Context. Particle systems and particle effects are used to simulate a realistic and appealing atmosphere in many virtual environments. However, they do occupy a significant amount of computational resources. The demand for more advanced graphics increases by each generation, likewise does particle systems need to become increasingly more detailed. Objectives. This thesis proposes a texture-based 3D vector field particle system, computed on the Graphics Processing Unit, and compares it to an equation-based particle system. Methods. Several tests were conducted comparing different situations and parameters for the methods. All of the tests measured the computational time needed to execute the different methods. Results. We show that the texture-based method was effective in very specific situations where it was expected to outperform the equation-based. Otherwise, the equation-based particle system is still the most efficient. Conclusions. Generally the equation-based method is preferred, except for in very specific cases. The texture-based is most efficient to use for static particle systems and when a huge number of forces is applied to a particle system. Texture-based vector fields is hardly useful otherwise.

To efficiently examine volumetric data sets from CT or MRI scans good volume rendering applications are needed. This thesis describes the design and implementation of an application programming interface (API) to be used when developing volume-rendering applications. A complete application programming interface has been designed. The interface is designed so that it makes writing application programs containing volume rendering fast and easy. The interface also makes created application programs hardware independent. Volume rendering using 3d-textures is implemented on Windows and Unix platforms. Rendering performance has been compared between different graphics hardware.

O presente trabalho objetiva estudar uma aplicação biomimética, sustentada por estudos acerca dos passeriformes da espécie Sicalis flaveola (canário-da-terra), associada ao design de produtos conferindo a estes características intangíveis. A biomimética prioriza o estudo de sistemas e elementos naturais para a aplicação em projetos de demanda que busquem estratégias e soluções devidamente proporcionadas pela natureza. Os passeriformes (pássaros) são elementos naturais de grande relevância devido as suas características encantadoras de sobrevivência e formação estrutural. Neste contexto, o estudo desses elementos se mostra bastante relevante para o desenvolvimento de projetos que visem suprir as necessidades e exigências do mercado de consumo, considerando a associação com aspectos intangíveis, os quais interferem no significado simbólico do produto agregando valor emocional. No trabalho específico, busca-se o desenvolvimento de texturas baseadas na morfologia das penas do Sicalis flaveola para a aplicação em superfícies materiais, com base em análises macroscópicas e microscópicas que visem realçar as principais características estruturais, funcionais e estéticas das penas em estudo. Para isso, depois de definidas e aplicadas as texturas em chapas de diferentes materiais, estas foram disponibilizadas ao um público específico para verificar a interação entre usuário e objeto proposto a partir da realização das técnicas de análises sensoriais e entrevistas. Durante a execução do trabalho foram utilizadas, ainda, diferentes técnicas metodológicas, de pesquisas e análises referentes ao objeto de estudo, tais como, revisão literária, estudo de campo e experimentação do produto. Dessa forma, por meio das pesquisas e estudos realizados, buscou-se compreender a interação do usuário com as texturas propostas para possível aplicação em projetos de produtos, verificando as percepções sensoriais associadas às mesmas que agregam valor aos produtos e interferem na decisão de compra. / This work aims to establish an interaction between user and product, from a biomimetic point of view, supported by studies about the passerines Sicalis flaveola, associated with product design and intangible characteristics. Biomimetics prioritizes the study of natural systems and elements for the implementation of projects seeking strategies and solutions offered by the nature. The passerines (birds) are natural elements of great importance because of its charming features and structural formation. In this context, the study of these elements are very important for the development of projects aimed to meet the needs and demands of the consumer market, whereas the association with intangibles aspects. In this specific work, textures were developed based on the morphology of the feathers of the Sicalis flaveola applied to different materials surfaces, according with macroscopic and microscopic analysis that seek to highlight the main features of structural, functional and aesthetic of the feathers in study. After defined and applied textures in samples of different materials, these were made available to consumers to verify the interaction between user and proposed object from the realization of sensory analysis techniques and interviews. During the execution o f work were used also other different methodological techniques, research and analysis related to the object of study, such as literary review, field study and experimentation of product. Therefore, by means of these research and studies, the work sought to understand the user's interaction with the textures proposals for possible application in product design, verifying sensory perceptions associated with them that add value to products and influence the buying decision.

