In existing virtual environments, conventional ground surfaces often impair a user's sense of immersion due to their static nature. This thesis presents a novel approach to enhance one's sense of presence through a floor interface platform that mimics a variety of ground terrains. The ambient system records the force profile of footsteps, synthesizes appropriate responses, and delivers these signals through vibrating floor tiles to imitate the feel and sound of walking on various surfaces. High-quality interactive graphics provided by overhead projectors complete the multimodal experience. Virtual snow and ice environments were developed that allow users to create footprints and crack a frozen ice sheet. Moreover, a perceptual experiment involving the recognition of eight vibration patterns, or haptic icons, delivered to the feet was performed to gauge its discrimination ability. It was found that the interaction afforded to users by the augmented floor was both engaging and perceptually convincing. / A present, dans les milieux virtuels, les surfaces de planchers conventionnelles nuisent a la sensation d'immersion a cause de leur nature statique. Cette these de recherche propose une approche nouvelle pour ameliorer l'experience de l'utilisateur en utilisant un plancher interactif capable de reproduire plusieurs sortes de terrains. Le systeme ambiant capte le profile de force applique au plancher par les pas de l'utilisateur, synthese une reponse appropriee et transmet ces signaux a l'aide de tuiles vibrantes ce qui reproduit la sensation tactile et sonore de marcher sur divers types de surfaces. De plus, la surface du plancher est illuminee par des projecteurs suspendus au plafond, permettant la projection de graphiques interactifs et de hautes qualites pour completer l'experience multimodale. Par exemple, des environnements virtuels hivernaux permettant aux utilisateurs de laisser leurs traces dans la neige ou de craquer la glace d'un etang gele ont ete developpes pour d ́emontrer les capacites du systeme. De plus, une etude de perception sur la reconnaissance de huit modeles de vibration, ou d'icones tactiles, transmis par notre plancher pour elucider la capacite de discrimination du pied a permit de d ́ecouvrir que notre systeme est perceptivement convaincant et prenant.

Machine tool’s productivity and ability to produce a component of the required quality is directly influenced by its dynamic stiffness at the tool center point. Lack of dynamic stiffness may lead to unstable regenerative chatter vibrations which are detrimental to the performance. The chatter vibrations are influenced by the changing structural dynamics of the machine as the tool moves along the tool path, resulting in position-varying machining stability of the system. Evaluation of these varying dynamics at the design stage is a complex process, often involving the use of large order finite element (FE) models. Complexity and computational costs associated with such FE models limit the analyses to one or two design concepts and at only a few discrete positions. To facilitate rapid exploration of several design alternatives and to evaluate and optimize each of their position-dependent dynamic behavior, a generalized bottom-up reduced model substructural synthesis approach is proposed in this thesis. An improved variant of the component mode synthesis method is developed and demonstrated to represent higher order dynamics of each of the machine tool components while reducing the computational cost. Reduced substructures with position-invariant response are synthesized at their contacting interfaces using novel adaptations of constraint formulations to yield position-dependent response. The generalized formulation is used to evaluate the position-dependent behavior of two separate machine tools: one with a serial kinematic configuration, and another with hybrid serial-parallel kinematics. The reduced machine model is verified against full order models and is also validated against measurements by including joint characteristics in the model. The effects of position and feed-direction-dependent compliances on machining stability are investigated by using a novel position and feed-direction-dependent-process-stability performance criterion that evaluates the productivity of machine tools in its entire work volume. Parameters limiting the target productivity levels are identified and modified; and, the complete dynamics are rapidly re-analyzed using the developed models. Optimal design modifications are shown to increase productivity by ~35%. The proposed methods in this thesis enable efficient simulation of structural dynamics, stability assessment as well as interactions of the CNC and cutting process with the machine tool structure in a virtual environment.

Although it has been argued that indoor workers in fact make up the majority of the sex industry, most of the literature on the transition out of sex work has looked at street-based workers. This interview-based qualitative research project aims to fill that gap. As such, this thesis examines the trajectories, challenges and strategies of women who transitioned or are in the process of transitioning from criminalized indoor sex work (escorting, erotic massage and domination) to the mainstream labour market. Using Ebaugh’s role exit theory and Goffman’s conceptualization of stigma, intersectional feminist analysis and labour theory, I position the transition as a re-negotiation of self, involving conflicts in identity and class location. My findings suggest that the transition out of sex work is characterized by multiple, parallel work trajectories, wherein the women were successfully able to transfer skills they had acquired in sex work to the mainstream labour market.

