National Repository of Grey Literature 385 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Length bounded cuts in graphs
Berg, Michal ; Kolman, Petr (advisor) ; Dvořák, Pavel (referee)
In this thesis we will focus on a problem of length bounded cut, also known as L-bounded cut. We are going to show a combinatorial algorithm for finding a minimal L-bounded cut on graphs with bounded treewidth based on dynamic programming. Then we going to show that this algorithm can also be used for finding minimal L-bounded cut on plannar graphs. We are also going to look at problem of (dG(s, t) + 1)-bounded cut. This problem is known to be NP-hard for general graphs. But it is an open problem whether this problem is also NP-hard on plannar graphs with special vertices on the outer face. We will try to outline a way, which might lead to showing that this problem is solvable in a polynomial time.
Diversity of microalgae from extreme habitats: linking phylogeny and ecology
Barcyte, Dovile ; Nedbalová, Linda (advisor) ; Dvořák, Petr (referee) ; Bock, Christina (referee)
The diversity of microalgae from extreme habitats is far from being fully explored and understood. This is due, in part, to limited sampling efforts along with complex algal taxonomy and systematics. In particular, little investigated extremely acidic (pH < 3.0) and polar habitats might veil novel, undescribed species. This doctoral thesis aimed to study algal strains isolated from acidic or acidic and hot, and cold environments using a polyphasic approach. It focused on coccoid (Coccomyxa and Watanabea), monadoid (Chloromonas and its relatives) and saccoderm (Cylindrocystis) green microalgae from the classes Trebouxiophyceae, Chlorophyceae, and Zygnematophyceae, respectively. In addition, coccoid red algae (Galdieria) from the class Cyanidiophyceae were covered. The main research methods included light and transmission electron microscopy combined with Sanger sequencing. Nuclear 18S rDNA and plastid rbcL sequences were used for construction of phylogenetic trees for taxonomic position evaluation. Comparisons of secondary structure models of the highly variable ITS2 rDNA molecular marker served for a more detailed genetic relationship estimation among close relatives. Results have shown that Coccomyxa and Watanabea are present in extremely acidic lakes and that acidity and increased availability of...
Design of 3D-printed Unmanned Aerial Vehicle
Sladký, Martin ; Jetela, Václav (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the design proposal of the unmanned aircraft produced by FDM technology. The introduction is devoted to a brief overview of 3D printing technologies and the research of design strategies used for the production of 3D printed aircrafts. The second part is devoted to the design itself. Two types of winglets, wing and central part of the aircraft were designed. The individual parts of the aircraft have been converted to G-code format and printed on a 3D printer. Finally, the aircraft was assembled.
Experimental evaluation of appropriate FDM technology for UAV production
Hubáček, Jan ; Klement, Josef (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with material analysis and design of technology for Fused Deposition modelling 3D printing method of unmanned aerial vehicles. Nine materials which are suitable for this application has been tested. Tension test has been used to determine mechanical properties of each material according ISO standards for plastics. Material had to met certain criteria, which are important for 3D print of aeroplanes, to pass to the next stage of experiment. Next three-point flexural test of wing has been used. In this test has been tested two glued sections of wing root and one separate section of wing. Results of tensile test and flexural test were compared and evaluated. It was discovered that material PLA, which is commonly used for printing aeroplanes, has not been overcome. Materials that seems to have better mechanical properties has been disadvantaged for its bad properties in 3D printing process.
Use GPS for in flight measurement
Čížková, Markéta ; Dvořák, Petr (referee) ; Jebáček, Ivo (advisor)
Bachelor thesis Use GPS for In-Flight Measurement addresses the applicability of Global Positioning System as a tool for aircraft certification. The theoretical part of thesis aims to acquire the GPS principle, it deals with accuracy of the system and methods of certification. The practical part contains a comparison of altitude measurement using GPS and Pitot-static system in a gliding flight.
