Thesis (M.S.W.)--University of Hong Kong, 1983.

published_or_final_version / Architecture / Master / Master of Landscape Architecture

<p> <p>&nbsp / </p> </p> <p align="left">The current study aimed to describe the paradox of risk through an exploration of the experiences and perceptions of sexuality and HIV/AIDS among physically disabled young people in Nyanga, South Africa. This is against the background that AIDS has become a national and global crisis, which requires all people to participate in efforts to contain the pandemic. Yet literature indicates that young people with disabilities are not participating in such efforts. There is also an assumption, that physically disabled young people do not experience challenges in expressing their sexuality and accessing HIV/AIDS prevention services, to the same extent as other disability groups such as the blind and those with intellectual disabilities. Hence there was a need to explore disabled young people&rsquo / s own understanding of risk and the factors that hinder or support their participation in existing sexuality education and HIV/AIDS prevention programmes. It was also important for this group to suggest ways in which they may participate in such programmes.</p>

In networked robot systems (NRS), robots and robotic devices are distributed in the environment; typically tasks are performed by cooperation and coordination of such multiple networked components. NRS offer advantages over monolithic systems in terms of modularity, flexibility and cost effectiveness, and they are thus becoming a mainstream approach to the inclusion of robotic solutions in everyday environments. The components of a NRS are usually robots and sensors equipped with rich computational and communication facilities. In this thesis, we argue that the capabilities of a NRS would greatly increase if it could also accommodate among its nodes simpler entities, like small ubiquitous sensing and actuation devices, home appliances, or augmented everyday objects. For instance, a domestic robot needs to manipulate food items and interact with appliances. Such a robot would benefit from the ability to exchange information with those items and appliances in a direct way, in the same way as with other networked robots and sensors. Combining such highly heterogeneous devices inside one NRS is challenging, and one of the major challenges is to provide a common communication and collaboration infrastructure. In the field of NRS, this infrastructure is commonly provided by a shared middleware. Unfortunately, current middlewares lack the generality needed to allow heterogeneous entities such as robots, simple ubiquitous devices and everyday objects to coexist in the same system. In this thesis we show how an existing middleware for NRS can be extended to include three new types of “citizens” in the system, on peer with the other robots. First, we include computationally simple embedded devices, like ubiquitous sensors and actuators, by creating a fully compatible tiny version of the existing robotic middleware. Second, we include augmented everyday objects or home appliances which are unable to run the middleware on board, by proposing a generic design pattern based on the notion of object proxy. Finally,we go one step further and include humans as nodes in the NRS by defining the notion of human proxy. While there exist a few other NRS which are able to include both robots and simple embedded devices in the same system, the use of proxies to include everyday objects and humans in a generic way is a unique feature of this work. In order to verify and validate the above concepts, we have implemented them in the Peis-Ecology NRS model. We report a number of experiments based on this implementation, which provide both quantitative and qualitative evaluations of its performance, reliability, and interoperability.

Thesis (M.S.W.)--University of Hong Kong, 1991.

