National Repository of Grey Literature 90 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Cryptography based on semirings
Mach, Martin ; Korbelář, Miroslav (advisor) ; El Bashir, Robert (referee)
Cryptography based on semirings can be one of the possible approaches for the post-quantum cryptography in the public-key schemes. In our work, we are interested in only one concrete semiring - tropical algebra. We are examining one concrete scheme for the key-agreement protocol - tropical Stickel's protocol. Although there was introduced an attack on it, we have implemented this attack and more importantly, stated its complexity. Further, we propose other variants of Stickel's protocol and we are investigating their potential for practical usage. During the process, we came across the theory of tropical matrix powers, thus we want to make an overview of it due to the use in cryptography based on matrices over the tropical algebra semiring. 1
Skin effect in high-speed electrical machines.
Klíma, Petr ; Bárta, Jan (referee) ; Mach, Martin (advisor)
This master thesis deals with the suppression of the skin and proximity effects in high-speed machines. The first part summarizes the general knowledge of high-speed machines. The second part is devoted to the principle and possible suppression of consequences caused by skin and proximity effects. The third part shows the simulation results of models of a synchronous machine with permanent magnets. The results of these simulations reveal the consequences of skin and proximity effects. In addition, design measures are proposed to limit these and other undesirable phenomena to achieve the highest possible efficiency.
Design of a high-speed electrical machine.
Šolc, Martin ; Klíma, Jiří (referee) ; Mach, Martin (advisor)
This diploma thesis is dedicated to design of highspeed induction motor with power 30 kW, 60 000 rpm. In the beginning of the thesis basic problematic of highspeed motors, used materials and motor types is discussed. The practical part of the thesis concerns design of the motor itself, creating a model in ANSYS Maxwell software, performing several simulations and optimalization of the designed machine. In the last parf of this thesis each simulation is evaluated and the final model of the machine is introduced.
Optimization of a small induction machine.
Jedlička, Lukáš ; Knebl, Ladislav (referee) ; Mach, Martin (advisor)
The goal of this thesis is to improve efficiency of an induction motor. In the first part, the working principle is described. The next part deals with the origin of losses and possible solutions to decreasing losses without impacting the production possibles. The third part of the thesis is focused on the calculation of parameters of a small serial production motor. In the fourth part, these parameters are verified using the analytical tool RMxprt which is included in Ansys Maxwell. The fifth chapter deals with the optimization using Matlab genetic algorithm. In the final chapter, the design modifications are verified using the method of finite element Ansys Maxwell 2D.
Consequences of increasing the efficiency of small motors.
Buchta, Martin ; Mach, Martin (referee) ; Hájek, Vítězslav (advisor)
This bachelor thesis deals with the consequences of increasing the efficiency of small asynchronous motors up to 1kW. This work is written in response to ever-increasing demands on minimal efficiency for asynchronous engines, whether through European Union legislation or just competition between manufacturers. The aim of the thesis is therefore to evaluate measures to increase efficiency. The evaluation refers to the consumption of the active material and the weight of the individual treatments. For the evaluation itself, it was necessary to first study the final papers written at this faculty concerning the efficiency of small asynchronous motors. After studying these works, it was necessary to select those measures which, with their minor costs, are least demanding, lead to an increase in efficiency of at least 1% and also to compare these measures with each other. The asynchronous engine of ATAS a.s. with a power of 600W. Three measures to improve efficiency were selected for this engine, mainly related to the diameters of the winding conductor used, the change in the number of threads, and, possibly, the extension of the length of the circuit. These three measures made a rough financial analysis of the price for active material. The prices of active material were found from manufacturers or suppliers.
Assessment of the safety risks of gas and petrol storage facilities and the process of their revision
Miadzvedzeu, Mikita ; Mach, Martin (referee) ; Veselka, František (advisor)
Bachelor’s thesis deals with the issue of revision of gas and oil products storage tanks. The task of the thesis is to explain the existence of the safety risks of gas and oil storage tanks and indicate ways of their elimination. Next objective is to prepare the review process of the selected type of tank, including the date of the following inspections and tests. Evaluate the lessons learned and propose appropriate measures.
Possibilities of elimination of electrostatic charge generation in the belt conveyor drive
Pavluš, Ondřej ; Mach, Martin (referee) ; Veselka, František (advisor)
The purpose of revision of electrical devices is to assess the device in regard to its safety. The main goal of this bachelor thesis is a revision of an electrical conveyor belt engine. We focus on safety from injury caused by electric current due to malfunction and methods for detection and prevention of electrostatic charge buildup. We conducted an inspection and prepared the required norms and measurements. After a careful analysis of results we determined, whether or not the device meets the safety requirements specified by the relevant industry norms. Based on the insights from the inspection, we took necessary precautions with regard to static electricity buildup.
Synchronous motor speed control
Šatava, Patrik ; Mach, Martin (referee) ; Ondrůšek, Čestmír (advisor)
This bachelor’s thesis deals mainly with methods for control of synchronous motors for use in electrical drives. In the first part of the thesis the generic theory of a synchronous machine is presented. Furthermore, this part also deals with Park’s linear transformation of the synchronous machine’s equations, and the stability of the machine. Subsequently, methods for control of a permanent magnet synchronous motor for use in electrical drives are presented. Two major presented methods include the vector control and the direct torque control. Furthermore, the thesis deals shortly with scalar control, which is, however, used rarely nowadays. The last part of the thesis presents measured data of two permanent magnet synchronous motors, powered by a variable frequency AC drive. The data was measured at no load with use of three control methods – scalar control, vector control in open loop-mode, and vector control in closed-loop mode; and at load with use of two control methods – scalar control, and vector control in closed-loop mode.
Electromagnetic calculation of an induction machine using an open source program
Bílek, Vladimír ; Mach, Martin (referee) ; Bárta, Jan (advisor)
This bachelor thesis deals with issues of finite element method and its use for electromagnetic calculation of induction machine. The first part of the thesis deals in details about finite elementh method, where the thesis describes the procedure of calculation of electromagnetic model and its use in simulation software. The second part contains and compares the list of paid and open-source simulation programs. The third part describes the creation of the specified electromagnetic model. The fourth part of thesis represents program ELMER, program's posibilites and how to set up scripts for simulation. The fifth part compares simulation results with measurments on real induction machine. The last part is the overall evalution of the thesis.
7,5 kW induction machine.
Hemzal, Martin ; Janda, Marcel (referee) ; Mach, Martin (advisor)
Bachelor thesis Induction motor 7,5 kW deals with analytic design of induction motor. The project is structured into 6parts. First part is about itroduction to a problem. The second part shortly analyses theory of induction motor. The next part deals with analytic calculation. In the next part the design is checked in the RMxprt module. In the conclusion both analytic calculation and RMxprt results are compared.

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See also: similar author names
1 MACH, Marek
4 MACH, Michal
4 MACH, Milan
2 Mach, M.
4 Mach, Michal
4 Mach, Milan
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