Based on an analysis of the existing literature, we extracted important features regarding 3D file organization and layout. In this way, three separate 3D file browsing techniques were evaluated in a comparison study. Block3D uses a priority weighting scheme to elevate and display files in a grid-based structure. Cluster3D uses sets of animated racks to display files. TreeCubePlus3D visualizes files and directories using groups of semi-transparent cubes within a larger cube-like structure. Across all techniques, each file was represented as a thumbnail image of the file's image, document or document with pictures data. The thumbnails were also augmented with meta-information such as filename and relevancy information to simulate a realistic search. Our experiment explores the effectiveness of each 3D file browsing technique in a manual file searching task. Our evaluation is based on task completion time and a post-questionnaire used to gather subjective feedback on each technique in terms of user preference. The results indicate that users completed the manual file search task significantly faster using Block3D than both TreeCubePlus3D and Cluster3D. Subjective ranking also showed users preferred the Block3D technique.

Shape plays an important role in our everyday life to interpret information about the surroundings whether we are aware or not. Together with visual and auditory information, we are able to obtain and process information for different purposes. Output devices such as monitors and speakers convey visual and auditory information while input devices such as touch screen and microphones receive that information for human machine interaction. Such devices have become commonplace but there has yet to be a fitting input/output device utilizing our haptic perception. Digital Clay is a next generation Human Machine Interface (HMI) device for 2.5D shape input/output via an array of hydraulic actuators. This device potentially has wide applications in the areas of engineering, sciences, medicine, military, entertainment etc. The user can perceive the shape of a computer programmed model in a tangible and concrete manner which means an added realism with the addition of the sense of touch. Conversely, the user can also use Digital Clay as an input device to the computer, by shaping and molding desired shapes on the device, no longer limited to drawing models with a mouse on CAD software. Shape display has been achieved with the current 5x5 prototype at the Georgia Institute of Technology but this research seeks to expand its capability to include haptic feedback and consequently shaping mode. This thesis gives an overview of the current 5x5 prototype and implements 2 commonly used haptic control methods, the admittance control and the impedance control. For implementing the admittance control, actuator displacement and velocity controllers and a proportional integral observer (PIO) are designed. The model-based unknown input observer is a solution for force estimation without added sensors in the actuators. For implementing the impedance control, a novel pressure control technique is designed to provide pressure feedback to the actuators array along with accurate and reliable displacement measurement. Both of the haptic control methods are evaluated, hardware and software limitations are outlined and possible future improvements are suggested.

Thesis (MSc (Computer Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The aim of this thesis is to develop a generic 3D virtual environment development platform for autism spectrum disorder (ASD) therapy tools. The potential of using computerised therapy tools for ASD therapy is well known. However, the development of such tools is expensive and time-consuming, and is language and culture speci c. This work intends to alleviate these problems. The design of the platform is based on known game engine designs, but adapted for the requirements of ASD therapy tools. It supports standard features such as 3D rendering, animation and audio output. Speci c features, aimed at ASD therapy tools and educational games, included in our engine are: replays, data capturing, remote monitoring over a network and language localisation. We also implemented an input hardware abstraction layer to allow support for non-standard input peripherals in the future, without modifying existing game implementations. Furthermore, to separate the development of games and tools from the engine, we include wrapper libraries in our engine for Lua and Java. We successfully developed our engine and implemented a number of prototype therapy tools and educational games. These implementations confirmed that the engine works as expected. Some of these programs are currently in use at a local primary school. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om 'n 3D virtuele omgewing en ontwikkelingsplatform vir outistiese spektrum versteuring (OSV) terapiemiddels te ontwikkel. Die gebruik van rekenaargebaseerde terapiemiddels vir OSV terapie is bekend. Om sulke terapiemiddels te ontwikkel is egter duur, tydrowend en is dikwels gerig op spesi eke taal- en kultuurgroepe. Hierdie werk het dit ten doel om hierdie probleme te bowe te kom. Die ontwerp van die platform is gebaseer op die ontwerp van bekende videospeletjie-enjins, maar is aangepas vir die benodigdhede van OSV terapiemiddels. Dit ondersteun standaard funksionaliteit soos 3D uitbeelding, animasie en klank. Ons platform sluit in spesi eke funksionaliteit, wat gerig is op OSV terapiemiddels en opvoedkundige speletjies, naamlik: kykweer, datavaslegging, afstandswaarneming oor 'n netwerk en taal-lokalisering. Verder is 'n abstrakte koppelvlak vir toevoerapparatuur ontwikkel, wat dit moontlik maak om in die toekoms nie-standaard toevoerapparatuur te ondersteun, sonder om bestaande speletjies se implementasies aan te pas. Verder, om die ontwikkeling van speletjies en terapiemiddels te skei van die enjin, is koppelvlakke ontwikkel wat dit moontlik maak om die enjin in Lua en Java te gebruik.

