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Analýza paralelizovatelnosti programů na základě jejich bytecode
Brabec, Michal ; Bednárek, David (advisor)
Analysis of automatic program parallelization based on bytecode There are many algorithms for automatic parallelization and this work explores the possible application of these algorithms to programs based on their bytecode or similar intermediate code. All these algorithms require the identification of independent code segments, because if two parts of code do not interfere with one another then they can be run in parallel without any danger of data corruption. Dependence testing is an extremely complicated problem and in general application, it is not algorithmically solvable. However, independences can be discovered in special cases and then they can be used as a basis for application of automatic parallelization, like the use of vector instructions. The first step is function inlining that allows the compiler to analyze the code more precisely, without unnecessary dependences caused by unknown functions. Next, it is necessary to identify all control flow constructs, like loops, and after that the compiler can attempt to locate dependences between the statements or instructions. Parallelization can be achieved only if the analysis discovered some independent parts in the code. This work is accompanied by an implementation of function inlining and code analysis for the .NET framework.
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Analysis of the mechanical behavior of wood by means of digital image correlation
Brabec, Martin
The full-field optical techniques such as e.g. a digital image correlation are capable to fully reflect the natural wood heterogeneity. Therefore, this thesis aspires to contribute to the experimental mechanics of wood and wood-based composites by the implementation of the full-field optical technique based on the digital image correlation to the standard mechanical tests. A supplementation of the conventional displacement sensors should help to obtain more precise mechanical characteristics and to do more sophisticated analyses of the deformation behaviour of wood and wood-based composites. The experimental part of the thesis is divided into the five independent case studies listed as the original papers. The measurements were carried out on the most wide-spread wood species in central Europe such as European beech (Fagus sylvatica, L.) and Norway spruce (Picea abies, L. Karst). Beside the solid wood, the new wood-based sandwich structure, which consists of a core made from birch plywood and the particleboard facings, was investigated too. The loading of the samples was carried out using of the standard mechanical tests such as tension, compression, three-point bending and torsion test. In the first study, the full-field deformation data were used to indentify reasons for the non-standard deformation behaviour of spruce and beech wood during compression parallel to grain. Reason for this was recognized in the abrubt compression of damage zones located near the compression plates, which induced the expansion of the middle zone located between them. The second study aimed to find out neutral axis position in native and thermally modified beech wood during the conventional three-point bending test. The relative neutral axis position was obtained from mutual position of the neutral axis and centroidal axis, which was determined based on the appropriate image processing methods. It was found that the neutral axis and centroidal sample axis are almost coincident. Objective of the third study was to determine both longitudinal shear moduli of beech wood with help of the full-field shear strains, obtained from a single torsion test, together with use of the appropriate analytical solutions for the calculation of the stress distribution within the radial and tangential direction on the longitudinal-radial and longitudinal-tangential sample surfaces. Both longitudinal shear moduli increasingly mutually differed as the load increases. Within the fourth study, verification of the elastic material model used in finite-element analyses was carried out with help of full-field deformations induced around notches within dog-bone shaped sample during the uniaxial tension. Great correlation was found between numerically predicted and experimentally measured strain data sets for both longitudinal-radial and longitudinal-tangential shear planes. The fifth study dealed with the characterization of elastic deformation behaviour of newly developed wood-based composite with a sandwich structure. Based on the full-field strain analysis the local strain concentrations were identified. They took place within the core during flatwise compression, and within the facings, when the edgewise compression test was done. A variety of presented results confirmed widespread applicability of optical methods in the mechanics of materials. Therefore, the utilization of full-field optical method based on digital image correlation in experimental mechanics of wood and wood-based composites can be highly recommended.
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The effect of production parameters on the plasticity of structural steel
Brabec, Martin ; Podaný, Kamil (referee) ; Peterková, Eva (advisor)
The master thesis deals with the influence of heat treatment and storage time on microstructure and mechanical properties of 26MnB5 steel, which is used in the production of tubular components in the quenched and tempered state. The objective was to increase the plasticity of the steel by the definition of new process parameters of the induction heat treatment line. New tempering diagrams of 26MnB5 steel for two various speeds of the heat treatment line were established and used to determine new tempering temperature and speed of the heat treatment line. Observation of the influence of storage time on mechanical properties of the steel did not reveal that it is liable to ageing.
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Self-ownership, its adequacy and comparison with autonomy
Matoška, Lukáš ; Brabec, Martin (advisor) ; Karásek, Jindřich (referee)
The bachelor's thesis deals with selected self-ownership approaches to abortion and suicide. It is based on the observation that in these two areas, the argumentation based on the assumption of self- possession is relatively widespread. The question is to what extent are these approaches adequate, i.e. to what extent do they correspond to real-life situations. A way to assess adequacy is proposed expanding on Margaret Olivia Little. The self-ownership approach to abortion is then shown to be inadequate in specific cases. The thesis also focuses on the libertarian approach to the issue of the right to consensual killing. Discussing the article by Peter Vallentyne, it is shown that defence of this right based on self-ownership may not be sufficient. In this context, it focuses on the relationship between self-ownership and autonomy. It shows that they enable two separate argumentative strategies by which to defend an individual's rights.
