increase, flooding, and to some extent drought conditions. Policies cover climate change mitigation and adaptation are various, starting from natural resource management, economic development, transportation plan, Green Infrastructure plan up to change of individual behaviour regarding energy consumption. In the course of the thesis framework, Climate Change adaptation is limited to Green Infrastructure application as an integral and important practice of the development process. Green Infrastructure Planning approach is an integration of planning at a different spatial level, so mainly two different special levels define the working environment, namely regional and metropolitan level. Also, Green Infrastructure provides a variety of ecosystem benefits. In the course of this study, the focus is on a certain function related to climatic, engineering and ecological benefits that will be used as the basic principal in developing the Green Infrastructure Plan at both Regional and City scale. The proposed GI Plan for Case Study Region (CSR) is an academic initiative at Regional level to identify and safeguard valued natural and cultural resources. The plan aims to bring together the region’s most important biodiversity areas, historical sites, and natural landscape including natural systems such as streams, Karez, watersheds, scenic landscape, and recreational site and to lesser extent working landscapes. In a dense conurbation like the Case Study City (CSC) where green spaces have to be multi-functional, the green infrastructure refers to the network of all green spaces that provides various benefits to the residents. Therefore the proposed GI Plan for Sulaimaniyah City (CSC) is an academic initiative at the municipal level to identify valued community green space resources. The plan aims to bring together the city most important green space resources with development of a new typology. With the provision of providing better climatic engineering function in and around the existing City, to improve the current climatic condition and as an adaptation strategy for climate change effects. So it is an initiative aiming to contribute to change the traditional conceptual understanding of green resource from something good to have, to an essential multifunctional resource that must be planned and developed in an integrated way.
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    Development of updated AWARE characterization factors for water scarcity footprinting using and comparing different hydrological datasets
    (2022) Seitfudem, Georg
    The Available WAter REmaining (AWARE) method is a widely accepted tool for assessing the impact of water consumption on other water users in the context of Life Cycle Assessment (LCA). It is based on the evaluation of runoff data obtained via global hydrological models. In preparation for a future revision, this thesis collects suggestions for further development of the calculation of AWARE characterization factors (CFs). The emphasis is on (i) increased precision of area values, (ii) the exclusion of irrelevant watersheds, and (iii) the calculation of the Environmental Water Requirements (EWRs) from the discharge input data. While the watershed exclusion has no effect on the remaining watersheds, the other modifications result in varying degrees of change in the CFs depending on the sensitivity of the watershed under consideration. The second part of this paper examines CFs calculated from different climate data inputs to hydrologic modeling. Observation-based climate data leads to less similar CFs than simulation-based data. The uncertainty in the observation-based climate data probably must be attributed to the simulation-based data, too, due to the strong link to the bias correction. Therefore, the uncertainty regarding observational data presumably contributes significantly to the overall uncertainty of the simulation-based data, and the selection of the bias-correction dataset could be more influential to the AWARE CFs than the selection of individual climate simulations.
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    Assessment of selected micropollutants and the effect of rain events in wastewater treatment plant and its receiving water body
    (2017) Riyahi, Amir
    Frequent detection of micropollutants in municipal wastewater raise the concern of these non-regulated pollutants and their adverse effects on aquatic life. The lack of comprehensive investigation and regulations in water policies regarded to micropollutants behavior may lead to the contamination of water resources. In contemplation of extending the groundwork for future water policies, an assessment of the behavior of micropollutants such as pharmaceuticals, industrial chemicals, personal care products and pesticides have been accomplished. Observation of the diurnal behavior, effect of rain events and combined sewer overflows, evaluation of comportment of conventional parameters and heavy metals with micropollutants and an estimation of average diurnal load per capita have been the objectives of this study. The influent and effluent of the wastewater treatment plant of Herbolzheim, its receiving water body and the combined sewer overflows in its catchment area have been investigated. In regard to non-polar substances, gas chromatography and mass spectrometry has been applied, whereas high performance liquid chromatography was used for polar micropollutants. Comparative demonstration of conventional parameters affirms the reliability of results to be compared with the micropollutants. Influent of Triclosan seems to follow a similar pattern as turbidity; moreover, the fluctuation of the ammonium and pharmaceuticals appears to be resemblance due to the same source of diffuse. Furthermore, the elimination percentage for different substances ranges from no degradation for substances such as Carbamazepine, to almost complete removal of 99% for the Ibuprofen. Correlation between the spectral absorption coefficient and the pharmaceuticals as well as turbidity and Triclosan seems to be strong; additionally the strength of the correlation among ammonium and the pharmaceuticals is related to the frequency of consumption of pharmaceuticals. The average effluent concentrations of this study in comparison with other studies in Europe and the state of Baden-Württemberg have been introduced. Influent load fluctuations seem to be almost constant for several substances, hence an average estimation of influent load per capita has been investigated and compared with other studies. Comportment of heavy metals and metals such as potassium and micropollutants is evident. Ultimately, the concentrations of micropollutants in combined sewer overflows in multiple cases are higher than the effluent and even of the influent of the wastewater treatment plant, which implies the necessity of the treatment before discharge into the water body. Enforcement of regulations will enhance the protection of water resources and diminish the pollutants from the diffuse sources.
