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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.
661

Obnova národa White Earth: sledování dlouhodobého procesu ústavní reformy / Rebuilding the White Earth Nation: Tracing the Long-Term Process of Constitutional Reform

Krausová, Anna January 2018 (has links)
Native nation building is a phenomenon largely neglected by mainstream political science. There are empirical and theoretical gaps in the study of political structures of Native nations. The empirical focus of this dissertation is on the rebuilding process of the White Earth Nation located in northwestern Minnesota. The objective is to investigate the long-term process of White Earth governance in order to get insights into the background of the present state of the White Earth institutional stalemate. I trace external and internal factors that influenced the formation, preservation, and transformation of the White Earth government established as part of the Minnesota Chippewa Tribe under the Indian Reorganization Act provisions in 1936. To understand this process, it is necessary to include the historical context of the White Earth constitutionalism from 1913 to the present. I analyze some hitherto unknown archival materials using a flexible theoretical framework which I designed specifically for the purpose of studying the White Earth nation-building process. This case-specific framework eclectically uses a combination of theoretical approaches of Native American studies, genealogy, Vincent Pouliot's practice tracing, and new institutionalism. My findings suggest that the White Earth...
662

Selhání a úspěchy veřejných politik: Případová studie organizační reformy na úřadech práce / Policy Failure and Policy Success: Case Study of Labor Offices Organizational Reform

Hiekischová, Michaela January 2018 (has links)
This thesis deals with policy failure and policy success and aims at introducing this issue into the context of the Czech Republic. The main perspective of the thesis follows approaches to analysis of policy success and policy failure developed by Mark Bovens, Paul 't Hart, and Allan McConnell. Their theoretical assumption is complex, as they evaluate the policies upon the criteria of the more general dimensions (process, program, and politics). The goal of the thesis is not only to utilize their theoretical background but also to refine and reconceptualize current theory of policy success and policy failure, respectively. The thesis is based on case study research design. The chosen case - organizational reform of labor offices - is considered as a typical policy failure. I describe and analyze in detail the selected case with a wide range of qualitative and quantitative methods. This reform was extensive and was realized in two stages. The first stage focused on the organizational structure (from decentralized to centralized management). The second stage included changes in the content of the public employment services provided by the labor offices (the newly introduced services were all non-insurance social benefits). The analysis of labor offices reform seeks to answer the following questions,...
663

3. Workshop "Meßtechnik für stationäre und transiente Mehrphasenströmungen", 14. Oktober 1999 in Rossendorf

Prasser, Horst-Michael January 1999 (has links)
Am 14. Oktober 1999 wurde in Rossendorf die dritte Veranstaltung in einer Serie von Workshops über Meßtechnik für stationäre und transiente Mehrphasenströmungen durchgeführt. Dieses Jahr kann auf auf 11 interessante Vorträge zurückgeblickt werden. Besonders hervorzuheben sind die beiden Hauptvorträge, die von Herrn Professor Hetsroni aus Haifa und Herrn Dr. Sengpiel aus Karlsruhe gehalten wurden. Erneut lag ein wichtiger Schwerpunkt auf Meßverfahren, die räumliche Verteilungen von Phasenanteilen und Geschwindigkeiten sowie die Größe von Partikeln bzw. Blasen der dispersen Phase zugänglich machen. So wurde über einen dreidimensional arbeitenden Röntgentomographen, ein Verfahren zur Messung von Geschwindigkeitsprofilen mit Gittersensoren und eine Methode zur simultanen Messung von Blasengrößen sowie Feldern von Gas- und Flüssigkeitsgeschwindigkeit mit einer optischen Partikelverfolgungstechnik vorgetragen. Daneben wurden interessante Entwicklungen auf dem Gebiet der lokalen Sonden vorgestellt, wie z.B. eine Elektrodiffusionssonde. Neue meßtechnische Ansätze waren ebenfalls vertreten; hervorzuheben ist der Versuch, die Methode der optischen Tomographie für die Untersuchung von Zweiphasenströmungen nutzbar zu machen. Der Tagungsband enthält die folgenden Beiträge: S. John, R. Wilfer, N. Räbiger, Universität Bremen, Messung hydrodynamischer Parameter in Mehrphasenströmungen bei hohen Dispersphasengehalten mit Hilfe der Elektrodiffusionsmeßtechnik E. Krepper, A. Aszodi, Forschungszentrum Rossendorf, Temperatur- und Dampfgehaltsverteilungen bei Sieden in seitlich beheizten Tanks D. Hoppe, Forschungszentrum Rossendorf, Ein akustisches Resonanzverfahren zur Klassifizierung von Füllständen W. Sengpiel, V. Heinzel, M. Simon, Forschungszentrum Karlsruhe, Messungen der Eigenschaften von kontinuierlicher und disperser Phase in Luft-Wasser-Blasenströmungen R. Eschrich, VDI, Die Probestromentnahme zur Bestimmung der dispersen Phase einer Zweiphasenströmung U. Hampel, TU Dresden, Optische Tomographie O. Borchers, C. Busch, G. Eigenberger, Universität Stuttgart, Analyse der Hydrodynamik in Blasenströmungen mit einer Bildverarbeitungsmethode C. Zippe, Forschungszentrum Rossendorf, Beobachtung der Wechselwirkung von Blasen mit Gittersensoren mit einer Hochgeschwindigkeits-Videokamera H.-M. Prasser, Forschungszentrum Rossendorf, Geschwindigkeits- und Durchflußmessung mit Gittersensoren
664