La quête de performance a été une constante à travers l’histoire des systèmes informatiques. Il y a plus d’une décennie maintenant, le modèle de traitement séquentiel montrait ses premiers signes d’épuisement pour satisfaire les exigences de performance. Les barrières du calcul séquentiel ont poussé à un changement de paradigme et ont établi le traitement parallèle comme standard dans les systèmes informatiques modernes. Avec l’adoption généralisée d’ordinateurs parallèles, de nombreux algorithmes et applications ont été développés pour s’adapter à ces nouvelles architectures. Cependant, dans des applications non conventionnelles, avec des exigences d’interactivité et de temps réel, la parallélisation efficace est encore un défi majeur. L’exigence de performance en temps réel apparaît, par exemple, dans les simulations interactives où le système doit prendre en compte l’entrée de l’utilisateur dans une itération de calcul de la boucle de simulation. Le même type de contrainte apparaît dans les applications d’analyse de données en continu. Par exemple, lorsque des donnes issues de capteurs de trafic ou de messages de réseaux sociaux sont produites en flux continu, le système d’analyse doit être capable de traiter ces données à la volée rapidement sur ce flux tout en conservant un budget de mémoire contrôlé La caractéristique dynamique des données soulève plusieurs problèmes de performance tel que la décomposition du problème pour le traitement en parallèle et la maintenance de la localité mémoire pour une utilisation efficace du cache. Les optimisations classiques qui reposent sur des modèles pré-calculés ou sur l’indexation statique des données ne conduisent pas aux performances souhaitées. Dans cette thèse, nous abordons les problèmes dépendants de données sur deux applications différentes : la première dans le domaine de la simulation physique interactive et la seconde sur l’analyse des données en continu. Pour le problème de simulation, nous présentons un algorithme GPU parallèle pour calculer les multiples plus courts chemins et des diagrammes de Voronoi sur un graphe en forme de grille. Pour le problème d’analyse de données en continu, nous présentons une structure de données parallélisable, basée sur des Packed Memory Arrays, pour indexer des données dynamiques géo-référencées tout en conservant une bonne localité de mémoire. / A busca por desempenho tem sido uma constante na história dos sistemas computacionais. Ha mais de uma década, o modelo de processamento sequencial já mostrava seus primeiro sinais de exaustão pare suprir a crescente exigência por performance. Houveram "barreiras"para a computação sequencial que levaram a uma mudança de paradigma e estabeleceram o processamento paralelo como padrão nos sistemas computacionais modernos. Com a adoção generalizada de computadores paralelos, novos algoritmos foram desenvolvidos e aplicações reprojetadas para se adequar às características dessas novas arquiteturas. No entanto, em aplicações menos convencionais, com características de interatividade e tempo real, alcançar paralelizações eficientes ainda representa um grande desafio. O requisito por desempenho de tempo real apresenta-se, por exemplo, em simulações interativas onde o sistema deve ser capaz de reagir às entradas do usuário dentro do tempo de uma iteração da simulação. O mesmo tipo de exigência aparece em aplicações de monitoramento de fluxos contínuos de dados (streams). Por exemplo, quando dados provenientes de sensores de tráfego ou postagens em redes sociais são produzidos em fluxo contínuo, o sistema de análise on-line deve ser capaz de processar essas informações em tempo real e ao mesmo tempo manter um consumo de memória controlada A natureza dinâmica desses dados traz diversos problemas de performance, tais como a decomposição do problema para processamento em paralelo e a manutenção da localidade de dados para uma utilização eficiente da memória cache. As estratégias de otimização tradicionais, que dependem de modelos pré-computados ou de índices estáticos sobre os dados, não atendem às exigências de performance necessárias nesses cenários. Nesta tese, abordamos os problemas dependentes de dados em dois contextos diferentes: um na área de simulações baseada em física e outro em análise de dados em fluxo contínuo. Para o problema de simulação, apresentamos um algoritmo paralelo, em GPU, para computar múltiplos caminhos mínimos e diagramas de Voronoi em um grafo com topologia de grade. Para o problema de análise de fluxos de dados, apresentamos uma estrutura de dados paralelizável, baseada em Packed Memory Arrays, para indexar dados dinâmicos geo-localizados ao passo que mantém uma boa localidade de memória. / The quest for performance has been a constant through the history of computing systems. It has been more than a decade now since the sequential processing model had shown its first signs of exhaustion to keep performance improvements. Walls to the sequential computation pushed a paradigm shift and established the parallel processing as the standard in modern computing systems. With the widespread adoption of parallel computers, many algorithms and applications have been ported to fit these new architectures. However, in unconventional applications, with interactivity and real-time requirements, achieving efficient parallelizations is still a major challenge. Real-time performance requirement shows up, for instance, in user-interactive simulations where the system must be able to react to the user’s input within a computation time-step of the simulation loop. The same kind of constraint appears in streaming data monitoring applications. For instance, when an external source of data, such as traffic sensors or social media posts, provides a continuous flow of information to be consumed by an online analysis system. The consumer system has to keep a controlled memory budget and deliver a fast processed information about the stream Common optimizations relying on pre-computed models or static index of data are not possible in these highly dynamic scenarios. The dynamic nature of the data brings up several performance issues originated from the problem decomposition for parallel processing and from the data locality maintenance for efficient cache utilization. In this thesis we address data-dependent problems on two different applications: one on physically based simulations and another on streaming data analysis. To deal with the simulation problem, we present a parallel GPU algorithm for computing multiple shortest paths and Voronoi diagrams on a grid-like graph. Our contribution to the streaming data analysis problem is a parallelizable data structure, based on packed memory arrays, for indexing dynamic geo-located data while keeping good memory locality.

