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Security of wireless computer networks
Jelínek, Martin ; Pelka, Tomáš (referee) ; Doležel, Radek (advisor)
The master's thesis deals with the issue of Wireless Local Area Network (WLAN) from the viewpoint of the security and functional principle of security mechanisms. The transition to the issue concerning the security is accompanied by the methods of wireless data transmission operating on the level of physical layer (FHSS, DSSS, OFDM, MIMO), which is followed by the summary of individual 802.11 standards. The next part deals with the issue of shared transmission medium (CSMA/CA), influence of interference and correcting mechanisms (RTS/CTS). Within the security, the principles of the authentication along with the commonly used methods of security (WEP, WPA, WPA2) are described in detail. The first part concerning security deals with the security in the form of the WEP protocol, which is considered insufficient nowadays and points out the imperfect implementation and the consequent risks. The following part describes the security in the form of WPA which eliminates the implementation weaknesses of the previous WEP security protocol. The description of commonly used mechanisms of authentication (PSK, 802.1x), required temporary key management (PTK, GTK), data integrity (MIC) and encryption which uses TKIP protocol are also included. The last part, possible WLAN security, is aimed at the full support of 802.11i standard, which is called WPA2 (sometimes RSN). That part describes the basic encryption security element CCMP, which is based on the AES block cipher modes. The practical part of the thesis deals with the security verification of current wireless networks. In the process of verification the accessible HW means and programming tools of Open Source Software (OSS) are used. By means of verification it has been pointed out that there are possible security risks resulting from the security method which has been used. Also several recommendations how to reduce the security risks of the used method to minimum are mentioned.
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High Performance Applications on Intel Xeon Phi Cluster
Kačurik, Tomáš ; Hrbáček, Radek (referee) ; Jaroš, Jiří (advisor)
The main topic of this thesis is the implementation and subsequent optimization of high performance applications on a cluster of Intel Xeon Phi coprocessors. Using two approaches to solve the N-Body problem, the possibilities of the program execution on a cluster of processors, coprocessors or both device types have been demonstrated. Two particular versions of the N-Body problem have been chosen - the naive and Barnes-hut. Both problems have been implemented and optimized. For better comparison of the achieved results, we only considered achieved acceleration against single node runs using processors only. In the case of the naive version a 15-fold increase has been achieved when using combination of processors and coprocessors on 8 computational nodes. The performance in this case was 9 TFLOP/s. Based on the obtained results we concluded the advantages and disadvantages of the program execution in the distributed environments using processors, coprocessors or both.
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Analysis of Cryptographic Algorithms 802.11
Vojtíšek, Jindřich ; Sobek, Jiří (referee) ; Novotný, Bohumil (advisor)
This work deals with wireless standard 802.11, primaly about security algorithms used in them. Further there is made analysis of algorithms WEP, WPA and WPA2. This algorithms are described how coding by them works and for easier understandig are added block schemes of their principles. In practical part is realized algorithms WEP, WPA and WPA2 in program Matlab simulink. Model is complemented by graphs which shows how data changes when comming throught this systems.
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Design of education board
Hadáček, Milan ; Buganská, Tamara (referee) ; Karásek, David (advisor)
The aim of my diploma thesis is to blueprint a design of multi-functional educational console. The dissertation contains several variant studies, color drawings and concrete shape execution. It entails a certain development in the area of positioning and multi-functional appliances. The thesis itself deals with the concrete shape execution of multi-touch educational console as well as seat in the form of gym ball. Short video cut from the area of interactive media forms a part of my work too.
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Efficient Implementation of High Performance Algorithms on Intel Xeon Phi
Šimek, Dominik ; Hrbáček, Radek (referee) ; Jaroš, Jiří (advisor)
This thesis is dedicated to the implementation of high performance algorithms on the Intel Xeon Phi coprocessor. The Xeon phi was introduced by Intel as a new MIC (Many Integrated Core) architecture in 2012. The theoretical part of the thesis is focused on the architecture of the coprocessor (with peak performance of 2 tFLOPS for a single precision data) and on the procedure of algorithms implementation and optimization. The theoretical knowledge is then applied to a practical examples with demonstration of the implementation and the optimization of algorithms and work with the coprocessor. In the practical part of the thesis, simple benchmarks such as a vector matrix multiplication and a matrix multiplication are explained and implemented. In the first benchmark 6.5% of theoretical coprocessor performance was achieved, in the second it was much more. In following chapter a more complex benchmark - simulation of a particles system (N-Body), that reached more than 35% of coprocessor performance (725 gFLOPS), is discussed. The following section is dedicated to some interesting problems such as optimization of a MATLAB module k-Wave (propagation of the ultrasound waves), extraction of I-vector (speech processing), cross-compilation of existing libraries, modules and programs. In the conclusion of the thesis the usage the potential of the Intel Xeon Phi is evaluated.
