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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

Zpracování 3D modelů scény / Processing of 3D Scene Models

Zdráhal, Lukáš January 2008 (has links)
Purpose of this document is acquite reader with basic principles of 3D model digitalization.This work describes general overview of 3D scanning devices, their physical principle and measurements methods. Next part of this document  describes basic method for polygonal mesh processing as smoothing an decimation which are necessary for 3D model processing.This document contains also algorithms description of implementation, user interface and publication part through WWW. Fundamental essence of this diploma thesis will be introduction with general principles of 3D scanning and working with Minolta VIVID-700 3D digitizer which is placed on our faculty. At the end are mentioned results evalution,demostration examples and next supposed project advancement.
72

Att ta brottsplatser till nya dimensioner : En jämförande studie mellan 2D-visning och VR-visning av 3D-skannade brottsplatser

Karlsson, Karl January 2023 (has links)
Denna studie har utförts i syfte att undersöka om Virtual Reality är användbart för att visa upp brottsplatser, exempelvis för personer som är inblandade i rättsprocesser. För att ta reda på det ställdes två frågor som besvarades med hjälp av data inhämtade från experiment. Experimentet gick ut på att deltagare fick ta del av (brotts)platser genom Virtual Reality och genom en interaktiv vy av 3D-modellen på en datorskärm. Den första frågan handlade om det gick att statistiskt skilja svaren från två observationsgrupper från varandra. Ena observationsgruppen innehöll observationer som är data hämtade efter att en deltagare fått ta del av en plats genom Virtual Reality. Den andra observationsgruppen innehöll observationer hämtade efter att en deltagare tagit del av en plats genom datorskärm. Observationsgruppernas svar analyserades senare i syfte att svara på den andra frågan, om ena gruppen går att skilja från den andra gruppen i förmåga att välja rätt svar på enkäten. Praktiskt fick deltagare alternera mellan att ta del av 3D-skannade (brotts)platser via Virtual Reality och datorskärm. Efter de tog del av en plats fick de svara på ett formulär. Experimentet utfördes med 24 deltagare, vilket resulterade i 12 svar per enkät. Detta genererade kvantitativa data, som senare användes i hypotestest. Hypotestesten som genomförts visade inte på någon signifikant skillnad mellan observationsgrupperna i 3 av 4 fall. Däremot visade ett av hypotestesten på signifikant skillnad i ett av fallen, där även observationsgruppen som tagit del av platsen genom datorskärm har presterat en högre median. Vad detta beror på är svårt att säga, men det finns vissa skillnader i hur detaljerat 3D-modellerna syns som kan vara en del av förklaringen till varför skillnader kunde påvisas.  Med bakgrund av detta resultat finns det ingen självklar fördel med att använda VR-teknologi (åtminstone inte som i denna implementation) i rättsfall. Det är dock viktigt att poängtera att studien och experimentet är utfört på kort tid och i liten skala. Vidare går utvecklingen inom detta område fort, och resultatet kan inte antas bli det samma med andra typer av implementationer. / This study was conducted in efforts to investigate whether Virtual Reality is useful for presenting crime scenes, for example, to individuals involved in legal proceedings. To answer this, two questions were posed and answered using data obtained from an experiment. The experiment involved participants experiencing (crime) scenes through Virtual Reality and through an interactive view of the 3D model on a computer screen. The first question was whether it was possible to statistically distinguish the responses from two observation groups. One observation group consisted of data collected after a participant experienced a location through Virtual Reality, while the other observation group consisted of data collected after a participant experienced a location through a computer screen. The responses from the observation groups were later analyzed to answer the second question: whether one group could be distinguished from the other in their ability to choose the correct response on the questionnaire. Practically, participants alternated between experiencing 3D-scanned (crime) scenes via Virtual Reality and a computer screen. After experiencing a location, they were asked to complete a questionnaire. The experiment was conducted with 24 participants, resulting in 12 responses per questionnaire. This generated quantitative data, which was later used in hypothesis testing. The conducted hypothesis tests did not show any significant difference between the observation groups in 3 out of 4 cases. However, one of the hypothesis tests showed a significant difference in one case, where the observation group that experienced the location through a computer screen also had a higher median. The exact reason for this is difficult to determine, but there are certain differences in the level of detail in the visibility of the 3D models that could partly explain why differences were observed. Based on these results, there is no obvious advantage to using VR technology (at least not in this implementation) in legal cases. However, it is important to note that the study and experiment were conducted in a short period and on a small scale. Furthermore, the development in this field is progressing rapidly, and the results cannot be assumed to be the same with other types of implementations.
73

