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Rychlý a zaručený aposteriorní odhad chyby
Vejchodský, Tomáš
The equilibrated residual method and the method of hypercircle are popular methods for a posteriori error estimation for linear elliptic problems. Both these methods are intended to produce guaranteed upper bounds of the energy norm of the error, but the equilibrated residual method is guaranteed only theoretically. The disadvantage of the hypercircle method is its globality, hence slowness. The combination of these two methods leads to local, hence fast, and guaranteed a posteriori error estimator.
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A Comparison of Two Models of the Energy Market Development in Czech Republic from 2015 to 2040
Dvořáková, Jitka ; Zeman, Martin (advisor) ; Lukášová, Tereza (referee)
The bachelor thesis is focused on the prediction of the energy market in the Czech Republic between 2015 and 2040 and on the comparison of potential costs related to two models of energy portfolio management. The first model was created according to the National Energy Concept from 2014, while the other one was designed artificially to simulate usage of the renewable resources in 50% of the electric energy production. The theoretical part of the thesis discusses the recent situation of the Czech energy market, defines types of energy resources and explains terms related to the discussed topic. In the practical part, direct production costs of different kinds of power plants were computed and used to estimate economic demands of the two considered models. The efficiency of both models was compared and evaluated. The aim of the thesis was to decide, which of the two models would be more favourable for the Czech national economy. Key words: energy, energy market, direct costs, economic advantage JEL classification: Q40, Q41, Q43, Q47
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Difúze 65Zn ve dvoufázové eutektické slitině Mg - 33 wt.% Al
Čermák, Jiří ; Stloukal, Ivo
Diffusion of zinc in a two-phase eutectic alloy Mg – 33 wt.% Al and in its components, Mg – Al solid solution and in the intermetallic compound Mg17Al12, was studied. The measurement of Zn diffusion coefficient was carried out by radiotracer technique in temperature interval 498 – 848 K. Zinc is believed to simulate the migration behavior of magnesium. It was observed that the interphase boundaries do not act as short-circuit paths. The study of the stability of the eutectic structure enabled to estimate the mean specific energy of the (Mg)/ Mg17A12 phase interface.
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Clustering and regression analysis of micro panel data
Sobíšek, Lukáš ; Pecáková, Iva (advisor) ; Komárek, Arnošt (referee) ; Brabec, Marek (referee)
The main purpose of panel studies is to analyze changes in values of studied variables over time. In micro panel research, a large number of elements are periodically observed within the relatively short time period of just a few years. Moreover, the number of repeated measurements is small. This dissertation deals with contemporary approaches to the regression and the clustering analysis of micro panel data. One of the approaches to the micro panel analysis is to use multivariate statistical models originally designed for crosssectional data and modify them in order to take into account the within-subject correlation. The thesis summarizes available tools for the regression analysis of micro panel data. The known and currently used linear mixed effects models for a normally distributed dependent variable are recapitulated. Besides that, new approaches for analysis of a response variable with other than normal distribution are presented. These approaches include the generalized marginal linear model, the generalized linear mixed effects model and the Bayesian modelling approach. In addition to describing the aforementioned models, the paper also includes a brief overview of their implementation in the R software. The difficulty with the regression models adjusted for micro panel data is the ambiguity of their parameters estimation. This thesis proposes a way to improve the estimations through the cluster analysis. For this reason, the thesis also contains a description of methods of the cluster analysis of micro panel data. Because supply of the methods is limited, the main goal of this paper is to devise its own two-step approach for clustering micro panel data. In the first step, the panel data are transformed into a static form using a set of proposed characteristics of dynamics. These characteristics represent different features of time course of the observed variables. In the second step, the elements are clustered by conventional spatial clustering techniques (agglomerative clustering and the C-means partitioning). The clustering is based on a dissimilarity matrix of the values of clustering variables calculated in the first step. Another goal of this paper is to find out whether the suggested procedure leads to an improvement in quality of the regression models for this type of data. By means of a simulation study, the procedure drafted herein is compared to the procedure applied in the kml package of the R software, as well as to the clustering characteristics proposed by Urso (2004). The simulation study demonstrated better results of the proposed combination of clustering variables as compared to the other combinations currently used. A corresponding script written in the R-language represents another benefit of this paper. It is available on the attached CD and it can be used for analyses of readers own micro panel data.
