National Repository of Grey Literature 110 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Extreme value theory
Pelinka, Adam ; Čabla, Adam (advisor) ; Gerthofer, Michal (referee)
Extreme value theory is a modern statistical method for modelling events with a very low probability. During the analysis, we deal with convergence of distribution of these extremal events to their limit distributions. These distributions are generalized extreme value distribution and generalized Pareto distribution, which estimate tails of empirical probability distribution, where extremal events occur. In the last years, extreme value theory is used in many fields of study, e.g. in estimating financial risk or in estimating size of floods. In this work, two methods of modelling extremal events are presented - block maxima method and peaks over threshold method. Both methods are used during the real data analysis of daily discharge of river Vltava and estimated models are summarized. Although both used methods give slightly different results, choice of the appropriate model is not clear.
Water management issues of Aral Sea
Chupík, Jan ; Hrkal, Zbyněk (advisor) ; Datel, Josef (referee)
In the introducion of this seminar paper author deals with former natural conditions of Aral lake. It focuses on climatic conditions, morphology, hydrology and local land use situation.Because the region of Central Asia has been historically wedged between the three empires, it is also appropriate to describe closer the historical and political development of the region. The focus of the thesis is to analyze the causes of hydrological changes, when the desertification of Aral Lake has a catastrophic impact on the ecosystem and human society in the region. The return of Aral Lake to the situation sixty years ago is, unfortunately, unrealistic, but various remedial measures are being implemented to improve the situation as much as possible. The goal is to make the most of the situation. This is also done through various international projects. Therefore, the vision of the future development of the region around Aral Lake is outlined. There are also similar cases in the world, most notably the Dead Sea. The work concluded that at least some hope for recovery unfortunately only has the northern part of Aral's lake, while the southern part is probably lost forever.
Application of UAV for mapping and assessment of flood effects
Vacková, Tereza ; Langhammer, Jakub (advisor) ; Kliment, Zdeněk (referee)
The aim of this thesis is to devise a method for objective classification of floodplain based on spatially accurate data from UAV that allows identification of the fundamental features of floodplain and channel arising from or affecting by the floods activities. Background research is focused on floodplain forming processes; types of flood on our territory and its geomorphological effects, as well as a brief description unmanned aerial vehicle and their applicability in natural science and the flood. Proposed method was carried out on the test section - a part of meander of Javoří stream in Šumava Mountain - then was tested on complex meander belt of the same stream. Proposed method is based on applicability of standard objective classification. Elementary products from photogrammetric analysis - 2D orthophoto and 3D digital surface model - are used as basic input data. Another aim of theses is to discuss applicability of this method for assessment of fluvial form, its limits and potential development. The results indicated that success of classification will increase significantly the involvement of 3D data to classification, which from standard data from the UAV, despite the lack of absence multispectral bands doing a very valuable source of information for mapping and analysis, for example, the...
UAV photogrammetry as tool for evaluation of fluvio-morphological changes of streams
Lörinc, Michal ; Langhammer, Jakub (advisor) ; Hartvich, Filip (referee)
This thesis is focused on a use of a technology that is relatively new and popular in geoscience applications, including the fluvial dynamics research. Unmanned aerial vehicles are becoming widely used in numerous geographical subdisciplines due to their capabilities and advantages of UAV imaging in comparison with other remote sensing techniques. These advantages and also limitations together with general characterization of UAVs are summarized in the secondchapter of the thesis. The following theoretical chapters deal with basics of UAV photogrammetry and also evaluate the potential of UAV imaging in fluvial geomorphology. The fifth chapter of the thesis comprises a case study that evaluates the use of an UAV equipped with a non-metric camera for fluvial environment reconstruction. Images of Javoří potok have been processed in Agisoft PhotoScan and ArcGIS to indicate geomorphological changes of the stream channel that happened during a 5 month period from November 2014 to April 2015. Keywords: UAV; photogrammetry; fluvial geomorphology; hydrology; channel
System for analysing hydrological time series
Válek, Josef ; Nečaský, Martin (advisor) ; Kopecký, Michal (referee)
The aim of this work is to design and implement system for operations with time series, in particular with hydrological time series. System is developed for Fiedler-Mágr company, which specializes mostly in manufacturing hydrological measurement devices. The core of the system is REST service written in PHP and supplemented with tools for data visualization. Implementing first stage of system for on-time warning against dangerous outflow - calculating water storage of soil profiles in Liz watershed - is a part of this work. Resulting system is operational and simply extensible for use in other similar tasks. The main function of the system is to combine more time series togeather. Powered by TCPDF (www.tcpdf.org)
Analysis and modelling the changes of water quality in the Olšava river basin.
