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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.
51

Apparence matérielle : représentation et rendu photo-réaliste / Material appearance : photo-realistic representation and rendering

Mohammadbagher, Mahdi 19 November 2012 (has links)
Cette thèse présente quelques avancées sur la représentation efficace de l’apparence matérielle dans une simulation de l’éclairage. Nous présentons deux contributions : un algorithme pratique de simulation interactive pour rendre la réflectance mesurée avec une géométrie dynamique en utilisant une analyse fréquentielle du transport de l’énergie lumineuse et le shading hiérarchique et sur-échantillonnage dans un contexte deferred shading, et une nouvelle fonction de distribution pour le modèle de BRDF de Cook-Torrance. Dans la première partie, nous présentons une analyse fréquentielle de transport de l’éclairage en temps réel. La bande passante et la variance sont fonction de l’éclairage incident, de la distance parcourue par la lumière, de la BRDF et de la texture, et de la configuration de la géométrie (la courbure). Nous utilisons ces informations pour sous-échantillonner l’image en utilisant un nombre adaptatif d’échantillons. Nous calculons l’éclairage de façon hiérarchique, en un seul passage. Notre algorithme est implémenté dans un cadre de deferred shading, et fonctionne avec des fonctions de réflectance quelconques, y compris mesurées. Nous proposons deux extensions : pré-convolution de l’éclairage incident pour plus d’efficacité, et anti-aliasing utilisant l’information de fréquence. Dans la deuxième partie, nous nous intéressons aux fonction de réflectance a base de micro-facette, comme le modèle de Cook-Torrance. En nous basant sur les réflectances mesurées, nous proposons une nouvelle distribution des micro-facettes. Cette distribution, Shifted Gamma Distribution, s’adapte aux donnée avec plus de précision. Nous montrons également comment calculer la fonction d’ombrage et de masquage pour cette distribution. Dans un deuxième temps, nous observons que pour certains matériaux, le coefficient de Fresnel ne suit pas l’approximation de Schlick. Nous proposons une généralisation de cette approximation qui correspond mieux aux données mesurées. Nous proposons par ailleurs une nouvelle technique d’optimisation, canal par canal, en deux étapes. Notre modèle est plus précis que les modèles existants, du diffus au spéculaire. / This thesis presents some advances in efficient representation of material appearance in a lighting simulation. The scope of this thesis is two-fold: an interactive shading algorithm to render measured reflectance with dynamic geometry using frequency analysis of light transport and hierarchical shading and up-sampling in deferred shading context, and a new normal distribution function for the Cook-Torrance micro-facet BRDF model, along with a new shadowing and masking function and a generalization of Schlick’s approximation of the Fresnel term. In the first part, we introduce a real-time frequency analysis of light transport framework that allows us to estimate the bandwidth and variance of the shading integrand. The bandwidth and variance are a function of frequencies in the illumination, distance traveled by light, BRDF and texture, and the geometry configuration (curvature). We use this information to under-sample the image, and also use an adaptive number of samples for shading. We devise a single-pass hierarchical shading and up-sampling scheme to assemble an image out of the sparsely shaded image pixels. We extend our interactive technique to use pre-convolved shading for real-time performance. We also take advantage of the bandwidth information to perform multi-sample anti-aliasing in deferred shading by subsampling only a small portion of image pixels whose bandwidth is smaller than 1 pixel^-1. In the second part, we propose a new distribution function for the Cook-Torrance micro-facet BRDF, based on our observations on the reflectance measurements. We isolate the distribution components of the reflectance data and directly observe that existing distribution functions are insufficient. Then we devise the Shifted Gamma Distribution (SGD) fitting more accurately to the data. We derive the shadowing and masking function from the distribution. We observe that not all materials have the Fresnel behavior expected by Schlick’s approximation. Hence, we generalize the Schlick’s approximation to more accurately fit the model to the measurements. We introduce a two-step fitting approach, that fits each RGB channel separately — accounting for wave-length dependent effects. We show that our shading model outperforms existing models and accurately represents a wider range of materials from diffuse to glossy and highly specular materials.
52

