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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vodoznačení statických obrazů / Image watermarking

Štágl, Luboš January 2009 (has links)
This diploma thesis is concerned in static pictures Security problems. That means, additional informations (watermark) are embedded to the original picture in a specific way. This complex picture structure (watermark) should be unremoval by different attacks runing processes. The main goal of this diploma thesis is realize two separated methods digital data watermarking in MATLAB program. For reason of a quite large scale of different watermarking methods are chosen at this time only two of take were choosen. First of the methods is Watermark injection in the spatial domain and the second in the freuquency domain. Both methods are set up in a special way and finish goals of the process. Expected result are, that digital picture user doesn't know about the watermarking technique was aplied on this picture and the watermarking data are the most resistant as possible as can be. These attacks were simulated in Checkmark program.
2

Robustní investiční portfolia / Robust Investment Portfolios

Konfršt, Zdeněk January 2014 (has links)
Robust Investment Portfolios Zdeněk Konfršt Abstract This master's thesis pursues the construction of stable, robust and growth portfo- lios in active portfolio management. These portfolios provide limited downside risks, short-time drawdowns and substantial growth prospects. We argue that the construc- tion of such portfolios is based on security selection as well as on portfolio theory (the Mean-Variance Model, MVM). The equity based portfolios were constructed and tested on real market data from the 1995-2014 period. The tested portfolios outperformed the S&P 500 out of and within the risk-reward ratio domain. Robust portfolios build on the MVM but they are less sensitive to errors of param- eters estimation. We experimented with several robust approaches and the results confirmed that the robust portfolios were less sensitive to outliers, less volatile and more stable (robust). The bottom-up process of security selection seems time consuming and labor intensive. Therefore we proposed an alternative approach to select stocks with so- called "cluster analysis". Generally, the cluster analysis classifies similar objects (companies) into similar groups. Technical and fundamental parameters of companies provided needed classification parameters. The classification was run over companies from the German DAX...
3

Citlivostní analýza různých typů rekonstruktoru stavu / Sensitivity analysis of different forms of state observers

Kadlec, Milan January 2012 (has links)
This master thesis is focused on the sensitivity analysis of selected kinds of state reconstructors. They are realized in a general form, via direct and parallel programing. Quantity that determines the quality of sensitivity is output signal difference of the reconstructor with the general form of the system. Testing will be based on different initial state conditions and on the parameters change of the feedback A matrix due to the rested reconstructors.
4

Hledání robustních cest pro více agentů / Robust multi-agent path finding

Nekvinda, Michal January 2020 (has links)
The thesis is devoted to finding robust non-conflict paths in multi-agent path finding (MAPF). We propose several new techniques for the construction of these types of paths and describe their properties. We deal with the use of contingency planning and we create a tree plan for the agents where the specific path is chosen by the agents during the execution based on the current delay. Next we present an algorithm that increases robustness while maintaining the original length of the solution and we combine it with the previous approach. Then we will focus on the method of increasing robustness by changing the speed of agents. Finally we experimentally verify the applicability of these techniques on different types of graphs. We will show that all the proposed methods are significantly more robust than the classic solution and they also have certain advantages over previously known constructions of robust plans.
5

Zobecněné úlohy o květinářce / Generalized flower-girl problems

Piskačová, Nikola January 2020 (has links)
This thesis deals with the multi-stage stochastic programming problems. In the first part, there are introduced two-stage and multi-stage stochastic programming problems. Next, two methods how to generate scenarios are described in detail - the moment method and paths-based methods. The second chapter describes the flower-girl problem, its various formulations and other extensions using ro- bustness and endogenous randomness. The practical part follows, where several different formulations of the flower-girl problem are solved. First, the problem when the florist sells roses with an unlimited life for one week is solved. Then this problem is reformulated as a two-stage problem and the results are compared. Then a formulation with a limited rose life of 2 days is presented. The greatest attention is paid to the problem with a limited rose life of 4 days - the basic formulation of the problem and several extended formulations are solved. 1
6