Simulation of bended planar waveguides for optical bus-couplers

Lorenz, Lukas, Nieweglowski, Krzysztof, Wolter, Klaus-Jürgen, Bock, Karlheinz 08 August 2019 (has links)
In our work an optical bus-coupler is proposed, which enables easy bidirectional connection between two waveguides without interrupting the bus using a core-to-core coupling principle. With bended waveguides the coupling ratio can be tuned by adjusting the overlap area of the two cores. In order to ensure large overlap areas at short coupling lengths, the waveguides have rectangular cross sections. To examine the feasibility of this coupling concept a simulation was performed, which is presented in this paper. Due to multimode waveguides, used in short range data communication, a non-sequential ray tracing simulation is reasonable. Simulations revealed that the bending of the waveguide causes a redistribution of the energy within the core. Small radii push the main energy to the outer region of the core increasing the coupling efficiency. On the other hand, at excessive lowered bend radii additional losses occur (due to a coupling into the cladding), which is why an optimum has to be found. Based on the simulation results it is possible to derive requirements and design rules for the coupling element.
665

Realistická animace kouře / Realistic Smoke Animation

Zubal, Miloš January 2007 (has links)
This work makes basic analysis of historical and current algorithms for smoke animation. Modern approaches to rendering volumetric data are briefly described. We choose algorithms for implementation on basis of this analysis. These algorithms are described in detail and we make emphasis on their important properties according to dedication of this work. Detailed description of implementation follows along with performance measurement. Conclusion evaluates results of work and proposes possible extensions.
666

