Number of found documents: 1689
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Tourist interest in illicit zone of ice caves
Nováková, Eva; Kuda, František; Kubalíková, Lucie
2018 - English
Ledové sluje (Ice Caves) in the Podyjí National Park represents one of the most spectacular sites within the area. It consists of the large boulder field and several pseudokarst caverns on the north-western slope of the ridge that are very important from the ecological and geomorphological point of view. The access to the site is restricted for the visitors of National Park as there exists a risk of damage and disturbance of these unique phenomena; tourist can use the marked paths leading around the site, they can reach the top part of the ridge.\nCurrently, there are only several persons who have legal access to the site (employees of the National Park Administration and other researches with the permission issued by NP Administration). However, the installed sensor that counts the passages proved that the site is visited more frequently than it should be. The number of people who visit this site (situated within the first zone of National Park where there is no marked path and so the access is forbidden by decree) is quite alarming. Based on these findings, some proposals for the solution of this unfavourable situation are proposed and other possibilities how to avoid this undesirable phenomenon are discussed.\n Keywords: Podyji National Park; restricted area; passages monitoring Available in a digital repository NRGL
Tourist interest in illicit zone of ice caves

Ledové sluje (Ice Caves) in the Podyjí National Park represents one of the most spectacular sites within the area. It consists of the large boulder field and several pseudokarst caverns on the ...

Nováková, Eva; Kuda, František; Kubalíková, Lucie
Ústav geoniky, 2018

Two Algorithms for Risk-averse Reformulation of Multi-stage Stochastic Programming Problems
Šmíd, Martin; Kozmík, Václav
2018 - English
Many real-life applications lead to risk-averse multi-stage stochastic problems, therefore effective solution of these problems is of great importance. Many tools can be used to their solution (GAMS, Coin-OR, APML or, for smaller problems, Excel), it is, however, mostly up to researcher to reformulate the problem into its deterministic equivalent. Moreover, such solutions are usually one-time, not easy to modify for different applications. We overcome these problems by providing a front-end software package, written in C++, which enables to enter problem definitions in a way close to their mathematical definition. Creating of a deterministic equivalent (and its solution) is up to the computer. In particular, our code is able to solve linear multi-stage with Multi-period Mean-CVaR or Nested Mean-CVaR criteria. In the present paper, we describe the algorithms, transforming these problems into their deterministic equivalents. Keywords: Multi-stage stochastic programming; deterministic equivalent; multi-period CVaR; nested CVaR; optimization algorithm Fulltext is available at external website.
Two Algorithms for Risk-averse Reformulation of Multi-stage Stochastic Programming Problems

Many real-life applications lead to risk-averse multi-stage stochastic problems, therefore effective solution of these problems is of great importance. Many tools can be used to their solution (GAMS, ...

Šmíd, Martin; Kozmík, Václav
Ústav teorie informace a automatizace, 2018

Problem of competing risks with covariates: Application to an unemployment study
Volf, Petr
2018 - English
The study deals with the methods of statistical analysis in the situation of competing risks in the presence of regression. First, the problem of identification of marginal and joint distributions of competing random variables is recalled. The main objective is then to demonstrate that the parameters and, in particular, the correlation of competing variables, may depend on covariates. The approach is applied to solution of a real example with unemployment data. The model uses the Gauss copula and Cox’s regression model. Keywords: statistical analysis; competing risks; unemployment study Fulltext is available at external website.
Problem of competing risks with covariates: Application to an unemployment study

The study deals with the methods of statistical analysis in the situation of competing risks in the presence of regression. First, the problem of identification of marginal and joint distributions of ...

Volf, Petr
Ústav teorie informace a automatizace, 2018

Balancing Exploitation and Exploration via Fully Probabilistic Design of Decision Policies
Kárný, Miroslav; Hůla, František
2018 - English
Adaptive decision making learns an environment model serving a design of a decision policy. The policy-generated actions influence both the acquired reward and the future knowledge. The optimal policy properly balances exploitation with exploration. The inherent dimensionality\ncurse of decision making under incomplete knowledge prevents the realisation of the optimal design. Keywords: Exploitation; Exploration; Bayesian estimation; Adaptive systems; Fully probabilistic design; Kullback-Leibler divergence; Decision policy; Markov decision process Fulltext is available at external website.
Balancing Exploitation and Exploration via Fully Probabilistic Design of Decision Policies

Adaptive decision making learns an environment model serving a design of a decision policy. The policy-generated actions influence both the acquired reward and the future knowledge. The optimal policy ...

