National Repository of Grey Literature 83 records found  beginprevious35 - 44nextend  jump to record: Search took 0.00 seconds. 
Analysis of Wi-Fi traffic
Bakó, Zdeněk ; Pospíšil, Ondřej (referee) ; Pospíšil, Jan (advisor)
This bachelor thesis deals with the capture and analysis of wireless traffic of Wi-Fi networks. The aim of this work is to describe the possibilities of capturing and analyzing the operation of Wi-Fi networks. It describes the IEEE 802.11 standard, its features such as architecture and current standards. A selection of a suitable router is performed on which traffic capture and analysis is performed. Some open-source firmware for routers is compared and the most suitable one is selected. Tools for capturing and analyzing Wi-Fi network traffic are compared and described. The differences between the promiscuous and monitoring capture mode and their possibilities of use are described. Finally, there are described options for analyzing captured 802.11 frames.
Security assessment of standards of IEEE 802.11 family
Řihánek, Tobiáš ; Pospíšil, Jan (referee) ; Pokorný, Jiří (advisor)
The aim of this work was to analyze the issue of security testing of the IEEE 802.11 protocols. The thesis includes a theoretical analysis of these protocols and a list of their vulnerabilities. Software used for testing the security was showcased. A utility was created to help with the testing. Finally, the thesis looks at the use of SDR as a way of testing security.
Recognition of security issues in LPWA type networks
Shestopalov, Artur ; Pospíšil, Jan (referee) ; Pospíšil, Ondřej (advisor)
The bachelor’s thesis deals with the issue of recognizing security incidents in LPWA (LowPower Wide Area) networks. Thesis contains information about the most used LPWA technologies, examines their security architecture and possible threats. Part of the work is a detailed description of LoRaWAN protocols, including architecture, possible attacks, distinguishing security architecture in the new and old versions. Work contains implementation of two security incident scenarios and their subsequent detection: jamming and gateway disconnection. As part of the detection, was created a web application that is able to detect real-time security incidents based on the average value of RSSI (Received Signal Strength Indicator) and the expected time of message transmission.
Passive capturing probe for IEEE 802.11 standard
Partnov, Denys ; Kubánková, Anna (referee) ; Pospíšil, Jan (advisor)
The bachelor's thesis deals with a general description of the 802.11 protocol, where the individual layers on which the protocol works are explained and described. Attention was also focused on the possibilities of securing wireless traffic. The practical part then deals with the creation of a complete tool for passive interception of traffic in IEEE 802.11 networks. Where it is mainly about processing traffic statistics. The resulting program, written in Python, allows the user to display current information such as: number of transmitted frames, channel, band, received signal strength, and more. Subsequently, the results can be displayed in the form of graphs. As part of the test measurement, the correct functionality of the program was verified.
Honeypot for LoRaWAN protocol
Zhukova, Viktoriia ; Pospíšil, Jan (referee) ; Pospíšil, Ondřej (advisor)
The bachelor’s thesis in the theoretical section focuses on LoRaWAN technology. It describes network communication, LoRaWAN security, vulnerabilities, and mitigation measures. The second half of the theoretical section focuses on describing honeypot technology and its distribution, listing its advantages and disadvantages, and comparing IoT honeypots. The practical section focuses on building an experimental environment. There is a description of the selected hardware and software. It describes the commissioning of the LoRaWAN network, the configuration of the gateway, and the startup of the LoRaWAN server. Next, the whole procedure of honeypot assembly is described. Two variants of high-interaction honeypot are described and investigated. One without the use of sandboxing and using a firewall, the other with the use of sandboxing and an implementation of chroot/jail.
Study of electrical and dielectric properties of ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor thesis is focused on the study of electrical and dielectric properties of ionic liquids. Two types of OECT substrates with different semiconductor channel lengths made of PEDOT:PSS were used to measure these properties. The dielectric properties were measured by impedance spectroscopy, where the dependence of the impedance value and its phase angle on the voltage frequency was measured. It was found from V-A characteristics, that the best closing of semiconductor layer occurs at a positive UGD voltage. The switching speeds of different ionic liquids were compared for this voltage.
Perovskite solar cells
Poláková, Simona ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The bachelor´s thesis deals with the study of perovskite solar cells. The theoretical part of this work is devoted to the stability of the perovskite layer and perovskite solar cells, especially chemical and thermal stability are discussed. Furthermore, deposition methods of perovskite active layer were described in more detail. The experimental part deals with the influence of the dropping of the diethyl ether solution during the deposition of the active layer (at different time intervals) on the final efficiency of solar energy conversion, with the preparation of the final perovskite solar cells and with the characterization of the basic electrical properties of the prepared structures.
Perovskite materials
Gavranović, Stevan ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
This bachelor´s thesis is focused on a study of electrical properties of perovskite single crystals prepared by inverse temperature crystallization (ITC). Measurements were done on the organic-inorganic halide perovskite monocrystal MAPbBr3 and on the completely inorganic halide perovskite monocrystal CsPbBr3. Crystalline structure and chemical composition of prepared single crystals were determined using x-ray diffraction analysis. Current-voltage characteristics of perovskite monocrystals were measured using solar simulator. Hole carrier mobility were calculated from determined current-voltage characteristics using SCLC method. Furthermore, the dependencies of dielectric permittivity on frequency of alternating current were measured. MAPbBr3 single crystal showed better electrical properties (higher hole carrier mobilities) than CsPbBr3.
Organic solar cells prepared by methods compatible with printing technologies
Babincová, Kristina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
The theoretical part deals mainly with basic properties of organic materials, which are used in electronics, and especially in the field of photovoltaic cells. The experimental part deals with preparation of photovoltaic cells by deposition from solution, characterization of their basic electrical properties and preparation of a photovoltaic cell with its own pattern. Samples of classical and inverted structures of photovoltaic cells with P3HT and PCBM bulk heterojunction were prepared. Reference samples were prepared under standard conditions (under nitrogen). Their efficiency was around 3 %. In addition, samples were prepared by spin coating under laboratory conditions and by spreading. In both cases, their efficiency was about 1.5 %. Large-scale photovoltaic cells (active area of about 1 cm^2) were prepared in the last experiment presented. Efficiency decreased to 0.75 %. From results mentioned above is clear that very simple methods and procedures that do not impair the price/performance ratio can be used to prepare photovoltaic cells.

National Repository of Grey Literature : 83 records found   beginprevious35 - 44nextend  jump to record:
See also: similar author names
46 POSPÍŠIL, Jan
1 Pospisil, J.
46 Pospisil, Jan
17 Pospíšil, Jakub
2 Pospíšil, Jaromír
6 Pospíšil, Jaroslav
2 Pospíšil, Jindřich
26 Pospíšil, Jiří
6 Pospíšil, Josef
2 Pospíšil, Juraj
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