This design project places itself in the field of knit, smart textiles and inclusive design. Knitting is a technique that can create interactive objects, for children with autism that may need support to interact with their surroundings. Therefore, this work sets out to support these individuals, using objects that offer different tactile sensations, to provide focus and calmness. To achieve this, the aim is to design inclusive knitted objects that encourage individuals with autism to interact with knitted forms through stimulating textures, vibration, and colours. Through technical research on Shima Seiki, Dubied and Silver Reed, 3D objects with various bindings are developed to create stimulating textures. Sensors and other electronics are also investigated and integrated, to make the textiles smart. Further investigations are made using surveys with an autism community, to accommodate their needs during the design process. The result of this project is three textile objects that provide two kinds of stimulation. Two pieces which react to touch with vibration, and one object with different tactile textures. As well as knowledge about how to knit forms with textures, and how to insert electronics into knitted structures. It is also how people with autism can be helped by using the objects as tools, to facilitate sensory processing or non-verbal communication, in their everyday life.

This work deals with experimental analysis of fluid film instability in rotor bearing systems stored in hydrodynamic plain bearings with focus on bearing surface modification. The experiments were performed on a journal bearing dynamics simulator. The aim was to determine the influence of individual operating parameters on the occurrence and course of turbulence instability. The emphasis here was on the effect of surface micro textures. The work also included the preparation of textured samples. Experiments were divided into experiments monitoring the influence of temperature, pressure, bearing geometry and surface modification. The output of the individual experiments were the values of the threshold speed of formation and termination of instability or the magnitude of the amplitude depending on the above described parameters. These values were plotted in graphs. This data was then confronted with previously published articles. The results showed that instabilityin rotor systems is very sensitive to temperature, pressure and bearing geometry changes. The fundamental influence on the unstable behavior of the rotor system has been demonstrated by the use of textured surfaces, where the threshold speed was significantly shifted to a higher speed range compared to the non-textured bearing.

Les propriétés d’emploi des pièces matricées en alliage de titane sont fortement dépendantes des conditions de matriçage (déformation, température de déformation, etc.) ainsi que des conditions de traitement thermique. Nos objectifs furent de caractériser la microstructure et la texture de l’alliage Ti6246 pour comprendre l’influence des paramètres du procédé sur le développement de la microstructure et les conséquences sur l’anisotropie des propriétés mécaniques.En particulier, nous nous sommes intéressés à l’évolution de la texture des grains β; ainsi qu’à la précipitation de la phase α; en fonction du taux de déformation. Des observations EBSD ont permis d’étudier les conditions de germination croissance de la phase α; au niveau des joints de grains β/β et les conditions de sélection des variants d’orientation de la phase αWI observées sur des échantillons fortement déformés. Des observations MEB couplées à un algorithme d'analyse d'image spécialement développé ont permis de déterminer l’influence des paramètres du cycle thermomécaniques sur les caractéristiques microstructurales de la phase αp (fraction de phase, taille…).Les propriétés mécaniques ont été caractérisées à partir d’essai de traction pour déterminer l’influence de l’anisotropie microstructurale induite par la mise en forme. L’observation des surfaces de rupture a mis en évidence le rôle des liserés αGB sur l’amorçage et la propagation des fissures.Les cartographies d’orientation ont montré des variations de propriétés élastiques à l’échelle des grains β; en relation avec la précipitation de la phase α. Il a ainsi été possible de relier les augmentations du bruit ultrasonore rétrodiffusé avec les évolutions de texture et les sélections de variant induites par le forgeage dans le domaine β. / Mechanical properties of closed die forging titanium alloys are very sensitive to variations of processing parameters (forging amount, forging temperature, etc.). The claims of this study were to characterize the microstructure and texture of Ti6246 alloys in order to understand the process parameters' impact on microstructure and their consequences on mechanical properties’ anisotropy.We investigate the impact of the forging amount on the β texture and α phase nucleation. The study of α nucleation and growth at β/β grains boundaries and variant selection in αWI phase conditions is carried out by EBSD measurements. SEM observations associate to an image analysis algorithm specially conceived give a good description of the thermo-mechanical processing parameters’ effects on the αp morphology (fraction, size …).Thanks to tensile testing, mechanical properties have been measured in order to evaluate the effects of microstructure anisotropy induced by forging. αGB-layers at β-grain boundaries dominate fracture toughness (cracks nucleation and cracks propagation) as observed on crack path profiles.Variations of elastic properties at β grains scale linked to α phase precipitation have been revealed by crystallographic orientation maps. Therefore the increasing of backscattered ultrasound noise can be linked to the texture evolution and the variant selections induced by β-forging.

