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The 2022 Election in the United States: Reliability of a Linear Regression Model
Kalina, Jan; Vidnerová, Petra; Večeř, M.
2023 - anglický
In this paper, the 2022 United States election to the House of Representatives is analyzed by means of a linear regression model. After the election process is explained, the popular vote is modeled as a response of 8 predictors (demographic characteristics) on the state-wide level. The main focus is paid to verifying the reliability of two obtained regression models, namely the full model with all predictors and the most relevant submodel found by hypothesis testing (with 4 relevant predictors). Individual topics related to assessing reliability that are used in this study include confidence intervals for predictions, multicollinearity, and also outlier detection. While the predictions in the submodel that includes only relevant predictors are very similar to those in the full model, it turns out that the submodel has better reliability properties compared to the full model, especially in terms of narrower confidence intervals for the values of the popular vote.
Klíčová slova:
elections results; electoral demography; linear regression; reliability; variability
Dokument je dostupný na externích webových stránkách.
The 2022 Election in the United States: Reliability of a Linear Regression Model
In this paper, the 2022 United States election to the House of Representatives is analyzed by means of a linear regression model. After the election process is explained, the popular vote is modeled ...
Growth of orbital resonances around a black hole surrounded by matter
Stratený, Michal; Lukes-Gerakopoulos, Georgios
2023 - anglický
This work studies the dynamics of geodesic motion within a curved spacetime around a Schwarzschild black hole, perturbed by a gravitational field of a far axisymmetric distribution of mass enclosing the system. This spacetime can serve as a versatile model for a diverse range of astrophysical scenarios and, in particular, for extreme mass ratio inspirals as in our work. We show that the system is non-integrable by employing Poincaré surface of section and rotation numbers. By utilising the rotation numbers, the widths of resonances are calculated, which are then used in establishing the relation between the underlying perturbation parameter driving the system from integrability and the quadrupole parameter characterising the perturbed metric. This relation allows us to estimate the phase shift caused by the resonance during an inspiral.
Klíčová slova:
geodesic motion; black holes; chaos
Dokument je dostupný na externích webových stránkách.
Growth of orbital resonances around a black hole surrounded by matter
This work studies the dynamics of geodesic motion within a curved spacetime around a Schwarzschild black hole, perturbed by a gravitational field of a far axisymmetric distribution of mass enclosing ...
Risk Assessment on Geodiversity Sites
Kubalíková, Lucie; Nováková, Eva; Kuda, František; Kirchner, Karel; Bajer, A.; Balková, M.
2023 - anglický
Geoconservation is an action of conserving and enhancing geological, geomorphological, hydrological and soil features and processes. Particular geoconservation measures are very often applied on the site-level to protect important geodiversity sites. Nevertheless, despite established legal protection and related geoconservation activities, threats to geodiversity sites related to the multiple use and human society demands can arise and reaching a compromise can be difficult. In this contribution, a two-level threat assessment is applied and discussed. The first level of threat assessment is based on the already used criteria within geosite/geomorphosite concept. The second level of threat assessment is represented by Risk Assessment Matrix, which may be considered a useful tool providing a complex view on the threats to geodiversity sites. The methods are applied on two different sites and their advantages and limits are discussed. Based on the assessment, specific management proposals may be implemented in order to balance conservation needs and demands resulting from human activities related to the sites.
Klíčová slova:
geoconservation; risk assessment matrix; degradation risk; geosites; geomorphosites
Dokument je dostupný na externích webových stránkách.
Risk Assessment on Geodiversity Sites
Geoconservation is an action of conserving and enhancing geological, geomorphological, hydrological and soil features and processes. Particular geoconservation measures are very often applied on the ...
Ceramic protection of anti-corrosion layers of 3-glycidyloxypropyl-triethoxysilane on steel
Pokorný, P.; Janata, Marek; Brožek, Vlastimil
2023 - anglický
There are various variations on the problem of steel reinforcement bond strength in concrete. Along with geometrical considerations, corrosion performance of steels with varying chemical compositions in interaction with variable chemical compositions of concrete are crucial. One approach is to cover steel surfaces with organosilane compounds, which increases the reinforcement resistance to corrosion in both acidic and alkaline conditions but, on the other hand, may weaken the reinforcement bond strength on concrete. The issue is resolved by intentionally forming a thin-walled, highly adhering corundum layer that is highly porous and impregnated with 3-glycidyloxypropyltriethoxysilane. This procedure also includes testing the adhesion properties between the ceramic and the metal and the cement prior to conducting a corrosion test in a chloride environment.
Klíčová slova:
ceramic protection; 3-glycidyloxypropyl-triethoxysilane; steel
Dokument je dostupný na externích webových stránkách.
Ceramic protection of anti-corrosion layers of 3-glycidyloxypropyl-triethoxysilane on steel
There are various variations on the problem of steel reinforcement bond strength in concrete. Along with geometrical considerations, corrosion performance of steels with varying chemical compositions ...
Determination of the initial stress tensor from deformation of underground opening-theoretical background and applications
Malík, Josef; Kolcun, Alexej
2023 - anglický
In this paper a method for the detection of initial stress tensor is proposed. The method is based on measuring distances between some pairs of points located on the wall of underground opening in the excavation process. This methods is based on the solution of eighteen auxiliary problems in the theory of elasticity with force boundary conditions. The optimal location of the pairs of points on the wall of underground work is studied. The pairs must be located so that the condition number of a certain matrix has the minimal value, which guarantees a reliable estimation of initial stress tensor.
Klíčová slova:
initial stress tensor; first boundary value problem of the theory of elasticity; condition number of matrices
Dokument je dostupný na externích webových stránkách.