I see how you reason: A Process-based Description of Abductive Reasoning

Klichowicz, Anja 04 May 2021 (has links)
Abductive reasoning is the process of finding the best explanation for a set of observations. The theory of abductive reasoning (TAR, Johnson & Krems, 2001) allows detailed process assumptions that were only partly tested in detail up until now. This thesis employs an artificial abductive reasoning task, the Black Box task, and eye tracking measures in order to gain insight into the process. The first part of this thesis aims at evaluating process measures based on eye tracking and using them in order to gain a better understanding of the processes postulated in TAR such as the construction of a situation model or retrieval of relevant information. The second part investigates the relationship between working memory and abductive reasoning by manipulating the amount of information stored in memory and examining the relationship between visual abductive reasoning and working memory skills. In a last part a perspective to the transferability of our results to everyday life tasks is given. The first study focuses on differentiating between processes that take place during the encoding and the evaluation of observation information by comparing eye movement measures. In the second study, we tested process assumptions such as the construction of a mental representation from TAR using memory indexing, an eye tracking method that makes it possible to trace the retrieval of explanations currently held in working memory. Gaze analysis revealed that participants encode the presented evidence (i.e., observations) together with possible explanations into memory. When new observations are presented, the previously presented evidence and explanations are retrieved. With the memory indexing method, we were able to assess the process of information retrieval in abductive reasoning, which was previously believed to be unobservable. The theory of abductive reasoning (TAR; Johnson & Krems, 2001) assumes that when information is presented sequentially, new information is integrated into a mental representation called a situation model, the central data structure on which all reasoning processes are based. Since working memory capacity is limited, the question arises how reasoning might change with the amount of information that has to be processed in memory. To answer this question, we conducted a third experimental study, in which we manipulated whether previous observation information and previously found explanations had to be retrieved from memory or were still present in the visual array. We analyzed individual ratings of difficulty as well as behavioral data and reasoning outcomes. Our results provide evidence that people experience differences in task difficulty when more information has to be retrieved from memory. This is also evident in changes in the mental representation as reflected by eye tracking measures. However, these differences are not evident in the reasoning outcome. These findings suggest that individuals construct their situation model from both information in memory as well as external memory stores. The complexity of the model depends on the task at hand: when memory demands are high, only relevant information is included. With this compensation strategy, people are able to achieve similar reasoning outcomes even when faced with more difficult tasks. The precise relationship between reasoning and working memory capacity remains largely opaque. Combining data of both studies from chapter 3 and 4, we firstly investigated if reasoning performance differs due to differences in working memory capacity. Secondly, using eye tracking, we explored the relationship between the facets of working memory and the process of visuospatial reasoning. Therefore both, a test for storage and processing, and content components (verbal-numerical/ spatial) of working memory as well as an intelligence measure, were engaged. Results show a clear relationship between reasoning accuracy, spatial storage and processing components as well as intelligence. Process measures suggest that high spatial working memory ability might lead to the use of strategies optimizing the content and complexity of the mental representation on which abductive reasoning is based. In a fifth study, we aimed to investigate whether there are also indicators for the mechanisms postulated by TAR in a task that is closer to real life reasoning. Therefore, we asked participants to solve 12 jigsaw puzzles whereby the abductive task was the identification of the motive presented on the puzzles. Thereby, the pieces of the puzzles posed as observation and hypotheses to the motive of the puzzle as explanations. As a process tracing measure, we used thinking aloud. Verbal protocols were