Indiana University-Purdue University Indianapolis (IUPUI) / In the last few decades, forensic science has played a significant role in bringing criminals to justice. Shoe and tire track impressions found at the crime scene are important pieces of evidence since the marks and cracks on them can be uniquely tied to a person or vehicle respectively. We have designed a device that can generate a highly accurate 3-Dimensional (3D) map of an impression without disturbing the evidence. The device uses lasers to detect the changes in depth and hence it is crucial to accurately detect the position of the laser. Typically, the forensic applications require very high resolution images in order to be useful in prosecutions of criminals. Limitations of the hardware technology have led to the use of signal and image processing methods to achieve high resolution images. Super Resolution is the process of generating higher resolution images from multiple low resolution images using knowledge about the motion and the properties of the imaging geometry. This thesis presents methods for developing some of the image processing components of the 3D impression scanning device. In particular, the thesis describes the following two components: (i) methods to detect the laser stripes projected onto the impression surface in order to calculate the deformations of the laser stripes due to 3D surface shape being scanned, and (ii) methods to improve the resolution of the digitized color image of the impression by utilizing multiple overlapping low resolution images captured during the scanning process and super resolution techniques.

University students learning object-oriented programming (OOP) encounter many complexities. This study undertook empirical research aimed at analysing learners’ interactions with the Alice visual programming environment, which seeks to engage and motivate learners to grasp concepts of OOP, whilst creating animated movies and video games. A mixed-methods approach was employed, using questionnaire surveys and interviews to investigate learners’ experiences with Alice and their understanding of OOP. Findings indicated that learners lacked problem-solving abilities; were unable to grasp programming concepts on an abstract level and spent insufficient time practicing programming exercises. Alice proved to be an effective tool in helping to address these challenges and in improving learners’ grasp of OOP. Learners found Alice to have good usability. Furthermore, test and exam results revealed a statistically significant difference between performances of learners who had been taught Alice in comparison to similar learners who were not exposed to the Alice intervention. / Computing / Information Systems / M. Sc. (Information systems)

Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2005. / The West Coast Fossil Park near Langebaanweg in the Western Cape, South Africa, is known for its abundance of marine, freshwater and terrestrial fossils of Mio-Pliocene age. The fossil bearing deposits reflect the complex and varied depositional environments, which were influenced by the change in course of the Berg River and regressions and transgressions of sealevel. The fossil deposits at this site are world-renowned for their species richness and uniqueness and there was a need to gain an in-depth understanding of the events that gave rise to this situation. To understand these complexities, it was necessary to construct a composite model of the pre-history of the West Coast Fossil Park, incorporating topological, geological and palaeontological data. GIS provided the ideal platform to integrate data from such varied sources, using spatial correlation to interpret commonalities. Subsequently, a spatially explicit database of the present-day study area, from Dwarskersbos in the north to just north of Yzerfontein in the south, was constructed. The oldest geological formation, the basement layer, as well as three successive formations was reconstructed on a regional scale using borehole data. Interpolation of point data to regional surfaces was a dual process incorporating expert opinion and purpose-built tools within ESRI’s ArcInfo and ArcMap 8.3. A similar reconstruction at a finer scale was done for the West Coast Fossil Park area using kriging as an interpolation method. These reconstructed geological layers can be used to predict the depth and location of fossil-bearing deposits. There is scope for further study and analysis to compare the accuracy of alternative interpolation methods, and combining it with field-based validation of modelled outputs.

