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Detection of AE Sources During Long-term Fatigue Tests of Riveted Aircraft Wing Flange
Chlada, Milan ; Převorovský, Zdeněk
Fracture is the primary threat to the integrity, safety, and performance of nearly all highly stressed mechanical structures, e.g., aircrafts, building units or pressure vessels. Contemporary exacting demands on reliability and safety of material structures are not realizable without effective means of NDT and continuous state monitoring. AE monitoring of structures needs new robust and fast methods for emission source location and classification. Recently proposed AE source location method using so-called signal arrival time profiles and artificial neural networks (ANN) was applied for monitoring of growing defects during long-term fatigue testing of riveted aircraft wing flange. The potentialities of the method regarding the on-line monitoring of dangerous crack growth in selected critical parts of aircraft structures are discussed.
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Are elections lists fair or nudging?
Regéczy, Martin ; Bartoň, Petr (advisor) ; Hudík, Marek (referee)
It is generally believed that those candidates listed earlier on the ballot paper are likely to receive more votes than those listed later. This assumption was proved to be true on a sample of 100 election results collected from university elections across the whole Czech Republic in the years 2001-2009. These elections have one important feature -- all candidates are listed in alphabetical order. Those candidates with surname initials closer to the beginning of the alphabet tend to receive more votes and, as a past research says, the non-rational voters are to be blamed. No one, however, has yet analyzed the behavior of candidates. Hypothesis that candidates with better fitted surnames are more likely to enter elections, and by that create a ballot paper already with alphabetical bias, has not been proved. Other cue to voters such as the title of a candidate present on the ballot paper proved to be an important signal of quality for female candidates who were hugely advantaged compared to men who were disadvantaged due to this fact. Possible different reasons to alphabetical bias have been tested (e.g. name letter effect), but have not been found to be present.
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Conditional preparation of members of the Police of the Czech Republic
Agh, Karel ; Přívětivý, Lubomír (advisor) ; Konrád, Antonín (referee)
Résumé Name of the Project: Conditional preparation of members of the Police of the Czech Republic The aim of the Project: The aim of this Project is to resume and to evaluate contemporary situation of conditional preparation and its testing applied to the members of the Police of the Czech Republic in the selected districts of the Central Bohemian Region. Methods: I have received information necessary for completion of my diploma work from research of available literature, law and other sources that deal with the given problem. I have analysed documents and evaluated obtained data (results of revisions) to confirm or rebut the specified hypothesis. Furthermore, I have questioned anonymously policemen in the selected districts of the Central Bohemian Region. Afterwards, I have evaluated the questionnaires and have resumed obtained data for final interpretation and final comparison and evaluation. Results: Discovered knowledge presents overall state and testing of conditional preparation and introduces opinions and attitudes of policemen towards conditional preparation. Key words: conditional preparation, physical fitness, movement abilities, motoric tests, lawful rules.
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Evaluation of corrosion on selected aluminium alloys
Skýba, Pavel ; Tulka, Jaromír (referee) ; Pacal, Bohumil (advisor)
The thesis focuses on the corrosion research of AlCu4Mg1 aluminium alloys of square shape and sheet metal coated in 99.5% aluminium. The theoretical part deals with the characteristics of aluminium, the classification and naming of aluminium alloys and the impact of admixtures on aluminium alloys. In the following chapter a general introduction to metal corrosion, its differentiation according to the type of corrosion attack, mechanisms of corrosion, the impact of corrosive environment, according to the choice of anti-corrosion protection, etc. is given. The main part is devoted to the corrosion of aluminium with a special importance of the impact of admixtures on aluminium alloys, the types of corrosion attack, the impact of corrosive environment as well as of the anti-corrosion protection of aluminium alloys. The corrosion tests in controlled atmosphere are considered in the next chapter, while the last one deals with the evaluation methodology of the process of corrosion. At the beginning of the experimental part all the used samples and materials are introduced. The thesis continues then with an overview and a description of the methods used for experiments. The measurement procedure and the results of the experiments are presented in the following chapter that focuses on the metallographic analysis of the aluminium alloy samples before the experiment and after the corrosion attack. The main part of the chapter deals with the dependence of corrosion speed of the individual aluminium alloy samples on time after being exposed in the climate chamber and the salt fog chamber
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Effect of snowpack on runoff generation during rain on snow event.