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Development of algorithms state estimation of experimental vehicle
Lamberský, Vojtěch ; Krejsa, Jiří (referee) ; Grepl, Robert (advisor)
This thesis deals with the filter algorithm design, implementing mathematical model to improve algorithm performance. Designed algorithms are implemented in a control unit of the experimental vehicle (filters signal used in the closed-loop controller). The improvement of the position estimation using Kalman Filter is demonstrated on the experimental vehicle. In the next part the design process of algorithm developing for dsPIC microcontroller using Matlab is described.
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Total daily energy expenditure of women in different trimesters of pregnancy
Malíková, Petra ; Hronek, Miloslav (advisor) ; Kudláčková, Zděnka (referee)
Background: Total daily energy expenditure of Czech women in particular trimesters of pregnancy is a lowly explored part of energy metabolism. Objective: The purpose of our study was to estimate total daily energy expenditure and basal metabolic rate in particular trimesters of pregnant women in the Czech Republic and to compare our values with these presented in foreign literature. Design: The study was based on 409 assessments. The base was created by questionnaires where women described all of their activities of a certain day. Women also gave details of an exact time of duration for each activity. For matematical assessmetns there were used a specially designed program Energy expenditure 2 and a statistic program GraphPad Prism 4. As the value of basal metabolic rate were considerated values obtained according to Harrise-Benedict equation and consequently modified by multiplication factors (1,035 for the first trimester, 1,062 for the second trimester and 1,177 for the third trimester). These factors were obtained from clinical assessment of basal metabolic rate in Teaching hospital in Hradec Králové. The same factors were used for estimating of total daily energy expenditure. In our study there are described also other energy characteristics - activity energy expenditure, psysical activity...
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Effect of snowpack on runoff generation during rain on snow event.
Juras, Roman ; Máca, Petr (advisor) ; Ladislav , Ladislav (referee)
During a winter season, when snow covers the watershed, the frequency of rain-on-snow (ROS) events is still raising. ROS can cause severe natural hazards like floods or wet avalanches. Prediction of ROS effects is linked to better understanding of snowpack runoff dynamics and its composition. Deploying rainfall simulation together with hydrological tracers was tested as a convenient tool for this purpose. Overall 18 sprinkling experiments were conducted on snow featuring different initial conditions in mountainous regions over middle and western Europe.
Dye tracer brilliant blue (FCF) was used for flow regime determination, because it enables to visualise preferential paths and layers interface. Snowpack runoff composition was assessed by hydrograph separation method, which provided appropriate results with acceptable uncertainty. It was not possible to use concurrently these two techniques because of technical reasons, however it would extend our gained knowledge. Snowmelt water amount in the snowpack runoff was estimated by energy balance (EB) equation, which is very efficient but quality inputs demanding. This was also the reason, why EB was deployed within only single experiment.
Timing of snowpack runoff onset decrease mainly with the rain intensity. Initial snowpack properties like bulk density or wetness are less important for time of runoff generation compared to the rain intensity. On the other het when same rain intensity was applied, non-ripe snowpack featuring less bulk density created runoff faster than the ripe snowpack featuring higher bulk density. Snowpack runoff magnitude mainly depends on the snowpack initial saturation. Ripe snowpack with higher saturation enabled to generate higher cumulative runoff where contributed by max 50 %. In contrary, rainwater travelled through the non-ripe snowpack relatively fast and contributed runoff by approx. 80 %.
Runoff prediction was tested by deploying Richards equation included in SNOWPACK model. The model was modified using a dual-domain approach to better simulate snowpack runoff under preferential flow conditions. Presented approach demonstrated an improvement in all simulated aspects compared to the more traditional method when only matrix flow is considered.
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Markovská lokalizace pro mobilní roboty: simulace a experiment
Krejsa, Jiří ; Věchet, S.
Summary: Localization of the robot is a task of estimating robot position in known environment from sensor observation. The paper describes basic principles of Markov localization technique, succesfully used for localization task. Method is robust against sensor errors and can deal with global uncertainty when robot position is completely unknown. Both simulation and experimental verification of method usability are included.
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