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Systems for checing electronic texts
Zouhar, Petr ; Malý, Jan (referee) ; Pfeifer, Václav (advisor)
The work deals with the possibility of control of electronic texts. Whether it is a source codes or standard text documents. The first chapter is devoted to a brief explanation of the term plagiarism and its characters. Sequentially we describe the methods and metrics used to detect plagiarist. Then we pay attention to detect plagiarism in the free text and source codes. We describe the way of preprocessing of a file and choice of basic units, which represent the document in the comparing. Source codes have a exact syntax. Therefore we attend to the syntax and semantic analysis in the chapter, which describes the check of source codes. The second half of the work is focused on the practical part, particularly on programs intended to control the source codes. The programs are divided to the freely available and the commercial. This is followed by their brief description and if it is a free trial possible we mention the results from this comparing. So we created a corpus of source codes. At the end of the work we focus on design of a program, which compares two source codes on the basis of statistical similarities.
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Fatigue crack front shape estimation
Zouhar, Petr ; Klusák, Jan (referee) ; Hutař, Pavel (advisor)
The presented master’s thesis deals with fatigue crack front shape estimation. The aim of this thesis is to create an iterative process leading to the real fatigue crack front shape. Thesis is solved using finite element method. The work is divided into two logical parts. The first part of the thesis describes the basic concepts of linear elastic fracture mechanic (LEFM), methods used for estimation of stress intensity factor and stress singularity exponent. The first part further describes some phenomenon’s accompanying the mechanism of fatigue crack growth as for example crack tip curving and crack closure. In the second part of the thesis there is studied an affect of the free surface on the fracture parameters, especially the affected distance from the free surface is determined. Based on the assumption of a constant stress intensity factor and stress singularity exponent along the crack front, an iterative process leading to fatigue crack front shape is presented. The accuracy of the result is discussed by comparing of obtained crack front shapes with experimental data at the end of the thesis.
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Possibilities of estimation of selected fracture parameters under conditions of LEFM
Zouhar, Petr ; Hutař, Pavel (referee) ; Ševčík, Martin (advisor)
The presented bachelor´s thesis deals with possibilities of estimation of selected fracture parameters under conditions of linear elastic fracture mechanic (LEFM). The aim of this thesis is to quantify the accuracy of specific methods for the estimation of fracture parameters from a known stress and strain field obtained using numerical methods. Thesis is solved using finite element method. The work is divided into two logical parts. The first part of the thesis describes the basic concepts of LEFM and selected methods used for estimation of fracture parameters, namely the stress intensity factor, strain energy release rate and J-integral. A detailed description of the numerical model, a sensitivity analysis of the FEM mesh density and obtained results are described in the second part, focused on the solution of the problem,. The accuracy of each method is expressed by comparing with a known reference value of stress intensity factor. The applicability of selected methods for estimation of the stress intensity factor is shown on a practical example of three-dimensional body containing a crack.
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Random number generator
Zouhar, Petr ; Martinásek, Zdeněk (referee) ; Sobotka, Jiří (advisor)
The thesis deals with issues of random numbers, their generating and use in cryptography. Introduction of work is aimed to resolution of random number generators and pseudo--random number generators. There is also included often used dividing generators on software and hardware. We mention advantages and disadvantages of each type and area of their use. Then we describe examples of random and pseudorandom numbers, mainly hardware based on physical phenomenon such as the decay of radioactive material or use atmospheric noise. The following part is devoted to suggestion own random number generator and a description of its functionality. In the second half of the work we devote to the field of cryptography. We know basic types of cryptographic systems, namely symmetric and asymmetric cryptosystems. We introduce a typical representant the various type and their properties. At the end of the work we again return to our random number generator and verify the randomness generated numbers and obtained cryptograms.
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Management of the Construction Project
Šrotová, Zuzana ; Zouhar, Petr (referee) ; Waldhans, Miloš (advisor)
This thesis describes the basic procedures of the management of a construction project. For a better understanding of the processes here explains the concepts that are contained in this work. The goal is to become familiar with the specific procedures and methods of project management during the implementation of construction projects.