Juras, Roman ; Máca, Petr (advisor) ; Ladislav , Ladislav (referee)
During a winter season, when snow covers the watershed, the frequency of rain-on-snow (ROS) events is still raising. ROS can cause severe natural hazards like floods or wet avalanches. Prediction of ROS effects is linked to better understanding of snowpack runoff dynamics and its composition. Deploying rainfall simulation together with hydrological tracers was tested as a convenient tool for this purpose. Overall 18 sprinkling experiments were conducted on snow featuring different initial conditions in mountainous regions over middle and western Europe.
Dye tracer brilliant blue (FCF) was used for flow regime determination, because it enables to visualise preferential paths and layers interface. Snowpack runoff composition was assessed by hydrograph separation method, which provided appropriate results with acceptable uncertainty. It was not possible to use concurrently these two techniques because of technical reasons, however it would extend our gained knowledge. Snowmelt water amount in the snowpack runoff was estimated by energy balance (EB) equation, which is very efficient but quality inputs demanding. This was also the reason, why EB was deployed within only single experiment.
Timing of snowpack runoff onset decrease mainly with the rain intensity. Initial snowpack properties like bulk density or wetness are less important for time of runoff generation compared to the rain intensity. On the other het when same rain intensity was applied, non-ripe snowpack featuring less bulk density created runoff faster than the ripe snowpack featuring higher bulk density. Snowpack runoff magnitude mainly depends on the snowpack initial saturation. Ripe snowpack with higher saturation enabled to generate higher cumulative runoff where contributed by max 50 %. In contrary, rainwater travelled through the non-ripe snowpack relatively fast and contributed runoff by approx. 80 %.
Runoff prediction was tested by deploying Richards equation included in SNOWPACK model. The model was modified using a dual-domain approach to better simulate snowpack runoff under preferential flow conditions. Presented approach demonstrated an improvement in all simulated aspects compared to the more traditional method when only matrix flow is considered.
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Screening test of emotive traumatization in children's painting
Myslivcová, Klára ; Vaníčková, Eva (advisor)
The aim of my degree work has been the verification of screening methods. The examination is based on emotional traumatization of the juvenile subject. As far as screening examination is concerned the method of Hardin and Peterson has been used (L.W.Peterson, M.E.Hardin, 1997). Twenty children (including boys as well as girls) were chosen to undergo the research. Children haven't been chosen randomly but with the disposition to risk factor. As a matter of fact conditions of the method were observed and according to the instructions every child drew a human body, on which the presence of certain indicators were identificated. The amount of indicators were counted together. As a result of the research the outcome was classified into 3 groups (0-2 without a danger, 3-5 low danger, 6 and more high danger). 90% of observed children has been without any risk at all. 10% of children pictures were evaluated as a low danger ones. In that case a chat with that child has been done and that may have confirmed the analysis. In conclusion I may claim that the method I have chosen in suitable for screening examination. Even though it is very fast and accurate there is one point I would like to reproach - children are chosen to according to teacher which may be a problem. Therefore my suggestin is to realise this...