recorded, transcripted and carefully coded according to the operators and explanation types postulated in TAR. We found evidence that participants use most of the operators with a likeliness that significantly lies above chance level. We also found evidence of the existence of the different explanation types. Eye movements were able to give insight in the interrelations between working memory, attention, and action. Therefore, this work contributes to understanding abductive reasoning, not only by testing the assumptions of TAR, but also by finding relations between memory, action and thought. The results do not only account for abductive reasoning in an artificial task but also in everyday life reasoning.:1 Introduction 1 1.1 Theories on Abductive Reasoning and Beyond 4 1.1.1 Theory of Abductive Reasoning 4 1.1.2 Other Theories 7 1.2 Reasoning, Working Memory, and Mental Representation 9 1.3 Process Tracing 11 1.4 An Artificial Abductive Task: The Black Box 12 1.5 Overview and Research Objectives 15 1.5.1 Differentiating between Encoding and Processing 15 1.5.2 Current Explanations in Memory 16 1.5.3 Information Stored in Memory 16 1.5.4 More than Storage of Information 17 1.5.5 In the Context of Everyday Life 18 1.5.6 Summary, Perspectives, and Conclusion 18 2 The Possibilities of Eye Tracking: Differentiating between Encoding and Processing 21 2.1 Abstract 22 2.2 Introduction 23 2.3 Method 26 2.3.1 Participants 26 2.3.2 Task and Apparatus 27 2.3.3 Procedure 28 2.3.4 Analysis 29 2.4 Results 30 2.5 Discussion 32 3 Tracing Current Explanations in Memory: A Process Analysis Based on Eye Tracking 37 3.1 Abstract 38 3.2 Introduction 39 3.2.1 Current Explanations of Abductive Reasoning 41 3.2.2 Tracing the Reasoning Process 44 3.2.3 Present Study 45 3.3 Method 48 3.3.1 Participants 49 3.3.2 Apparatus 49 3.3.3 Material 50 3.3.4 Procedure 53 3.4 Results 54 3.4.1 Performance 54 3.4.2 Gaze Analyses 55 3.4.3 Hypothesis 1: Information Stored in the Situation Model 57 3.4.4 Hypothesis 2: Different Types of Explanations—Concrete vs. Abstract 61 3.5 Discussion 67 3.5.1 Information Stored in the Situation Model 68 3.5.2 Concretely and Abstractly Explained Observations 68 3.5.3 TAR and Current Theories on Abductive Reasoning 70 3.5.4 Tracing Memory Processes 72 3.5.5 Conclusion 74 Appendix 3.1 75 Appendix 3.2 76 Appendix 3.3 77 Appendix 3.4 78 4 Information Stored in Memory Affects Abductive Reasoning 79 4.1 Abstract 80 4.2 Introduction 81 4.2.1 The Reasoning Process 82 4.2.2 Visual Attention 85 4.2.3 Research Objectives 86 4.2.4 This Study 87 4.2.5 Using Eye Movements as a Method to Assess Memory Retrieval 89 4.2.6 Hypotheses 89 4.3 Method 92 4.3.1 Participants 92 4.3.2 Apparatus 92 4.3.3 The Black Box Task 92 4.3.4 Procedure 95 4.3.5 Pairwise Comparisons 96 4.4 Results 96 4.4.1 Performance 96 4.4.2 Gaze Analysis 99 4.4.3 Hypothesis 1: Differences Experienced in Task Difficulty 101 4.4.4 Hypothesis 2: Elements of the Situation Model 102 4.4.5 Hypothesis 3: Integrative Solutions 105 4.5 Discussion 107 4.5.1 Differences Experienced in Task Difficulty 108 4.5.2 Elements of the Situation Model 108 4.5.3 Integrative Solutions 110 4.5.4 Summary 112 5 More than Storage of Information – What Working Memory Contributes to Visual Abductive Reasoning 113 5.1 Abstract 114 5.2 Introduction 115 5.2.1 Working memory 116 5.2.2 Relations between Abductive Reasoning Working Memory Capacity 118 5.2.3 Eye Movements as a Process Tracing Method 119 5.2.4 Abductive Reasoning Outcomes and Working Memory Ability. 120 5.2.5 Abductive Reasoning Processes and Working Memory Ability 121 5.3 Method 123 5.3.1 Participants 124 5.3.2 Apparatus 124 5.3.3 Material 125 5.3.4 Procedure 127 5.4 Results 128 5.4.1 Analysis 128 5.4.2 Abductive Reasoning Accuracy and Working Memory Ability 131 5.4.3 Abductive Reasoning Processes and Working Memory Ability 132 5.5 Discussion 135 5.5.1 The Interaction of Reasoning Accuracy and Memory Ability 135 5.5.2 The Interaction of the Process of Reasoning and Memory Ability 136 5.5.3 Conclusion 138 6 The Theory of Abductive Reasoning in the Context of Everyday Life 141 6.1 Abstract 142 6.2 Introduction 143 6.2.1 Abduction in “Real Life” 145 6.3 Method 146 6.3.1 Participants 146 6.3.2 Task 147 6.3.3 Material 148 6.3.4 Apparatus 148 6.3.5 Procedure 149 6.3.6 Coding system 150 6.4 Results 153 6.4.1 Analysis 153 6.4.2 Descriptive Data 153 6.3.3. Likeliness of Operator Use 155 6.5 Discussion 156 6.5.1 Operator Use 156 6.5.2 Explanation Types 157 6.5.3 Perspectives 158 7 Summary, Perspectives, and Conclusion 159 7.1 The Process of Abductive Reasoning 159 7.2 Contributions of other Theories 162 7.3 Eye Tracking and its Methodological Implications 164 7.4 Future Research and Applications 167 7.5 Conclusion 169 8 References 171 Curriculum Vitae 191 Publications 196
667

