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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Dynamická analýza válcových komínů stojících za sebou / Dynamic analysis of an in-line arranged cylindrical chimney

Harazim, Petr January 2013 (has links)
The diploma thesis deals with the response of a steel smokestack structure to wind loads. A detailed computational model implementing the finite element method was created in accordance with the available drawing documentation. The new smokestack was placed next to an existing one, thus it can be assumed that these two structures will affect each other. The thesis also elaborates on the problems of aerodynamic and aeroelastic stability of the earlier smokestack; in particular, the occurrence of vortex shedding in resonance with eigenfrequency of the structure, with the use of the program ANSYS CFX. The evaluation of the structure includes survey of the strength and deflections of the structure. The calculations are in accordance with valid ČSN EN norms.
72

Ověřování identity uživatele založené na behaviorálních charakteristikách / User Identity Verification Based on Behavioral Characteristics

Kuchyňová, Karolína January 2020 (has links)
Verifying the identity of a user logged into a secure system is an important task in the field of information security. In addition to a password, it may be appropriate to include behavioral biometrics in the authentication process. The biometrics-based system monitors the user's behavior, compares it with his usual actions, and can thus point out suspicious inconsistencies. The goal of this thesis is to explore the possibility of creating a user identity verification model based on his behavior (usage of mouse and keyboard) in a web application. The work includes creation of a new keystroke and mouse dynamics dataset. The main part of the thesis provides the analysis of features (user characteristics) which can be extracted from the obtained data. Subsequently, we report the authentication accuracy rates achieved by basic machine learning models using the selected set of features. 1
73

Zobrazování animovaných oblaků v reálném čase / Real-Time Cloud Rendering

Kučera, Vít Unknown Date (has links)
Clouds are ubiquitous and ever-changing feature of the outdoors. They are an integral factor in Earth's weather systems. Component of water circulation in a nature and a strong indicator of weather patterns and changes. Clouds are important component of the visual simulation of any outdoor scene, but the complexity of cloud formation, dynamics, and light interaction makes cloud simulation and rendering difficult in real time. In an interactive flight simulation, users would like to fly in and around realistic, volumetric clouds. I Present, two main ways of representation cloud in computer graphic, where one way use for modelling Perlin noise and second one use for modelling fluid dynamic system.
74

Dynamika revitalizovaného koryta Sviňovického potoka / Channel dynamics of the restored Sviňovický Brook

Hujslová, Jana January 2010 (has links)
The aim of this thesis was to monitor and to evaluate development and morphological dynamics of the Sviňovický Brook channel after the restoration in 2005. Field surveying and aerial images by low-flying model planes were used to detect recent channel dynamics after the restoration in 2005. Channel changes were compared to water level measurements. The additional method was grain size analysis of bed sediments. Orthoimage and cadastral maps were utilized to document changes in channel position over the past 160 years. Field surveying detected intensive bed and bank erosion in restored channel caused by high stream velocity from the fortified upper flow. The restored channel has markedly widened and deepened. The largest changes occurred during floods in July 2006. The intensive eroding- depositing processes remodeled the channel. The changes in channel bed level were up 30 cm and bank erosion locally exceeded 1 meter. The longitudinal profile of the channel was leveled. The road bridge began to be obstacle to the longitudinal profile development. It causes deposition upstream and erosion downstream. The largest bank disruptions in the sector up the road bridge were fortified by quarried stones at the end of 2007. The channel has not shown any significant changes since 2007. With the growing density...
75

Molekulové simulace nukleace ledu / Molekulové simulace nukleace ledu

Pluhařová, Eva January 2010 (has links)
Title: Molecular simulations of ice nucleation Author: Eva Pluhařová Department: Department of Physical and Macromolecular Chemistry Faculty of Science UK Advisor: doc. Mgr. Pavel Jungwirth, DSc., IOCB AS CR, v.v.i. Advisor's e-mail address: pavel.jungwirth@uochb.cas.cz Abstract: By means of molecular dynamics simulations we have systematically investigated homogeneous ice nucleation in neat and surface contaminated water. As models of the adsorbates we have assumed pentanol and pentanoic acid. In neat water nucleation preferentially starts in the subsurface region, which accommodates better than the bulk the volume increase associated with freezing. Homogeneous ice nucleation is affected more by alcohol than by acid. Water slabs covered by a disordered layer of pentanol exhibit negligible preference for subsurface nucleation and longer nucleation times in comparison with neat water, while nucleation times are almost unaffected by the presence of pentanoic acid and the subsurface preference is only slightly decreased. We tried to rationalize the differences between the effects of different compounds by their ability to orient water molecules and to change their mobility. The fact that adsorbates differ in the influence on homogeneous ice nucleation has important implications for the microphysics of...
76

Etologie a akustická komunikace kaloně egyptského (Rousettus aegyptiacus) / Behaviour and acoustic communication in Egyptian fruit bat

