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Neural Networks for Optical Music Recognition
Vlach, Vojtěch ; Kohút, Jan (referee) ; Hradiš, Michal (advisor)
This thesis consideres the problem of optical music recognition from images to text using Artificial inteligence and neural networks. I have choosed particularly the field of printed polyphonic music (more notes and voices at the same time). The goal of this thesis is to create a model capable of recognising complex notations and its accuracy compare with previous literature and other known models. I solved the chosen problem by utilizing the Vision Transformer architecture, where I tested several network variants to find the most powerful one. And by creating a new dataset with polyphonic music. The work presents the process of creating the dataset by synthesizing images from MusicXML format using the MuseScore program. The most successful variant of the Vision Transformer architecture achieves an error rate of only 7.86 %, which is very promising for further development and utilization. The main finding is that the architecture has the potential to dominate in this field, just as it does in other areas of research, and there is a functional solution for the specific task of polyphonic music notation recognition, which has been only up for a debate until now.
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Hydrological drought in headwater areas of the Ore Mountains
Vlach, Vojtěch
Changes in the hydrological cycle are one of the expected impacts of climate change. Until recently, Central European mountain ranges have not been considered to be affected by water scarcity. Nevertheless, recent years have suggested an increasing risk of drought occurrence also in these regions, which have a major impact on the water supply to rivers that drain them. The master thesis deals with the evaluation of hydrological drought in the headwater areas of three catchments in the Ore Mountains for the period from 1967 to 2018. The main aim is to compare the of hydrological drought characteristics in the catchment areas of upper Svatava River, upper Rolava River and Načetínský brook based on available hydrological and climatic data. In connection with this, the work aims to detect the long-term trends of drought occurrence in selected basins. Furthermore, the emphasis is given on the evaluation of natural conditions, especially the historical and current land cover changes in the study catchments. The results point to a significant change in the seasonality of the occurrence of hydrological drought in the second half of the studied period, when the streamflow deficits concentrate between August and October. Furthermore, increasing trends in deficit volumes were found in the catchment areas of...
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Long-term changes in winter and spring runoff in mountain catchments in Czechia
Klinkovská, Simona ; Jeníček, Michal (advisor) ; Vlach, Vojtěch (referee)
Climate changes occurring on Earth influence most of the natural processes. This also includes snow storages which have been decreasing in many mountain regions over the last decades. Besides increasing air temperature, changes in snowfall fraction, snow storages and snowpack duration also occur. For snow dominated mountain catchments, runoff timing from snowmelt is essential. Due to air temperature increase, runoff occurs earlier. Additionally, evapotranspiration increases as well. This thesis summarizes current knowledge regarding snowpack and runoff changes in mountain catchments. It further analyzes changes in 14 Czech mountain catchments over a 50-year period (1965-2014) using a Mann-Kendall trend test which identifies trends in selected time series. The trend analysis was followed by quantification of trends using Sen's slope estimator. The results showed that the day of 50% of total annual runoff occurred earlier in all catchments. Increased winter runoff was found in the Krkonoše catchments. Significant and extensive negative trends were detected in May for most of the catchments. There were almost no significant trends detected in the Beskydy catchments. Key words: snow, snowmelt runoff, trends, climate changes
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Hydrological drought in headwater areas of the Ore Mountains
Vlach, Vojtěch ; Matoušková, Milada (advisor) ; Kliment, Zdeněk (referee)
Changes in the hydrological cycle are one of the expected impacts of climate change. Until recently, Central European mountain ranges have not been considered to be affected by water scarcity. Nevertheless, recent years have suggested an increasing risk of drought occurrence also in these regions, which have a major impact on the water supply to rivers that drain them. The master thesis deals with the evaluation of hydrological drought in the headwater areas of three catchments in the Ore Mountains for the period from 1967 to 2018. The main aim is to compare the of hydrological drought characteristics in the catchment areas of upper Svatava River, upper Rolava River and Načetínský brook based on available hydrological and climatic data. In connection with this, the work aims to detect the long-term trends of drought occurrence in selected basins. Furthermore, the emphasis is given on the evaluation of natural conditions, especially the historical and current land cover changes in the study catchments. The results point to a significant change in the seasonality of the occurrence of hydrological drought in the second half of the studied period, when the streamflow deficits concentrate between August and October. Furthermore, increasing trends in deficit volumes were found in the catchment areas of...
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Extreme hydrological events in the Rolava River basin
Vlach, Vojtěch ; Matoušková, Milada (advisor) ; Blahušiaková, Andrea (referee)
6 Abstract This bachelor thesis deals with characteristics of extreme hydrological events in the Rolava river basin, which is located in the Ore Mountains in northwestern part of Czech Republic. The main aim of this study is a comparison of hydrological extremes in headwater catchments of Rolava River and Slatinný brook using data from the experimental monitoring of Department of Physical Geography and Geoecology, Faculty of Science, Charles University in Prague and Czech Hydrometeorological Institute. The other object is a field survey of the impacts of hydrological extremes on fluvial-morphological dynamics of the streams, focused on river-bed forming processes. The opening part of this thesis deals with the physical geographical and hydrographical characteristics. The main part is devoted to the comparison of extreme events in the monitored catchments focusing on floods and drought. As a final result, it was found out that Slatinný brook has a greater tendency to extremity of peak discharges. Another part of the results is an analysis of the five-year flood seasonality change on upper course of the Rolava River in two periods 1967-1990 and 1991-2014. Key words: extreme events, flood, drought, fluvial dynamics, Rolava, Slatinný brook
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