Higher-Order Factor Analysis of the Swedish Version of the Personality Inventory for DSM-5

Baurne, Yvette January 2018 (has links)
The Personality Inventory for DSM-5 (PID-5) is an emerging measure used to map pathological personality traits. In this thesis, the reliability and facet structure of the Swedish version of the PID-5 is evaluated. Further, the possible occurrence of higher-order factors of the pathological personality traits is explored. Using a sample of 275 observations, the facet structure and higher-order factors are investigated using structural equation modeling (SEM). Results show that the internal consistency, measured with Cronbach's alpha, is strong for the facets and adequate for the domains from the PID-5. The theorized facet structure could not be confirmed for the Swedish version of the PID-5. Treating the five domains as observed variables, support for a general factor of psychopathology and indications of the two factors internalizing and externalizing are found.
53

Recoloração convexa de caminhos / Convex recoloring of paths

Karla Roberta Pereira Sampaio Lima 16 November 2011 (has links)
O foco central desta tese é o desenvolvimento de algoritmos para o problema de recoloração convexa de caminhos. Neste problema, é dado um caminho cujos vértices estão coloridos arbitrariamente, e o objetivo é recolorir o menor número possível de vértices de modo a obter uma coloração convexa. Dizemos que uma coloração de um grafo é convexa se, para cada cor, o subgrafo induzido pelos vértices dessa cor é conexo. Sabe-se que este problema é NP-difícil. Associamos a este problema um poliedro, e estudamos sua estrutura facial, com vistas ao desenvolvimento de um algoritmo. Mostramos várias inequações válidas para este poliedro, e provamos que várias delas definem facetas. Apresentamos um algoritmo de programação dinâmica que resolve em tempo polinomial o problema da separação para uma classe grande de inequações que definem facetas. Implementamos um algoritmo branch-and-cut baseado nesses resultados, e realizamos testes computacionais com instâncias geradas aleatoriamente. Apresentamos adicionalmente uma heurística baseada numa formulação linear que obtivemos. Estudamos também um caso especial deste problema, no qual as instâncias consistem em caminhos coloridos, onde cada cor ocorre no máximo duas vezes. Apresentamos um algoritmo de 3/2-aproximação para este caso, que é também NP-difícil. Para o caso geral, é conhecido na literatura um algoritmo de 2-aproximação. / The focus of this thesis is the design of algorithms for the convex recoloring problem on paths. In this problem, the instance consists of a path whose vertices are arbitrarily colored, and the objective is to recolor the least number of vertices so as to obtain a convex coloring.Acoloring of a graph is convex if, for each color, the subgraph induced by the vertices of this color is connected. This problem is known to be NP-hard. We associate a polyhedron to this problem and investigate its facial structure. We show various classes of valid inequalities for this polyhedron and prove that many of them define facets.We present a polynomial-time dynamic programming algorithm that solves, in polynomial time, the separation problem for a large class of facet-defining inequalities.We report on the computational experiments with a branch-and-cut algorithm that we propose for the problem. Additionally, we present a heuristic that is based on a linear formulation for the problem. We also study a special case of this problem, restricted to instances consisting of colored paths in which each color occurs at most twice. For this case, which is also NP-hard, we present a 3/2-approximation algorithm. For the general case, it is known a 2-approximation algorithm.
54

A Software Reuse Paradigm for the Next Generation Network (NGN)