Amine plasma polymers preparation and their interaction with ECM proteins
Dvořák, Pavel ; Kozáková, Zdenka (referee) ; Zajíčková, Lenka (advisor)
The bachelor thesis deals with the preparation of amine plasma polymers which were prepared in low pressure radiofrequency capacitively coupled plasma discharge using cyclopropylamine (CPA) monomer. The amine functionalized surfaces find application as scaffolds for the immobilization of biomolecules. In this work, the interaction of plasma polymers with ECM proteins, specifically with collagen, was investigated.
Design of folding propeller for UAVs
Dítě, Radovan ; Dvořák, Petr (referee) ; Popela, Robert (advisor)
This master's thesis deals with the design of foldable propeller for UAVs. The design of the foldalble propeller is created based on theory of propellers and also on tha detail ana-lyzis of existing foldalble propellers with similar dimensions. The propeller is then manufac-tured and tested. One of the part of this thesis also describes design of central hub. At the end the methodical procedure of creating foldable propellers is suggested.
Comparison of conventional CT and VT with current and voltage sensors
Dvořák, Petr ; Drápela, Jiří (referee) ; Orságová, Jaroslava (advisor)
The diploma thesis deals with conventional transformers and current and voltage sensors. The first half of thesis describes mainly the basic concepts and accuracy classes of these converters used in electrical substations. The emphasis is given primarily on the differences. In the second half of thesis is presented an exact type of converters, which are installed in the substation Medlánky. There is an analysis of measured data from long – term monitoring from this substation and comparing the results from conventional transformers compared to the results from more modern sensors.
Design of an optimized multicopter propeller
Zeman, Petr ; Matějů, Jiří (referee) ; Dvořák, Petr (advisor)
Výdrž a účinnost multicopterů jsou z velké části ovlivněny výběrem pohonného systému, zejména pak vrtulí. Avšak u malých bezpilotních prostředků, které většinu času stráví ve visu (např. multicoptery), pracují vrtule při nízkých Reynoldsových číslech, případně i v režimu odtržení. Tyto problémy a efekty spojené s rotací jsou řešeny pomocí korekcí aerodynamických koeficientů a aplikovány na vírovou teorii. Tento přístup vede k významnému zvýšení přesnosti výpočtu leteckých vrtulí. Nicméně pro nulovou rychlost nabíhajícího proudu mají tyto korekce tendenci nadhodnocovat hodnoty tahu vrtule. Pro snížení výpočetní náročnosti a času nezbytného k získání potřebných aerodynamických vlastností pro různá Reynoldsova a Machova čísla jsou použity neuronové sítě. Celý proces je implementován do prostředí MATLAB (včetně grafického rozhraní, neuronových sítí a adaptivních algoritmů) a validován na pěti různých vrtulích k prokázání, že vypočtené výkony vrtulí se shodují s experimentálními daty. Variační počet byl vybrán jako metoda pro návrh optimalizované vrtule, jelikož s jeho využitím lze navrhnout vrtuli s maximálním tahem pro zadaný výkon. Pro ověření zvoleného přístupu byla navrhnuta optimalizovaná vrtule, jejíž koeficient tahu je vyšší než odpovídající vrtule, se kterou je srovnávána, při zachování stejné hodnoty koeficientu výkonu.
Evaluation of Business Performance Through Financial Analysis Tools
Veselý, Tomáš ; Dvořák, Petr (referee) ; Ptáček, Roman (advisor)
The topic of this bachelor thesis is „Evaluation of the efficiency of the company using financial analysis tools“. This bachelor thesis deals with evaluation of the financial situation of the company TOS Znojmo a.s., which is focused on development, production and sale of transmission equipment. The thesis is divided into three parts. The first part is focused on principles financial analysis and its use in practice. In the second part is made an analysis of the chosen company and in the third part there will be determined measures and proposals for improvement of financial situation based on the results of financial analysis.

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