Background. Shadow mapping is a method that is used for generating and imitating shadows in 3D-spaces. This technique has been used in the entertainment media industry in the form of games, movies and 3D renderings of environments to create a more realistic experience for consumers. Shadow mapping is not a perfect technique, and is performance costing on the GPU; however, some methods save performance by reducing the complexity of geometrical shapes and textures depending on the distance between observer and object. These techniques are based on that the observer will not notice the complexity reductions; can the usage of such methods be extended to textures covered in shadows without any consequences in the aspect of visual appearance and preference? Objectives. This thesis aims to examine if there is a possibility to extend the usage of LOD techniques to shadowed textures and to analyze individuals’ preferences of texture variants that are covered in shadows. Additionally, proposing the method of lowering texture resolution by using DirectX:s sampler data type, which is configurable to increase the level of details with mipmapping when sampling textures. Methods. This document presents a user study using the Two-alternative forced choice method and PsychoPy application to create a visual test. The visual test was conducted in a controlled and observed environment with volunteering participants. The objective of the visual test was to go through several sets of different images, and to choose which image of each set that was preferred. The stimulus was repeated with the initial images fading in and out slowly to prevent carry over effects. After the test participants were asked to fill out a questionnaire. The questionnaire assessed if they noticed any differences within the shadows, and if they had any additional thoughts about the experiment. Results. The results from the study were then evaluated through a binomial test that yielded that there was no statistically significant difference in preference between the lowered texture resolution in shadows and normal texture resolution in shadows. Separately evaluating the environments showed that there was a preference for shadowed low-resolution textures in environments that were dark. The environments with high illumination had more varied results. There were 17 participants that volunteered in the test and were ranging from the ages 18 to 29. Conclusions. With the results presented it was shown that the shadowed lowresolution textures were preferred in environments with low illumination. This suggests that the proposed concept method is better suited for similar environments. However, several factors may have affected the results. Factors such as images being too dark, the lack of exaggerated images, images fading in and out too fast, few participants, more partaking will assure there is less chance for bias.

Hyaenids reached their peak diversity during the Mio-Pliocene, when an array of carnivorous species emerged alongside dwindling civet-like and mongoose-like insectivorous/omnivorous taxa. Significantly, bone-cracking morphological adaptations were poorly developed in these newly-emerged species. This, their general canid-like morphology, and the absence/rarity of canids in Eurasia and Africa at the time, has led researchers to hypothesise that these carnivorous Mio-Pliocene hyaenas were ecological vicars to modern canids. To shed further light on their diets and foraging strategies, we examine and compare the dental microwear textures of Hyaenictitherium namaquensis, Ikelohyaena abronia, Chasmaporthetes australis, and Hyaenictis hendeyi from the South African Mio-Pliocene site of Langebaanweg with those of the extant feliforms Crocuta crocuta, Acinonyx jubatus, and Panthera leo (caniforms are not included because homologous wear facets are not directly comparable between the suborders). Sample sizes for individual fossil species are small, which limits confidence in assessments of variation between the extinct taxa; however, these Mio-Pliocene hyaenas exhibit surface complexity and textural fill volume values that are considerably lower than those exhibited by the living hyaena, Crocuta crocuta. Dental microwear texture analysis thus supports interpretations of craniodental evidence suggesting low bone consumption in carnivorous Mio-Pliocene hyaenas.