Jagot, Bilal Abdull Rahim 17 November 2006 (has links)
MSc thesis - Faculty of Engineering / Service creation in the Next Generation Network (NGN) is focused around software creation and borrows heavily from the Software Engineering community. In the NGN, telecommunication companies demand simple, rapid and economical service creation. The key to this type of service creation is software re-use. Software re-use is a conundrum where limited, dedicated solutions exists. These solutions include amongst others Enterprise JavaBeansTM (EJBs), design patterns and object-oriented programming. The Telecommunications Information Networking Architecture- Conformance And Testing (TINA-CAT) workgroup has done work on a functionality centric concept called RP-facets. This report proposes a redefinition of RP-facets, as Facets, for software re-use across the design and code level. We redefine Facets as functionality centric reusable components. A Facet is independent of the implementation language and the execution platform. Facets allow containment in a structured manner via a user defined Facet Hierarchy. Facets are resource, context and data agnostic. They also introduce a structured way to allow source code to be changed based on design level decisions. Also, possessing the ability to allow the simultaneous use of other reuse solutions and programming paradigms. Abstraction of detail from developers and platform migration can be achieved by using Facets. Facets are composed of a Generic definition and any number of Implementation definitions. The definitions are supported by an underlying informational model called meta-¼. Meta- ¼ is a model at the M3 meta-level that focuses on describing entities. Most of the Facet’s capabilities are enabled by the meta-¼ model. An environment for developing Facets is created, called the Facet Development Environment (FDE). The Facet Developer (FD) role is introduced to develop and maintain Facets. The FD verifies programmes from programmers to be included into the catalogue of Facets via the FDE. The FD interacts with service creation teams to determine which Facets can be used in the service they wish to develop. Facets prove their capability in targeted areas, yet lack in other categories. It is recommended that the underlying informational model should be revised to form a more robust and flexible entity describing model. In addition, a cataloging capability to easily find Facets with particular functionality should be appended to the capabilities of the facet. It is proposed, for future work, that a development environment be created that encompasses a process for using Facets to create services.
55

Stereolithography (STL) File Modification by Vertex Translation Algorithm (VTA) for Precision Layered Manufacturing

Navangul, Gaurav D. 20 September 2011 (has links)
No description available.
56

Enveloppe convexe des codes de Huffman finis / The convex hull of Huffman codes

Nguyen, Thanh Hai 10 December 2010 (has links)
Dans cette thèse, nous étudions l'enveloppe convexe des arbres binaires à racine sur n feuilles.Ce sont les arbres de Huffman dont les feuilles sont labellisées par n caractères. à chaque arbre de Huffman T de n feuilles, nous associons un point xT , appelé point de Huffman, dans l'espace Qn où xT est le nombre d'arêtes du chemin reliant la feuille du ième caractère et la racine.L'enveloppe convexe des points de Huffman est appelé Huffmanoèdre. Les points extrêmes de ce polyèdre sont obtenus dans un premier temps en utilisant l'algorithme d'optimisation qui est l'algorithme de Huffman. Ensuite, nous décrivons des constructions de voisinages pour un point de Huffman donné. En particulier, une de ces constructions est principalement basée sur la construction des sommets adjacents du Permutoèdre. Puis, nous présentons une description partielle du Huffmanoèdre contenant en particulier une famille d'inégalités définissant des facettes dont les coefficients, une fois triés, forment une suite de Fibonacci. Cette description bien que partielle nous permet d'une part d'expliquer la plupart d'inégalités définissant des facettes du Huffmanoèdre jusqu'à la dimension 8, d'autre part de caractériser les arbres de Huffman les plus profonds, i.e. une caractérisation de tous les facettes ayant au moins un plus profond arbre de Huffman comme point extrême. La contribution principale de ce travail repose essentiellement sur les liens que nous établissons entre la construction des arbres et la génération des facettes / In this thesis, we study the convex hull of full binary trees of n leaves. There are the Huffman trees, the leaves of which are labeled by n characters. To each Huffman tree T of n leaves, we associate a point xT , called Huffman point, in the space Qn where xT i is the lengths of the path from the root node to the leaf node marked by the ith character. The convex hull of the Huffman points is called Huffmanhedron. The extreme points of the Huffmanhedron are first obtained by using the optimization algorithm which is the Huffman algorithm. Then, we describe neighbour constructions given a Huffman point x. In particular, one of these constructions is mainly based on the neighbour construction of the Permutahedron. Thereafter, we present a partial description of the Huffmanhedron particularly containing a family of inequalities-defining facets whose coeficients follows in some way the law of the well-known Fibonacci sequence. This description allows us, on the one hand, to explain the most of inequalities-defining facets of the Huffmanhedron up to the dimension 8, on the other hand, to characterize the Huffman deepest trees, i.e a linear characterization of all the facets containing at least a Huffman deepest tree as its extreme point. The main contribution of this work is essentially base on the link what we establish between the Huffman tree construction and the facet generation.
57

