2025-02-09 00:17 |
A Comparison of the Use of Local and Global Soil Dataset for Hydrological Modelling
Horáček, M. ; Krpec, Petr
Soil property data represent the key input for the process of hydrological modelling. Purposive sampling of the catchment is both time and money consuming. Therefore, global or legacy data are frequently applied. The study compares the use of the SoilGrids global map and the map originating from legacy data for hydrological modelling. The research work was carried out using the SWAT model for the Olesna catchment (the area of 33 km(2)). The SoilGrids dataset generally shows the finer soil texture and the higher organic carbon content than the dataset based on local legacy data. This fact results in worse prediction of nitrate loading by the SoilGrids model.
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2025-02-09 00:17 |
Enlightening Metaphors of Artificial Intelligence
Wiedermann, Jiří
Metaphors offer a great way to understand new concepts. In this essay, we introduce several metaphors by prominent AI luminaries that have recently appeared in the media and are used to enlighten the concept of AI in general and LLMs in particular. None of these metaphors completely captures the essence of the notion at hand, but each illuminates some aspects. It is hoped that the union of all intuitions behind all these metaphors will result in an original mental image leading to a new apprehension and appreciation of the respective technologies and their potential. In the accompanying talk, we will discuss the weak and strong points of the individual metaphors.
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2025-02-09 00:17 |
VERTICAL DISTRIBUTION OF CARBONACEOUS AEROSOLS EMITTED DURING THE TRADITIONAL BURNING OF THE WITCHES
Mbengue, Saliou ; Vodička, P. ; Komínková, Kateřina ; Schwarz, J. ; Zíková, N. ; Lhotka, R. ; Windell, L.C. ; Suchánková, Lenka ; Hanuš, Vlastimil ; Vítková, Gabriela ; Prokeš, Roman ; Holubová Šmejkalová, A. ; Pokorná, P. ; Ždímal, V. ; Holoubek, Ivan
Biomass burning from wildfires, prescribed burns, agricultural fires, and domestic heating emits large amounts of carbonaceous matter, having adverse effects on air quality, human health, and climate change (Chen et al., 2017). In the Czech Republic and neighboring states (i.e., Germany), the traditional Burning of the Witches (BoW) is celebrated during the night from 30th April to 1st May by lighting bonfires made of biomass material (woodpile, dry grass, etc.). According to the Czech Fire Department, around 8,000 fire spots were reported in 2023 (Czech Fire Rescue Service, 2024), making this event the largest non-heating open-air biomass burning experiment in Central Europe. In this study, the vertical distribution of carbonaceous aerosol was investigated during the \nBoW, combining measurements at the foot and on the top of a 250 m tall tower.
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2025-02-09 00:17 |
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2025-02-09 00:17 |
The effect of meteorology and aerosol size distribution on light scattering properties at a rural background site in Central Europe
Suchánková, Lenka
Atmospheric aerosols significantly influence the radiative forcing of the Earth1. They directly impact the Earth’s climate system by scattering or absorption of incoming solar and outgoing infrared radiations and indirectly by altering the clouds properties and their lifetime2. The reasons behind the large uncertainty of aerosols in the climate modeling are not yet fully understood. Although there are studies addressing aerosol impact on local climate3–5, there has been a scarcity of long-term series measured at rural background sites. The aim of this study is to characterize the light scattering properties of aerosols at the rural background site National Atmospheric Observatory Košetice (NAOK 49°34'20.787 N, 15°4'48.155 E') in Central Europe, namely the total light scattering (σsp) and backscattering (σbsp) coefficients, the Ångstrӧmexponent(SAE),backscattering ratio (b), and asymmetry factor (g) with the special focus on the influence of meteorology and aerosol size distribution on these properties.
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2025-02-09 00:17 |
Apparent Young's modulus of human cranial cancellous bone
Votava, T. ; Marcián, P. ; Borák, L. ; Fuis, Vladimír ; Zikmund, T. ; Kaiser, J. ; Wolff, J.
This study investigates the biomechanical behavior of cancellous bone in the os occipitale through finite element modeling. Utilizing micro-computed tomography scans, 47 bone segments were analyzed, and their apparent Young's moduli of each segment were determined in three orthogonal directions. The results revealed strong directional dependencies of Young’s modulus on bone volume fractions. In contrast, nondirectional dependency exhibited a weaker correlation, indicating an orthotropic elasticity. The derived correlation equations offer an efficient means to describe cancellous bone in cranial biomechanical simulations, especially when a detailed trabecular representation is impractical.
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2025-02-09 00:17 |
Influence of Berkovich indenter tilt on the projected contact area at nanoindentation test
Kovář, J. ; Fuis, Vladimír
At the nanoindentation test, the tilt of the indenter or specimen surface can occur. This deviation influences the projected contact area, which is important for the evaluation of the Young modulus and hardness. This paper is aimed on the derivation of the analytical expressions for the projected contact area if the indenter is tilted in 3D space. Then the projected contact area is the same as the area of indenter cross-section by the plane corresponding to the specimen surface. The calculated results for tilted and ideal indenter were compared and the influence of the indenter tilt was evaluated. The cross-sections were plotted for few indenter tilts to better describe the change of the projected contact area. The results show that indenter tilt can have significant impact on the results if the indenter tilt is big enough.
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2025-02-09 00:17 |
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2025-02-09 00:17 |
Augmented M5 geometry of human vocal fold in phonatory position – pilot results
Hájek, P. ; Horáček, Jaromír ; Švec, J. G.
The presented contribution deals with a newly designed parametric planar geometry of the vocal fold – the augmented M5 model – which is fitted to a real-shaped human vocal fold. The real shape of the vocal fold during a phonatory position for 112 Hz was obtained from a plaster cast and was digitized by optical scanning. The geometry model of the vocal fold surfaces was constructed based on the data from the optical scanner and the augmented M5 model was fitted to a coronal slice of the selected vocal fold surface. The equations of the augmented M5 model are explained and its parameters, tuned to the real vocal fold geometry, are provided. The fitting is done in Python 3.8.5 using the scipy.optimize.curve fit package, which contains nonlinear least squares method. It is shown that the augmented M5 model fits the real data with coefficient R2 close to 1 and the tuned parameters are in a good agreement with the overall vocal fold dimensions and with the parameters of the original 2D M5 model.
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2025-02-01 00:00 |
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