Visualization of Volumetric Data

Import 26/06/2013Práce shrnuje současné techniky zobrazování volumetrických dat a popisuje implementaci jedné vlastní metody. Cílem práce bylo vytvoření netriviálního renderovacího algoritmu pro vizualizaci medicínských řezů získaných z lékařských přístrojů. Text hodnotí v několika kapitolách aktuální problematiku zpracovávání objemových dat, v další části pak komentuje vývoj metody vlastní vycházející z představené teorie. Implementovaný renderer vychází z principu přímého volumetrického zobrazování (DVR) a využívá moderních stochastických postupů (Monte Carlo) k efektivnějšímu běhu. Poslední částí práce je pak akcelerace algoritmu na GPU s využitím architektury CUDA a představení měření a dosažených výsledků.This thesis summarizes present techniques for rendering volumetric data and describes implementation of our own method. The aim of thesis was to create nontrivial rendering algorithm for visualization of volumetric slices obtained from medical devices. This text is commenting actual issues of processing volumetric data in few chapters. The next part is about developing of our method which is based on the discussed theory. Render follows the principles of DVR and uses modern Monte Carlo algorithms to make it more efficient. The last part of the thesis is about accelerating of the render on a GPU via CUDA architecture and summarizing measured values and obtained results.460 - Katedra informatikyvýborn

Utilization of the discrete differential evolution for optimization in multidimensional point clouds

The Differential Evolution (DE) is a widely used bioinspired optimization algorithm developed by Storn and Price. It is popular for its simplicity and robustness. This algorithm was primarily designed for real-valued problems and continuous functions, but several modified versions optimizing both integer and discrete-valued problems have been developed. The discrete-coded DE has been mostly used for combinatorial problems in a set of enumerative variants. However, the DE has a great potential in the spatial data analysis and pattern recognition. This paper formulates the problem as a search of a combination of distinct vertices which meet the specified conditions. It proposes a novel approach called the Multidimensional Discrete Differential Evolution (MDDE) applying the principle of the discrete-coded DE in discrete point clouds (PCs). The paper examines the local searching abilities of the MDDE and its convergence to the global optimum in the PCs. The multidimensional discrete vertices cannot be simply ordered to get a convenient course of the discrete data, which is crucial for good convergence of a population. A novel mutation operator utilizing linear ordering of spatial data based on the space filling curves is introduced. The algorithm is tested on several spatial datasets and optimization problems. The experiments show that the MDDE is an efficient and fast method for discrete optimizations in the multidimensional point clouds.Web of Scienceart. no. 632953

Automation of cleaning and ensembles for outliers detection in questionnaire data

This article is focused on the automatic detection of the corrupted or inappropriate responses in questionnaire data using unsupervised outliers detection. The questionnaire surveys are often used in psychology research to collect self-report data and their preprocessing takes a lot of manual effort. Unlike with numerical data where the distance-based outliers prevail, the records in questionnaires have to be assessed from various perspectives that do not relate so much. We identify the most frequent types of errors in questionnaires. For each of them, we suggest different outliers detection methods ranking the records with the usage of normalized scores. Considering the similarity between pairs of outlier scores (some are highly uncorrelated), we propose an ensemble based on the union of outliers detected by different methods. Our outlier detection framework consists of some well-known algorithms but we also propose novel approaches addressing the typical issues of questionnaires. The selected methods are based on distance, entropy, and probability. The experimental section describes the process of assembling the methods and selecting their parameters for the final model detecting significant outliers in the real-world HBSC dataset.Web of Science206art. no. 11780

