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Diamond coated AlGaN/GaN high electron mobility transistors - effect of deposition process on gate electrode
Vanko, G. ; Ižák, Tibor ; Babchenko, O. ; Kromka, Alexander
We studied the influence of the diamond deposition on the degradation of Schottky gate electrodes (i.e. Ir or IrO2) and on the electrical characteristics of AlGaN/GaN high electron mobility transistors (HEMTs). In present study, the diamond films were selectively deposited on the AlGaN/GaN circular HEMT by focused (ellispoidal cavity reactor) and linear antenna (surface wave) microwave plasma at different temperatures from 400°C to 1100°C. The preliminary results on electrical measurements on the diamond-coated c-HEMTs showed degraded electrical properties comparing to c-HEMTs before deposition process, which was attributed to degradation of the Ir gate electrodes even at temperatures as low as 400°C. On the other hand, metal oxide gate electrode layer (IrO2) can withstand diamond CVD process even at high temperatures (~900°C) which make it suitable for fabrication of all-in-diamond c-HEMT devices for high-power applications.
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Optimization of network flow monitoring
Žádník, Martin ; Lhotka,, Ladislav (referee) ; Matoušek, Radomil (referee) ; Sekanina, Lukáš (advisor)
The thesis deals with optimization of network flow monitoring. Flow-based network traffic processing, that is, processing packets based on some state information associated to the flows which the packets belong to, is a key enabler for a variety of network services and applications. The number of simultaneous flows increases with the growing number of new services and applications. It has become a challenge to keep a state per each flow in a network device processing high speed traffic. A flow table, a structure with flow states, must be stored in a memory hierarchy. The memory closest to the processing is known as a flow cache. Flow cache management plays an important role in terms of its effective utilization, which affects the performance of the whole system. This thesis focuses on an automated design of cache replacement policy optimized to a deployment on particular networks. A genetic algorithm is proposed to automate this process. The genetic algorithm generates and evaluates evolved replacement policies by a simulation on obtained traffic traces. The proposed algorithm is evaluated by designing replacement policies for two variations of the cache management problem. The first variation is an evolution of the replacement policy with an overall low number of state evictions from the flow cache. The second variation represents an evolution of the replacement policy with a low number of evictions belonging to large flows only. Optimized replacement policies for both variations are found while experimenting with various encoding of the replacement policy and genetic operators. The newly evolved replacement policies achieve better results than other tested policies. The evolved replacement policy lowers the overall amount of evictions by ten percent in comparison with the best compared policy. The evolved replacement policy focusing on large flows lowers the amount of their evictions two times. Moreover, no eviction occurs for most of the large flows (over 90%). The evolved replacement policy offers better resilience against flooding the flow cache with large amount of short flows which are typical side effects of scanning or distributed denial of service activities. An extension of the replacement policy is also proposed. The extension complements the replacement policy with an additional information extracted from packet headers. The results show further decrease in the number of evictions when the extension is used.
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Dynamics of N2O emissions after C and N amendments of soil at the cattle overwintering area
Hynšt, Jaroslav ; Brůček, Petr ; Čuhel, Jiří ; Šimek, Miloslav
Field experiments were carried out at the cattle overwintering area in South Bohemia, Czech Republic, focused on the emissions of N2O after soil amendments with nitrate and glucose. Emissions were estimated using a permanent static chamber technique. Nitrate and glucose amendments caused very sharp increases of N2O fluxes, which however diminished after 2-3 days. Total amount of N2O escaping the soil was related to the amount of N and C added, and was calculated to 1-15 kg N.ha-1 (0.2-3% of N applied). Emissions were heterogeneous, which is shown by great differences among the individual chambers. Emissions were variable in time and very probably were controlled by temperature, as they approximately followed the air and surface soil temperature patterns. Despite the timing of amendment application, peaks of emissions were always determined 6 hours after the amendments.
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Multivalued logic systems for technical applications
Turek, Vojtěch ; Druckmüller, Miloslav (referee) ; Martišek, Dalibor (advisor)
Velmi často je vyžadováno, aby automatizovaná zařízení byla jistým způsobem "inteligentní", tedy aby jejich řídicí systémy uměly emulovat rozhodovací proces. Tato diplomová práce poskytuje obecný formální popis vícehodnotových logických systémů schopných zmíněné emulace a jejich souvislost s teorií fuzzy množin. Jsou uvedeny způsoby vytváření matematických modelů založených na lingvistických datech. Dále se práce zabývá znalostními bázemi a jejich vlastnostmi. Součástí této práce je také počítačový program sloužící k tvorbě slovních modelů.
