National Repository of Grey Literature 143 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Analysis of Network Security Alerts
Dobeš, Erik ; Žádník, Martin (referee) ; Wrona, Jan (advisor)
The goal of this work is to find groups of IP addresses in network security reports, which were detected in the same, or very similar, time interval. The work introduces an algorithm, which transforms data from security reports into time series. Between all the time series, similar pairs are searched. Subsequently, in the found pairs, we are looking for similar threesomes, in which we try to find similar foursomes, etc. The created solution successfully found 208 similar groups in the set of analyzed data, the largest of which contains 11 similar IP addresses. Based on the data found it is possible to detect machines that are part of the so-called botnet in network security reports.
Dependence of the value of the construction enterprise on the size of the equity
Bahenský, Miloš ; Kocmanová, Alena (referee) ; Špirková,, Daniela (referee) ; Korytárová, Jana (advisor)
The doctoral thesis deals with the valuer issues of business valuation with construction production in the condition of the Czech economy. The business valuation issue is, and will always be, highly relevant in a market economy environment, with regard to both methodical and practical approaches. The main aim of the doctoral thesis is to demonstrate the dependence constructing empirical regression model to determine the value of the construction enterprise by the chosen income valuation method based on the equity (book value of equity in historical costs). The first part of the doctoral thesis is a research study describing the approach of the authors to the current state of knowledge concerning the issues of business valuation, aspects of equity, using the principles of system methodology. Based on these findings, a space is defined in which it is possible to propose a solution of a partial problem in terms of selecting the enterprise value category and the associated income valuation methods suitable for extensive time-series analysis. An integral part of the doctoral thesis is the determination of the sample size of construction enterprises according to the assumptions and limitations of the chosen methodology. Empirical research for data collection is based on database. Another important part is, in the spirit of system approach principles, the choice and application of the method of system discipline for the solved problem of doctoral thesis. The result of the solution is an empirical regression model, which after subsequent validation in multiple case studies could also be recommended for wider verification in valuers practice. Part of the thesis will also include discussions in the wider context of the potential benefits of the doctoral thesis for practical, theoretical and pedagogical use.
Departure from nucleate boiling in nuclear reactors
Bednář, Michal ; Števanka, Kamil (referee) ; Foral, Štěpán (advisor)
This bachelor thesis deals with problem of boiling crisis in nuclear reactors and how this problem influences working od nuclear reactor. This thesis is focused on power water reactors, with focus on VVER 1000 reactor type, which fuel assembly is described in this thesis in more detail. In this thesis there are described terms related to boiling crisis and two-phase flow regimes. In the last part, the thesis is dedicated to the correlations for the critical condition and individual correlations are compared.
Radar antenna diagnostic module
Pacner, Petr ; Urbanec, Tomáš (referee) ; Kubíček, Michal (advisor)
Faults like open and short circuit in electrical wirings pose a significant threat on functionality of the whole application. This thesis describes conceptual design of a fault identification module for coaxial cables between transmitter and antenna in radar systems, and focuses on faults localization. The main goal is to select from existing a suitable method for such faults analysis and create a demonstration module serving as a basis for further development. This contains theory regarding basic classification of wiring faults and principles of frequently used detection methods including some of their prameters, advantages and disadvantages which altogether build a foundation for method selection. The chosen method is analyzed by simulations and further on laboratory equipment controlled by a set of computer applications. In the end the chosen method is implemented on a development kit, which is then used for measurements of wire sample.
Clustering of ECG cycles
Ředina, Richard ; Smíšek, Radovan (referee) ; Ronzhina, Marina (advisor)
The bachelor thesis explores the aplication of cluster analysis on diferent ECGs in order to create a reliable algorithm for detecting different QRS complexes. Algorithm comprises filtration, R-wave positions adjustment, model cycle creation and comparasion based on mean square error and correlation. Both, correlation and mean square error, become data for k-means clustering. The number of clusters is derived from silhouette values for diferent numbers of clusters.
Passive emitter tracking
Hrach, Jan ; Klusáček, David (advisor) ; Mareš, Martin (referee)
We have implemented a TDOA multilateration of transmitters on an unmodified rtl-sdr receiver using transmitters with known location as a timing reference. We present a brief theoretical background and describe the measurement process which includes several approaches that correct the timing and frequency errors between the receivers. Additionally, we have implemented an angle of arrival direction finder using coherent rtl-sdr.
Statistical analyzes of fires in the natural environment during the period 2008 - 2017 in the South Bohemian Region
The aim of the work was to perform a statistical analisys of fires in the declared II. the degree of fire alarm (based on selected parameters "damage", "protected value", "direct cost") and in carrying out a systematic analisys of the economic aspects of fire exits in declared II. fire alarm level. The first objective (statistical analisys) was fulfilled by the verification of partial hypotheses H21 to H24, which were created by dividing the H2 hypothesis (the division of the H2 hypothesis into partial hypotheses was generated by defining the current state of the solved problem). The second objective (systemic analisys of economic aspects) was fulfilled by the verification of the H1 hypothesis, on the basis of the algorithm of economic aspects of exits to the outdoor fires, it was possible to quantify the direct exit costs. The hypotheses and their verification were as follows: H1: On the basis of equipment, deployment of forces and means at the exit of the unit, it will be possible to develop a table algorithm for calculating the detailed price of exit costs The assumption of the hypothesis can be illustrated by the relationship for the calculation of direct costs: Xpn =((V Sv)/100) Xphm+(Sm Mth) Xphm+(Xtc Xo)Xpm H2: The selected unit exit parameters will be regression in the selected period and correlation relationship H21 Regression and correlation results can be expected by examining the amount of damage related to individual fires in the period under review, indicating a significant role of lower and medium damage (accepting the hypothesis as evidenced by the shape of the regression line) H22 Investigating the values of values saved in relation to individual fires a regression and correlation result can be expected in the period under review, indicating a significant role of the lower and middle value saved (the hypothesis is supported by the shape of the regression line) H23 Regression and correlation results can be expected by examining the amount of direct costs in relation to individual fires in the period under review, indicating a significant role for direct costs of lower and medium costs (hypothesis assumed by the shape of the regression line) H24 Due to the choice of only three parameters of the examined outdoor fires regression and correlation results between pairs of statistical traits can be expected only at the level of very weak positive or negative correlation in the monitored period (acceptance of the hypothesis is evidenced by the shape of the regression line (the hypothesis is confirmed by defining weak positive and negative correlations, often the results were close to non-correlation) The thesis has theoretical benefits (eg operability of two-dimensional regression and correlations made without scaling and scaling) and practical (defining the formula for calculating direct costs). It was also proposed to continue with follow-up research - to use homogenized sets of fires (harvesting fire, harvested field fires, fodder fires and forest fires) for research, eg on a nationwide scale.