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    Geklebte Verbindungen von Brettsperrholz-Platten in der Nebentragrichtung unter Verwendung von CNC/ robotisch gefrästen Anschlussleisten aus Furnierschichtholz
    (2020) Claus, Marian
    Im Zuge dieser Arbeit wird sich mit der Entwicklung einer geklebten Brettsperrholzplattenverbindung in Nebentragrichtung beschäftigt. Die Verbindung soll es ermöglichen, vorgefertigte Brettsperrholzplattenelemente baustellenseitig so miteinander zu verbinden, dass sie in Nebentragrichtung Momente übertragen können. Dies soll die Leistungsfähigkeit des verwendeten Systems steigern und dem Planer neue Möglichkeiten im Entwurf bieten. Die Verbindung wurde zunächst analytisch betrachtet und weiterentwickelt und anschließend mit der FE-Software Abaqus untersucht und optimiert. Um die Simulation zu validieren und die Verbindung in der Praxis zu testen wurde die Verbindung in Kooperation mit dem IfW hergestellt und an der MPA in Form von 4-Punkt-Biegeversuchen getestet.
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    Bayesian Model Selection for hydro-morphodynamic models
    (2017) Mohammadi, Farid
    A good grasp of hydro-morphodynamic processes plays a major role in modern river management to accommodate its often-conflicting functions. In the last century, a variety of models has been developed to improve our perception of sediment transport and the resulting changes in river bed topography, using several empirical formulations. Therefore, there is a demonstrated need to establish a framework that helps the river engineer to select the closest model to the measurements. This study suggested a Bayesian Model Selection (BMS) framework to direct the modeler towards the most robust and sensible representation of the hydro-morphodynamic conditions of the river under investigation. The proposed framework employs Bayesian Model Evidence (BME) resulting from Bayesian Model Averaging (BMA) as a model evaluation yardstick for ranking competing models. BMA performs a compromise between bias and variance, i.e. it blends a measure for goodness of fit with a penalty for unacceptable model complexity. This approach requires many model simulations, which are computationally expensive. However, this issue can be diminished by a mathematically optimal response surface via the aPC technique projects the original model. This response surface, also known as a reduced (surrogate) model can exhibit the reliance of the model on all relevant parameters for calibration at high order accuracy. The proposed framework was implemented in the model selection of two test cases; namely a test case model, based on an experiment done by Yen and Lee (1995) and a river model of a 10-km stretch of the lower Rhine, provided by the FederalWaterways Research Institute (BAW) in Karlsruhe. The results demonstrated that the proposed framework was acceptably able to detect the most desirable model in which a good agreement existed between the simulation results and measurement data when the complete knowledge of initial parameters lacked. Further, the BMS framework could direct us to the most probable parameter regions for the task of optimization via probability density distributions of uncertain variables. Overall, this research fills a void in the literature with respect to the selection of sediment transport equation for representation of hydro-morphodynamics of natural rivers. The suggested approach provides an objective guidance in the model selection to assist even less experienced users by reducing the professional expertise required for further optimization tasks.