Kárný, Miroslav; Hůla, František
Ústav teorie informace a automatizace, 2018

Classification of distances in cosmology
Křížek, Michal; Mészáros, A.
2018 - English
In cosmology many different distances are defined: angular, comoving, Euclidean, Hubble, light-year, luminosity, Minkowski, parallax, proper motion, redshift, ... distance. There is not one single natural distance, since the universe is expanding, curved, and we look back in time. In this survey paper we will concentrate on geometrical interpretations of the above-mentioned distances. Keywords: standard cosmological model; cosmological principle; Friedmann equation; cosmological parameters; Einstein static universe Available in digital repository of the ASCR
Classification of distances in cosmology

In cosmology many different distances are defined: angular, comoving, Euclidean, Hubble, light-year, luminosity, Minkowski, parallax, proper motion, redshift, ... distance. There is not one single ...

Křížek, Michal; Mészáros, A.
Matematický ústav, 2018

Cultural heritage and geodiversity of landforms in the landscape of the Archdiocese of Olomouc
Kirchner, Karel; Kuda, František; Kubalíková, Lucie; Havlíček, M.; Machar, I.; Pechanec, V.
2018 - English
Within the framework of the NAKI II project – Cultural heritage of landscape of the Archdiocese of Olomouc - research, presentation and management (DGB 16P02B014), we focus on the results that will contribute to the sustainable development of regional cultural identity through applied cultural heritage research in the cultural landscape of the area of interest. As part of the material cultural heritage, we include the landforms that originated from the conscious activity of man - the anthropogenic relief forms. These landforms complement the geodiversity of the landscape and are referred to as secondary geodiversity. Therefore, their identification and interpretation will make it possible to complement and enhance the diversity of cultural heritage and to specify the development of the cultural landscape. The first results from the area of Central Moravia will be presented with the using of the historical maps, the digital model of the relief DMR5G and the field research. Keywords: cultural heritage; secondary geodiversity; Archdiocese of Olomouc Available in a digital repository NRGL
Cultural heritage and geodiversity of landforms in the landscape of the Archdiocese of Olomouc

Within the framework of the NAKI II project – Cultural heritage of landscape of the Archdiocese of Olomouc - research, presentation and management (DGB 16P02B014), we focus on the results that will ...

Kirchner, Karel; Kuda, František; Kubalíková, Lucie; Havlíček, M.; Machar, I.; Pechanec, V.
Ústav geoniky, 2018

Nonparametric Bootstrap Techniques for Implicitly Weighted Robust Estimators
Kalina, Jan
2018 - English
The paper is devoted to highly robust statistical estimators based on implicit weighting, which have a potential to find econometric applications. Two particular methods include a robust correlation coefficient based on the least weighted squares regression and the minimum weighted covariance determinant estimator, where the latter allows to estimate the mean and covariance matrix of multivariate data. New tools are proposed allowing to test hypotheses about these robust estimators or to estimate their variance. The techniques considered in the paper include resampling approaches with or without replacement, i.e. permutation tests, bootstrap variance estimation, and bootstrap confidence intervals. The performance of the newly described tools is illustrated on numerical examples. They reveal the suitability of the robust procedures also for non-contaminated data, as their confidence intervals are not much wider compared to those for standard maximum likelihood estimators. While resampling without replacement turns out to be more suitable for hypothesis testing, bootstrapping with replacement yields reliable confidence intervals but not corresponding hypothesis tests. Keywords: robust statistics; econometrics; correlation coefficient; multivariate data Fulltext is available at external website.
Nonparametric Bootstrap Techniques for Implicitly Weighted Robust Estimators

The paper is devoted to highly robust statistical estimators based on implicit weighting, which have a potential to find econometric applications. Two particular methods include a robust correlation ...

