Iskanje po katalogu digitalne knjižnice

Opis: This paper proposes a new string transformation technique called Move with Interleaving (MwI). Four possible ways of rearranging 2D raster images into 1D sequences of values are applied, including scan-line, left-right, strip-based, and Hilbert arrangements. Experiments on 32 benchmark greyscale raster images of various resolutions demonstrated that the proposed transformation reduces information entropy to a similar extent as the combination of the Burrows–Wheeler transform followed by the Move-To-Front or the Inversion Frequencies. The proposed transformation MwI yields the best result among all the considered transformations when the Hilbert arrangement is applied.
Ključne besede: computer science, algorithm, string transformation, information entropy, Hilbert space filling curve
Objavljeno v DKUM: 22.05.2024; Ogledov: 151; Prenosov: 8
Celotno besedilo (26,44 MB)
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Opis: An analysis of Slovenian legends about Turkish raids was made to identify and analyze religious elements in them. The legends express superiority of Christianity, but also contain belief elements that diverge from Christian teachings, such as traditional Slavic beliefs about the afterlife. The mixture of different beliefs can summarized under the term “vernacular religion”. The Turks in folklore represented an archetypal demonic “Other” and as such they threaten the “Our” world. In these legends traditional and pre-Christian beliefs were intermixed with Christian symbolism and characters and as such they express the diversity and flexibility of religious imagery.
Ključne besede: Turkish raids, vernacular religion, Christianity, otherness, sacred space, sacrilege, the world beyond, miracles
Objavljeno v DKUM: 25.01.2024; Ogledov: 342; Prenosov: 7
Celotno besedilo (1,92 MB)
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Opis: In the space industry, the continuous effort to reduce the weight of structural components is of utmost importance due to the high cost of launching mass into space. Structural analyses and optimizations with numerical methods play a crucial role in achieving this goal by minimizing material usage while ensuring structural integrity. The objective of this dissertation is to implement and demonstrate the accuracy and effectiveness of meshless methods in numerical studies compared to the Finite Element Method (FEM), focusing on designing cost-effective and lightweight components. Through benchmark examples and extensive research on optimal parameters, the accuracy and effectiveness of these methods are established. Furthermore, practical application is demonstrated by optimizing the spoke of NASA's Rover Perseverance wheel, resulting in more optimized structures with significantly reduced mass and lower mechanical stresses. Additionally, analysis of different materials for the wheel's spoke is performed with the aim of further reducing mass and increasing performance. By utilizing structural optimization, this work not only highlights the diverse applications and benefits of integrating structural optimization in the product design phase but also contributes to the ongoing efforts in the space industry to reduce material mass and enhance performance, addressing the challenges associated with launching mass into space while ensuring the adequate structural resistance. Furthermore, this thesis also contributes to the development of the meshless methods in structural optimization, showcasing its effectiveness and potentials.
Ključne besede: Space technology, Mars Rover, Structural Optimization, Meshless Methods
Objavljeno v DKUM: 08.11.2023; Ogledov: 370; Prenosov: 31
Celotno besedilo (41,26 MB)

Opis: This thesis aims to implement an open-source framework for the automatic alignment and tracking of the KORUZA v2 Pro free-space optical solution. Free-space optical systems are explored and current optical alignment and tracking solutions are analyzed. We use Neural Network-based object detection approaches to complement the essential collection of framework functionality. We train a Neural Network to detect KORUZA v2 Pro units with data gathered from currently deployed links. The out-of-the-box solution for automatic alignment and tracking can be freely modified and extended.
Ključne besede: free-space optics, automatic alignment, neural networks, object detection, open-source framework
Objavljeno v DKUM: 14.03.2022; Ogledov: 795; Prenosov: 85
Celotno besedilo (4,68 MB)

Opis: In this thesis the classical and quantum dynamics in billiard systems are considered. Extensive numerical studies of the classical transport properties in several examples of billiard families including the ergodic Bunimovich stadium and cut-circle billiards and the mixed-type Robnik and lemon billiards are performed. The analysis of the transport is based on the random model of diffusion which assumes that due the strongly chaotic dynamics the motion of the orbit on the discretized phase space is temporally uncorrelated. The cause of the deviations from the random model dynamics is traced to dynamical trapping due to stickiness. A novel approach to locally quantifying stickiness based on the statistics of the recurrence times is presented and applied to distinguish between exponential decays of recurrence times and other types of decays. This enables the identification of sticky areas in the chaotic components. Detailed maps of their structure for a wide range of parameter values, mapping the evolution of the mixed-phase spaces and revealing some particularly interesting special examples are presented. The recurrence time distributions in sticky areas are found to be well described by a mixture of exponential decays. The transport of particle ensembles in the momentum space of classical billiards is described by using an inhomogeneous diffusion model and the classical transport times are determined. The classical transport times are vital for the analysis of the localization of chaotic eigenstates in quantum billiards. The control parameter that describes the the degree of localization of the chaotic quantum eigenstates is the ratio between the Heisenberg time (Planck's constant divided by the mean level spacing) and the classical transport time. Extensive numerical calculations of the high-lying spectra and eigenstates of the stadium, Robnik and lemon quantum billiards are performed. The spectral statistics are analysed in terms of the standard methods of quantum chaos. The level repulsion exponent of localized eigenstates is found to be a rational function of the control parameter. The degree of localization is determined with respect to localization measures based on the Poincaré-Husimi representation of the eigenstates. The mean localization measure is found to be a rational function of the control parameter and linearly related to the level repulsion exponent. The distributions of the localization measures are analysed and found to be of a universal shape well described by a two parameter empirical distribution in billiards with no apparent stickiness. The nonuniversal system specific features of localization measure distributions are related to the presence of sticky areas in the phase spaces of classical billiards with specific examples shown.
Ključne besede: Transport, localization, chaos, quantum chaos, Hamiltonian systems, level spacing distribution, mixed phase space, billiard, quantum billiard, Husimi functions, stickiness, cantorus, chaotic eigenstates, level repulsion.
Objavljeno v DKUM: 13.01.2021; Ogledov: 1543; Prenosov: 158
Celotno besedilo (24,93 MB)