Optimization of Wireless Networks against Attacks

Práce se zabývá návrhem bezdrátové sítě a problémů týkající se této technologie. V teoretické části se zabývá seznámení se sítí, použité technologie bezpečnosti a návrhu bezdrátové sítě. V praktické části je popsána simulace a změření síly signálu a rovněž zajištění bezpečnosti pomoc WPA, autentizace Radius, šifrování dat TKIP a možnosti prolomení do sítě. V dalších kapitolách je řešeno připojení uživatelů do sítě (domény), uplatnění VOIP telefonie na této síti. Poslední část popisuje rozšíření sítě a problémy s tím spojené.The work describes the design of wireless networks and the problems relating to this technology. In the theoretical part it deals with the learning network, the security technology and design wireless network. In the practical part it describes the simulation and measure of the signal strength. The ensuring of the safety by aid WPA as well as Radius authentication, TKIP data encryption, and the possibility of breaking into the network. The following chapters deal with the connection of the users to the network (domain) and with the application of VOIP telephony on the network. The last part describes the extension of the network and the associated problems.

Correlation of the prediction curve of the creep behaviour of polymeric materials

This study deals with the study corellation of regression curve parameters on the prediction of possibilities of measured data. In this study, the necessary introduction of polymeric materials and their material structure, which influences their physical and mechanical properties is described. Thereafter, the method of testing materials using the DMA device which enables this measurement is presented. In the next section, these measured data are processed by a creep module in which the regression curve methods and their match with the measured data are applied. In the final part of the thesis is evaluated the conformity of the measured data with the data obtained from the regression curve. © 2017, World Scientific and Engineering Academy and Society. All rights reseved

The influence of injection molding on tensile and tear properties of EPDM rubber

In industry the control of physical properties of rubber products produced by injection molding is mostly performed on testing samples produced by another method-cutting out of a compression molded plate according to ISO standard. This different method of producing testing samples and final products may have a different impact on physical properties. The paper compares and evaluates the selected physical properties (tensile strength, modulus of elasticity and tear strength) of EPDM rubber samples prepared by the standard method (cutting out of a compression molded plate) and injection molded samples and finally third method-cutting out of an injection molded plate. The results have shown that using the injection molded samples we will achieve more objective results mainly to determine the tear strength. In the case of tensile strength, the differences are not so significant. © 2018, World Scientific and Engineering Academy and Society. All rights reserved

Influence of measurement conditions and used devices on consequential creep modulus

This research deals with study of the possibilities of the creep properties measurement on dedicated devices for the creep measurement and on devices, which enable the creep properties measurement. A comparison of these two different measurement methods show the influence of boundary conditions on the measurement result. Simultaneously, the effort to shorten the long-term tests, because of time saving during research and development of new materials, is confronted here. Radiation crosslinking samples of high-density polyethylene (HDPE), which enable the change of the internal structure to the spatial network by the influence of beta radiation, were chosen as an example for comparison.TBU in Zlin [IGA/FT/2016/010]; Ministry of Education, Youth and Sports of the Czech Republic [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089

Design of highway bridge formed by beam girder

Cílem diplomové práce je návrh smyšlené mostní konstrukce přes stávající komunikace. Byly vypracovány a následně porovnány tři studie přemostění. Jako nejvhodnější varianta byla vybraná dvoutrámová konstrukce bez náběhů, která byla dále podrobněji zpracována. Konstrukce byla posuzována dle mezních stavů únosnosti a použitelnosti.The aim of diploma thesis is to design a made-up bridge construction over the road network.There were made three studies of bridging which were compared consequently. Two-joint ginder without haunched was selected as the most suitable option and it was designed in details. The construction was assessed according to the ultimate and serviceability limit state.