[en] NEW TECHNOLOGIES AND THE PARADIGMS IN JEWELRY DESIGN: CONCEPTS AND EXPLORATIONS / [pt] NOVAS TECNOLOGIAS E OS PARADIGMAS NO DESIGN DE ADORNOS PESSOAIS: CONCEITOS E EXPLORAÇÕES

THAYANE DE SOUSA TAVARES 16 June 2020 (has links)
[pt] As novas tecnologias trazem novos paradigmas para o design de adornos pessoais. Apesar da sua adoção, essas tecnologias são comumente empregadas para executar as mesmas formas de adornos produzidas em banca de ourives, portanto a inovação pode ficar limitada aos processos de fabricação. A tendência à virtualização do mundo físico também impõe novos desafios ao design de adornos. Esta pesquisa tem como objetivo trazer reflexões para o design de adornos sobre como as novas tecnologias podem contribuir para dar sentidos inovadores aos produtos. Para isso, apresenta e discute características específicas do design de adornos, assim mostrando o paradigma do emprego dessas tecnologias. Posto isso, delimita o escopo das novas tecnologias pertinentes à pesquisa, expondo seus efeitos e impactos no design de adornos. Com base em uma pesquisa documental, mostra o potencial expressivo dessas tecnologias através da seleção de casos. A seguir, através de uma revisão bibliográfica, analisa a mediação que o design pode fazer entre adornos pessoais e novas tecnologias. Em conjunto à contextualização, foram realizadas atividades de experimentação em realidade virtual, digitalização tridimensional e design computacional, que buscaram explorar o potencial dessas tecnologias de forma inovadora através do design. Os experimentos desenvolvidos demonstraram aspectos específicos das novas tecnologias abordadas e, em conjunto, esses procedimentos expuseram a relação entre elas e o processo de inovação de significados no design de adornos. / [en] New technologies bring new paradigms for jewelry design. Despite their adoption, these technologies are commonly used to create the same styles of jewelry produced by hand by goldsmiths, so innovation may be limited to manufacturing processes. The shift towards virtualization of the physical world also poses new challenges to jewelry design. This research aims to reflect on how new technologies in jewelry design can give innovative meanings to products. For this, it presents and discusses specific characteristics of jewelry design, thus showing the paradigm of the use of these technologies. That said, it delimits the scope of new technologies relevant to this research, exposing their effects and impacts on jewelry design. Based on documentary research, a selection of cases is made to show the expressive potential of these technologies. Then, through a literature review, it analyzes the mediation that design can make between jewelry and new technologies. Along with the contextualization, experimentation activities in virtual reality, 3D scanning and computational design were carried out, seeking to explore the potential of these technologies through design in an innovative way. The experiments demonstrated specific aspects of the new technologies addressed in this research and also exposed the relationship between them and the process of innovation of meanings in jewelry design.
74

3D-skanning för kvalitetsarbete i produktionsprocessen för krafttransformatorer : Kartläggning av möjligheter för potentiella processförbättringar hos Hitachi ABB Power Grids / 3D-scanning for quality management in the production process of power transformers