Kaiglová, Jana
The main goal of the thesis is to create an accurate model of the current state of water quality modelling in the river basin. The basin of the Olšava River, as found in the bachelor thesis "Analysis of Water Quality in the Basin", is polluted with large concentrations of total phosphorus PTot. The master thesis analyses sources of nutrients in the basin that is mainly listed in the vulnerable areas indentified under the Nitrates Directive 91/676/EEC, on the protection of waters against pollution caused by nitrates from agricultural sources. For the water resources management and environmental policy is crucial to recognize distribution of pollution sources throughout main categories. The thesis is concerned with the seasonal variability of the average mass concentrations along the river channel. Broadly used mathematical modelling software of water quality is discussed in the sense of reliability, availability and user interface. Last but not least is a suggestion of two improvements of the water quality based on the MIKE Basin modelling software. The main aim of these proposals is to be realistic in the economical and environmental sense. Proposals consider both in point and non-point sources. Key words: Mathematical modelling, MIKE Basin, Water Quality, Water Quality models, Hydrology, Olšava
Applicability of distance data for hydromorphological assessment on the example of Elbe river
Vacková, Tereza ; Langhammer, Jakub (advisor) ; Hartvich, Filip (referee)
The aim of this thesis is to evaluate the applicability of distance data for hydromorphological assessment. Background research is focused on different types of distance data sources and selected hydromorphological methods. Applicability of distance data in hydromorphological assessment was tested on four selected sections of Elbe River, on which there was previously conducted field survey. Hydromorphological assessment was based on methodology HEM (Hydroecological monitoring). Results from the field survey were used as a reference resources for comparison with the own results achieved by the assessment with distance data using public available data sources. The results indicated that use of distance data for hydromorphological assessment can be regarded as an alternative to the field survey. At the same time the study pointed to clear limitations in assessment of some parameters, namely of river bottom, where the field survey cannot be replaced by any known distance data source. The results proved that the application of distance data can lead to the results comparable to the field survey while respecting uncertainty, given by impossibility to determine some of the parameters.
Hydrology of Amateur cave and sinking streams focused on tracer tests
Gregorová, Anita ; Bruthans, Jiří (advisor) ; Vojtěchová, Anna (referee)
This study briefly summarizes methodology of tracer studies in karst areas (the way how they were carried out and their evaluation). Second part of the study specifies geological, hydrogeological and hydrological situation of the area of interest - northern part of the Moravian Karst, surroundings of Sloup - using available literature on that topic. Description of the area was completed with field measurements done by the author. Their results can be used as a basis for possible future surveys.
Analysis and modelling the changes of water quality in the Olšava river basin.
Kaiglová, Jana ; Langhammer, Jakub (advisor) ; Kliment, Zdeněk (referee)
The main goal of the thesis is to create an accurate model of the current state of water quality modelling in the river basin. The basin of the Olšava River, as found in the bachelor thesis "Analysis of Water Quality in the Basin", is polluted with large concentrations of total phosphorus PTot. The master thesis analyses sources of nutrients in the basin that is mainly listed in the vulnerable areas indentified under the Nitrates Directive 91/676/EEC, on the protection of waters against pollution caused by nitrates from agricultural sources. For the water resources management and environmental policy is crucial to recognize distribution of pollution sources throughout main categories. The thesis is concerned with the seasonal variability of the average mass concentrations along the river channel. Broadly used mathematical modelling software of water quality is discussed in the sense of reliability, availability and user interface. Last but not least is a suggestion of two improvements of the water quality based on the MIKE Basin modelling software. The main aim of these proposals is to be realistic in the economical and environmental sense. Proposals consider both in point and non-point sources. Key words: Mathematical modelling, MIKE Basin, Water Quality, Water Quality models, Hydrology, Olšava

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