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Effect of Housing Temperature on Body Composition in Laboratory Mouse
Kružíková, Nikola ; Zouhar, Petr (advisor) ; Ferenčáková, Michaela (referee)
Development of obesity and associated disorders is caused by imbalance between energy intake and energy expenditure. Significant part of energy expenditure can be represented by energy cost of maintaining stable body temperature. In this thesis, the effect of thermoneutrality and high fat feeding on body composition was characterized in female C57BL/6 mice. These mice were housed either at 22 řC (standard temperature) or at 30 řC (thermoneutrality) and fed by standard chow or high fat diet for 13 weeks. Energy intake of chow-fed thermoneutral animals was lowered in comparison to mice housed at standard temperature, reflecting lower energy cost of thermogenesis. This reduction of food intake was prevented by high fat feeding resulting in adipose tissue accumulation in particular in high fat-fed thermoneutral animals. While studying this model, protocol for assessment of body composition using newly acquired dual energy X-ray absorptiometry system was validated. Reflecting the development of obesity, glucose and lipid homeostasis was deteriorated in these mice. In line with earlier notions in literature describing male mice, our data suggest critical importance of housing temperature in efficiency of high fat feeding even in female mice. Keywords: thermoneutrality, obesity, body composition, DEXA
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Role of antioxidant defense in the synthesis of antidiabetic lipokines
Domanská, Veronika ; Kuda, Ondřej (advisor) ; Zouhar, Petr (referee) ; Vrkoslav, Vladimír (referee)
Fatty acid esters of hydroxy fatty acids (FAHFAs) are a recently discovered group of lipokines consisting of a fatty acid attached to a hydroxy fatty acid with an ester bond resulting in a diverse group of compounds with many different biological activities. Antidiabetic and anti-inflammatory activities are the most studied. The thesis aimed to study this group of bioactive lipids to elucidate the metabolism of FAHFAs and describe the role of antioxidant defense, namely peroxiredoxin 6 (Prdx6), in their biosynthesis with the help of isotopic labeling together with in vitro and in vivo experiments. All the samples, including white adipose tissue, liver, and even human breast milk, were subjected to untargeted or targeted lipidomic and metabolomics analysis using LC-MS/MS. We used the data from isotopically labeled experiments to describe the role of 5-PAHSA in glucose uptake and to show which specific pathways are stimulated by 5-PAHSA administration and which by insulin to compare the effect of both antidiabetic agents. In our samples, we analyzed TAG estolides, which function as intracellular reservoirs of FAHFAs, and managed to describe the role of specific lipases in their metabolism. We reported the role of Prdx6 and the specific enzymatic activity involved in synthesizing precursors that could...
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Relation between n-3 polyunsaturated fatty acids and cellular sensors of energetic state
Zouhar, Petr ; Flachs, Pavel (advisor) ; Pecina, Petr (referee)
The important factor in regulation of metabolic processes is regulatory proteins, which are able to react by feed-back to energetic state of the cell. Big attention is focused on the AMP activated kinase (AMPK) and NAD+ activated deacetylase SIRT1. These enzymes interact together and their stimulation increases mitochondrial biogenesis and fatty acid oxidation. Due to this it functions beneficially against the onset of obesity, insulin resistance and ageing. Fasting, exercise and some antidiabetogenic drugs act by these regulators. n-3 polyunsaturated fatty acids (PUFA) are also known because of their stimulative effects on mitochondrial biogenesis and -oxidation. Previous work of our group have showed that intake of higher dose of n-3 polyunsaturated fatty acids (PUFA) in diet lead to increase in activity of AMPK in white adipose tissue. New results presented in this thesis show that SIRT1 is essential for increase in expression of stimulators of -oxidation (PPAR etc) in response to n-3 PUFA in diet. n-3 PUFA futher improve the metabolic profile synergistically with calorie restriction probably through SIRT1.
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