A utilização mais eficiente dos recursos naturais tem levado a indústria a aumentar a eficiência dos produtos manufaturados. Veículos de transporte Diesel estão incluídos neste cenário. Nos motores Diesel, um componente importante do sistema de injeção é o bico injetor. Uma legislação recente no Brasil introduziu limites de emissões EURO5. Estes novos parâmetros tiveram impacto no projeto do bico injetor com tolerâncias sendo reduzidas, em especial na área da sede do corpo do bico injetor, alterando o parâmetro funcional de pressão de abertura do produto. Neste cenário, o impacto desta superfície cônica retificada sobre a pressão de abertura é grande, bem como, sobre o desempenho do motor Diesel. Este estudo tem como objetivo analisar o defeito de topografia superficial típico e recorrente no processo de retificação interna cônica da sede do corpo dos bicos injetores. Um experimento planejado foi realizado de acordo com método Taguchi e determinou-se a relação sinal-ruído para dois parâmetros de topografia 2D. A superfície da sede também foi analisada utilizando análise topográfica 3D. Os resultados deste estudo incluem a indicação de possíveis causas do defeito recorrente, caracterização dos principais elementos do processo de retificação, caracterização da superfície retificada e otimização dos parâmetros do processo de retificação. / Industries of manufactured products have increased their efficiency optimizing the natural resources usage and Diesel commercial vehicles are included in this scenario. For Diesel engines, one of the most important components of the injection system is the nozzle injector. In Brazil, EURO5 legislation was recently introduced, bringing new emission limits for Diesel engines. Because of this, the nozzle injector design has changed and some manufacturing tolerances were reduced, in special the body seat geometry. This also changed the nozzle opening pressure. In this new process, the body seat grinded conical surface impacts on this functional parameter and consequently the Diesel engine performance. This study has as target to analyze a recurrent defect in the internal conic grinding process of the nozzle body seat. A trial was performed in this process according to Taguchi method and signal / noise ratio for 2D topographic parameters were defined. The body seat surface was also analyzed using 3D topographic analysis. The results of this study include the possible cause of the recurrent failure, characterization of the ground surface, process main elements integrity assessment and optimization of the grinding process parameters.

University students learning object-oriented programming (OOP) encounter many complexities. This study undertook empirical research aimed at analysing learners’ interactions with the Alice visual programming environment, which seeks to engage and motivate learners to grasp concepts of OOP, whilst creating animated movies and video games. A mixed-methods approach was employed, using questionnaire surveys and interviews to investigate learners’ experiences with Alice and their understanding of OOP. Findings indicated that learners lacked problem-solving abilities; were unable to grasp programming concepts on an abstract level and spent insufficient time practicing programming exercises. Alice proved to be an effective tool in helping to address these challenges and in improving learners’ grasp of OOP. Learners found Alice to have good usability. Furthermore, test and exam results revealed a statistically significant difference between performances of learners who had been taught Alice in comparison to similar learners who were not exposed to the Alice intervention. / Computing / Information Systems / M. Sc. (Information systems)