<p>Kreiranje 3D modela i njihova vizuelizacija postali su sastavni deo procesa razvoja novih ili redizajniranja postojećih proizvoda. U ovom istraživanju pažnja je posvećena re&scaron;avanju problema 3D digitalizacije kod blisko-predmetne fotogrametrije zasnovane na određivanju strukture iz kretanja, na povr&scaron;ima bez karakterističnih obeležja primenom projektovanja sintetički generisanih slika u vidu svetlosnih tekstura. Akcenat je stavljen na generisanje novih sintetičkih slika koje imaju izraženu vizuelnu teksturu, njihovu evaluaciju i primenu na objektima sa monotonim vizuelnim povr&scaron;ima sa ciljem podizanja ukupne tačnosti rekonstruisanih 3D modela. Verifikacija primene sintetičkih slika i njihovih svetlosnih tekstura sa aspekta geometrijske i dimenzione tačnosti je realizovana primenom računarom podržane inspekcije (CAD inspekcije).</p> / <p>The creation of 3D models and their visualization have become an integral part of the process of developing new or redesigning existing products. In this research, attention was paid to solving the problem of 3D digitization in close-range photogrammetry based on the structure from motion on surfaces without characteristic features by designing synthetically generated images in the form of light textures. An accent is placed on the generation of new synthetic images that have a pronounced visual texture, their evaluation, and application on objects with monotonous visual surfaces with the aim of raising the overall accuracy of reconstructed 3D models. The verification of the application of synthetic images and their light textures from the aspect of geometric and dimensional accuracy was realized through the use of computer-aided inspection (CAI inspection).</p>

Le traitement et la synthèse des sons environnementaux sont devenue un sujet important. Une classe des sons, qui est très important pour la constitution d'environnements sonore, est la classe des textures sonores. Les textures sonores sont décrit par des relations stochastiques et qui contient des composantes non-sinusoïdales à caractère fortement bruité. Il a été montré récemment que la reconnaissance de textures sonores est basée sur des mesures statistiques caractérisant les enveloppes dans les bandes critiques. Il y actuellement très peu d'algorithmes qui permettent à imposer des propriétés statistiques de façon explicite lors de la synthèse de sons. L'algorithme qui impose l'ensemble de statistique qui est perceptivement relevant pour les textures sonore est très couteuse en temps de calcul. Nous proposons une nouvelle approche d'analyse-synthèse qui permet une analyse des statistiques relevant et un mécanisme efficace d'imposer ces statistiques dans le domaine temps-fréquence. La représentation temps-fréquence étudié dans cette thèse est la transformée de Fourier à court terme. Les méthodes proposées par contre sont plus générale et peuvent être généralisé à d'autres représentations temps-fréquence reposant sur des banques de filtres si certaines contraintes sont respectées. L'algorithme proposé dans cette thèse ouvre plusieurs perspectives. Il pourrait être utilisé pour générer des textures sonores à partir d'une description statistique créée artificiellement. Il pourrait servir de base pour des transformations avancées comme le morphing, et on pourrait aussi imaginer à utiliser le modèle pour développer un contrôle sémantique de textures sonores. / The processing of environmental sounds has become an important topic in various areas. Environmental sounds are mostly constituted of a kind of sounds called sound textures. Sound textures are usually non-sinusoidal, noisy and stochastic. Several researches have stated that human recognizes sound textures with statistics that characterizing the envelopes of auditory critical bands. Existing synthesis algorithms can impose some statistical properties to a certain extent, but most of them are computational intensive. We propose a new analysis-synthesis framework that contains a statistical description that consists of perceptually important statistics and an efficient mechanism to adapt statistics in the time-frequency domain. The quality of resynthesised sound is at least as good as state-of-the-art but more efficient in terms of computation time. The statistic description is based on the STFT. If certain conditions are met, it can also adapt to other filter bank based time-frequency representations (TFR). The adaptation of statistics is achieved by using the connection between the statistics on TFR and the spectra of time-frequency domain coefficients. It is possible to adapt only a part of cross-correlation functions. This allows the synthesis process to focus on important statistics and ignore the irrelevant parts, which provides extra flexibility. The proposed algorithm has several perspectives. It could possibly be used to generate unseen sound textures from artificially created statistical descriptions. It could also serve as a basis for transformations like stretching or morphing. One could also expect to use the model to explore semantic control of sound textures.