Analysis of selected chemical parameters of Temelín Nuclear Power Plant primary circuit coolant
The aim of the thesis was to define the meaning of radiochemical processes which take place in coolant of the primary circuit of the Nuclear Power Plant; and to describe the way of measurement of chemical parameters. The second aim was to define the significance of dissolved hydrogen to compensate for corrosion-threatening corrosion-safe operation of plant and to describe the method of generating hydrogen by ammonia. The third aim was to investigate the time courses of ammonia and hydrogen concentrations within the two production units. The last aim was to investigate unilateral dependence between ammonia and hydrogen concentrations. The first two aims were met by using system analysis of coolant chemical parameters, methods of measuring them, and ongoing radiochemical processes in the coolant. Ammonia and hydrogen were selected for deeper investigation, because of the results of the analysis. H1, H2 and H3 hypotheses have been formulated to meet the other two aims. The H1 hypothesis was used to verify the empirical distribution of ammonia and hydrogen concentration measurements by non-parametric normality testing. Hypothesis H2 investigated the time dependence of ammonia and hydrogen concentrations by regression analysis. In case of verification of H3 hypothesis the method of regression and correlation dependency was used. The verifying of hypothesis has shown that the empirical distribution of the measurement of hydrogen and ammonia concentrations is more closely related to the theoretical normal distribution. Furthermore, it was verified that the linear regression function of the time dependence of ammonia and hydrogen concentration measurements is close to the parallel to the timeline during the fuel campaign. Linear regression and correlation analysis confirmed that the correlation between hydrogen and ammonia concentrations is similar on both blocks and close to strong positive correlation. Verification of required regressive and correlative bending between ammonia and generated hydrogen can be understood as a practical contribution.
Correlation of Cs - 137 content between soil and sponge Deer truffle
DŽURNÝ, Vladan
In recent years, the issue of increased contamination of Cs-137 wild boar meat has come to the fore. One of the dominant agents of this contamination is Deer truffle because of its ability to accumulate Cs-137 in large quantities. The so-called transfer factor (hereinafter referred to as "TF") allows us to assess the ability of Deer truffle to absorb Cs-137. The aim of this work is to measure TF Cs-137 in the fungus Deer truffle and compare it with TF for other fungi. In order to calculate TF, the weight activity of Cs-137 in the individual samples was determined (Deer truffle and the soil in which it was found). The Cs-137 mass activity was measured in the laboratory of the SÚJB Regional Center in České Budějovice using the HPG gamma detector and subsequently determined in the Gamwin program. A total of 6 samples from the South Bohemian Region were measured. The highest measured value of Cs-137 activity was found in Okrouhlá I (soil: 105, (Deer truffle: 2030 The largest calculated TF = 19.3 (Okrouhlá I) was compared to the TF of 26 fungal species from the selected publication. A very strong correlation was found between the amount of Cs-137 in the soil and the Deer truffle. The observed TF is significantly greater than the TF of the compared fungi. The strong correlation and significant TF value represent the potential of Deer truffle to absorb much larger amounts of Cs-137 than the fungal species compared, confirming the work hypothesis. The results of the work can help to clarify the origin of the high content of Cs-137 in the meat of wild boars and can also provide a basis for further investigation of this issue.
Central Bank Communication and Correlation between Financial Markets: Evidence from the Euro Area
Kučera, Milan ; Horváth, Roman (advisor) ; Krištoufek, Ladislav (referee)
The aim of this thesis is to assess the effect of ECB's communication on financial market co- movements between Italy, Spain, Germany and France using MGARCH family of models. Author addresses partially the potential problem of endogeneity of central bank communication by using Composite indicator of systemic stress and excess liquidity. The author estimates the impact of ECB's communication on correlations of government bond yield changes using daily data from 2008 to 2014. For this purpose author employs bivariate diagonal BEKK(1,1) and bivariate scalar BEKK(1,1) with surprises of macroeconomic announcements under control. The results are consistent and robust for all models, the results suggest that communication does not have statistically significant effect on financial market correlations in the Euro area. Furthermore, author defines delta functions which describe and quantify the immediate and full effect of explanatory variables on conditional correlations in bivariate diagonal BEKK(1,1) and bivariate scalar BEKK(1,1). To the best of author's knowledge this thesis is the only one in the literature which examines this effect of ECB's communication by MGARCH models. Keywords: Financial markets, central bank communication, correlation, MGARCH, BEKK Author's e-mail:

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