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Dynamic card of cost indicator of house
Vrbka, Marek ; Tajbr,, Aleš (referee) ; Krejza, Zdeněk (advisor)
This master thesis describes a detached house, requirements for the detached house, price, technical-economic index and card of cost indicator. The author performed an analysis of selected houses and itemized budgets of selected houses. Different shapes, technologies and solutions of materials are included in the analysis. The author, from the analysis, inferred the behavior of technical-economic index (TEI) of detached houses. The author described behavior in the particular and sub models. The author suggested methodology of calculation of the price data, the spatial data and the structure of price TEICF2 (technical-economic index, complex formula, version 2) of planned detached house. The author founded his methodology on particular and sub models. The principle of methodology TEICF2 consists in the analogy of the planned detached house with the model with same parameters. The author implemented TEICF2 into application dyCBI. Application dyCBI is working on Microsoft Excel.
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The application of marketing mix - case study
Otavová, Petra ; Sieber, Martina (referee) ; Vlček, Josef (advisor)
The final aim of my study is to create marketing mix for selling luxury eyeglasses. This study is worked out in conditions of the company named Optik Otava which does not use professional marketing strategic planning. First of all the optical profession is presented and the optical market is analyzed. In the second part, there is prepared a theoretical base for marketing mix creation. Marketing mix is just one part of marketing strategic planning, therefore I also have to speak of particular methods used for situation analysis processing, the marketing aims, marketing strategies and segmentation of the market. Then the detailed elaboration of fundamental parts in marketing mix (product, price, place and promotion) is realized. The last part is the case study. There is description of the company which is mentioned above, as well as, there is created the structure of its marketing mix. The value of nonprofessional marketing mix is not low. Despite of this fact there are suggested proposals and recommendations at the end, which could positively affect marketing mix of that company. The most important one relevant to the place proposes to establish the own wholesale. This would affect also the price and the product. The whole study should be valuable for the company. It should help its to develop the marketing...
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Doped DLC coatings for biomedical applications
Písařík, Petr
Nowadays there are materials having excellent properties for use in medicine (Diamond-like carbon, Hydroxyapatite, …). Diamond-like carbon (DLC) is a metastable form of amorphous carbon containing bonded carbon atoms of sp2 and sp3 hybridized orbital. DLC layers are semiconductors with high mechanical hardness, chemical inertness, low coefficient of friction, high thermal conductivity, good electrical and optical properties, biocompatibility and no cytotoxicity. All properties of the films are not always ideal, so it is necessary to modify the layer. One example of how to modify the properties of thin layers are dopations. The incorporation of dopants in films may lead to greater multifunctionality and much improved properties. Most modifications were made to modify contact angle and surface energy, to reduce internal stresses, to decrease surface roughness, coefficient of friction or wear....
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The Purpose and Implementation of Fingerprint Scanning in Personal Computers
Varadinov, Petr ; Pecinovský, Rudolf (advisor) ; Rais, Aziz Ahmad (referee)
This diploma thesis deals with fingerprint recognition applied in personal computers. The topic is analyzed both chronologically in historical context and in connection with other biometric methods. The thesis provides a comprehensive survey of the topic. It starts with physical layer, goes through hardware parts and ends with software architecture. A special attention is paid to programming fingerprint recognition support into end-user applications. These are the aims of the thesis: to place the silicon fingerprint sensing technology into the historical context and describe its evolution in connection with personal computers till the present times, to provide the results of market research of fingerprint sensors used in personal computers, to work out the summary of the functions the end-users have at their disposal, to present the market research results of fingerprint software, to work out the overview and the comparison of available software development kits (SDKs) and that of application programming interfaces (APIs) used for the described fingerprint sensor devices, and last but not least to develop a demonstration application that communicates with a fingerprint sensor device. Technical literature, market researches together with my own experience from the work in this field were used so as to meet the set aims. As for the demo application of this technology it is my own innovative approach. The thesis is divided into seven chapters where Chapter II -- Chapter VI directly deal with the mentioned topics. The completion of a missing angle of approach to the subject from end-users' and application programmers' perspective is the main asset of this thesis. The work also allows orientation on the silicon fingerprint sensor market and fingerprint software market. Moreover it shows possibilities how to extend this technology, it provides a detailed analysis of the software layer and presents programming samples showing that show how to use this technology. The demo application allowing audio volume control by a fingerprint device is an innovation in the branch of computer input devices.
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