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New Methods for Increasing Efficiency and Speed of Functional Verification
Zachariášová, Marcela ; Dohnal, Jan (referee) ; Steininger, Andreas (referee) ; Kotásek, Zdeněk (advisor)
Při vývoji současných číslicových systémů, např. vestavěných systému a počítačového hardware, je nutné hledat postupy, jak zvýšit jejich spolehlivost. Jednou z možností je zvyšování efektivity a rychlosti verifikačních procesů, které se provádějí v raných fázích návrhu. V této dizertační práci se pozornost věnuje verifikačnímu přístupu s názvem funkční verifikace. Je identifikováno několik výzev a problému týkajících se efektivity a rychlosti funkční verifikace a ty jsou následně řešeny v cílech dizertační práce. První cíl se zaměřuje na redukci simulačního času v průběhu verifikace komplexních systémů. Důvodem je, že simulace inherentně paralelního hardwarového systému trvá velmi dlouho v porovnání s během v skutečném hardware. Je proto navrhnuta optimalizační technika, která umisťuje verifikovaný systém do FPGA akcelerátoru, zatím co část verifikačního prostředí stále běží v simulaci. Tímto přemístěním je možné výrazně zredukovat simulační režii. Druhý cíl se zabývá ručně připravovanými verifikačními prostředími, která představují výrazné omezení ve verifikační produktivitě. Tato režie však není nutná, protože většina verifikačních prostředí má velice podobnou strukturu, jelikož využívají komponenty standardních verifikačních metodik. Tyto komponenty se jen upravují s ohledem na verifikovaný systém. Proto druhá optimalizační technika analyzuje popis systému na vyšší úrovni abstrakce a automatizuje tvorbu verifikačních prostředí tím, že je automaticky generuje z tohoto vysoko-úrovňového popisu. Třetí cíl zkoumá, jak je možné docílit úplnost verifikace pomocí inteligentní automatizace. Úplnost verifikace se typicky měří pomocí různých metrik pokrytí a verifikace je ukončena, když je dosažena právě vysoká úroveň pokrytí. Proto je navržena třetí optimalizační technika, která řídí generování vstupů pro verifikovaný systém tak, aby tyto vstupy aktivovali současně co nejvíc bodů pokrytí a aby byla rychlost konvergence k maximálnímu pokrytí co nejvyšší. Jako hlavní optimalizační prostředek se používá genetický algoritmus, který je přizpůsoben pro funkční verifikaci a jeho parametry jsou vyladěny pro tuto doménu. Běží na pozadí verifikačního procesu, analyzuje dosažené pokrytí a na základě toho dynamicky upravuje omezující podmínky pro generátor vstupů. Tyto podmínky jsou reprezentovány pravděpodobnostmi, které určují výběr vhodných hodnot ze vstupní domény. Čtvrtý cíl diskutuje, zda je možné znovu použít vstupy z funkční verifikace pro účely regresního testování a optimalizovat je tak, aby byla rychlost testování co nejvyšší. Ve funkční verifikaci je totiž běžné, že vstupy jsou značně redundantní, jelikož jsou produkovány generátorem. Pro regresní testy ale tato redundance není potřebná a proto může být eliminována. Zároveň je ale nutné dbát na to, aby úroveň pokrytí dosáhnutá optimalizovanou sadou byla stejná, jako u té původní. Čtvrtá optimalizační technika toto reflektuje a opět používá genetický algoritmus jako optimalizační prostředek. Tentokrát ale není integrován do procesu verifikace, ale je použit až po její ukončení. Velmi rychle odstraňuje redundanci z původní sady vstupů a výsledná doba simulace je tak značně optimalizována.
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Simple one-chip microcontroller programmer
Verner, Lukáš ; Číž, Radim (referee) ; Daněček, Vít (advisor)
The main purpose of my bachelor thesis is acquaint with issue programming of Atmel AVR microcontrollers and to create a simple chipprogrammer with component units like LEDs, switches, LCD display, DA converter for testing and development. The first part deal about questions of theory programming memory inside microcontrollers and descrption of programming algorithm. The memories is possible program in three way. The most used method is method call „In System Programming“ ISP. This method provide easy and fast manupulation. Order method of programming memory require 12V supply. These method are parallel and serial high voltage programming. The concept of programmer is design to all method of programming memory. From previous information about programming memory was written source code of program to control programmer that receive command from computer and ensure performing of right algorithm in target microcontroller. In the next chapter is clarified design of hardware items and there is the simple user manual of items and installation of programmer. The final part of thesis explains how to use programmer's tworowconnectors and setting jumpers for programing in daily work. In attachments are electrical scheme, list of devices, printed circuit board, files of circuit board and scheme in Eagle format, source code and binary program to control microcontroller of simple chipprogrammer. These attachments are needed for make a chipprogrammer.
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