On millimeter and submillimeter wave focal plane arrays implemented with MEMS waveguide switches

Frid, Henrik January 2017 (has links)
This thesis presents research towards enabling micromachined millimeter and submillimeter wave focal plane arrays (FPAs). The FPAs operate under the following principle: a switch network consisting of microelectromechanical (MEMS) switches, integrated with micromachined waveguides, is used to feed an array of antenna elements, located in the focal plane of a high-gain quasi-optical system. Hence, it is possible to switch between a set of narrow beams in different directions. Such beam steering systems are needed for future millimeter and submillimeter wave imaging and communication systems. The contributions to future MEMS-switchable FPAs presented here are organized in three papers, as described below. Paper I presents a criterion on the spacing between adjacent FPA elements which results in -3 dB overlap between the switched beams, for the special case when an extended hemispherical dielectric lens is used as the optical system. A key step towards this criterion is a closed-form relation between the scan angle and the FPA element's position, which results in an expression for the effective focal length of extended hemispherical lenses. A comparison with full-wave simulations demonstrates an excellent agreement with the presented theoretical results. Finally, it is shown that the maximum feasible FPA spacing when using an extended hemispherical lens is about 0.7 wavelengths. Paper II presents a numerical study of silicon-micromachined planar extended hemispherical lenses, with up to three matching regions used to reduce internal reflections. The effective permittivity of the matching regions is tailor-made by etching periodic holes in the silicon wafer. The optimal thickness and permittivity of the matching regions were determined using TRF optimization, in order to yield the maximum wide-band aperture efficiency and small side-lobes. We introduce a new matching region geometry, referred to as shifted-type matching regions, and it is demonstrated that using three shifted-type matching regions results in twice as large aperture efficiency as compared to using three conventional concentric-type matching regions. Paper III presents a submillimeter-wave single-pole single-throw (SPST) 500-750 GHz MEMS waveguide switch, based on a MEMS-reconfigurable surface inserted between two waveguide flanges. A detailed design parameter study is carried out to select the best combination of the number of horizontal bars and vertical columns of the MEMS-reconfigurable surface, for achieving a low insertion loss in the transmissive state and a high isolation in the blocking state. A method is presented to model the non-ideal electrical contacts between the vertical cantilevers of the MEMS surface, with an excellent agreement between the simulated and measured isolation. It is shown that the isolation can be improved by replacing an ohmic contact by a new, capacitive contact. The measured isolation of the switch prototype is better than 19 dB and the measured insertion loss is between 2.5 and 3 dB. / Denna avhandling presenterar forskning som syftar till att möjliggöra fokalplans-gruppantenner (FPAs) för våglängder i millimeter och submillimeterområdet. Principen för en sådan FPAs funktion är följande: ett nätverk bestående av mikroelektromekaniska (MEMS) switchar, används för att välja mellan de olika antenn-elementen i en gruppantenn, som placerats i fokalplanet av ett optiskt system. Därmed blir det möjligt att välja från en uppsättning av smala lober i olika riktningar. Sådana lob-styrningssystem behövs för framtida radar- och kommunikationssystem i millimeter och submillimeterområdet. Resultaten är uppdelade i tre vetenskapliga artiklar, som beskrivs nedan. I den första artikeln (Paper I) presenteras ett villkor för avståndet mellan närliggande FPA-element som resulterar i -3 dB överlappning mellan de switchade loberna, för specialfallet då en förlängd hemisfärisk lins används som optiskt system. Det viktigaste steget mot att hitta detta villkor är att bestämma en analytisk relation mellan avsökningsvinkeln och FPA-elementens position. Detta resulterar i ett uttryck för den effektiva fokallängden för denna typ av lins. En utmärkt överensstämelse har funnits mellan dessa relationer och simuleringar. Slutligen visas det att de största möjliga FPA-avstånden för en förlängd hemisfärisk lins är ungefär 0.7 våglängder, vilket uppnås för linser med låg permittivitet. I den andra artikeln (Paper II) presenteras en numerisk studie av plana förlängda hemisfäriska linser, som kan produceras från en kiselskiva. Linserna har upp till tre matchningsregioner, som används för att reducera interna reflektioner. Den effektiva permittiviteten av de matchande regionerna skräddarsys genom etsning av periodiska hål i kiselskivan. Den optimala tjockleken och permittiviteten av de matchande regionerna har bestämts med hjälp av TRF-optimering, för att ge maximal bredbandig direktivitet och minimala sidlober. En ny geometri introduceras för matchningsregionerna, som vi kallar matchningsregioner av skiftad typ. Vi visar att användning av tre matchningsregioner av skiftad typ resulterar i en dubbelt så hög apertur-effektivitet, jämfört med att använda tre konventionella matchningsregioner av koncentrisk typ. I den tredje artikeln (Paper III) presenteras en MEMS-switch för rektangulära vågledare, för frekvensområdet 500-750 GHz. Baserat på en designparameterstudie har den bästa kombinationen av antalet horisontella rader och vertikala kolumner hos den MEMS-konfigurerbara ytan valts ut, för att uppnå låga förluster i det öppna tillståndet och hög isolation i det blockerande tillståndet. I artikeln presenteras en metod för att modellera icke-perfekta elektriska kontakter mellan de fixerade och de rörliga delarna i MEMS-ytan. Denna metod uppvisar en utmärkt överensstämmelse mellan den simulerade och den uppmätta isolationen. Vi visara att isolationen kan förbättras med hjälp av en ny typ av kapacitiv kontakt. Den uppmätta isolationen hos den presenterade switch-prototypen är högre än 19 dB, och den uppmätta förlusten är mellan 2.5 och 3 dB. / <p>QC 20161206</p>
668