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Speed of sound prediction
Řežábková, Jana ; Hartman, David (advisor) ; Brabec, Marek (referee)
This bachelor thesis presents a novel approach for speed of sound pre- diction in aqueous electrolytic solutions using machine learning techniques. A single model capable of accurately predicting the speed of sound in se- lected electrolytic aqueous solutions at different temperatures and molalities is trained. The machine learning experiment is designed to exploit the dis- sociation of electrolytes in water. Electrolytes are viewed as cation/anion pairs. Therefore, electrolyte description is based purely on its constituting ions. This approach allows to view the available data as a matrix in which rows represent cations, columns anions and each cell a full electrolyte. The idea of being able to fill cells for which no speed of sound data is yet avail- able is tested within the thesis. The final model's accuracy is compared to existent research on speed of sound prediction. However, some of the model approaches are novel and have no existing comparable settings. 1
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Logos liberal democracy?
Brabec, Martin
The paper presents conceptual analyzes of liberal democracy. It shows that liberal democracy appears as harmonic association of different spheres and rights but it inside contains contradiction betwen democracy (collective decision) and liberal principle which emphasis constitutional personal rights. Misunderstanding of this distinction lead to confusion of democracy with liberal democracy.
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Procedural code integration in streaming environments
Brabec, Michal ; Bednárek, David (advisor) ; Krall, Andreas (referee) ; Šimeček, Ivan (referee)
Title: Procedural code integration in streaming environments Author: Mgr. Michal Brabec Department: Department of Software Engineering Supervisor: David Bednárek, Ph.D. Abstract: Streaming environments and similar parallel platforms are widely used in image, signal, or general data processing as means of achieving high perfor- mance. Unfortunately, they are often associated with domain specific program- ming languages, and thus hardly accessible for non-experts. In this work, we present a framework for transformation of a procedural code to a streaming ap- plication. We selected a restricted version of the C# language as the interface for our system, because it is widely taught and many programmers are familiar with it. This approach will allow creating streaming applications or their parts using a widely known imperative language instead of the intricate languages specific to streaming. The transformation process is based on the Hybrid Flow Graph - a novel inter- mediate code which employs the streaming paradigm and can be further convert- ed into streaming applications. The intermediate code shares the features and limitations of the streaming environments, while representing the applications without platform specific technical details, which allows us to use well known graph algorithms to work with the...
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Single Point Incremental Forming
Brabec, Martin ; Podaný, Kamil (referee) ; Peterková, Eva (advisor)
Incremental metal sheet forming has gone through a period of development and enjoys increased attention of industry for its unique benefits and properties. This work aims for an up to date state-of-the-art review of incremental metal sheet forming focused mainly on single point incremental forming appended by a review of used tools, machines and applications.
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Mechanical analysis of scarf joint fastened using cylindrical wooden dowel
Tippner, J. ; Milch, J. ; Kunecký, Jiří ; Kloiber, Michal ; Brabec, M. ; Sebera, V.
Traditional all-wooden woodworking joints play an important role in the behaviour of timber structures. These joints are also widely used when historically valuable constructions are being reconstructed and the connections are usually the masterpieces that testify to the high carpentry skills and knowledges of the overall mechanical behaviour. Within historical timber structures traditional carpentry joints were used while wooden dowel fixed mutual position of elements. Main aim of this study was to contribute to knowledge base about prediction and analysis of the mechanical performance of frequently used scarf joints made from spruce wood fastened using oak dowels. The objectives were to determine the joints' slip moduli and load-carrying capacity by means of theoretical and experimental approaches, in next to assess the mechanical behaviour of dowels through experimental investigation, and finally to perform a strain analysis of dowels. For these purposes, the optical technique employing three-dimensional full-field digital image correlation was used. The experiments were done on the full-scale specimens meeting the requirements of European standards (EN 383 and EN 26891), which were made from Norway spruce (Picea abies L. Karst.) and English oak (Quercus robur L.). The mechanical load consisted in tensile parallel and perpendicular to grain direction within the main components. The results of this study showed good correlation between theoretical approach based on based on Beam on Elastic Foundation theory and European yield model theory and experimental observations.
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Analýza paralelizovatelnosti programů na základě jejich bytecode
Brabec, Michal ; Bednárek, David (advisor)
Analysis of automatic program parallelization based on bytecode There are many algorithms for automatic parallelization and this work explores the possible application of these algorithms to programs based on their bytecode or similar intermediate code. All these algorithms require the identification of independent code segments, because if two parts of code do not interfere with one another then they can be run in parallel without any danger of data corruption. Dependence testing is an extremely complicated problem and in general application, it is not algorithmically solvable. However, independences can be discovered in special cases and then they can be used as a basis for application of automatic parallelization, like the use of vector instructions. The first step is function inlining that allows the compiler to analyze the code more precisely, without unnecessary dependences caused by unknown functions. Next, it is necessary to identify all control flow constructs, like loops, and after that the compiler can attempt to locate dependences between the statements or instructions. Parallelization can be achieved only if the analysis discovered some independent parts in the code. This work is accompanied by an implementation of function inlining and code analysis for the .NET framework.
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