Sub-Riemannian geometry and its applications to Image Processing

Master's Thesis in MathematicsMAT399MAMN-MA

Portmerion, Proportion and Perspective

The holiday village of Portmerion was created by Bertram Clough Williams-Ellis (1883 1978) over a period of fifty-one years, starting in 1926. It was grade II listed in 1971. However, Portmerion has become a part of western popular culture rather than of mainstream architectural history. Its use as the setting for the cult 1967 television series “The Prisoner” ensures continued worldwide interest and a constant stream of visitors. Williams Ellis’ design methods were empirical, initial designs being adjusted by eye on site in close collaboration with trusted builders. This paper analyses the development of Portmerion as a gesamtkunstwerk; considering the experience of movement through the village as a dynamic composition of shifting vistas, focussing the visitor on a series of constructed views. Through this analysis, Portmerion is revealed as both a manifestation of the architecture of pleasure and an exercise in the pleasure of architecture

Human experience in the natural and built environment : implications for research policy and practice

22nd IAPS conference. Edited book of abstracts. 427 pp. University of Strathclyde, Sheffield and West of Scotland Publication. ISBN: 978-0-94-764988-3

Brain Learning, Attention, and Consciousness

The processes whereby our brains continue to learn about a changing world in a stable fashion throughout life are proposed to lead to conscious experiences. These processes include the learning of top-down expectations, the matching of these expectations against bottom-up data, the focusing of attention upon the expected clusters of information, and the development of resonant states between bottom-up and top-down processes as they reach an attentive consensus between what is expected and what is there in the outside world. It is suggested that all conscious states in the brain are resonant states, and that these resonant states trigger learning of sensory and cognitive representations. The model which summarize these concepts are therefore called Adaptive Resonance Theory, or ART, models. Psychophysical and neurobiological data in support of ART are presented from early vision, visual object recognition, auditory streaming, variable-rate speech perception, somatosensory perception, and cognitive-emotional interactions, among others. It is noted that ART mechanisms seem to be operative at all levels of the visual system, and it is proposed how these mechanisms are realized by known laminar circuits of visual cortex. It is predicted that the same circuit realization of ART mechanisms will be found in the laminar circuits of all sensory and cognitive neocortex. Concepts and data are summarized concerning how some visual percepts may be visibly, or modally, perceived, whereas amoral percepts may be consciously recognized even though they are perceptually invisible. It is also suggested that sensory and cognitive processing in the What processing stream of the brain obey top-down matching and learning laws that arc often complementary to those used for spatial and motor processing in the brain's Where processing stream. This enables our sensory and cognitive representations to maintain their stability a.s we learn more about the world, while allowing spatial and motor representations to forget learned maps and gains that are no longer appropriate as our bodies develop and grow from infanthood to adulthood. Procedural memories are proposed to be unconscious because the inhibitory matching process that supports these spatial and motor processes cannot lead to resonance.Defense Advance Research Projects Agency; Office of Naval Research (N00014-95-1-0409, N00014-95-1-0657); National Science Foundation (IRI-97-20333

‘Inauthentic’ \u3ci\u3eSukumbasi:\u3c/i\u3e The Politics of Aesthetics and Urgency in Kathmandu

This article discusses how claims of the urban poor for the right to the city come up against governmental programs seeking to secure norms of private property, environmental sustainability, and elite aesthetics. Here, the city in question is Kathmandu, Nepal, and the urban poor are referred to as sukumbasi, squatters. Baviskar (2011) defines ‘elite politics’ as a mode of expressing anxieties of the self in relation to one’s physical surroundings. I interpret a liberal environmentalist project— the Bagmati Action Plan—in terms of such an elite politics, and explore the ways in which this river restoration program was taken up by the Nepali state. I show how bourgeois liberal environmentalism, when it encounters ‘the slum,’ produces spatial imaginaries, such as ‘pure rivers’ and ‘green riverbanks,’ and representations of sukumbasi as ‘inauthentic’ residents. This logic often furnishes the rationale for violently expelling sukumbasi from the slum and the city. Adopting the state’s governmental frames to distinguish between ‘authentic’ and ‘inauthentic’ sukumbasi, the Bagmati Action Plan’s leadership produced class cleavage among the landless—between squatters, who were alleged to be ‘landed’ and those given a ‘landless’ designation. As such, this article asks two questions: How does the threat of violence forge sukumbasi political subjectivity and inform renewed strategies of inhabitance? And, what implications these strategies have for understanding the challenges facing the politics of the poor? These inquiries locate the practices of the poor within the context of a ‘politics of urgency’— an ad hoc creative and counterintuitive ‘non-movement’ forged in the crucible of crisis, in which the organized practice of everyday life is disrupted and stretched in new and uncertain directions

Total variation regularization for manifold-valued data

We consider total variation minimization for manifold valued data. We propose a cyclic proximal point algorithm and a parallel proximal point algorithm to minimize TV functionals with $\ell^p$-type data terms in the manifold case. These algorithms are based on iterative geodesic averaging which makes them easily applicable to a large class of data manifolds. As an application, we consider denoising images which take their values in a manifold. We apply our algorithms to diffusion tensor images, interferometric SAR images as well as sphere and cylinder valued images. For the class of Cartan-Hadamard manifolds (which includes the data space in diffusion tensor imaging) we show the convergence of the proposed TV minimizing algorithms to a global minimizer