Study of the influence of structure on the resistivity of silicate composites

Electroconductive silicate-based composites are advanced materials that allow building structures to perform several different functions simultaneously. Addressing the issues of their development and use is a suitable topic for research work. The aim of this work is to study the effect of structure on the resistivity of silicate composite. The structure of electrically conductive composites is studied on dry cement paste and mortar mixtures as well as on test bodies made of hardened cement paste and mortar after 28 days of curing. Based on the analysis of the raw materials, six suitable electroconductive fillers are selected based on particle size, resistivity, and water absorption. The parameters of dry cement paste and hardened cement paste with replacement of 4-19 wt. % cement by the selected fillers are determined. Two of the fillers are selected for use in dry and hardened mortar. Resistivity is determined for all dry mixes and hardened composites variants, and percolation thresholds are approximately determined. By studying the structure of the selected variants, it is shown that the most important parameters that have the greatest influence on the resistivity of the silicate composites are mainly the particle size and the intrinsic resistivity of the electrically conductive filler. For silicate composites in the hardened state, the volume of hydration products, especially portlandite and C-S-H gels, also has a significant influence. For both dry blends and hardened composites, it was found that the smaller the particle size of the electroconductive filler, the smaller the representation needed to reach the percolation threshold. Portlandite and C-S-H gels in the volume of the hardened composite cause its high resistivity. The resistivity of the hardened composite is always higher than that of the dry blends. Thus, the proportion of electroconductive filler needed to reach the percolation threshold is higher in hardened composites than in dry mixes. The resis

Proposition of new type of injection material with electrically conductive function

Bakalářská práce se zabývá návrhem nového typu injektážní hmoty s elektricky vodivou funkcí vhodné pro překlenutí trhlin a mezer v systémech ochrany stavebních konstrukcí před úderem blesku a vznikem přepětí. V teoretické části je shrnuta důležitá problematika injektování, představen stav současného poznání v oblasti ochrany budov před bleskem a přepětím a také jmenovány předpoklady elektrické vodivosti kompozitních materiálů na bázi cementu. V praktické části jsou nejprve shrnuty vybrané vlastnosti, které by elektricky vodivá injektážní hmota měla vykazovat a jsou popsány příslušné normami popsané zkoušky pro experimentální ověření vybraných vlastností. Je sestaveno široké spektrum primárních i druhotných plniv a vybrány z nich ty nejvhodnější pro docílení nízké hodnoty elektrické rezistivity vyvíjené hmoty. V závěru práce je proveden návrh receptur na základě nashromážděných poznatků a využívající druhotných plniv pro snížení dopadu výroby vyvinuté hmoty na životní prostředí. Podařilo se prokázat sníženou rezistivitu u receptur využívajících odpadní uhlík a sekaná uhlíková vlákna, ale nepodařilo se zcela vyhovět normovým požadavkům. Výsledkem práce jsou ověřené receptury a nové poznatky, které mohou dobře posloužit jako základ pro pokračovaní dalšího výzkumu.The bachelor thesis deals with the design of a new type of grouting material with electrically conductive function suitable for connecting cracks and gaps in building protection systems against lightning strikes and surges. The theoretical part summarizes the important knowledge about the grouting and grouting materials, introduces the current state of knowledge in the field of lightning and surge protection of buildings and also the preconditions of electrical conductivity of cement-based composite materials. In the practical part are summarized selected properties, which the electrically conductive grouting material should have and the relevant standards tests for experimental verification of selected properties are described. A wide range of primary and secondary fillers are studied and the most suitable ones are chosen to achieve a low electrical resistivity value. At the end of the thesis, there are recipes based on amassed knowledge and using secondary fillers to reduce the environmental impact of the developed materials during mass production. Reduced resistivity has been demonstrated in recipes using waste carbon and chopped carbon fibers, but has failed to fully meet standard requirements. The result of the work are new recipes and knowledge that can serve as a basis for further research.

