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Evolution of link layer loop prevention protocols
Březina, Jiří ; Frolka, Jakub (referee) ; Slavíček, Karel (advisor)
This bachelor thesis deals with the possibility of eliminating and creation loops on theData Link layer of the OSI model. At first, it was necessary to determine what arethe loops and how they are formed. Then the solution of the problem with loops waspresented as the Spanning Tree protocol, where did the protocol come from, protocoloperation, his advantages and disadvantages. In next section were discussed other vari-ants of original STP, as well as his alternatives, like for example the TRILL or the SPBprotocol. The practical part of this work is based on the theoretical and shows howSpanning Tree protocols work in practice on real devices. This part is mainly focusedto testing the speed of convergence each of protocols and also their extensions. In theend is mentioned a laboratory task, which is part of the appendices and forms the mainbenefit of the whole thesis, because future students at school subject “network architec-ture” can try to configure protocols that was mentioned above and better understandhow these protocols work.
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Time progression of metrological characteristics of electromagnetic current meters
Březina, Jiří ; Brázda, Martin (referee) ; Žoužela, Michal (advisor)
This experimental diploma thesis investigates the changes in the metrological characteristics of the electromagnetic current meter of velocity. The theoretical part of the thesis includes a brief summary of technical and metrological characteristics of these types of devices. In addition, it describes the tested device, the test track, and the measurement procedure, which consists of two variants: long-term monitoring with a relatively regular monthly measurement interval and short-term monitoring with a regular daily measurement interval. The evaluation of the experimental work focuses on the repeatability and variability of the displayed point speed values and their stability over time. Furthermore, the parameters reported by the meter during long-term and short-term monitoring are compared to each other. The results are also compared with similar experiments.
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Concept of Education at the Chamber of Financial Consultants
Březina, Jiří ; Mátl, Roman (referee) ; Lajtkepová, Eva (advisor)
The subject of this thesis „Concept of Education at the Chamber of Financial Consultants“ is to analyse the current situation on the financial consultancy market whose absences have led to the concept proposal for the education of financial consultants to extend the knowledge of consultants and to improve the quality of their services. In the practical part I propose options, how the concept of education in the framework of the chamber's financial advisors should be applied.
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Cyber security tester of elements used in industrial networks and energy industry
Březina, Jiří ; Mlýnek, Petr (referee) ; Lieskovan, Tomáš (advisor)
This thesis deals with the issue of security analysis of DLMS/COSEM protocol and exploitation of these vulnerabilities in real Smart Grid environment. Thesis starts with a description of power grids in the past and present, introducing the environment of modern power grids and the smart grid elements used in it this power grids to reader. This is followed by a detailed discussion of the communication protocols that operate in these networks, beginning from the older and more industrially based Modbus protocol to the DLMS/COSEM protocol which is most used today and his various components and security. The most common current models of link vulnerability attacks are also summarized in the paper. The thesis aims to implement a tester that tests the security of smart grid elements, mainly on the vulnerabilities described in the thesis. The tester primarily focuses on the vulnerability called replay attack and evaluating the execution of this attack in a laboratory environment.
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Electromagnetic current meters of velocity
Březina, Jiří ; Zubík, Pavel (referee) ; Žoužela, Michal (advisor)
This bachelor thesis explains the issue of electromagnetic current meter of velocity. A survey of all available standards on these devices is carried out. Devices are described technically and metrologically. There are also described the possibilities of usage, operating conditions as well as problems of calibration of these devices. Information on available commercially available devices is provided along with a description of all relevant parameters. One selected device model is put to the test of measurement the velocity on the calibration tank of the laboratory, thus the experiences from real calibration measurement are gained and described.
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Multiobjective shortest path problem with interval costs
Březina, Jiří ; Hladík, Milan (advisor) ; Fink, Jiří (referee)
The multiobjective shortest path problem with interval costs is a gener- alization of the single-pair shortest path problem. In this problem, the edge weights are represented as tuples of intervals. The aim is to find the path that minimizes the maximum regret. We present theorems regarding the compu- tation of the regret and the efficiency of a feasible solution to the problem. The main result of the thesis is an algorithm seeking for the solution with the least regret in the interval multiobjective shortest path problem. 1
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CX3CR1+ migratory dendritic cells in the mechanisms of central tolerance
Březina, Jiří ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
Display of thousands of self-antigens in the thymus is fundamental for the establishment of central tolerance as its failure can lead to the development of autoimmunity. Medullary thymic epithelial cells (mTECs) and thymic dendritic cells (DCs) constitute essential populations of antigen presenting cells (APCs) which present these self-antigens to developing T cells. While mTECs produce and present antigens in self-autonomous manner, DCs can hijack mTEC-derived antigens by the process of cooperative antigen transfer (CAT). It is well found that CAT is essential for working central tolerance, however, the overall heterogeneity of thymic APCs participating in CAT remains unclear. Using transgenic mouse models and multicolor flow cytometry analysis, we determined that APCs involved in CAT are exclusively of CD11c+ phenotype. Within these cells, we identified previously unrecognized CX3CR1+ subset of migratory DCs (mDCs) exhibiting monocyte/macrophage markers. These CX3CR1+ mDCs are more efficient in CAT than their CX3CR1- counterparts and reveal robust antigen presenting properties with the capability to present CAT-acquired antigen. Genetic ablation of CX3CR1+ mDCs resulted in increased cellularity of CD8+ and CD4+ thymocytes, indicating importance of this mDC subset for negative selection of...
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Cyber security tester of elements used in industrial networks and energy industry
Březina, Jiří ; Mlýnek, Petr (referee) ; Lieskovan, Tomáš (advisor)
The following is a detailed discussion of the communication protocols that work in these networks, from the older and more industrially based Modbus protocol, through the IEC 60870 protocol suite, to the most commonly used protocol today, DLMS/COSEM. The paper also summarizes the most common current attack patterns on DLMS/COSEM protocol vulnerabilities. The thesis aims to implement a tester that tests the security of smart grid elements mainly on the vulnerabilities described in the thesis. The tester primarily focuses on the vulnerabilities of overwhelm and replay attacks and evaluating the execution of these attacks in a laboratory environment.
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Cyber security tester of elements used in industrial networks and energy industry
Březina, Jiří ; Mlýnek, Petr (referee) ; Lieskovan, Tomáš (advisor)
This thesis deals with the issue of security analysis of DLMS/COSEM protocol and exploitation of these vulnerabilities in real Smart Grid environment. Thesis starts with a description of power grids in the past and present, introducing the environment of modern power grids and the smart grid elements used in it this power grids to reader. This is followed by a detailed discussion of the communication protocols that operate in these networks, beginning from the older and more industrially based Modbus protocol to the DLMS/COSEM protocol which is most used today and his various components and security. The most common current models of link vulnerability attacks are also summarized in the paper. The thesis aims to implement a tester that tests the security of smart grid elements, mainly on the vulnerabilities described in the thesis. The tester primarily focuses on the vulnerability called replay attack and evaluating the execution of this attack in a laboratory environment.
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Recursive sets and diofantine equations
Březina, Jiří ; Holub, Štěpán (advisor) ; Krajíček, Jan (referee)
Main theme of this thesis are diophantine equations and diophantine sets. In the first chapter we also briefly introduce recursive sets and recursive enumerable sets and show how they are connected with diophantine sets. Whole second chapter is devoted to constructive proof that prime numbers are diophantine and also stating a polynomial which set of positives values is identical to the set of prime numbers. 1
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