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Výskyt antimikrobiální rezistence u streptokoků (převážně beta-hemolytických) z ran pacientů
Kuropata, Daniel
Recently, a frequent occurrence of antibiotic resistance has been observed, and is still increasing. Therefore, it is important to constantly monitor this resistance, which was the aim of this work for Streptococcus genera. The literature review is focused on the selected species of streptococci (S. agalactiae, S. dysga-lactiae subsp. equisimilis, S. pyogenes, S. mitis and S. oralis), antibiotics, including their mechanism of action, and antibiotic resistance with an emphasis on its emergence, spread, mechanisms, determining genes and the risks it presents. In the experimental part, the occurrence of resistance in streptococci (especially beta-haemolytic) isolated from patients’ wounds at the Trauma Hospital in Brno was monitored. For this purpose, determination of the minimum inhibitory concentration (MIC), analysis of the resistance phenotype to macrolides, lincosamides and streptogramin B (MLS) using the D-test and resistance gene screening by polymerase chain reaction (PCR) were used. Among the 31 clinical isolates the prevalence of resistance to cotrimoxazole (96.8%), ciprofloxacin (71%), tetracycline (29%), erythromycin (25.5%), clidamycin (16 .1%), ampicillin (3.2%) and oxacillin (3.2%) was found by using MIC. Resistance to chloramphenicol, gentamicin, vancomycin, teicoplanin, linezolid, tigecycline and nitrofurantoin has not been detected. The D-test was performed with erythromycin-resistant isolates. The constitutive (cMLS) phenotype was detected in 62.5% of erythromycin-resistant isolates, inducible (iMLS) in 25% and M phenotype in 12.5%. The PCR method confirmed the presence of selected resistance genes, namely ermA (16.1%), ermB (6.5%), mefA (3.2%), tetO (3.2%), tetM (25.8%) and intTn (32.3%). This study demonstrated that all streptococcal isolates from patients’ wounds are resistant to some of the tested antibiotics. Moreover, multiresistance was detected in some isolates.
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Navržení vhodného bakteriálního inokula pro podporu procesu kompostování gastroodpadu
Malinová, Lucie
Composting of food waste is an increasingly studied branch of waste management. Many works deal with the microbial composition of food waste itself and methods that would speed up the whole process. We tried to design a bacterial inoculum that would support the composting process in this study. We focused on bacteria of genes Lacto-bacillus, primarily on Lactobacillus acidophilus (CCM 4833), Ligilactobacillus salivarius (CCM 7274), and Limosilactobacillus fermentum (CCM 91). The bacterial inoculum was added during the mesophilic phase of food waste composting, where it was confirmed that the pH decreased in the initial phases. In another experiment, the adaptation of bacteria to an acidic environment was investigated, so that acidic compost juices were added to the liquid nutrient medium with bacteria of the genus Lactobacillus. The results showed that getting used to an acidic environment helps the bacteria to survive such extreme conditions and Lactobacillus bacteria can be a suitable inoculum to promote composting.
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Impact of selected emulsifiers and different emulsification methods on the growth of Staphylococcus aureus and Escherichia coli.
KOLDOVÁ, Kamila
The main topic of this bachelor's thesis is to determine the minimum inhibitory and bactericidal concentration of selected types of emulsifiers and plant extracts on the growth of Escherichia coli and Staphylococcus aureus bacteria. The thesis also examines the effect of selected emulsifiers and their methods of emulsification on emulsion stability. The theoretical part provides basic information about the bacteria used, their morphological characteristics, pathogenesis, and the diseases they cause. It also describes emulsifiers and their general characteristics, including emulsion stability. The final theoretical part of the thesis focuses on plant extracts, their properties, and their applications. The methodology section of this thesis illustrates the procedures for preparing emulsifiers and plant extracts, as well as determining the minimum inhibitory and bactericidal concentrations. These determinations were performed in a 96-well microtiter plate and measured spectrophotometrically. The method for preparing emulsion stability was conducted in glass test tubes, Eppendorf tubes, and centrifuge tubes. Based on these methodts, the stability of emulsion of Mueller-Hinton broth and sugar solution was determined. The results of minimum inhibitory and bactericidal concentration were processed into tables and evaluated. Emulsion stability was processed and evaluated using obtained photographs.