Všímavost u homosexuálně orientovaných osob / Mindfulness in homosexually oriented individuals

Porkertová, Martina January 2012 (has links)
The focus of this work is to bring the idea of mindfulness closer, in terms of connection with other personality traits. Additionally it highlights the use of mindfulness in psychotherapy practice, specifically in regard to homosexually orientated clients. The study summarizes the main findings on the mindfulness phenomenon, highlighting the important aspects of adopting a new identity within this demographic. The study also monitors the connection of coming out process with particular aspects of mindfulness. In the empirical section the results of the FFMQ questionnaire, in which participated 294 persons of both male and female gender and of both heterosexual and homosexual orientation are compared using quantitative methods. By means of statistical analysis of variance (ANOVA) it was determined that the homosexually orientated do not differ significantly from those of heterosexual orientation. Furthermore there was no significant statistical difference in mindfulness between genders within the research sample. Keywords: mindfulness, psychotherapy, mindfulness definitions, Five Facet Mindfulness Questionnaire, sexual orientation, coming out, homosexual identity, personality
58

Designing optical multi-band networks : polyhedral analysis and algorithms / Conception de réseaux optiques multi-bandes : Analyse polyédrale et algorithmes

Benhamiche, Amal 12 December 2013 (has links)
Dans cette thèse, on s'intéresse à deux problèmes de conception de réseaux, utilisant la technologie OFDM multi-bandes. Le premier problème concerne la conception d'un réseau mono-couche avec contraintes spécifiques. Nous donnons une formulation en PLNE pour ce problème et étudions le polyèdre associé à sa restriction sur un arc. Nous introduisons deux familles d'inégalités valides définissant des facettes et développons un algorithme de coupes et branchements pour le problème. Nous étudions la variante multicouche du problème précédent et proposons plusieurs PLNE pour le modéliser. Nous identifions plusieurs familles de facettes et discutons des problèmes de séparation associés. Nous développons un algorithme de coupes et branchements utilisant l'ensemble des contraintes identifiées. Enfin, une formulation compacte et deux formulations basées sur des chemins sont proposées pour le problème. Nous présentons deux algorithmes de génération de colonnes et branchements pour le problème. / In this thesis we consider two capacitated network design (CND) problems, using OFDM multi-band technology. The first problem is related to single-layer network design with specific requirements. We give an ILP formulation for this problem and study the polyhedra associated with its arc-set restriction. We describe two families of facet defining inequalities. We devise a Branch-and-Cut algorithm for the problem. Next, we investigate the multilayer version of CND using OFDM technology. We propose several ILP formulations and study the polyhedron associated with the first (cut) formulation. We identify several classes of facets and discuss the related separation problem. We devise a Branch-and-Cut algorithm embedding valid inequalities of both single-layer and multilayer problems. The second formulation is compact, and holds a polynomial number of constraints and variables. Two further path formulations are given which yield two efficient Branch-and-Price algorithms for the problem.
59

The effect of manipulation, heat therapy and cryotherapy on cervical facet syndrome