Ce travail de thèse, inclus dans un projet structurant plus vaste, projet SIMOVI (SImulation des MOuvements du VIsage), s’attache à étudier spécifiquement la mimique faciale en corrélant les déplacements visibles du revêtement cutané et les mouvements musculaires internes à travers le développement de plusieurs méthodologies. L’ensemble de la mimique faciale ne pouvant être étudié, étant donné la multitude d’expressions, les mouvements pertinents à étudier dans nos travaux ont été identifiés. Ces mouvements ont été caractérisés chez 23 sujets jeunes dans une analyse descriptive qualitative et clinique, basée sur une méthodologie s’appuyant sur l’analyse d’enregistrements vidéoscopiques, et le développement d’un codage issu du FACS (Facial Action Coding System). Une cohorte de référence a ainsi été constituée. Après avoir validé notre méthodologie pour la caractérisation externe de la mimique, l’analyse des muscles peauciers par l’IRM a été réalisée sur 10 hémifaces parmi les sujets sains issus de la cohorte. Cette caractérisation a fait appel, à partir d’une anatomie in vivo, à une modélisation de certains muscles peauciers (zygomaticus major en particulier) afin d’extraire des paramètres morphologiques, de réaliser une analyse plus fine de la morphologie musculaire en 3 dimensions, et d’apporter une meilleure compréhension du comportement cinématique du muscle dans différentes positions. Par son intégration dans un questionnement plus vaste :- comment caractériser objectivement la mimique faciale ? - quels sont les indicateurs qualitatifs et quantitatifs de la mimique que nous pouvons recueillir, et comment réaliser ce recueil ? - comment utiliser les développements technologiques dans les applications cliniques ? Ce travail constitue une étape préliminaire à d’autres travaux. Il pourra fournir des données de référence à des fins de modélisation, de simulation de la mimique faciale, ou de développements d’outil de mesures pour le suivi et l’évaluation des déficits de la mimique faciale. / The aim of this research is to study facials mimics movements and to correlate externat soft tissue (i.e., cutaneous) movement during facial mimics with internal (i.e., facial mimic muscle) movement. The entire facial mimicry couldn't be studied, that's why relevant movements had been selected. Those movements were characterised by a clinically qualitative analysis in 23 young healthy volunteers. The analysis was performed with video recordings including scaling derived from the FACS (Facial Action Coding System). After the validation of external characterisation by this method, internal characterisation of the mimic facial muscle was carried out in 10 volunteers. A modelization of selected facial mimic muscle as Zygomaticus Major was achieved. With this work, morphological parameters could be extracted, 3D morphometric data were analysed to provide a better understanding of cinematic behaviour of muscle in different positions.This research is included in the Simovi Project, which aims to determine to what extent a facial mimic can be evaluated objectively, to select the qualitative and quantitative indicators for evaluation of mimic facial disorders, and to transfer our technological developments in clinical field. This research is a first step and provides data for simulation or developments of measurement tools in evaluation and follow-up of mimic facial disorders.

Indiana University-Purdue University Indianapolis (IUPUI) / In crime scene investigations it is necessary to capture images of impression evidence such as tire track or shoe impressions. Currently, such evidence is captured by taking two-dimensional (2D) color photographs or making a physical cast of the impression in order to capture the three-dimensional (3D) structure of the information. This project aims to build a digitizing device that scans the impression evidence and generates (i) a high resolution three-dimensional (3D) surface image, and (ii) a co-registered two-dimensional (2D) color image. The method is based on active structured lighting methods in order to extract 3D shape information of a surface. A prototype device was built that uses an assembly of two line laser lights and a high-definition video camera that is moved at a precisely controlled and constant speed along a mechanical actuator rail in order to scan the evidence. A prototype software was also developed which implements the image processing, calibration, and surface depth calculations. The methods developed in this project for extracting the digitized 3D surface shape and 2D color images include (i) a self-contained calibration method that eliminates the need for pre-calibration of the device; (ii) the use of two colored line laser lights projected from two different angles to eliminate problems due to occlusions; and (iii) the extraction of high resolution color image of the impression evidence with minimal distortion.The system results in sub-millimeter accuracy in the depth image and a high resolution color image that is registered with the depth image. The system is particularly suitable for high quality images of long tire track impressions without the need for stitching multiple images.