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Clustering procedures suitable for the analysis of very high-dimensional data are needed for many modern data sets. One model-based clustering approach called high-dimensional data clustering (HDDC) uses a family of Gaussian mixture models to model the sub-populations of the observed data, i.e., to perform cluster analysis. The HDDC approach is based on the idea that high-dimensional data usually exists in lower-dimensional subspaces; as such, the dimension of each subspace, called the intrinsic dimension, can be estimated for each sub-population of the observed data. As a result, each of these Gaussian mixture models can be fitted using only a fraction of the total number of model parameters. This family of models has gained attention due to its superior classification performance compared to other families of mixture models; however, it still suffers from the usual limitations of Gaussian mixture model-based approaches. Herein, a robust analogue of the HDDC approach is proposed. This approach, which extends the HDDC procedure to include the mulitvariate-t distribution, encompasses 28 models that rectify one of the major shortcomings of the HDDC procedure. Our tHDDC procedure is fitted to both simulated and real data sets and is compared to the HDDC procedure using an image reconstruction problem that arose from satellite imagery of Mars' surface. / Thesis / Master of Science (MSc)

Turbulent flows and turbulent flames are inherently multi-dimensional in space and transient in time. Therefore, multidimensional diagnostics that are capable of resolving such spatial and temporal dynamics have long been desired; and the purpose of this dissertation is to investigate three such diagnostics both for the fundamental study of flow and combustion processes and also for the applied research of practical devices. These multidimensional optical diagnostics are a 2D (two dimensional) two-photon laser-induced fluorescence (TPLIF) technique, a 3D hyperspectral tomography (HT) technique, and a 4D tomographic chemiluminescence (TC) technique. The first TPLIF technique is targeted at measuring temporally-resolved 2D distribution of fluorescent radicals, the second HT technique is targeted at measuring temperature and chemical species concentration at high speed, and the third TC technique is targeted at measuring turbulent flame properties. This dissertation describes the numerical and experimental evaluation of these techniques to demonstrate their capabilities and understand their limitations. The specific aspects investigated include spatial resolution, temporal resolution, and tomographic inversion algorithms. It is expected that the results obtained in this dissertation to lay the groundwork for their further development and expanded application in the study of turbulent flow and combustion processes. / Ph. D.

Dimensional Stacking is a technique for displaying multivariate data in two dimensional screen space. This technique involves the discretization and recursive embedding of dimensions, each resulting N-dimensional bin occupying a unique position on the screen. This thesis describes the extension of this technique to a three dimensional projection. In addition to the visual enhancements, hashing was used to improve the scalability of records and dimensions. The resulting visualization was evaluated by a usability study.

The inter-dimensional system of a three-dimensional bulk and a two-dimensional interface is analyzed for bosons with quasirelativistic dispersion relation. Using the energy-dependent Green's function, the inter-dimensional quasirelativistic density of states inside the interface is solved analytically. We find that in the low-energy limit the inter-dimensional quasirelativistic density of states shows three-dimensional behaviour, while in the high-energy limit the density of states shows two-dimensional behaviour. This work is the first step in a process that will lead to a fully-analytical model for fermions in topological materials.

Dimensional variation analysis (DVA) is a computer based simulation process used to identify potential assembly process issues due the effects of component part and assembly variation during manufacture. The sponsoring company has over a number of years developed a DVA process to simulate the variation behaviour of a wide range of static mechanical systems. This project considers whether the current DVA process used by the sponsoring company is suitable for the simulation of complex kinematic systems. The project, which consists of three case studies, identifies several issues that became apparent with the current DVA process when applied to three types of complex kinematic systems. The project goes on to develop solutions to the issues raised in the case studies in the form of new or enhanced methods of information acquisition, simulation modelling and the interpretation and presentation of the simulation output Development of these methods has enabled the sponsoring company to expand the range of system types that can be successfully simulated and significantly enhances the information flow between the DVA process and the wider product development process.

Approved for public release; distribution is unlimited / The thesis deals with the detection and tracking of dim point targets in infrared images. Research topics include image process modeling with adaptive two-dimensional Least Mean Square (LMS) and Recursive Least Squares (RLS) prediction filters. Target detection is performed by significance testing the prediction error residual. A pulse tracker is developed which may be adjusted to discriminate target dynamics. The methods are applicable to detection and tracking in other spectral bands. / http://archive.org/details/adaptivedimpoint00dema / Major, United States Marine Corps

Orientador: Lidia Parsekian Martins / Resumo: OBJETIVO: Identificar e quantificar diferenças nas propriedades mecânicas de quatro resinas para impressão por estereolitografia em função do tempo de exposição à luz ultravioleta pós impressão e quantificar diferenças dimensionais em modelos odontológicos produzidos por estereolitografia em relação à inserção de barra estabilizadora transversal na região posterior, à orientação de impressão, vertical ou horizontal, tipo de modelo, oco ou maciço, e pós cura com luz ultravioleta ou não, por meio de medições lineares. MÉTODOS: 140 espécimes foram impressos em impressoras 3D do tipo SLA (estereolitografia a laser) e DLP (estereolitografia por processamento digital de luz) para cada teste mecânico realizado e foram divididos em 28 grupos, de acordo com a resina (4 tipos: Blue, Gray, Surgical Guide, Standard) e o tempo de pós cura com luz ultravioleta (7 tempos: 0, 5, 10, 15, 30, 60 e 120 minutos). Foram realizados os testes de microdureza Vickers, tração diametral e flexão três pontos. Os dados obtidos foram submetidos a uma ANOVA de dois níveis e ao pós teste de Tukey. Para a avaliação das alterações dimensionais de modelos odontológicos foram realizados dois experimentos distintos. No primeiro, 56 modelos odontológicos do arco maxilar em formato de ferradura foram impressos na impressora MoonRay S100 (SprintRay) com a resina Gray (SprintRay), variando a orientação de impressão, a presença de barra e o processo de pós cura. Depois de impressos foram escaneados em escâner de mesa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: OBJECTIVE: To identify and quantify differences in the mechanical properties of four resins for stereolithography printing varying time of exposure to ultraviolet light and to quantify dimensional differences in dental models produced by stereolithography regarding the insertion of a transverse stabilizer bar in the posterior region, the printing orientation, vertical or horizontal, model type, hollow or solid, and post-cure with ultraviolet light or not, by means of linear measurements. METHODS: 140 specimens were printed by SLA (laser stereolithography) and DLP (digital light processing stereolithography) printers for each mechanical test performed and were divided into 28 groups, according to the resin (4 types: Blue, Gray, Surgical Guide, Standard) and the post-cure time with ultraviolet light (7 times: 0, 5, 10, 15, 30, 60 and 120 minutes). Vickers microhardness tests, diametrical traction and three point flexion were performed. The data obtained were submitted to a two-way ANOVA and the Tukey post-test. To evaluate the dimensional changes of dental models, two different experiments were carried out. In the first, 56 horseshoe-shaped dental models of a maxillary arch were printed on the MoonRay S100 (SprintRay) with Gray resin (SprintRay), varying the printing orientation, the presence of a bar and the post-curing process. After printing, they were scanned on a R700 table scanner (3Shape) and then measurements between canines, first and second premolars and molars and ar... (Complete abstract click electronic access below) / Doutor

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