A New Laser Pointer Driven Optical Microheater for Precise Local Heat Shock

Placinta, Mike 01 January 2009 (has links) (PDF)
The zebrafish has emerged as an important genetic model system for the study of vertebrate development. However, while genetics is a powerful tool for the study of early gene functions, the approach is more limited when it comes to understanding later functions of genes that have essential roles in early embryogenesis. There is thus a need to manipulate gene expression at different times, and ideally only in some regions of the developing embryo. Methods for conditional gene regulation have been established in Drosophila, C.elegans and the mouse, utilizing conditional gene activation systems such as the Gal4-UAS system (fly) and the cre/lox recombination system (mouse). While these tools are also being developed in zebrafish, the accessibility of the zebrafish embryo makes other approaches both possible and desirable. We have taken advantage of a heat-shock inducible system that uses the hsp70 promoter that is activated by cellular stress, such as heat. Having established that this global heat shock method allows temporal control of gene expression, we aimed to spatially control gene expression by applying controlled thermal heat to only a small region of the embryo. This would allow us to determine cell- and tissue-autonomous roles for developmentally important genes in an embryo with otherwise normal gene function. We have now developed a device that uses a laser to heat a defined region of the embryo, and thus activate the hsp70 promoter only in restricted regions of the embryo. The output of a 75 mW red laser pointer was focused into the 50 µm diameter core of an optical fiber, whose cleaved and coated end was used to heat, and thus induce, gene expression in a defined area. We have established conditions that allow controlled heating and trans-gene activation in small regions of the embryo without inducing cell death. This new tool will allow us to study the cell-autonomous roles of embryonic signaling molecules in cell differentiation, proliferation, and survival in a variety of tissues and at different times.
669

Fluid Experience

Jane, Sarah January 2012 (has links)
No description available.
670

[pt] DESENVOLVIMENTO E VALIDAÇÃO DE SENSOR LIDAR VIRTUAL / [en] DEVELOPMENT AND VALIDATION OF A LIDAR VIRTUAL SENSOR

GUILHERME FERREIRA GUSMAO 25 June 2020 (has links)
[pt] As tecnologias de imageamento em três dimensões (3D) vêm tendo seu uso cada vez mais disseminado no meio acadêmico e no setor industrial, especialmente na forma de nuvens de pontos, uma representação matemática da geometria e superfície de um objeto ou área. No entanto, a obtenção desses dados pode ainda ser cara e demorada, reduzindo a eficiência de muitos procedimentos que são dependentes de um grande conjunto de nuvens de pontos, como a geração de datasets para treinamento de aprendizagem de máquina, cálculo de dossel florestal e inspeção submarina. Uma solução atualmente em voga é a criação de simuladores computacionais de sistemas de imageamento, realizando o escaneamento virtual de um cenário feito a partir de arquivos de objetos 3D. Este trabalho apresenta o desenvolvimento de um simulador de sistema LiDAR (light detection and ranging) baseado em algoritmos de rastreamento de raio com paralelismo (GPU raytracing), com o sensor virtual modelado por parâmetros metrológicos e calibrado por meio de comparação com um sensor real, juntamente com um gerador flexível de cenários virtuais. A combinação destas ferramentas no simulador resultou em uma geração robusta de nuvens de pontos sintéticas em cenários diversos, possibilitando a criação de datasets para uso em testes de conceitos, combinação de dados reais e virtuais, entre outras aplicações. / [en] Three dimensional (3D) imaging technologies have been increasingly used in academia and in the industrial sector, especially in the form of point clouds, a mathematical representation of the geometry and surface of an object or area. However, obtaining this data can still be expensive and time consuming, reducing the efficiency of many procedures dependent on a large set of point clouds, such as the generation of datasets for machine learning training, forest canopy calculation and subsea survey. A trending solution is the development of computer simulators for imaging systems, performing the virtual scanning of a scenario made from 3D object files. At the end of this process, synthetic point clouds are obtained. This work presents the development of a LiDAR system simulator (light detection and ranging) based on parallel ray tracing algorithms (GPU raytracing), with its virtual sensor modeled by metrological parameters. A way of calibrating the sensor is displayed, by comparing it with the measurements of a real LiDAR sensor, in addition to surveying error models to increase the realism of the virtual scan. A flexible scenario creator was also implemented to facilitate interaction with the user. The combination of these tools in the simulator resulted in a robust generation of synthetic point clouds in different scenarios, enabling the creation of datasets for use in concept tests, combining real and virtual data, among other applications.

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