Overview of knowledge of children in primary and secondary school about the integrated rescue system

Title: Overview of knowledge of children in primary and secondary school about the integrated rescue system. Objectives: The aim of this bachelor thesis is to find out what knowledge students in primary and secondary school have about the integrated rescue system. Furthermore, to compare individual answers of students between the two schools. Methods: For this research, an electronic questionnaire was created on the survio.com website. Results: Pupils from both schools have a great overview of the integrated rescue system. The high school students answered flawlessly, with some exceptions. All results are recorded in the work in the form of graphs. Keywords: integrated rescue system, Police of the Czech Republic, Medical Rescue Service, Fire Rescue Corp

Individual Professional Practice in the Company

Import 04/07/2011Práce o praxi prováděné ve firmě ISSA CZECH s.r.o. zaměřené na vývoj webových aplikací a informačních systémů. Cílem praxe byla spolupráce na vývoji internetové „půjčovny“ filmů Topfun.cz. Web bude sloužit k prodeji filmů v digitální podobě, které si uživatel může stáhnout na disk, nebo přehrát v prohlížeči formou přehrávače Windows Media Player. Jednalo se především o naprogramování a nastylování administrační části webu a ORM dle požadavků zadavatele na základě předpřipravené datové analýzy. Mimo to bylo zapotřebí naprogramovat několik JavaScriptových funkcí a widgetů pro zefektivnění ovládání uživatelského rozhraní či načítání dat přes AJAX.This is a thesis about a job done in the company ISSA CZECH s.r.o. which is specialized in a development of web aplications and information systems. The aim of the professional practise was a cooperation in a programming of internet aplication Topfun.cz which is focusing on distribution of movies. Web was made for selling movies which can be downloaded to a hard drive or played with Windows Media Player in a browser. I was supposed to program and design administration of the web and its ORM according to requirements of customer and a prepared data analysis. Beside this I had to program some JavaScript functions and widgets to make a user interface more efficient or to load data via AJAX.Prezenční460 - Katedra informatikyvýborn

The Effect of Exposure Conditions on the Properties of Cementitious Composites with Reduced Electrical Resistivity

Cement composite materials with reduced resistivity are specialized building materials, which are constantly pushing their limits. Research into these composites requires a study of the influences of exposure conditions on resistivity. The mixes selected for the purpose of the research included the reference, pure cement mix, and mixes with proportions of graphite under and above the percolation threshold, with two different types of graphite. It was found that the resistivity of all the tested mixes decreases if moisture grows; the influence of moisture is more significant for mixes with graphite proportions below the percolation threshold. The resistivity of all the tested mixes decreases with increasing temperatures; the influence of a higher temperature (50 °C) is more significant for mixes with graphite proportions above the percolation threshold; however, these mixes are, at the same time, more resistant to permanent changes in resistivity caused by frost (−10 °C). It was found that the action of CO2 causes a reduction in resistivity. Mixes with proportions of graphite above the percolation threshold show higher stability when exposed to CO2. Mixes with proportions of graphite below the percolation threshold are extremely sensitive to horizontally oriented pressure loads. Increases in resistivity caused by vertical pressure loads were by 20–40%. The resistivity of the mixes with proportions of graphite above the percolation threshold was less sensitive to the pressure load

Hierarchical Hexagonal Clustering and Indexing

Space-filling curves (SFCs) represent an efficient and straightforward method for sparse-space indexing to transform an n-dimensional space into a one-dimensional representation. This is often applied for multidimensional point indexing which brings a better perspective for data analysis, visualization and queries. SFCs are involved in many areas such as big data analysis and visualization, image decomposition, computer graphics and geographic information systems (GISs). The indexing methods subdivide the space into logic clusters of close points and they differ in various parameters including the cluster order, the distance metrics, and the pattern shape. Beside the simple and highly preferred triangular and square uniform grids, the hexagonal uniform grids have gained high interest especially in areas such as GISs, image processing and data visualization for the uniform distance between cells and high effectiveness of circle coverage. While the linearization of hexagons is an obvious approach for memory representation, it seems there is no hexagonal SFC indexing method generally used in practice. The main limitation of hexagons lies in lacking infinite decomposition into sub-hexagons and similarity of tiles on different levels of hierarchy. Our research aims at defining a fast and robust hexagonal SFC method. The Gosper fractal is utilized to preserve the benefits of hexagonal grids and to efficiently and hierarchically linearize points in a hexagonal grid while solving the non-convex shape and recursive transformation issues of the fractal. A comparison to other SFCs and grids is conducted to verify the robustness and effectiveness of our hexagonal method