Vašíčková, Pavla January 2014 (has links)
Egyptian fruit bats were observed in Prague Zoo, where stable conditions are provided (year-round food supply, stable temperature and roosts). The colony has bimodal breeding cycle. Births are synchronized and occur on the turn of April and May and in September. The mating occurs throughout the year but there is an increase during lactation and in the period outside parturitions. There is no obvious pattern in cluster dynamics. Bats roost in four clusters (left, middle, upper right and lower right). The presence of clusters throughout the year is stable except upper right cluster. There are changes in the number of clusters and in the number of individuals inside each cluster. Fruit bats occupy approximately the same spots in clusters, however young individuals show the highest variability. An autogrooming is balanced throughout the year, there is no regular pattern in the observation period and even no increase after artificial twilight. From these activities a licking of wing membranes and fur are the most often. The mother cares for her young especially during lactation and weaning, while the care decreases with a development of the young. This is especially true for the licking of the wing membranes. An allogrooming is the most common between male and female during lactation and in the period...
77

Ovlinění dechových pohybů pomocí Power Breathe / Influence of the breathing muscles using POWERbreathe.

Čapková, Alena January 2015 (has links)
Title: Influence of the breathing muscles using POWERbreathe. Objective: The main object of this thesis is to determine, if it is possible to use 3D kinematic analysis to measure changes of trunk shapes during quiet breathing and breathing when using POWERbreathe and if it is possible to identify the changes. The thesis is divided to two parts. The first part contains theoretical part, focused on issue of kinesiology and biomechanics of breathing. The special part is concentrated on research, where I find changes of trunk kinematics during application of POWERbreathe. Method: Measurements were made on 6 probands in the same age category (women), when each measurement was performed during quiet breathing, maximum inhale/exhale, resistive breathing when using POWERbreathe and then another quiet breathing and maximum inhale/exhale. Quiet breathing was chosen as benchmark. The experimental measurements was done during one day. The research was used 3D kinematic motion analysis using system Qualysis. Were observed changes in the shape of the trunk and possibly caused breath changes during using POWERbreathe. Results: Measurements has confirmed, that the system Qualysis is able to detect mobility and the trunk shape changes. At a certain threshold load device POWERbreathe prevailed movements cranial...
78

Změny středoevropské netopýří fauny na hranici pliocen/pleistocen: rod Myotis / Changes in mid-European bat fauna along the Plio/Pleistocene boundary: denus Myotis

Trávníčková, Eva January 2016 (has links)
This diploma thesis summarizes results of the detailed morphometric analysis of extensive fossil materials of the genus Myotis from the upper Pliocene deposits of Javoříčské caves (Czech Republic) and Urwista cave (Poland). Patterns of phenotype variation of particular fossil populations were analyzed with aid of uni- and multivariation techniques, compared with type series of fossil taxa described from MN15 site Gundersheim and a comparative series of extant European species. Nine fossil and 10 extant species were identified and further reexamined in terms of their phenotype variation and possible phylogenetic relations. The phenotype structure of fossil assemblages were compared to that of Gundersheim and extant European fauna: samples from Urwista cave show clear resemblances to the former one, those from Javoříčské cave exhibit certain similarities to the extant European fauna despite clear differences in variation patterns of particular species. Technical preparation, documentation by photographic material, measurement and statistical analysis is included in this work. Key words: bats, Pliocene, phenotype dynamics, community structure
79

Návrh, parametrizace a ověření mezoskopického modelu DNA / Design, parameterization and verification of a coarse-grained model of DNA

Dršata, Tomáš January 2012 (has links)
Structure and mechanical properties of DNA play a key role in its biological functioning. A lot of well-established conclusions about the DNA structure and its sequence-dependent variabil- ity came from various experimental and computational studies of the Dickerson-Drew dodecamer (DD), a prototypic B-DNA molecule of the sequence (5')CGCGAATTCGCG(3'). In this study we present a detailed analysis of structural and mechan- ical properties of DD based on extensive atomistic molecular dynamics (MD) simulations with explicit representation of wa- ter and ionic environment. We analyze three simulated systems covering different ionic conditions and water models. Two MD trajectories are reported for the first time, one of them being 2.4 µs long. An extensive comparsion with one recent NMR struc- ture and four recent X-ray structures is made. It is found that the end basepairs can adopt two different pairing motifs dur- ing the simulation: the canonical Watson-Crick pair or a non- canonical trans Watson-Crick/Sugar Edge pair. These states can significantly influence the structure of DD even at the third step from the end. A clear relationship is found between the BI/BII backbone substates and the basepair step conformation. A model of rigid bases is used to study mechanical properties of the DNA. The non-local...
80

Dynamika textu v biblích melantrišské řady (1549-1613) / Textual Dynamism in Bibles of Melantrichian Tradition (1549-1613)

Kapitolová, Zuzana January 2013 (has links)
The topic of this diploma thesis was an analysis and comparison of the Bibles of Melantrichian tradition. In the first part of the thesis, we briefly described the history of the Bible translations in Europe and in Czech lands and then we outlined the importance of Melantrichian Bibles in Czech history and literature. At the end of this part of the thesis, we summarized the conclusions of previous analyses of this topic. In the main part of the thesis, we analyzed differences between all Melantrichian Bi- bles divided into five sections - graphics and orthography, phonology, morphology, syntax and textual changes. We used textual probes into the Old Testament and the New Testament as the method for our analysis. Subsequently, we compared our results with the previous analyses of the topic.

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