The problem of this study was to ascertain the status of Texas secondary school industrial arts programs in regard to serving physically handicapped students and to analyze the attitudes of industrial arts teachers toward the physically handicapped students in industrial arts classes. The purposes of this study were, (1) to describe the nature and extent of participation by industrial arts programs in Texas secondary schools in complying with federal and state laws concerning the education of handicapped children, and (2) to acquire and interpret information which may be included in college courses for preparing industrial arts teachers and/or in-service programs for industrial arts teachers. Among the major findings revealed by an analysis of the data are the following. 1. Of the 366 industrial arts teachers surveyed, 86 per cent had no pre-service courses and 79 per cent had no in-service instruction concerning handicapped students; however, 67 per cent had experience teaching physically handicapped students. 2. Of the 37,659 students who were served by 355 industrial arts teachers during the 1977-78 school year, 727, or 2 per cent, were physically handicapped; 171 students were in separate special classes and 566 were integrated into regular classes. 3. Of the 727 physically handicapped students, 47 per cent attended senior high schools; 87 per cent attended schools with an enrollment of over 550 students; 83 per cent were in an urban or suburban educational setting; and the four predominate industrial arts areas in which they were enrolled are, in order: Drafting, Woodworking, General Shop, and Metalworking. 4. The attitudes of industrial arts teachers toward physically handicapped students and the attitudes of industrial arts teachers toward the integration of physically handicapped students were slightly positive. The industrial arts teachers' attitude toward the potential success of physically handicapped students in the world of work was positive. The industrial arts teachers' assessment of their own competencies to teach physically handicapped students was neither positive nor negative. 5. The attitudes of the industrial arts teachers were not significantly influenced by their age, education, teaching experience, type of school organization, type of educational setting or total enrollment of the schools in which they taught. Female teachers and teachers with experience in teaching physically handicapped students were significantly more positive in their attitudes toward the physically handicapped.

Dans cette thèse, nous proposons de nouvelles representations pourles poses du mouvement humain, apprises sur des données réelles, envue d’une synthèse de nouveaux mouvements en temps-réel. Dans unepremière partie, nous exploitons une méthode statistique adaptée auxgroupes de Lie (Analyse en Géodésiques Principales, AGP) pour approximerla variété des poses d’un sujet en mouvement, à partir de donnéesde capture de mouvement. Nous proposons un algorithme de cinématiqueinverse exploitant cette paramétrisation réduite, permettantpar construction de synthétiser des poses proches des données initiales.Nous validons ce modèle cinématique par une application à la compressionde données de mouvements, dans laquelle seules quelques trajectoiresdes extrémités des membres du squelettes permettent de reconstruireune bonne approximation de l’ensemble des données initiales.Dans une deuxième partie, nous étendons cette approche à l’animationphysique de personnages virtuels. La paramétrisation réduitepar AGP fournit les coordonnées généralisées de la formulation Lagrangiennede la mécanique. Nous dérivons un intégrateur temporelexplicite basé sur les intégrateurs variationnels. Afin d’en améliorer lastabilité, nous proposons un modèle d’amortissement inspiré de l’algorithmede Levenberg-Marquardt. Nous présentons également une méthodegéométrique d’apprentissage des limites angulaires sur des donnéesde capture de mouvement, ainsi que leur application comme contraintescinématiques.Dans une troisième partie, nous abordons le problème du contrôledu mouvement. En formulant les