Niroozad, Ellika, Dellerer, Josefine January 2021 (has links)
Hitachi ABB Power Grids is a world leading manufacturer of power transformers, operating on an increasingly competitive market. With the advancements in digitalization and electrification, the production of power transformers has been subject of higher demands, both in terms of product quality and production efficiency. To stay ahead of market rivals, constant development of the business and its production processes is necessary, which has been enabled by increased access to innovative technical solutions. Novel appliances and areas of development has been investigated, of which 3D-scanning is one of the promising technologies that has proven useful in the manufacturing industry.  The purpose of this study has been to map the production process of power transformer manufacturing at Hitachi ABB Power Grids, with the intention of identifying potential areas for use of 3D-scanning technology in quality management. By analyzing each individual production segment, the study has sought to answer to where in the production system that 3D-scanning technology can be beneficial, what type of improvements it can contribute with, and what risks and limitations that using the technology might entail.  The results were obtained by analyzing empirical data, collected through both qualitative and quantitative methods. Interviews with employees and on-site observations has been the main sources of data, together with documentation and statistics from the company’s own data bases.  Central factors that the analysis was built upon are the registered costs of failure and reported quality defects, combined with the appropriateness of 3D-scanning technology in each segment regarding the practical usability, advantage in time, economic profitability, and the feasibility of implementation in the production system. A value assessment was made of the device’s potential, leading to identifying improvements in transparency, traceability, and efficiency. Some of the discussed drawbacks were limited visual access, faulty handling of the equipment, and excessive reliance on the technology. / Hitachi ABB Power Grids är en världsledande tillverkare av krafttransformatorer, agerandes på en alltmer konkurrensbenägen marknad. Med digitaliseringens och elektrifieringens framfart ställs högre krav på produktionen av krafttransformatorer, både gällande produktkvalitet och produktionseffektivitet. För att bibehålla en ledande position krävs därför ständig utveckling av verksamheten och dess processer, vilket bland annat möjliggjorts av den ökade tillgången till innovativa tekniska lösningar. Nya verktyg och förbättringsområden undersöks, varpå en av de uppmärksammade teknikerna är 3D-skanning, vilket visat sig användbart inom tillverkningsindustrin.  Syftet med studien har varit att kartlägga processen för krafttransformatortillverkning hos fallstudieföretaget Hitachi ABB Power Grids, med avsikt att identifiera möjligheterna kring användning av 3D-skanningsteknik i kvalitetsarbetet. Genom att undersöka varje individuellt delmoment i produktionsprocessen har studien sökt besvara var i produktionssystemet som 3D-skanningstekniken kan medföra förbättringar, vilken typ av förbättringar som kan åstadkommas, samt de risker och begränsningar som användning av tekniken eventuellt kan medföra.  Resultaten erhölls genom analys av empiriska data som samlats in genom både kvalitativa och kvantitativa metoder. Intervjuer med personal och observationer på anläggningen har utgjort de huvudsakliga källorna till information, tillsammans med dokumentation och statistik från företagets interna databaser.  Centrala faktorer som analysen har byggt på är produktionens registrerade felkostnader och rapporterade kvalitetsfel, i kombination med 3D-skanningsteknikens lämplighet för respektive avsnitt gällande praktisk användbarhet, tidsmässig fördel, ekonomisk lönsamhet och implementerbarhet i produktionssystemet. En värdering gjordes därefter av teknikens potential, och förbättringar i form av transparens, spårbarhet och effektivitet kunde identifieras. Några av de brister som uppmärksammades var begränsad visuell åtkomst, felaktig manövrering av utrustningen och överdriven tillförlitlighet till tekniken.
75

En studie om fotskanningsteknik : Hur fotskanning upplevs av och kan påverka konsumenternas returvanor. / A study about foot scanning technology : How foot scanning is perceived by and can affect customers' return habits

Lundvall, Sofie January 2022 (has links)
I denna studie har användningen av fotskanning för att minska returer av skor köpta online och konsumenternas inställning till och kunskap om fotskanning undersökts. Fotskanning är en teknik för att skanna fötter. Efter att foten har skannats skapas en 3D modell över hur foten ser ut och den modellen används sedan för olika ändamål. Det området som denna studie har fokuserat på är online handeln av skor. Metoden som studien använde är blandad med en induktiv ansats. Empirin samlades genom en kvantitativ enkätstudie av konsumenter och en semistrukturerad kvalitativ intervju med ett företag. Efter datainsamlingen redovisades och analyserades resultaten innan en diskussion utfördes där slutsatser drogs i relation till forskningsfrågorna. Studien visar att fotskanning påverkar returer av skor positivt. Det blev färre returer med hjälp av fotskanningstekniken. När det gäller konsumenternas kunskapsnivå och inställning till fotskanning visar studien att de har en låg kunskap om fotskanning, men en vilja till att använda tekniken. På det stora hela visar fotskanning en stor potential i framtiden och med vidare forskning på ämnet kan studien användas som en indikation på om implementering av fotskanning i ett företag är nästa steg. / In this study, the use of foot scanning to reduce returns of shoes purchased online and consumers' attitudes towards and knowledge of foot scanning have been investigated. Foot scanning is a technique used for scanning feet. After the foot has been scanned, a 3D model of what the foot looks like is created and that model is then used for various purposes. The area that this study has focused on is the online trade of shoes. The method that the study used is mixed with an inductive approach. The experience was gathered through a quantitative survey study of consumers and a semi-structured qualitative interview with a company. After the data collection, the results were reported and analyzed before a discussion was carried out where conclusions were drawn in relation to the research questions. The study shows that foot scanning has a positive effect on the returns of shoes. There were fewer returns with the help of the foot scanning technology. Regarding the consumers' level of knowledge and attitude towards foot scanning, the study shows that they have a low level of knowledge on the subject, but have a willingness to use the technology. In conclusion, foot scanning shows great potential in the future and with further research on the subject, this study can be used as an indication of whether implementing foot scanning in a company is the next step.
76

3D Digitization and Wear Analysis of Sauropod Teeth

Steiner, Alexis K. 24 July 2018 (has links)
No description available.
77

3D-electron microscopic characterization of interstitial cells in the human bladder upper lamina propria

Neuhaus, Jochen, Schröppel, Birgit, Dass, Martin, Zimmermann, Hans, Wolburg, Hartwig, Fallier-Becker, Petra, Gevaert, Thomas, Burkhardt, Claus J., Minh Do, Hoang, Stolzenburg, Jens-Uwe 19 February 2018 (has links)
1) Aims To explore the ultrastructure of interstitial cells in the upper lamina propria of the human bladder, to describe the spatial relationships and to investigate cell-cell contacts. 2) Methods Focused ion beam scanning electron microscopy (FIB-SEM), 3-View SEM and confocal laser scanning microscopy were used to analyze the 3D ultrastructure of the upper lamina propria in male and female human bladders. 3) Results 3View-SEM image stacks as large as 59µm x 59µm x 17µm (xyz) at a resolution of 16nm x 16nm x 50 nm and high resolution (5nm x 5nm x 10nm) FIB-SEM stacks could be analyzed. Interstitial cells with myoid differentiation (mIC) and fibroblast like interstitial cells (fIC) were the major cell types in the upper lamina propria. The flat, sheet-like ICs were oriented strictly parallel to the urothelium sheet-like morphology. No spindle shaped cells were present. We furthermore identified one branched cell (bIC) with several processes contacting urothelial cells by penetrating the basal membrane. This cell did not make any contacts to other ICs within the upper lamina propria. We found no evidence for the occurrence of telocytes in the upper lamina propria. 4) Conclusions Comprehensive 3D-ultrastructural analysis of the human bladder confirmed distinct subtypes of interstitial cells. We provide evidence for a foremost unknown direct connection between a branched interstitial cell and urothelial cells of which the functional role has still to be elucidated. 3D-ultrastructure analyses at high resolution are needed to further define the subpopulations of lamina propria cells and cell-cell interactions.
78

Algorithmen zur automatisierten Dokumentation und Klassifikation archäologischer Gefäße