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The level of Czech rhythmic gymnastics during the 2022-2024 Olympic cycle
Kadlečková, Natálie ; Holá, Iveta (advisor) ; Novotná, Viléma (referee)
In this bachelor's thesis a level of Czech and world rhythmic gymnastics was compared using video-based observation method of free routines performed by selected rhythmic gymnasts in senior category, specifically free routines with ball and clubs. Title: The level of Czech rhythmic gymnastics during the 2022-2024 Olympic cycle Objectives: The aim of the bachelor's thesis is to assess and compare the established difficulty of free routines based on internationally valid FIG rules for selected gymnasts. Methods: The observed file consists of 3 rhythmic gymnasts. Each of them was analysed for free routines with ball and clubs. Thus, a total of six routines were assessed with the help of experts and then compared with each other. Results: The results of selected free routines analysis are summarized in simple charts. The analysis of the routines was firstly performed individually for each gymnast and then the results were compared with each other. The findings relate primarily to the content and overall difficulty of the routine. The observed difference in the level between the world's best gymnast and the Czech representative provides an incentive to reflect on the top-level preparation of Czech rhythmic gymnasts. Keywords: artistry, ball, clubs, current rules, difficulty, execution, gymnastic...
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USE OF COMPLEX EXTRACTS FROM PLANT AND MICROORGANISMS IN FOODS AND COSMETICS
Uhlířová, Renata ; Kovalčík, Adriána (referee) ; Vorlová, Lenka (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on optimalization of preparation of extracts of various origin (plant and microbial). The influence of extraction agent, disintegration of microbial cells as well as special techniques for enhancement of extraction process effectiveness (ultrasound and microwaves) were monitored. As part of the characterization, considering the source material, the composition of the prepared extracts was analyzed both spectrophotometrically and using liquid and gas chromatography. The most suitable extraction procedure varies depending on the type of material. For herbal samples, the highest content of active substances was achieved when the extraction facilitated by microwaves was used. Contrarily, the optimal method for cyanobacteria is the traditional extraction method, which is carried out for 24 hours at laboratory temperature. The most suitable method for extracting the active substances from yeast was a combination of DMSO, ethanol and hexane. Further, the effect of extracts on microbial cultures of bacteria (E. coli, S. epidermidis, C. acnes) and yeast (C. glabrata) was observed. For cytotoxicity evaluation MTT and LDH assays were performed on HaCaT and Caco2 human cell lines. The antimicrobial tests have demonstrated the antimicrobial, antibacterial and antifungal effect of a numerous extracts, especially the essential oils of Lavandula angustifolia and Mentha piperita. On the other hand, the cytotoxicity tests showed that the most of the extracts were safe for the use in the food industry and cosmetics within a range of up to 10% by volume. To improve stability, the prepared extracts were enclosed into liposomal particles enriched with PHB polymer (0–100%). Using a ZeteSizer NanoZS device, the particles' size, polydispersity index, and colloidal stability were assessed. The cryoTEM was used to examine the particle´s morphology. Liposomes and liposomes with the addition of 20 % PHB (PHB20) were evaluated as the most suitable particles for encapsulation of the prepared extracts. Excellent stability and high encapsulation efficiency were displayed by the produced particles. Genotoxicity testing with SOS chromotest on the model organism E. coli did not reveal any genotoxic effects. As an alternative method to achieve stabilization of active substances, nanofibers from PHB were prepared by three different techniques and gelatin nanofibers by electrospinning. The fibers were monitored for their diameter, uniformity, distribution on the collector using SEM and the gradual release of active substances from the fiber structure. The evaluations revealed that the forcespinning and electrospinning techniques were the most appropriate for further investigation. A continuous release of active ingredients was achieved by incorporating extracts into nanofibers. Several applications of prepared materials in the food industry and cosmetics were designed and developed as part of this work. The base emulsion's stability and general qualities were improved when green coffee and carotenogenic yeast extracts were added. The usage of emulsions containing coffee and yeast extracts would be suitable as sunscreens, and after the addition of Spirulina extract, as day or night anti-wrinkle creams. Energy drinks of the new type based on coffee with the addition of encapsulated plant extracts enable gradual release of caffeine and antioxidants during digestion.
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