étapes de la simulation physique d’unepart, et de la cinématique inverse d’autre part comme deux programmesquadratiques, nous proposons un algorithme de pseudo-contrôle parinterpolation des métriques, permettant un compromis intuitif entre simulationphysique non-contrôlée, et cinématique inverse. Cette approchefaisant intervenir des forces externes, nous proposons une formulationalternative, utilisant uniquement les forces associées à la paramétrisationréduite des poses. Cette formulation est obtenue par relaxationdu problème théorique de contrôle sous contraintes unilatérales, nonconvexe,en un programme quadratique convexe. Ces algorithmes sontévalués sur des contrôleurs d’équilibre et de suivi. / In this thesis, we propose novel, data-driven representations for humanposes, suitable for real-time synthesis of novel character motion. Inthe first part, we exploit Lie group statistical analysis techniques (PrincipalGeodesic Analysis, PGA) to approximate the pose manifold of amotion capture sequence by a reduced set of pose geodesics. We proposean inverse kinematics algorithm using this reduced parametrizationto automatically produce poses that are close to the learning set. Wedemonstrate the efficiency of the resulting pose model by an applicationto motion capture data compression, where only a few end-effector trajectoriesare used to recover a good approximation of the initial data.In the second part, we extend this approach to the physically-basedanimation of virtual characters. The PGA-reduced parametrization providesgeneralized coordinates in a Lagrangian formulation of mechanics.We derive an explicit time integrator by approximating existingvariational integrators, and propose a damping model based on theLevenberg-Marquardt algorithm. We also describe a geometric, datadriven,angular limit learning algorithm, and the associated kinematicconstraints.In the third part, we reach the problem of task-space motion control.By formulating both physical simulation and inverse kinematicstime stepping schemes as two quadratic programs, we propose a simplepseudo-control algorithm that interpolates between the two metrics.This allows for an intuitive trade-off between uncontrolled simulationand kinematic manipulation. Since this approach makes use of externalforces, we propose an alternate formulation using only the generalizedforces associated to the pose parametrization. A control algorithmis obtained by the relaxation of the exact, non-convex control problemunder unilateral constraints, into a convex quadratic program. Thesealgorithms are evaluated on simple balance and tracking controllers.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Hydrossedimentological monitoring and modeling have been used as important tools to evaluate and simulate the hydrosedimentological processes in rural watersheds, in order to effectively propose conservation practices in environmentally sensitive locations. The objective of this research was to evaluate the performance of a physically based hydrological model (LISEM - Limburg Soil Erosion Model) in quantifying runoff and erosion in a rural catchment with high spatial variability (horizontally and vertically) physical and hydrological characteristics of the soil. The catchment has an area of 1.19 km2 and is situated in the northeastern region of the Rio Grande do Sul state, Brazil. Soils are characterized by reduction of water flow in the vertical soil profile either by the small thickness (Entisols and Inceptisols) or textural gradient between horizons (Ultisols) - and are associated with variations of relief, which is composed of soft hills in the top section and mountainous in the bottom section of the catchment. The predominant land use is tobacco farming (Nicotiana tabacum L.), where the surface layer of the soil is tilled to form ridges. In the first stage of the study, five slopes of the basin used for tobacco cultivation were sampled to characterize the physical and hydraulic properties at different points in the relief (top, middle slope and lowland) and four soil layers (0.00 to 0.04, from 0.20 to 0.24, from 0.40 to 0.44 