Study of the influence of structure on the resistivity of silicate composites

Silikátové kompozity se sníženou rezistivitou jsou moderními materiály, které umožňují stavebním konstrukcím plnit několik odlišných funkcí současně. Řešení problematiky jejich vývoje a použití je vhodným námětem k tématům výzkumných prací. Cílem této práce je studium vlivu struktury na rezistivitu silikátového kompozitu. Struktura elektrovodivých kompozitů je studována na suchých směsích cementových past a malt i na zkušebních tělesech ze zatvrdlé cementové pasty a malty po 28 dnech zrání. Na základě analýzy surovin je vybráno šest vhodných elektrovodivých plniv podle velikosti částic, rezistivity a nasákavosti. Jsou stanoveny parametry suchých cementových past a zatvrdlé cementové pasty s náhradou 4–19 hm. % cementu vybranými plnivy. Dvě z plniv jsou vybrána pro použití v suché a zatvrdlé maltě. Pro všechny varianty suchých směsí i zatvrdlých kompozitů je stanovena rezistivita a jsou přibližně stanoveny perkolační prahy. Studiem struktury vybraných variant je prokázáno, že nejdůležitějšími parametry, které mají největší vliv na rezistivitu silikátových kompozitů, jsou zejména velikost částic a vlastní rezistivita elektrovodivého plniva. U silikátových kompozitů v zatvrdlém stavu má rovněž velký vliv objem hydratačních produktů, zejména portlandit a C S H gely. Pro suché směsi i zatvrdlé kompozity bylo zjištěno, že čím menší je velikost částic elektrovodivého plniva, tím je třeba menšího zastoupení k dosažení perkolačního prahu. Množství portlanditu a C-S-H gelů v objemu zatvrdlého kompozitu určuje jeho rezistivitu. Rezistivita zatvrdlých kompozitů se zvyšuje s rostoucím množstvím hydratačních produktů. Rezistivita zatvrdlého kompozitu je vždy vyšší než rezistivita suché směsi stejného složení. Tedy i potřebné zastoupení elektrovodivého plniva k dosažení perkolačního prahu je u zatvrdlých kompozitů vyšší než u suchých směsí. Rezistivita, objemová hmotnost, pevnost v tahu za ohybu a pevnost v tlaku zatvrdlých kompozitů vždy klesá se zvyšujícím se množstvím elektrovoElectroconductive silicate-based composites are advanced materials that allow building structures to perform several different functions simultaneously. Addressing the issues of their development and use is a suitable topic for research work. The aim of this work is to study the effect of structure on the resistivity of silicate composite. The structure of electrically conductive composites is studied on dry cement paste and mortar mixtures as well as on test bodies made of hardened cement paste and mortar after 28 days of curing. Based on the analysis of the raw materials, six suitable electroconductive fillers are selected based on particle size, resistivity, and water absorption. The parameters of dry cement paste and hardened cement paste with replacement of 4-19 wt. % cement by the selected fillers are determined. Two of the fillers are selected for use in dry and hardened mortar. Resistivity is determined for all dry mixes and hardened composites variants, and percolation thresholds are approximately determined. By studying the structure of the selected variants, it is shown that the most important parameters that have the greatest influence on the resistivity of the silicate composites are mainly the particle size and the intrinsic resistivity of the electrically conductive filler. For silicate composites in the hardened state, the volume of hydration products, especially portlandite and C-S-H gels, also has a significant influence. For both dry blends and hardened composites, it was found that the smaller the particle size of the electroconductive filler, the smaller the representation needed to reach the percolation threshold. Portlandite and C-S-H gels in the volume of the hardened composite cause its high resistivity. The resistivity of the hardened composite is always higher than that of the dry blends. Thus, the proportion of electroconductive filler needed to reach the percolation threshold is higher in hardened composites than in dry mixes. The resist