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Systems Design of Correction Coding
Křivánek, Vítězslav ; Němec, Karel (advisor)
Due to growing transmission speed burst-forming errors tend to occur still more frequently not exclusively in data transmission. The presented paper concentrates on the search for alternative burst error correction solutions complementing the existing methods in use. Its objective is an elaboration of a detailed analysis of the issue of convolution codes for error burst correction which can be used in individual anti-error systems and thus an achievement of better results than those attained by mass application of the existing solutions. First the methods implemented to remove or suppress burst errors are briefly characterized. This part is followed by a detailed description of the individual systematic convolution codes by means of mathematical tools which extend the set of possible evaluative criteria of anti-error systems which can be applied while assessing proposals for individual solutions. The acquired code properties are compared with convolution codes as well as with other versions of proposals for message protection against an error burst. The processed convolution codes are subject to testing by means of Matlab mathematical programme simulation in order to validate the correctness of the derived mathematical tools. This is because simulation represents the principal method applied to verify and present an already proposed security process and enables the acquisition of a better overview of the issue at hand. The feasibility of the individual anti-error systems is then confirmed by way of creating a circuit behaviour description in the VHDL language. Its high portability presents a big advantage when drafting individual systems of the actual implementation.
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Stainless steel for steam sterilizer components
Hradil, David ; Němec, Karel (referee) ; Pacal, Bohumil (advisor)
The thesis titled "Stainless steel for steam sterilizer components" is focused on the selection of the optimum stainless steel for the device, in our case, pure steam generator. In this thesis are introduced the main mechanisms and types of corrosion. There are divided and characterized by various types of stainless steels. The choice of material is carried out with regard to the working environment and the technological possibilities of the individual types of stainless steels.
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The reduction of pores in welds
Němečková, Monika ; Molliková, Eva (referee) ; Němec, Karel (advisor)
This bachelor thesis dealt with the reduction of pores in the welds. These welds were in pressure stacks which are made by the Bosch company. There are Common Rail diesel injection systems in which are those pressure stacks used in. An analysis was compiled, which consisted of dates of scrap rates in the yeas 2016, and the values in which the media changed in washing machines where the pressure stacks were cleaned of grease. From the following graphs is obvious when the scraps appeared mostly and according to these results there is a proposal to reduce the porosity in the welds.
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Static and Fatigue Properties of Selected Al - alloy
Skoumalová, Zuzana ; Němec, Karel (referee) ; Věchet, Stanislav (advisor)
The present bachelor thesis focuses on material properties of wrought aluminium alloy AlZn4Mg1. The thesis deals with the interrelations between the alloy structure and its static as well as fatigue properties, especially with the latter. The first part of the thesis provides a summary of current knowledge in the studied field, experimental results can be found in the second part. Static properties of the alloy were examined with the help of measurements of hardness and a tension test, fatigue properties on the basis of experiments in high- and low-cycle regions.
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Hardness testing of metallic materials
Dufková, Hana ; Věchet, Stanislav (referee) ; Němec, Karel (advisor)
The aim of this thesis is to define and describe the hardness of material, possibilities of its testing, including the history and development of individual tests of hardness. The practical part of this work consists of the application of some of these tests on selected samples, including the evaluation of the results.
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Energy Chains
Oríšek, Petr ; Němec, Karel (referee) ; Molliková, Eva (advisor)
The thesis points to the importance of energy chains in the engineering practice and the wide range of their usage. The elaboration of this topic includes presentation of various types of energy chains, information about their construction, application and history. The emphasis is put on defining the properties that the chosen material must have in order to meet all requirements for energy chain. The thesis provides general information about the materials suitable for production of the chains and their properties and presents concrete materials used in the practice. Furthermore, a part of the work is dedicated to flexible cables which are inserted to the energy chains and their properties. There is a number of companies producing energy chains worldwide. The thesis makes use of the information furnished by one of these companies.
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Pyrolytic graphite
Chýlková, Adéla ; Adam, Ondřej (referee) ; Němec, Karel (advisor)
The purpose of this bachelor thesis was to write a literature search summarizing knowledge about carbon-based materials and experimental determination of thermal expansion and thermal balance of samples of various types of graphite and evaluation of measured data. The research part of the work describes most of the currently known types of carbonaceous materials, with a more thorough study of pyrolytic graphite. The whole next chapter was devoted to a more thorough study of pyrolytic graphite. The second part of the thesis is focused on the experimental determination of thermal expansion and thermal balance on selected graphite samples (natural, expanded, pressed expanded and pyrolytic graphite). We used dilatometric analysis and thermogravimetry to solve this task. Finally, the measurement data were processed into graphs and relevant tables and conclusions were deduced.
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Data transmition security with Reed-Müller codes
Hrouza, Ondřej ; Burda, Karel (referee) ; Němec, Karel (advisor)
The aim of this work is to propose a Reed-Muller code that secure data transfer to t = 4 independent errors, the information rate R ? 0,5 and for this code to produce a detailed proposal for implementation of the codec. In order to implement this proposal, it is necessary to familiarize themselves with the basic properties Reed-Muller codes. To understand the function of codec Reed-Muller code is in this thesis analyzed the process of encoding and decoding, which is based on a method of using the majority logic. For the design of codec, which consists of encoder and decoder, are used programmable logic circuits FPGA. These circuits are programmed in VHDL language, when for the design source codes is used Xilinx ISE 10.1. In thesis is examined in detail the structure and function of the encoder and decoder chosen Reed-Muller code and there are presented parts of the proposed source codes. Verify the functional ability of the codec is achieved by simulation in program ModelSim SE 5.7f. The simulation results together with the another proposal realization are output of this work.
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Properties and the Use of Metal Foams
Křivánek, Robin ; Liškutín, Petr (referee) ; Němec, Karel (advisor)
In this thesis are summarized the findings of metal foams, with prevailing constraints on aluminum foam, because in them hides the greatest potential. The first part is described the production of porous materials, especially the way of floam production by thermal decomposition of floaming agent and melt gas injection. There are also written stress tests to gain a deeper knowledge of their properties, but also the latest exploring methods of foams, such as using a radioscopiy and CT scanner from which then creates a voxel model of foam. They are summarized here the basic ways of processing. Finally we must mention the possibility of using these materials with a focus on commercially produced foams Alporas® and Duocel®. Mass using foams mainly prevents high production costs and in some cases difficult reproducibility of properties.
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