OPTIONS REPORT synchronous machine

Cílem této práce je teoreticky posoudit zkoušky (typové a kusové) synchronních generátorů a posléze i prakticky změřit a vyhodnotit ve výsledném typovém protokolu. Teoretická část obsahuje rozbor norem pro jednotlivé zkoušky a popis skutečného provedení na zkušebně elektrických strojů. Součástí práce je poukázat na nákladnost zkoušek s rozborem na dílčí náklady a stanovení nejistoty měření.The aim of this work is to theoretically evaluate the test (type and routine) of synchronous generators and then practically measure and evaluate in the resulting protocol type. The theoretical part contains an analysis of standards for individual tests and a description of the actual design in the test room of electrical machines. Part of this work is to show the cost of the tests with the analysis of the incremental costs and measurement uncertainty.

Frame bridge over a local brook

Cílem této bakalářské práce je návrh železobetonového mostu o jednom poli přes místní potok. Most je navržen jako rámová konstrukce s lichoběžníkovou deskou a s oboustrannými náběhy. Jednotlivé části konstrukce byly posouzeny z hlediska mezního stavu únosnosti a mezního stavu použitelnosti.The main aim of this bachelor thesis is the design of reinforced concrete bridge in one field over the local stream. The brigde is designed as a frame construction with trapezoidal board and with reciprocal pitch. Individual parts of the construction were assessed from the point of view of ultimate and serviceability limit state.

Nano-mechanical properties and morphology of irradiated glass fiber filled polypropylene

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behavior. This paper describes the effect of electron beam irradiation on the surface properties (nano-indentation test) of glass fiber filled polypropylene (30%). These nano-mechanical properties were measured by the DSI (Depth Sensing Indentation) method on samples which were non-irradiated and irradiated by low (33, 66 and 99 kGy) and high (132 and 165 kGy) doses of the β – radiation. Nano-indentation test was performed at (400mN) indentation loads. The purpose of the article is to consider to what extent the irradiation process influences the resulting nano-mechanical properties measured by the DSI method. The polypropylene tested showed significant changes of indentation hardness and modulus. The best results were achieved by irradiation at doses of 99 and 132 kGy (increase about 68%) by which the highest nano-mechanical properties of filled polypropylene were achieved. These changes were examined and confirmed by X-ray diffraction and Gel content. © 2017, World Scientific and Engineering Academy and Society. All rights reserved.CZ.1.05/2.1.00/03.0089, ERDF, European Regional Development Fun

Influence of applied electron radiation on the properties of a polyamide 11 surface layer

This article deals with the influence of the radiation cross-linking of polyamide 11 (PA 11) on the mechanical properties. The aim of this study is to provide more detailed knowledge of the relation between the radiation dosage and the properties of cross-linked PA 11 and its mechanical behaviour. Electron-beam-unmodified and modified PA 11 test samples were exposed to electron radiation with dosages from 0 kGy to 198 kGy, which were graded at 33 kGy. The surface-layer properties of the modified PA 11 were tested using a state-of-the-art indentation technique, which detects the immediate change in the indentation depth, depending on the applied force. The evaluation of the measured mechanical properties (indentation hardness, modulus and creep) was done by the Oliver and Pharr method. A significant influence of the radiation cross-linking on the PA 11's mechanical properties improvement was confirmed by the measurements. This enhancement grows with the increasing radiation dosage. Due to the electron-radiation modification of PA 11, the mechanical properties of the surface layer were increased by up to 59 % compared with the unaltered material. Radiation crosslinking is an important thermoplastic modification method by which the desired properties can be achieved in a relatively short period of time. The main advantage is that the process is executed on the final product.European Regional Development Fund under the project CEBIA-Tech Instrumentation [CZ.1.05/2.1.00/19.0376]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Program [LO1303 (MSMT-7778/2014)]; Internal Grant Agency of TBU in Zlin [IGA/2020/003

Effect of ionizing beta radiation on the mechanical properties of poly(ethylene) under thermal stress

It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene). In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE). These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared) and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.TBU in Zlin [IGA/FT/2016/010]; Ministry of Education, Youth and Sports of the Czech Republic [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089