Robustní lineární regrese / Robust linear regression

Rábek, Július January 2021 (has links)
Regression analysis is one of the most extensively used statistical tools applied across different fields of science, with linear regression being its most well-known method. How- ever, the traditional procedure to obtain the linear model estimates, the least squares approach, is highly sensitive to even slight departures from the assumed modelling frame- work. This is especially pronounced when atypical values occur in the observed data. This lack of stability of the least squares approach is a serious problem in applications. Thus, the focus of this thesis lies in assessing the available robust alternatives to least squares estimation, which are not so easily affected by any outlying values. First, we introduce the linear regression model theory and derive the least squares method. Then, we char- acterise different types of unusual observations and outline some fundamental robustness measures. Next, we define and examine the robust alternatives to the classical estimation in the linear regression models. Finally, we conduct a comprehensive simulation study comparing the performance of robust methods under different scenarios. 1
7

Evropské letecké uzly v kontextu sítě a její odolnosti vůči narušení / European air hubs in the context of network and its resistance against disturbances

Šulc, David January 2019 (has links)
EUROPEAN AIR HUBS IN THE CONTEXT OF NETWORK AND ITS RESISTANCE AGAINST DISTURBANCES Abstract The submitted master thesis is addressing the theme of connectivity of European Air Transport Network, its properties and resistance against negative influences based on data from flight schedules for winter season 2018. The main objective of the thesis is to analyse European Air Transport Network from the point of connectivity in order to find out the most important airport hubs according to their geographic conditions, community structure and resistance of the whole network. Used methods are based on the Graph Theory and the centrality measures as indicators of connectivity. The empiric part of the thesis is divided into three parts. The aim of the first part is to find out, what airports are the most important in the European Air Transport Network. In the second part are explored properties and structure of the network. The last part is aiming to analyse the resistance of the European Air Transport Network from the view of robustness and resilience. Among the most important air hubs in Europe belong airports, that are serving world cities and tourist attractive localities. There is a strong dominance of the Schiphol airport in Amsterdam, the El Prat airport in Barcelona and the Frankfurt Airport. The European Air...
8

Vícekriteriální a robustní zobecnění úlohy prodavače novin / Multicriteria and robust extension of news-boy problem

Šedina, Jaroslav January 2018 (has links)
This thesis studies a classic single-period stochastic optimization problem called the newsvendor problem. A news-boy must decide how many items to order un- der the random demand. The simple model is extended in the following ways: endogenous demand in the additive and multiplicative manner, objective func- tion composed of the expected value and Conditional Value at Risk (CVaR) of profit, multicriteria objective with price-dependent demand, multiproduct exten- sion under dependent and independent demands, distributional robustness. In most cases, the optimal solution is provided. The thesis concludes with the nu- merical study that compares results of two models after applying the Sample Average Approximation (SAA) method. This study is conducted on the real data. 1
9

Nástroj pro testování odolnosti webových služeb / A Tool for Robustness Testing of Web-Services

Zelinka, Tomáš January 2013 (has links)
This project deals with testing of web services. The result of this work will be a tool for load testing of web services using fault injection in their communication. The first part of the project discusses the basic aspects of testing web services. The second part of the work is more focused on testing high loads in combination with fault injection. The tool will allow automated run of the tests. The distributed model of the tool was designed to simulate real loads. In the last chapter are summarized achieved results.
10

Optimalno i suboptimalno podešavanje parametara robusnih linearnih regulatora necelog reda / Optimal and suboptimal parameter tuning of robust, linear controllers of noninteger order

Jakovljević Boris 14 July 2015 (has links)
<p>Rad je posvećen robusnom upravljanju sistemima čiji je linearni regulator i/ili dinamika necelog reda, kao i upravljačkim problemima gde regulator necelog reda u sebi poseduje i linearnu i nelinearnu dinamiku, a koji upravlja procesima čija dinamika može i linearna i nelinearna.</p> / <p>The thesys is dedicated to robust control systems problems with linear<br />controllers and/or process dynamics of noninteger order, as well as control<br />issues with combination of linear and nonlinear controllers of noninteger<br />order that control either linear or nonlinear systems.</p>

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