Kalina, Jan
Ústav informatiky, 2018

Dynamic Bayesian Networks for the Classification of Sleep Stages
Vomlel, Jiří; Kratochvíl, Václav
2018 - English
Human sleep is traditionally classified into five (or six) stages. The manual classification is time consuming since it requires knowledge of an extensive set of rules from manuals and experienced experts. Therefore automatic classification methods appear useful for this task. In this paper we extend the approach based on Hidden Markov Models by relating certain features not only to the current time slice but also to the previous one. Dynamic Bayesian Networks that results from this generalization are thus capable of modeling features related to state transitions. Experiments on real data revealed that in this way we are able to increase the prediction accuracy. Keywords: Dynamic Bayesian Network; Sleep Analysis Fulltext is available at external website.
Dynamic Bayesian Networks for the Classification of Sleep Stages

Human sleep is traditionally classified into five (or six) stages. The manual classification is time consuming since it requires knowledge of an extensive set of rules from manuals and experienced ...

Vomlel, Jiří; Kratochvíl, Václav
Ústav teorie informace a automatizace, 2018

Comparison of Shenoy’s Expectation Operator with Probabilistic Transforms and Perez’ Barycenter
Jiroušek, R.; Kratochvíl, Václav
2018 - English
Shenoy’s paper published in this Proceedings of WUPES 2018 introduces an operator that gives instructions how to compute an expected value in the Dempster-Shafer theory of evidence. Up to now, there was no direct way to get the expected value of a utility function in D-S theory. If eeded, one had to find a probability mass function corresponding to the considered belief function, and then - using this probability mass function - to compute the classical probabilistic expectation. In this paper, we take four different approaches to defining probabilistic representatives of a belief function and compare which one yields to the best approximations of Shenoy’s expected values of various utility functions. The achieved results support our conjecture that there does not exist a probabilistic representative of a belief function that would yield the same expectations as the Shenoy’s new operator. Keywords: expected utility; Dempster-Shafer theory; Shenoy's operator Fulltext is available at external website.
Comparison of Shenoy’s Expectation Operator with Probabilistic Transforms and Perez’ Barycenter

Shenoy’s paper published in this Proceedings of WUPES 2018 introduces an operator that gives instructions how to compute an expected value in the Dempster-Shafer theory of evidence. Up to now, there ...

Jiroušek, R.; Kratochvíl, Václav
Ústav teorie informace a automatizace, 2018

OLGA – efficient full wave code for the coupling of LH grills
Preinhaelter, Josef; Hillairet, J.; Urban, Jakub
2018 - English
The full wave code OLGA, for determining the coupling of a single row lower hybrid launcher (waveguide grills) to the plasma, is extended to handle multirow multijunction active passive structures (like the C3 and C4 launchers on TORE SUPRA) by implementing the scattering matrix formalism. The extended code is still computationally fast because of the use of (i) 2D splines of the plasma surface admittance in the accessibility region of the k-space, (ii) high order Gaussian quadrature rules for the integration of the coupling elements and (iii) utilizing the symmetries of the coupling elements in the multiperiodic structures. The extended OLGA code is benchmarked against the ALOHA-1D, ALOHA-2D and TOPLHA codes for the coupling of the C3 and C4 TORE SUPRA launchers for several plasma configurations derived from reflectometry and interferometery. Unlike nearly all codes (except the ALOHA-1D code), OLGA does not require large computational resources and can be used for everyday usage in planning experimental runs. In particular, it is shown that the OLGA code correctly handles the coupling of the C3 and C4 launchers over a very wide range of plasma densities in front of the grill. Keywords: lower hybrid waves; coupling; large multirow multijunction grills; tokamak; full-wave Fulltext is available at external website.
OLGA – efficient full wave code for the coupling of LH grills

The full wave code OLGA, for determining the coupling of a single row lower hybrid launcher (waveguide grills) to the plasma, is extended to handle multirow multijunction active passive structures ...

Preinhaelter, Josef; Hillairet, J.; Urban, Jakub
Ústav fyziky plazmatu, 2018

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