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In this dissertation we address the problem of adapting frequency domain tiling using the curvelet transform as the basis algorithm. The optimal tiling, for a given class of images, is computed using denoising performance as the cost function. The major adaptations considered are: the number of scale decompositions, angular decompositions per scale/quadrant, and scale locations. A global optimization algorithm combining the three adaptations is proposed. Denoising performance of adaptive curvelets is tested on seismic and face data sets. The developed adaptation procedure is applied to a number of different application areas. Adaptive curvelets are used to solve the problem of sparse data recovery from subsampled measurements. Performance comparison with default curvelets demonstrates the effectiveness of the adaptation scheme. Adaptive curvelets are also used in the development of a novel image similarity index. The developed measure succeeds in retrieving correct matches from a variety of textured materials. Furthermore, we present an algorithm for classifying different types of seismic activities.

Cosmologists are interested in topological defects as a possible source for the primordial density perturbations which seeded structure formation through gravitational instability. In this thesis, the gravitational properties of various topological defects are studied in the context of low-energy string theory, a likely modification of Einstein gravity at the high energy scales prevalent in the early universe. We consider in turn global monopole, local monopole, global cosmic string and global texture defects, allowing for an arbitrary coupling of defects to the string theory dilaton. For global defects we find the following behaviour. If the dilaton is massless, this modification to general relativity generically destroys the global good behaviour of the monopole and cosmic string, making their spacetimes singular. For the texture non-singular spacetimes exist, but only for certain values of the matter-dilaton coupling, dependent on the gravitational strength of the defect; in addition, this non-singular behaviour exists only in a certain frame. In the case of a massive dilaton, the metric behaviour of these defects is similar to that found in Einstein gravity, though we find they generically induce a long-range dilaton cloud. For the local monopole, which we study only in the presence of a massless dilaton, a rich variety of behaviour is found. For particular parameter values the local monopole spacetime approximates that of an extremal dilaton black hole.

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ABSTRACT Stirred yogurt is a cultured dairy product produced by mixed cultures of lactic acid bacteria. It is a semi-viscous liquid whose rheological properties are major quality determinants. These are influenced by several manufacturing factors such as heat treatment of the yogurt milk. Improvement of the properties of stirred yogurt made under different manufacturing conditions was the key focus in this research. The research included an investigation of the key factors involved in the development of nodulation which is an unsightly defect, as consumers expect stirred yogurt to have a smooth consistency. This research consisted of three main experimental parts: 1. Effect of different heat treatments on the properties of stirred yogurt; 2. Factors involved in nodulation in stirred yogurt; and 3. The physical and chemical nature of nodules. The types and levels of heat treatment have a major influence on the properties of stirred yogurt. In this study, yogurt milk was treated at pasteurization and UHT conditions. The milk heated at pasteurization, 80-95oC, and UHT, 130-145oC, conditions had similar levels of whey protein denaturation, approximately 85-99%, while the milk treated at low temperature for a long time, 65oC for 4 hr, had a significantly lower level of denaturation (~55%). Yogurt made from milk pasteurized at 85oC for 30 min and 92oC for 7 min and UHT treated milk at 130-145oC for 5 s had similar hardness and viscosity while yogurt made from milk treated at 65oC for 4 hr had significantly lower hardness and viscosity than corresponding yogurts from high heat treatments. In addition, the water-holding capacity and syneresis of yogurts made from either pasteurized or UHT milk were not significantly different. Yogurt (made from either pasteurized or UHT-treated milk) enriched with non-dairy ingredients, gelatin, inulin and sugar, showed higher hardness, viscosity, water-holding capacity than yogurt made with only dairy ingredients. These yogurts also showed no syneresis. This can be largely attributed to the gelatin which improves the texture, binds additional water and prevents syneresis. The formation of nodules in yogurt has been reported to be influenced by several factors. In this study, the heat treatment of the yogurt milk, the types and levels of sugar added, and the type of starter cultures were found to significantly influence the level of nodulation in the stirred yogurts. Severe pasteurization heat treatments, at temperatures < 100ºC, caused more nodules than mild heat treatments at temperatures in this range. The type of heat treatment was also important, with yogurt made from UHT-treated milk showing much less nodulation than yogurt made from pasteurized. This was observed when the levels of whey protein denaturation in the pasteurized and UHT milk were similar, indicating that the extent of whey protein denaturation alone is not a major factor in the development of nodules. Sucrose added either before or after heat treatment of yogurt milk also affected the extent of nodulation. Increasing the amount of added sucrose from 0 to 6.5% caused correspondingly higher numbers of nodules. In addition, there was a positive synergistic effect between heat treatment and sugar addition on nodulation; the highest numbers of nodules appeared when the yogurt milk was severely heated and sugar was added at the highest level, 6.5%. Addition of lactose or fructose instead of sucrose did not promote nodule formation while glucose caused nodulation in a similar manner to sucrose. The use of different starter cultures affected the numbers of nodules; yogurts made with the culture ABT 10 had much less nodulation than those made with ABT5 and ABT6, even under heating conditions and sugar addition conducive to nodule development. The amount of exopolysaccharide (EPS) produced by the starter cultures, ABT5 and ABT10, did not correlate with the extent of nodulation in the yogurt. Disturbance during yogurt fermentation by changing the temperature (from 37 to 42 or 45 to 42oC) when the gel was forming increased the numbers of nodules while refrigerated storage of yogurt and altering the pH during heat treatment (from pH 6.46 to 6.90) did not affect the number of nodules. Ultrasonication of the yogurt milk caused a reduction in the numbers of nodules in the yogurt. This was attributed to disruption of clumps of starter culture bacteria, thus preventing excessive localised build-up of acid around the bacterial clumps which could form the nucleus of nodules. The major conclusions from this study are that heat treatment of the yogurt milk and the level and type of added sugar are important factors affecting the extent of nodulation of stirred yogurt. Other factors such as the type of starter culture bacteria and their degree of clumping are also significant. Optimisation of these factors would allow yogurt manufacturers to minimise nodulation in stirred yogurt.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 145-156).

Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.A.)--York University, 2003. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 102-107). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ82940.

Thesis (doctoral)--Helsinki University of Technology, 2008. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Hamid Garmestani, FAMU-FSU College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Sept. 19, 2006). Document formatted into pages; contains xiii, 101 pages. Includes bibliographical references.