31 July 2012 (has links)
M.Tech. / Purpose: This randomised, controlled, comparative pilot study was undertaken in order to investigate the effectiveness of the chiropractic manipulation alone, the chiropractic manipulation followed by heat therapy or the chiropractic manipulation followed by cryotherapy in the treatment of cervical facet syndrome. It was hypothesised that all three treatment protocols would be effective, but that applying chiropractic manipulation followed by heat therapy would be the most effective protocol in the treatment of cervical facet syndrome. Method: Forty-five participants were recruited by means of advertisements posted around the University of Johannesburg Doornfontein campus and surrounding businesses. Only those participants who conformed to the inclusion criteria were accepted to form a part of the study. The forty-five participants were randomly placed into three groups of fifteen each. Procedure: Group 1 received chiropractic manipulation only as their treatment protocol. Group 2 received chiropractic manipulation followed by heat therapy as their treatment protocol and group 3 received chiropractic manipulation followed by cryotherapy as their treatment protocol. Each participant received six treatments over a two week period and attended a follow-up consultation in the third week. The follow-up consultation was used to assess the lasting effects of the treatment protocol. Results: The objective data in the form of cervical range of motion was obtained by means of the Cervical Range of Motion instrument. The subjective data was collected by means of the Vernon-Mior Neck Pain and Disability Index and the Numerical Pain Rating Scale. At the end of the trial, statistical analysis was performed to determine whether one treatment protocol was more effective compared to the other treatment protocols. The results indicated that group 2 (Chiropractic manipulation followed by heat therapy) proved to be the most effective treatment protocol. Although the other treatment protocol as well as the control group showed good objective results. Subjective results showed that although all three groups showed statistically significant results, group 2 showed the best results. Thus it is noted that in order to achieve a potentially lasting increase in range of motion and a decrease in pain and disability, the treatment protocol used for group 2 should be the treatment of choice. Conclusion: Trends indicate the most effective treatment protocol in the treatment of cervical facet syndrome is when chiropractic manipulation is followed by heat therapy. The advantage of this combination is that each treatment modality is used to its full potential, thereby providing the patient with the best results in terms of lasting benefits.
60

Sistemas de classificação do conhecimento na filosofia e na biblioteconomia: uma visão histórico-conceitual crítica com enfoque nos conceitos de classe, de categoria e de faceta / Sistemas de classificação do conhecimento na filosofia e na biblioteconomia: uma visão histórico-conceitual crítica com enfoque nos conceitos de classe, de categoria e de faceta