and from 0.60 to 0,64 m). Field trials were also conducted to determine the infiltration rate on the slopes, and equations were also established to estimate the saturated hydraulic conductivity in each layer of soil sampled. In the second step, the LISEM model was calibrated to represent the hydrograph and sedimentograph of 20 rainfall events monitored in the river mouth from 2009 to 2012. The results of the first stage show that there is horizontal and vertical variability of physical and hydraulic properties on the slopes, being that the hillsides have a higher saturated hydraulic conductivity due to its coarser texture. Both the hydraulic conductivity and the infiltration rate were effective in identifying the horizontal variability of water flow on the slopes. The hydraulic conductivity can be estimated with good accuracy when variables from subsoil layers, for example, the total sand content, are used. The results of the second stage of the study revealed that the LISEM had a good performance in modeling the hydrograph. However, it was not possible to represent the sedimentograph, and there was an overestimate in sediment production. The model s equations related to erosion do not represent the dynamics that occur in this catchment. / O monitoramento e a modelagem hidrossedimentológica têm sido utilizados como ferramentas importantes para avaliar e simular os processos hidrossedimentológicos em bacias hidrográficas rurais, com o intuito de propor, de forma eficaz, práticas conservacionistas em locais ambientalmente frágeis. O objetivo desta pesquisa foi avaliar o desempenho de um modelo hidrológico de base física (LISEM Limburg Soil Erosion Model) em quantificar o escoamento superficial e o processo erosivo em uma bacia hidrográfica rural com grande variabilidade espacial (no sentido horizontal e vertical) das características físico-hídricas de solo. A bacia hidrográfica possui 1,19 km2 e está situada na região nordeste do estado do Rio Grande do Sul, Brasil. Os solos são caracterizados pela redução do fluxo de água na direção vertical do perfil de solo seja pela pequena espessura (Neossolos e Cambissolos) ou pelo gradiente textural entre horizontes (Argissolos) e estão associados às variações do relevo, que é ondulado na fração superior e montanhoso na fração inferior da bacia. O uso do solo predominante é o cultivo do tabaco (Nicotiana tabacum L.), em que a camada superficial do solo é revolvida para a construção de camalhões. Na primeira etapa do estudo, cinco encostas da bacia utilizadas para o cultivo do tabaco foram amostradas para caracterização das propriedades físico-hídricas em diferentes pontos do relevo (topo, meia encosta e várzea) e em quatro camadas de solo (0,00 a 0,04, 0,20 a 0,24, 0,40 a 0,44 e 0,60 a 0,64 m). Também foram realizados ensaios de campo para determinação da taxa de infiltração básica nas encostas e, ainda, foram construídas equações para estimativa da condutividade hidráulica saturada em cada camada de solo amostrada. Na segunda etapa, o modelo LISEM foi calibrado para representar o hidrograma e o sedimentograma de 20 eventos monitorados no exutório da bacia entre no período de 2009 a 2012. Os resultados da primeira etapa comprovam que há variabilidade horizontal e vertical das propriedades físico-hídricas nas encostas, sendo que a meia encosta apresenta maior condutividade hidráulica saturada devido à textura mais grosseira neste local. Tanto a condutividade hidráulica quanto a taxa de infiltração básica foram eficazes em identificar a variabilidade horizontal do fluxo de água nas encostas. A condutividade hidráulica saturada pode ser estimada com boa precisão quando são usadas variáveis das camadas subsuperficiais do solo como, por exemplo, o teor de areia total. Os resultados da segunda etapa do estudo revelaram que o LISEM apresentou bom desempenho na modelagem do hidrograma. No entanto, não foi possível a representação do sedimentograma, sendo que houve superestimativa da produção de sedimentos. As equações do modelo relacionadas com o processo erosivo não representam a dinâmica que ocorre nesta bacia hidrográfica.