Hörr, Christian 23 June 2011 (has links)
Gegenstand der vorliegenden Dissertation ist die Entwicklung von Algorithmen und Methoden mit dem Ziel, Archäologen bei der täglichen wissenschaftlichen Arbeit zu unterstützen. Im Teil I werden Ideen präsentiert, mit denen sich die extrem zeitintensive und stellenweise stupide Funddokumentation beschleunigen lässt. Es wird argumentiert, dass das dreidimensionale Erfassen der Fundobjekte mittels Laser- oder Streifenlichtscannern trotz hoher Anschaffungskosten wirtschaftlich und vor allem qualitativ attraktiv ist. Mithilfe von nicht fotorealistischen Visualisierungstechniken können dann wieder aussagekräftige, aber dennoch objektive Bilder generiert werden. Außerdem ist speziell für Gefäße eine vollautomatische und umfassende Merkmalserhebung möglich. Im II. Teil gehen wir auf das Problem der automatisierten Gefäßklassifikation ein. Nach einer theoretischen Betrachtung des Typbegriffs in der Archäologie präsentieren wir eine Methodologie, in der Verfahren sowohl aus dem Bereich des unüberwachten als auch des überwachten Lernens zum Einsatz kommen. Besonders die letzteren haben sich dabei als überaus praktikabel erwiesen, um einerseits unbekanntes Material einer bestehenden Typologie zuzuordnen, andererseits aber auch die Struktur der Typologie selbst kritisch zu hinterfragen. Sämtliche Untersuchungen haben wir beispielhaft an den bronzezeitlichen Gräberfeldern von Kötitz, Altlommatzsch (beide Lkr. Meißen), Niederkaina (Lkr. Bautzen) und Tornow (Lkr. Oberspreewald-Lausitz) durchgeführt und waren schließlich sogar in der Lage, archäologisch relevante Zusammenhänge zwischen diesen Fundkomplexen herzustellen. / The topic of the dissertation at hand is the development of algorithms and methods aiming at supporting the daily scientific work of archaeologists. Part I covers ideas for accelerating the extremely time-consuming and often tedious documentation of finds. It is argued that digitizing the objects with 3D laser or structured light scanners is economically reasonable and above all of high quality, even though those systems are still quite expensive. Using advanced non-photorealistic visualization techniques, meaningful but at the same time objective pictures can be generated from the virtual models. Moreover, specifically for vessels a fully-automatic and comprehensive feature extraction is possible. In Part II, we deal with the problem of automated vessel classification. After a theoretical consideration of the type concept in archaeology we present a methodology, which employs approaches from the fields of both unsupervised and supervised machine learning. Particularly the latter have proven to be very valuable in order to assign unknown entities to an already existing typology, but also to challenge the typology structure itself. All the analyses have been exemplified by the Bronze Age cemeteries of Kötitz, Altlommatzsch (both district of Meißen), Niederkaina (district of Bautzen), and Tornow (district Oberspreewald-Lausitz). Finally, we were even able to discover archaeologically relevant relationships between these sites.
79

Investigations of Flow Patterns in Ventilated Rooms Using Particle Image Velocimetry : Applications in a Scaled Room with Rapidly Varying Inflow and over a Wall-Mounted Radiator