Determination of the initial stress tensor from deformation of underground opening-theoretical background and applications
In this paper a method for the detection of initial stress tensor is proposed. The method is based on measuring distances between some pairs of points located on the wall of underground opening in the ...
Dynamics of a cantilever beam with piezoelectric sensor: Finite element modeling
Cimrman, Robert; Kolman, Radek; Musil, Ladislav; Kotek, Vojtěch; Kylar, Jaromír
2023 - anglický
An elastodynamical model of a cantilever beam coupled with a piezoelectric sensor is introduced and its discretization using the finite element method is presented. The mathematical model includes additional terms that enforce the floating potential boundary condition for keeping a constant charge on an electrode of the sensor. The behaviour of the model is illustrated using a numerical example corresponding to an experimental setup, where vibrations of the beam and the potential on the sensor are measured.
Klíčová slova:
finite element method; piezo-electricity; floating potential; dynamic simulation
Dokument je dostupný na externích webových stránkách.
Dynamics of a cantilever beam with piezoelectric sensor: Finite element modeling
An elastodynamical model of a cantilever beam coupled with a piezoelectric sensor is introduced and its discretization using the finite element method is presented. The mathematical model includes ...
Detailed Investigation of Human Galectins -1 and -3 by employing selectively deoxyfluorinated N-acetyllactosamines
Kurfiřt, Martin
2023 - anglický
This work is focused on a detailed investigation of supramolecular recognition events between human galectins -1 and -3 and monodeoxyfluorinated N-acetyllactosamine probes, which were previously prepared in our laboratory. The recognition was studied using a combination of X-ray crystallography, isothermal titration calorimetry and several advanced NMR techniques, such as 19F T2-filter, 1H–1H STD, 1H–15N CSP or 19F EXSY. These techniques provided insight into the thermodynamics and kinetics of recognition and enabled us to uncover of subtle differences between both investigated galectins. Such differences could be potentially exploited in the selective targeting of individual galectins with important implications for the galectins-focused\npharmaceutic industry.
Klíčová slova:
galectins; NMR techniques; pharmaceutic industry
Plné texty jsou dostupné v digitálním repozitáři NUŠL
Detailed Investigation of Human Galectins -1 and -3 by employing selectively deoxyfluorinated N-acetyllactosamines
This work is focused on a detailed investigation of supramolecular recognition events between human galectins -1 and -3 and monodeoxyfluorinated N-acetyllactosamine probes, which were previously ...
The electrodiffusional theory for wall shear stress measurement by a two-strip probe: a journey to near-wall region hydrodynamics
Harrandt, Václav
2023 - anglický
This contribution deals with a new theory describing mass transport in the vicinity of the measuring two-segment strip probe. Analytical formulas for the mass transfer coefficients of the front and the rear electrodes were derived. At the same time, the correctness of these formulas was confirmed by the numerical solution of the convectiondiffusion transport equation.
Klíčová slova:
transport phenomena; electrodes; wall shear stress
Plné texty jsou dostupné v digitálním repozitáři NUŠL
The electrodiffusional theory for wall shear stress measurement by a two-strip probe: a journey to near-wall region hydrodynamics
This contribution deals with a new theory describing mass transport in the vicinity of the measuring two-segment strip probe. Analytical formulas for the mass transfer coefficients of the front and ...
Direct construction of reciprocal mass matrix and higher order fininite element method
Cimrman, Robert; Kolman, Radek; González, J. A.; Park, K. C.
2023 - anglický
When solving dynamical problems of computational mechanics, such as contact-impact problems or cases involving complex structures under fast loading conditions, explicit time-stepping algorithms are usually preferred over implicit ones. The explicit schemes are normally combined with the lumped (diagonal) mass matrix so that the calculations are efficient and moreover dispersion errors in wave propagation are partially eliminated. As an alternative to lumping with advantageous properties, the reciprocal mass matrix is an inverse mass matrix that has the same sparsity structure as the original consistent mass matrix, preserves the total mass, captures well the desired frequency spectrum and leads thus to efficient and accurate calculations. In the contribution we comment on the usability of the reciprocal mass matrix in connection with higher order FEM.
Klíčová slova:
higher-order finite element method; reciprocal mass matrix; transient problems; explicit time integration; lumping process
Dokument je dostupný na externích webových stránkách.
Direct construction of reciprocal mass matrix and higher order fininite element method
When solving dynamical problems of computational mechanics, such as contact-impact problems or cases involving complex structures under fast loading conditions, explicit time-stepping algorithms are ...
Reduced basis solver for stochastic Galerkin formulation of Darcy flow with uncertain material parameters
Béreš, Michal
2023 - anglický
In this contribution, we present a solution to the stochastic Galerkin (SG) matrix equations coming from the Darcy flow problem with uncertain material coefficients in the separable form. The SG system of equations is kept in the compressed tensor form and its solution is a very challenging task. Here, we present the reduced basis (RB) method as a solver which looks for a low-rank representation of the solution. The construction of the RB consists of iterative expanding of the basis using Monte Carlo sampling. We discuss the setting of the sampling procedure and an efficient solution of multiple similar systems emerging during the sampling procedure using deflation. We conclude with a demonstration of the use of SG solution for forward uncertainty quantification.
Klíčová slova:
stochastic Galerkin method; reduced basis method; Monte Carlo method; deflated conjugate gradient method
Dokument je dostupný na externích webových stránkách.
Reduced basis solver for stochastic Galerkin formulation of Darcy flow with uncertain material parameters
In this contribution, we present a solution to the stochastic Galerkin (SG) matrix equations coming from the Darcy flow problem with uncertain material coefficients in the separable form. The SG ...
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