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Crytographic attacks on TLS protocol
Oupický, Jan ; Tůma, Jiří (advisor) ; Boháček, Milan (referee)
The aim of this work is to introduce the reader to the protocol TLS and a few selected attacks against the protocol. In the first part we will define the necessary cryptographic definitions used in the following chapters. In the second part we will briefly talk about the history of procotols TLS and SSL and then we will closely look into how they work. The last part is about the analysis of the chosen cryptographically interesting attacks (Padding oracle on CBC mode, POODLE, BEAST and CRIME) against protocols TLS and SSL. 1
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Linear Algebra at Business Universities and High Schools
Ulrychová, Eva ; Málek, Josef (advisor) ; Tůma, Jiří (referee) ; Hájková, Vladimíra (referee)
The thesis consists of two equal parts - of a part dealing with didactic aspects of teaching linear algebra, and of an unconventionally approached textbook Fundamentals of Linear Algebra, which is appended as a separate attachment. The didactic part deals with teaching mathematics, especially linear algebra, at the University of Economics in Prague, namely from the historical and methodological point of view. The thesis also includes a detailed evaluation of students' knowledge tests. The conclusions are largely portable to other non- technically oriented universities. The textbook is designed with respect to two levels of difficulty; it is written in the form accessible for students with lighter assumptions for the study of mathematics. The textbook is designed especially for students of universities where mathematics is not the main focus; it may also serve to interested high schools students as an introduction to a more advanced study of linear algebra.
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Position coding on line and plane
Těthalová, Gabriela ; Tůma, Jiří (advisor) ; Žemlička, Jan (referee)
The introduction into the position coding consists of two examples of position codes on line which use the positional number system of base 4 and De Bruijn sequence constructed with the use of LFSR. The main aim of this thesis is the description of two positional codes on plane based on the patents of the Swedish company Anoto. These positional codes use mixed radix number representation and also a specific type of sequences called quasi De Bruijn sequences. The second of the described position codes represents an application of the Chinese Remainder Theorem. The thesis focuses on the position code construction, description of decoding, and the proofs of detectability. A detailed comparison of the principles of the coding of the coordinate y of both discussed codes is provided in the final part of the thesis. Keywords: positional code, quasi De Bruijn sequence, mixed radix, Anoto Pattern Powered by TCPDF (www.tcpdf.org)
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Binární znaménkové reprezentace celých čísel v kryptoanalýze hashovacích funkcí
Vábek, Jiří ; Tůma, Jiří (advisor) ; Kůrka, Petr (referee) ; Holub, Štěpán (referee)
Title: Binary Signed Digit Representations of Integers in Cryptanalysis of Hash Functions Author: Jiří Vábek Department: Department of Algebra Supervisor: doc. RNDr. Jiří Tůma, DrSc., Department of Algebra Abstract: The work summarizes two main papers, A New Type of 2-block Colli- sions in MD5 and On the Number of Binary Signed Digit Representations of a Given Weight, while containing also the wider introduction to the topic of crypt- analysis of MD5 and binary signed digit representations (BSDR's). In the first paper we have implemented and applied Stevens algorithm to the newly proposed initial message differences and constructed a new type of collisions in MD5. In the second paper we have introduced and proved a new improved bound for the number of optimal BSDR's and also a new recursive bound for the number of BSDR's of a given integer with a given overweight. In addition to the results in mentioned papers, the generalized result is stated with the new bound for the number of optimal D-representations of natural numbers with D = {0, 1, 3}. Keywords: hash function, MD5, binary signed digit representation (BSDR), non- adjacent form (NAF) 1
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Crank mechanism with a high mechanical efficiency
Drápal, Lubomír ; Tůma, Jiří (referee) ; Páv,, Karel (referee) ; Píštěk, Václav (advisor)
This document describes the possibilities of increasing the mechanical efficiency of the crank train of an internal-combustion engine. For this purpose, a concept with a reduced number of main bearings is chosen and its contribution is verified experimentally. The proposed solution consists of an innovative crankshaft design of a four-cylinder spark-ignition engine with only three main journal bearings and laser-welded sheet metal crank webs. The new design is compared to the mass-produced one in terms of friction losses, vibrations and loading of engine parts by means of simulations of crank train dynamics using the Multi-Body System. The increase in vibration, accompanied by a reduction in friction losses, is compensated by a torsional vibration damper and its effect is experimentally verified. Experimental research of laser welds on the crankshaft in terms of fatigue life is also described. The overall potential is also summarised and further possible development of this innovative and patented design is outlined.
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Gauss'calculation of Ceres' orbit
Beďatš, Daniel ; Tůma, Jiří (advisor) ; Růžička, Pavel (referee)
In 1801, a Sicilian astronomer Giuseppe Piazzi discovered a faint star-like object, which disappeared in the glare of the Sun after six weeks of observations. A year later, the object named Ceres was rediscovered thanks to calculations provided by Carl Friedrich Gauss. This thesis aims to present the full process of Gauss's contribution to the dis- covery of Ceres with focus on elementary and straightforward mathematical language. We introduce some basic notions and properties concerning elliptical orbits and develop a thorough account of Gauss's calculations. We also provide justification for multiple unexplained steps in the method. 1
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Rotary lifting table with higher load capacity
Nytra, Tomáš ; Tůma, Jiří (referee) ; Omes, Jiří (advisor)
This Master thesis deals with construction design of pop-up turntable with load capacity 120 tons and 1500 mm stroke. The driveline will supply by combination of hydromotor and planetary gearbox.The first part of this thesis deals with research in the field of current offer of pop-up turntables and construction elements used in pop-up turntables.Then is acceded to design of 3 different construction variants, of which is chosen one based on evaluation properties of each variant. After this part, follows on constuction design of chosen variant, including both desinging and calculating part. Part of the thesis is also required technical drawing documentation.
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Design of direct drive tool turret for CNC lathe
Mrkos, Jan ; Štěpánek, Vojtěch (referee) ; Tůma, Jiří (advisor)
The diploma thesis deals with the design of a direct drive tool turret, which serves as a tool magazine for a CNC lathe. In the introductory part of the work, a research was performed in the field of automatic tool change with a focus on tool turrets and their main structural units. The introductory research is followed by the main part of the work, which begins with the selection of appropriate design solutions, followed by a presentation of the tool turret design created in CAD software Autodesk Inventor 2021 and in the final part of thesis the key elements of the proposed design are verified by calculations.
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A design of pneumatic stationary chuck
Hurtík, Daniel ; Pavlík, Jan (referee) ; Tůma, Jiří (advisor)
This Bachelor’s thesis is focused on the construction of a pneumatic stationary chuck, but it also mentions something in the field of workpiece clamping and machine vices for rotating workpieces. The first part contains a brief search in the field of clamping, which focuses mainly on the clamping of rotating parts. The next chapter focuses on possible solutions that would meet our requirements. The main components of the chuck are then calculated and designed so that subsequent construction can be performed in any CAD software, which is the content of the next chapter. Finally, some requirements for chuck operation are summarized.
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