Aromatic compounds comprise approximately 25% of the Earth`s biomass. Accordingly, turnover of these thermostable compounds is essential to the biogeochemical carbon cycle. Specialized microbial enzymatic pathways are largely responsible for mineralization of aromatic compounds, and are extensively studied for bioremediation purposes. The phenylacetic acid degradation pathway (PAA) is of particular interest as it is utilized for degradation of a multitude of aromatic compounds, including environmental pollutants, and appears to be widely distributed among bacteria. Intriguingly, the PAA pathway has also been implicated as a virulence factor in the cystic fibrosis pathogen, Burkholderia cenocepacia. As such, detailed biochemical characterization of the PAA pathway holds great potential for improving bioremediation strategies for aromatic pollutants, as well as understanding carbon source utilization during B. cenocepacia infection. A striking feature of the PAA pathway in B. cenocepacia is the presence of two genes encoding the phenylacetate CoA ligase (PCL) enzyme (paaK1 and paaK2), responsible for the initial CoA activation of phenylacetic acid. PCLs are members of the adenylate forming enzyme superfamily. However, sequence alignments reveal several intriguing features, including a potentially novel microdomain consisting of the initial ~80 N-terminal residues, which possesses percent identity to any structurally characterized family member. Furthermore, this superfamily utilizes a complicated catalytic mechanism, exploiting several conserved motifs during the reaction process. The precise roles of many key conserved residues are not yet well understood, especially during the pre-adenylation, ATP bound state, for which few high quality crystal structures exist. In order to define the early stages of the catalytic mechanism, and to assess how the divergent polypeptide region may impact the PaaK enzymes, we have pursued a detailed structural characterization of the paralogs, complemented with functional assessments. Specifically, we have produced a 1.6 Å resolution crystal structure of PaaK1 in complex with ATP, which reveals a novel helical bundle arrangement at the N-terminal domain never before seen in this superfamily. Remarkably, homodimerization of PaaK1 appears to reconstitute potentially important β sheet interactions observed in the classical N-terminal arrangement of family members. Moreover, our structure is one of few which contain well ordered β and γ phosphates, allowing for detailed examination of significant protein-ATP interactions with conserved catalytic residues. To better comprehend the roles of these residues over the course of the reaction, we have produced additional crystal structures of PaaK1 and PaaK2 in complex with the phenylacetyl adenylate intermediate. Notably, PaaK2 was captured following the domain reorientation, poised to catalyze thioesterification of phenylacetyl adenylate, providing insight into the later stages of the reaction process. Furthermore, the intermediate co-structures divulge the location of the aryl substrate binding pocket for both paralogs. Detailed comparisons of the binding pockets accompanied kinetic characterizations for both paralogs, demonstrating that PaaK2 possesses an apparent KM of 150 μM for phenylacetic acid, more than double that of PaaK1 (62 μM). Our findings provide preliminary evidence for distinct functional roles of the PaaK paralogs in B. cenocepacia, while imparting additional insight into catalytic roles of conserved residues within the adenylate forming superfamily at large. / Graduate

This thesis explores the tensions between constitutional forms of democracy and the practice-based understanding of democracy found among ancient Greek and recent post-structural theorists. In drawing from Plato’s discussion of the constitutions of varying political regimes, this thesis hones in on his assertion that the democratic city does not have a single constitution due to the freedom of its citizens. Contemporary understandings of democracy, such as deliberative democratic theory, have largely overlooked the kind of power embodied in democracy by focusing attention on deepening the forms of participation in existing practices of government. By drawing from a practice-based understanding of democracy, this thesis responds to the problems of exclusion produced by statist accounts of democracy. Taking the example of First Nations in Canada, the thesis asks whether new forms of protest, such as Idle No More, embody the spirit of democratic practice outlined by the ancient Greeks. / Graduate

This thesis explores three object tracking algorithms for image sequences. These algorithms include the ensemble tracker, the EM-like mean-shift colour-histogram tracker, and the wandering-stable-lost scale-invariant feature transform (WSL-SIFT) tracker. The algorithms are radically different from one another. Despite their differences, they are evaluated on the same publicly available, moderately sized, research data sets which include 129 test cases in 13 different scenes. The results aid in fostering an understanding of their respective behaviours and in highlighting their flaws and failures. Lastly, an implementation setup is described that is suited to large-scale, grid computing, batch testing of these algorithms. Results clearly indicate that none of the evaluated trackers are suited to general purpose use. However, one may intelligently choose a tracker for a well-defined application by analysing the known scene characteristics.

Frank Lloyd Wright (1867 - 1959) is amongst the most famous architects of all time, and is known as the greatest American architect. His personal life was filled with publicized difficulties and scandal, and he was well-known for his flamboyant and charismatic personality, his innovation modern design philosophies, and for the enormous number of realised and unrealised projects (approximately 450 buildings and another 550 unrealized projects) completed during his career which spanned seventy four years. / When he developed his Prairie style of design in the mid-1880s, inspired by the teachings of his mentor Louis Sullivan, he began a revolution in domestic architecture, firstly in America, but which then exerted a powerful impact on other Western countries. He and his work became icons of a new modern organic architecture. In Europe he influenced progressive architects and contributed to the development of Modernism when the spirit of his work and ideas was adopted and then reflected in the creation of the Modernist aesthetic. / Thesis (MArchitecture)--University of South Australia, 2005.

Thesis (B.Com.(Hons.))--University of Adelaide, Dept. of Commerce, 1997. / Includes bibliographical references (leaves 52-54).

Thesis (M. Sc.)--University of Toronto, 2007. / Source: Masters Abstracts International, Volume: 46-06, page: 3168.

Thesis (Ed.D.)--Indiana University, School of Education, 2007. / Title from PDF t.p. (viewed Nov. 5, 2008). Source: Dissertation Abstracts International, Volume: 68-07, Section: A, page: 2744. Adviser: Leonard Burrello.