L'utilisation de pesticides sur les surfaces agricoles conduit à une contamination généralisée des eaux de surface et de subsurface en France. Dans l'attente d'une évolution profonde des pratiques agricoles et d'une baisse durable de l'utilisation des pesticides, il est intéressant de chercher à limiter des transferts des zones agricoles aux zones aquatiques. Pour mieux agir sur les voies de transfert, il est nécessaire d'approfondir les connaissances des processus en jeu et de leurs interactions éventuelles et de tirer au mieux partie des observations du terrain.L'objectif de cette thèse est l'intégration de processus de transferts réactif dans le modèle hydrologique à base physique CATHY (CATchment HYdrology), capable de simuler en 3 dimensions les écoulements de l'eau de façon couplée surface-subsurface et le transport advectif dans des situations variablement saturées. En subsurface, les processus d'adsorption linéaire et de dégradation du premier ordre sont implémentés. Un module de mélange des solutés entre la lame ruisselante et la première couche de sol est ajouté, qui permet de simuler la remobilisation des solutés de la subsurface dans le ruissellement. Le couplage surface-subsurface des écoulement est très efficace dans ce modèle, et le couplage du transport de soluté adoptant la même stratégie a été amélioré pour mieux respecter la conservation de la masse.Le modèle est en premier lieu testé sur des données issues d'expérimentations de transfert de subsurface sur une maquette de laboratoire à petite échelle (2 m de long, o.5 m de large, 1 m de profondeur). Les résultats sont confrontés aux chroniques de flux massiques observées et une analyse de sensibilité de type Morris est menée. Le modèle est capable de reproduire de façon satisfaisante les observations, et très satisfaisante après une légère calibration. Les conductivités à saturation horizontale et verticale, la porosité et le paramètre $n$ de la courbe de rétention influencent de façon non négligeable les résultats hydrodynamiques et de transfert de soluté. Dans un second temps, le modèle est évalué sur les données issus d'un versant viticole réel (0.6 ha) dans un contexte orageux avec de fortes interactions surface-subsurface. Une analyse de sensibilité globale est menée, et met en valeur les mêmes paramètres que la méthode de Morris. Les interactions entre les paramètres influencent fortement la variabilité des sorties hydrodynamiques et de transfert. La conservation de la masse est très correctement assurée malgré la complexité de la simulation.Le modèle auquel on aboutit correspond bien aux objectifs de départ, sa validation est solide, même si elle n'est rigoureusement valable que dans les contextes précis où elle a été réalisée. On a montré que le modèle était robuste et capable de reproduire des données observées. D'autres processus manquent encore pour représenter toutes les voies de transfert à l'échelle du versant, notamment la représentation du transfert préférentiel en subsurface et du transport sédimentaire en surface. / Pesticide use on agricultural surfaces leads to a broad surface and subsurface water contamination in France. Awaiting a deep agricultural practices evolution and a sustained fall of the pesticide use, it is of interest to limit transfers form agricultural fields to rivers. In order to constrain those transfers, a deepen knowledge of processes at stake and their potential interactions is necessary, as well as taking full advantages of fields observations.The aim of this PhD is the reactive transfer processes integration in the Hydrological physically-based model CATHY (CATchment HYdrology) which simulates surface-subsurface coupled water flow and advectiv solute transport in three dimensions and in variably saturated situations. Linear adsorption and first order decay are implemented in subsurface. A mixing modules is added, and evens the concentration between surface runoff and subsurface first layer. This module simulates the solute mobilisation from soil to surface runoff. The water flow surface-subsurface coupling procedure is very accurate in CATHY, and the transport coupling procedure is improve in order to respect the mass conservation.The model is first evaluated on subsurface transfer laboratory experimentation data at a small scale (2 m long, o.5 m wide, 1 m deep). Results are compared to mass flux evolution in time and a Morris sensitivity analysis is conducted. The model is able to acceptably reproduce observation, and properly after a slight calibration. Horizontal and vertical saturated conductivities, porosity and the $n$ parameter of retention curve significantly influence hydrodynamics and solute transport. As a second step, the model is evaluated on data from a field wine hillslope on an intense rain event, therefore in a context with a lot of surface-subsurface interactions. A global sensitivity analysis is conducted and highlights same parameters as the Morris method. Interactions between parameters highly influence the variability of hydrodynamic and solute transfer outputs. Mass conservation is accurate despite the complexity of the context.The resulting model meets the objectives, its evaluation is strong even if its theoretically only valid in the precise context in which the evaluations where conducted. The model is robust and able to reproduce observed data. Some complementary processes are still missing in the model to properly represent transfer ways at the hillslope scale, such as subsurface preferential transfers and surface sedimentary transport.