Anjos, Liane dos 02 March 2009 (has links)
A análise dos sistemas de classificação do conhecimento na Filosofia e na Biblioteconomia sob um ponto de vista histórico-conceitual crítico com enfoque nos conceitos de classe, categoria e faceta foi desenvolvida a partir dos objetivos específicos de acompanhar e delinear a trajetória das classificações dos saberes (classes) e dos seres (categorias) à luz da Filosofia; averiguar as possíveis influências que as classificações filosóficas historicamente exerceram sobre as classificações bibliográficas tradicionais; e verificar de que modo os conceitos específicos de categoria, de classe e de faceta têm sido definidos no âmbito das classificações biblioteconômicas tradicionais. Trata-se de uma pesquisa do tipo exploratório-descritivo, embasada na literatura pertinente, oriunda de ambas as áreas do conhecimento em questão. A partir do levantamento bibliográfico construiu-se o referencial teórico, conduzindo à objetivação, análise, discussão e o aprofundamento do objeto. É possível afirmar que tanto os princípios das classificações filosóficas em relação aos saberes e em relação aos seres, quanto as próprias classificações que dividem os saberes e os seres, apresentam-se como construtos destinados a conhecer e disciplinar o conhecimento do ser e do saber. A influência das classificações filosóficas sobre as classificações bibliográficas reside no fato de que as classificações bibliográficas são adaptações das classificações do conhecimento ou das ciências. As bibliográficas, frequentemente, utilizam termos originários das filosóficas, ressignificando-os e transformando-os em ferramentas. Em síntese, pode-se afirmar que, a partir da Filosofia, absorvida em explicações teóricas, até a Biblioteconomia, preocupada com soluções instrumentais e aplicativas (pragmáticas), os esquemas de classificação bibliográfica propostos tem se beneficiado da aproximação dessas duas áreas de conhecimento. A revisão conceitual com respeito às noções de classe, categoria e faceta aponta, por parte dos estudiosos da Classificação, para a necessidade de um cuidado maior no desenho, no planejamento e na estruturação de sistemas de classificação, na modificação e especificação de tabelas de classificação e até de linguagens de indexação, com vista à sua adequação e relevância. As contribuições daí resultantes, delineadas numa perspectiva funcional-instrumental, poderão ajudar os profissionais a reconsiderar os seus sistemas de idéias e procedimentos em relação à construção e avaliação de linguagens de indexação e à classificação habitual de documentos. Caberá à Ciência da Informação avançar na fundamentação teórica do seu campo de aplicação, discutindo criticamente a sua base conceitual, atenta às práticas de uso em voga na Biblioteconomia e Documentação com relação a termos e conceitos. O estudo valida as hipóteses inicialmente levantadas, determinando que a consistência terminológica de termos como categoria, classe ou faceta contribui para aperfeiçoar a operacionalização do processamento do conhecimento em Ciência da Informação e que aos esquemas categoriais não cabe um valor neutro, uma vez que sempre favoreceram uma determinada concepção de mundo, em que pese a sua natureza objetivamente pragmática. Por fim, apresentam-se algumas perspectivas decorrentes da investigação, selecionando-se questões relevantes e de interesse para futuras pesquisas. / The analysis of knowledge classification systems in Philosophy and Librarianship by a critical historical-conceptual point of view with an approach in the concepts of class, category and facet was developed from specific objectives to accompany and outline the path of knowledge (classes) and beings (categories) classification in relation to Philosophy; to investigate the possible influences that the philosophical classification historically exerted on traditional bibliographical classifications; and to verify in which way the specific concept of category, class and facet have been defined in the ambit of traditional librarianship classifications. This research is of exploratory-descriptive type, based upon pertinent literature, resulting from both areas of knowledge in discussion. From the studied bibliographical material, a theoretical reference was built, leading to objectivation, analysis, discussion and a profound study of the object. Its possible to affirm that even the principles of philosophical classifications in relation to knowledge and beings, as well as the classifications that divide knowledge and beings, are presented as constructs, purposed to understand and to train the information of beings and knowledge. The influence of philosophical classifications on bibliographical classification is settled by bibliographical classifications, which are adaptations of knowledge or science. The bibliographical ones, frequently utilize terms originated from philosophical that are modified and transformed into tools. In synthesis, it may be stated that, from Philosophy, absorbed in theoretical explanations, even Librarianship, worried with instrumental and application (pragmatic) solutions, the proposed plans of bibliographical classifications have been beneficiated from the approximation of this two areas of knowledge. The conceptual review in relation to notions of class, category and facet needs a better attention in design, planning and in the structuring of classification systems, as pointed out by experts on Classification, in the modification and specification of classification tables and also indexation languages, aiming its adequacy and significance. The resulting contributions, outlined by a functional-instrumental perspective, would help professionals to reconsider their systems of ideas and procedures in relation to construction and evaluation of indexation languages and regular classification of documents. The information science will be responsible to develop theory fundamentation of its application field, discussing critically its conceptual basis, with attention to the practices in use by Librarianship and Documentation in relation to terms and concepts. The study validates the hypothesis initially described, determining that the terminological consistency of terms as category, class or facet contribute to improve the operacionalization of knowledge processing in Information Science and that to category schemes it doesnt fit a neuter value, since that always favored a certain conception of the world, in which predominates its pragmatic nature As result of the investigation, some perspectives are presented, selecting questions of extreme relevancy and interest for future researches.

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