Sattari, Amir January 2015 (has links)
This thesis introduces and describes a new experimental setup for examining the effects of pulsating inflow to a ventilated enclosure. The study aimed to test the hypothesis that a pulsating inflow has potential to improve ventilation quality by reducing the stagnation zones through enhanced mixing. The experimental setup, which was a small-scale, two-dimensional (2D), water-filled room model, was successfully designed and manufactured to be able to capture two-dimensional velocity vectors of the entire field using Particle Image Velocimetry (PIV). Using in-house software, it was possible to conclude that for an increase in pulsation frequency or alternatively in the flow rate, the stagnation zones were reduced in size, the distribution of vortices became more homogeneous over the considered domain, and the number of vortices in all scales had increased. Considering the occupied region, the stagnation zones were moved away in a favorable direction from a mixing point of view. In addition, statistical analysis unveiled that in the far-field occupied region of the room model, stronger eddies were developed that we could expect to give rise to improved mixing. As a fundamental experimental study performed in a 2D, small-scale room model with water as operating fluid, we can logically conclude that the positive effect of enhanced mixing through increasing the flow rate could equally be accomplished through applying a pulsating inflow. In addition, this thesis introduces and describes an experimental setup for study of air flow over a wall-mounted radiator in a mockup of a real room, which has been successfully designed and manufactured. In this experimental study, the airflow over an electric radiator without forced convection, a common room-heating technique, was measured and visualized using the 2D PIV technique. Surface blackening due to particle deposition calls for monitoring in detail the local climate over a heating radiator. One mechanism causing particle deposition is turbophoresis, which occurs when the flow is turbulent. Because turbulence plays a role in particle deposition, it is important to identify where the laminar flow over radiator becomes turbulent. The results from several visualization techniques and PIV measurements indicated that for a room with typical radiator heating, the flow over the radiator became agitated after a dimensionless length, 5.0–6.25, based on the radiator thickness. Surface properties are among the influencing factors in particle deposition; therefore, the geometrical properties of different finishing techniques were investigated experimentally using a structured light 3D scanner that revealed differences in roughness among different surface finishing techniques. To investigate the resistance to airflow along the surface and the turbulence generated by the surfaces, we recorded the boundary layer flow over the surfaces in a special flow rig, which revealed that the types of surface finishing methods differed very little in their resistance and therefore their influence on the deposition velocity is probably small. / Det övergripande syftet med den första studien i avhandlingen var att undersöka hypotesen att ett pulserande inflöde till ett ventilerade utrymme har en potential till att förbättra ventilationens kvalitet genom att minska stagnationszoner och därigenom öka omblandningen. För genomförande av studien byggdes en experimentuppställning i form av en tvådimensionell (2D) småskalig modell av ett ventilerat rum. Strömningsmediet i modellen var vatten. Det tvådimensionella hastighetsfältet registrerades över hela modellen med hjälp av Particle Image Velocimetry (PIV). Vid ett stationärt tillflöde bildas ett stagnationsområde i centrum av rumsmodellen. Vid ett pulserade inflöde genererades sekundära virvlar. Med en egen utvecklad programvara var det möjligt att kvantifiera statistiken hos virvlarna. Det pulserade inflödet gjorde att inom området där det vid stationärt tillflöde fanns en stagnationszon ökade antalet virvlar i alla storlekar och fördelningen av virvlar blev mera homogen än tidigare. Detta kan förväntas ge upphov till förbättrad omblandning. Baserat på en grundläggande experimentell studie utförd i en småskalig tvådimensionell rumsmodell med vatten som strömningsmedium kan vi logiskt dra slutsatsen att ett pulserande tilluftsflöde har en potential att förbättra omblandningen.  I en fortsatt studie i avhandlingen visuliserades och mättes hastighetsfältet och därefter beräknades statistiska värden av exempelvis medelhastighet, standardavvikelse och skjuvspänning hos hastighetsfluktuationerna i luftströmmen över en väggmonterad radiator med 2D-PIV-teknik.  Bakgrunden till studien är att en bidragande orsak till partikelavsättning på väggytor är turbofores som uppträder vid en turbulent luftström. Studien genomfördes genom uppbyggnad av en fullskalig rumsmodell. Eftersom turbulens spelar en roll vid partikelavsättning genom turbofores är det viktigt att identifiera var det laminära flödet över radiatorn blir turbulent. Resultaten baserat på visualisering och PIV-mätningar indikerade att, för ett rum med denna typ av radiatoruppvärmning, blev flödet över radiatorn turbulent efter en dimensionslös längd lika med 5,0‒6,25 gånger radiatorns tjocklek. Ytors egenskaper är viktiga vid partikelavsättning. Därför har de geometriska egenskaperna hos några olika metoder för ytbehandling undersökts experimentellt med hjälp av en scanner för strukturerat 3D-ljus. Resultaten visar på skillnader i ytråhet hos de olika ytbehandlingsmetoderna. För att undersöka motståndet mot luftströmning längs ytan och den turbulens som genereras av ytorna registrerade vi gränsskiktsflödet över ytorna i en speciell luftströmningsrigg. Detta påvisade att motståndet hos de olika typerna av ytbehandlingsmetoder skilde sig mycket litet åt och därför är troligt vid deras påverkan på depositionshastigheten mycket liten. / <p>QC 20150525</p>
80

Considerations on Technical Sketch Generation from 3D Scanned Cultural Heritage

Hörr, Christian, Lindinger, Elisabeth, Brunnett, Guido 14 September 2009 (has links)
Drawing sketches is certainly one of the most important but at the same time elaborate parts of archaeological work. Currently, 3D scanning technology is affording a number of new applications, and only one of them is using virtual copies instead of the originals as the basis for documentation. Our major contribution are methods for automatically generating stylized images from 3D models. These are not only intuitive and easy to read but also more objective and accurate than traditional drawings. Besides some other useful tools we show several examples from our daily work proving that the system accelerates the whole documentation process considerably.

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