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ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / In this paper, we propose a novel technique using a single antenna for direction of arrival (DOA) estimation of broadband microwave signals. We designed and fabricated a microstrip-leaky-wave receiving antenna, which has good matching and reasonable radiation efficiency in the frequency range of interest: 2 - 3.5 GHz. Because the frequency response of the antenna is strongly incident-angle dependent, by using the spectral information at the antenna, we are able to estimate the DOA of a broadband microwave signal with a high degree of accuracy. Simulations and experiments show that the proposed technique enables good DOA estimation performance within a 90˚ range.

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We explore supersymmetric quantum field theories in three and four dimensions via an analysis of their BPS spectrum. In four dimensions, we develop the theory of BPS quivers which provides a simple picture of BPS states in terms of a set of building block atomic particles, and basic quantum mechanical interactions. We develop efficient techniques, rooted in an understanding of quantum-mechanical dualities, for determining the spectrum of bound states, and apply these techniques to calculate the spectrum in a wide class of field theories including ADE gauge theories with matter, and Argyres-Douglas type theories. Next, we explore the geometric content of quivers in the case when the four-dimensional field theory can be constructed from the six-dimensional (2; 0) superconformal field theory compactified on a Riemann surface. We find that the quiver and its superpotential are determined by an ideal triangulation of the associated Riemann surface. The significance of this triangulation is that it encodes the data of geodesics on the surface which in turn are the geometric realization of supersymmetric particles. Finally we describe a class of three-dimensional theories which are realized as supersymmetric domain walls in the previously studied four-dimensional theories. This leads to an understanding of quantum field theories constructed from the six-dimensional (2; 0) superconformal field theory compactified on a three-manifold, and we develop the associated geometric dictionary. We find that the structure of the field theory is determined by a decomposition of the three-manifold into tetrahedra and a braid which species the relationship between ultraviolet and infrared geometries. The phenomenon of BPS wall-crossing in four dimensions is then seen in these domain walls to be responsible for three-dimensional mirror symmetries. / Physics

Autism Spectrum Disorder (ASD) is a complex and lifelong neurodevelopmental disorder that is widely variable in presentation and intensity of defining features. ASD affects 1 in 94 Canadians and is increasing in prevalence. The variety of professionals who work with children with ASD have an accumulation of experiences that can be instructive and inspiring for other practitioners. This study explored how their wealth of experiences might be encapsulated as short vignettes or stories that could be analyzed and used as resources for educating current and future professionals. Six stories were collected from diverse professionals, and themes were summarized in order to demonstrate the types of lessons that can be learned from a clinician’s story of a significant moment or event in working with a child with ASD. The stories highlighted challenges and breakthroughs in communication and managing the child’s challenging behaviours, as well as skills and techniques that professionals have found effective in practice. The study shows that clinicians’ stories hold valuable information that can be shared with professionals in an interesting and memorable manner. Future research could expand on this study to build larger collections of stories with additional viewpoints and specific professional insights and experiences with a variety of children in their practice. / Graduate / 0518 / 0727 / 0758

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published_or_final_version / abstract / toc / Physics / Master / Master of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy