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The Global ETD Search service is a free service for researchers
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Showing 91 to 99 of 99 (0.022 seconds)Spelling suggestions: "subject:"[een] FUNK"" "subject:"[enn] FUNK""
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Reconstructing Functions on the Sphere from Circular MeansQuellmalz, Michael 09 April 2020 (has links)
The present thesis considers the problem of reconstructing a function f that is defined on the d-dimensional unit sphere from its mean values along hyperplane sections. In case of the two-dimensional sphere, these plane sections are circles. In many tomographic applications, however, only limited data is available. Therefore, one is interested in the reconstruction of the function f from its mean values with respect to only some subfamily of all hyperplane sections of the sphere. Compared with the full data case, the limited data problem is more challenging and raises several questions. The first one is the injectivity, i.e., can any function be uniquely reconstructed from the available data? Further issues are the stability of the reconstruction, which is closely connected with a description of the range, as well as the demand for actual inversion methods or algorithms.
We provide a detailed coverage and answers of these questions for different families of hyperplane sections of the sphere such as vertical slices, sections with hyperplanes through a common point and also incomplete great circles. Such reconstruction problems arise in various practical applications like Compton camera imaging, magnetic resonance imaging, photoacoustic tomography, Radar imaging or seismic imaging. Furthermore, we apply our findings about spherical means to the cone-beam transform and prove its singular value decomposition. / Die vorliegende Arbeit beschäftigt sich mit dem Problem der Rekonstruktion einer Funktion f, die auf der d-dimensionalen Einheitssphäre definiert ist, anhand ihrer Mittelwerte entlang von Schnitten mit Hyperebenen. Im Fall d=2 sind diese Schnitte genau die Kreise auf der Sphäre. In vielen tomografischen Anwendungen sind aber nur eingeschränkte Daten verfügbar. Deshalb besteht das Interesse an der Rekonstruktion der Funktion f nur anhand der Mittelwerte bestimmter Familien von Hyperebenen-Schnitten der Sphäre. Verglichen mit dem Fall vollständiger Daten birgt dieses Problem mehrere Herausforderungen und Fragen. Die erste ist die Injektivität, also können alle Funktionen anhand der gegebenen Daten eindeutig rekonstruiert werden? Weitere Punkte sind die die Frage nach der Stabilität der Rekonstruktion, welche eng mit einer Beschreibung der Bildmenge verbunden ist, sowie der praktische Bedarf an Rekonstruktionsmethoden und -algorithmen.
Diese Arbeit gibt einen detaillierten Überblick und Antworten auf diese Fragen für verschiedene Familien von Hyperebenen-Schnitten, angefangen von vertikalen Schnitten über Schnitte mit Hyperebenen durch einen festen Punkt sowie Kreisbögen. Solche Rekonstruktionsprobleme treten in diversen Anwendungen auf wie der Bildgebung mittels Compton-Kamera, Magnetresonanztomografie, fotoakustischen Tomografie, Radar-Bildgebung sowie der Tomografie seismischer Wellen. Weiterhin nutzen wir unsere Ergebnisse über sphärische Mittelwerte, um eine Singulärwertzerlegung für die Kegelstrahltomografie zu zeigen.
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Interaktiv musikkomposition / Interactive Music CompositionAndersson, Anders-Petter January 2012 (has links)
This dissertation, titled Interactive Music Composition, is a practice based Ph.D. thesis in the field of Musicology. The purpose is to explore if and how one can compose computer based interactive music, that is musically satisfying for an interacting audience, consisting of both laymen and skilled musicians. The text describes the design and reflection in two interactive music installations: Do-Be-DJ, open-air installation in a public park, and, Mufi, with modular and moveable interface. Based on methods and perspectives in Musicology and Interaction Design, a composition model for interactive music is developed. The model investigates the experience dimensions listen, explore, compose and collaborate. It also investigates the design dimensions of interaction, narrative structure, composition rule and sound node. The conceptual approach is to apply improvisation and composition methods from jazz, pop and groove based music on interactive music. It also uses the concepts of openess in musical structures and interpretation, musical mediation of actions and meaning and everyday use of music, when composing interactive music. The dissertation contributes to an understanding of how to create composition techniques for interactive music, such as: Direct, varied and shifting response. It reflects on the change in meaning of the musicological terms composition, improvisation, musical work, listener, musician and audience. And on the interaction design terms interaction, gameplay, system and user. The term co-creator is used to describe an actively, interacting and collaborating person, to complement traditional terms like audience, performer and user. / <p>Ljudfiler till avhandlingens bilaga 1, http://musicalfieldsforever.com/dobedj_more.html; Videodokumentation av Do-Be-DJ, Interaktiv installation, http://musicalfieldsforever.com/dobedj_more.html; Videodokumentation av Mufi I och II, Interaktiv installation, http://musicalfieldsforever.com/mufi_more.html; Doktorandtjänsten finansierades av Interactive Institute; Musikinspelning finansierades av Framtidens Kultur genom Skiften på Malmö högskola</p> / Interaktiv musikkomposition / Interactive Music Composition / Interaktiv ljuddesign / Interactive Sound Design / Musik och Hälsa / Music and Health
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Radio frequency ranging for precise indoor localizationSark, Vladica 15 February 2018 (has links)
In den letzten Jahrzehnten sind Satellitennavigationssysteme zu einem unverzichtbaren Teil des modernen Lebens geworden. Viele innovative Anwendungen bieten ortsabhängige Dienste an, welche auf diesen Navigationssystemen aufbauen. Allerdings sind diese Dienste in Innenräumen nicht verfügbar. Daher werden seit einigen Jahren alternative Lokalisierungsmethoden für Innenräume aktiv erforscht und entwickelt.
Der Schwerpunkt dieser Arbeit liegt darauf, die Genauigkeit von Lokalisationsmethoden in Innenräumen zu erhöhen, sowie auf der effektiven Integration der entsprechenden Verfahren in drahtlose Kommunikationssysteme. Es werden zwei Ansätze vorgeschlagen und untersucht, welche die Präzision von ToF-basierten Methoden erhöhen. Zum einen wird im „Modified Equivalent Time Sampling“ (METS) Verfahren eine überabgetastete Version der vom Radioempfänger gelieferten Wellenform erzeugt und zur ToF Bestimmung verwendet. Der zweite erforschte Ansatz hat zum Ziel, Fehler auf Grund von Taktfrequenz-Abweichungen zu kompensieren. Dieses ist für kooperative Lokalisationsmethoden (N-Way ranging) von Bedeutung. Das in der Arbeit entwickelte Verfahren führt zu einer erheblichen Reduzierung der Fehler in der Abstandsmessung und damit der Positionsbestimmung.
Darüber hinaus wurde eine neue Methode untersucht, um Lokalisationsverfahren in Funksysteme für die ISM Bänder bei 2,4 GHz und 5 GHz zu integrieren. Die Methode wurde auf einer Software Defined Radio (SDR) Plattform implementiert und bewertet. Es konnte eine Genauigkeit bis zu einem Meter in der Positionsbestimmung demonstriert werden. Schließlich wurde ein Verfahren vorgeschlagen und untersucht, mit welchem Lokalisationsfähigkeit in bestehende Funksysteme integriert werden kann. Die betrachtete Methode wurde in einem 60 GHz Funksystem mit hoher Datenrate implementiert. Die Untersuchungen zeigten eine Positionsgenauigkeit von 1 cm bei einer gleichzeitig hohen Datenrate für die Übertragung von Nutzdaten. / In the last couple of decades the Global Navigation Satellite Systems (GNSS) have become a very important part of our everyday life. A huge number of applications offer location based services and navigation functions which rely on these systems. Nevertheless, the offered localization services are not available indoors and their performance is significantly affected in urban areas. Therefore, in the recent years, a large number of wireless indoor localization systems are being actively investigated and developed.
The main focus of this work is on improving precision and accuracy of indoor localization systems, as well as on the implementation and integration of localization functionality in wireless data transmission systems. Two approaches for improving the localization precision and accuracy of ToF based methods are proposed. The first approach, referred to as modified equivalent time sampling (METS) is used to reconstruct an oversampled versions of the waveforms acquired at the radio receiver and used for ToF based localization. The second proposed approach is used to compensate the ranging error due to clock frequency offset in cooperative localization schemes like N-Way ranging. This approach significantly reduces the ranging and, therefore, localization errors and has much better performance compared to the existing solutions.
An approach for implementation of localization system in the 2.4/5 GHz ISM band is further proposed in this work. This approach is implemented and tested on a software defined radio platform. A ranging precision of better than one meter is demonstrated. Finally, an approach for integrating localization functionality into an arbitrary wireless data transmission system is proposed. This approach is implemented in a 60 GHz wireless system. A ranging precision of one centimeter is demonstrated.
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High angular resolution diffusion-weighted magnetic resonance imaging: adaptive smoothing and applicationsMetwalli, Nader 07 July 2010 (has links)
Diffusion-weighted magnetic resonance imaging (MRI) has allowed unprecedented non-invasive mapping of brain neural connectivity in vivo by means of fiber tractography applications. Fiber tractography has emerged as a useful tool for mapping brain white matter connectivity prior to surgery or in an intraoperative setting. The advent of high angular resolution diffusion-weighted imaging (HARDI) techniques in MRI for fiber tractography has allowed mapping of fiber tracts in areas of complex white matter fiber crossings. Raw HARDI images, as a result of elevated diffusion-weighting, suffer from depressed signal-to-noise ratio (SNR) levels. The accuracy of fiber tractography is dependent on the performance of the various methods extracting dominant fiber orientations from the HARDI-measured noisy diffusivity profiles. These methods will be sensitive to and directly affected by the noise. In the first part of the thesis this issue is addressed by applying an objective and adaptive smoothing to the noisy HARDI data via generalized cross-validation (GCV) by means of the smoothing splines on the sphere method for estimating the smooth diffusivity profiles in three dimensional diffusion space. Subsequently, fiber orientation distribution functions (ODFs) that reveal dominant fiber orientations in fiber crossings are then reconstructed from the smoothed diffusivity profiles using the Funk-Radon transform. Previous ODF smoothing techniques have been subjective and non-adaptive to data SNR. The GCV-smoothed ODFs from our method are accurate and are smoothed without external intervention facilitating more precise fiber tractography.
Diffusion-weighted MRI studies in amyotrophic lateral sclerosis (ALS) have revealed significant changes in diffusion parameters in ALS patient brains. With the need for early detection of possibly discrete upper motor neuron (UMN) degeneration signs in patients with early ALS, a HARDI study is applied in order to investigate diffusion-sensitive changes reflected in the diffusion tensor imaging (DTI) measures axial and radial diffusivity as well as the more commonly used measures fractional anisotropy (FA) and mean diffusivity (MD). The hypothesis is that there would be added utility in considering axial and radial diffusivities which directly reflect changes in the diffusion tensors in addition to FA and MD to aid in revealing neurodegenerative changes in ALS. In addition, applying adaptive smoothing via GCV to the HARDI data further facilitates the application of fiber tractography by automatically eliminating spurious noisy peaks in reconstructed ODFs that would mislead fiber tracking.
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Folked, funked, punked how feminist performance poetry creates havens for activism and change /Kyser, Tiffany S. January 2010 (has links)
Thesis (M.A.)--Indiana University, 2010. / Title from screen (viewed on July 19, 2010). Department of English, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Karen Kovacik, Peggy Zeglin Brand, Ronda C. Henry. Includes vitae. Includes bibliographical references (leaves 79-83).
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Folked, Funked, Punked: How Feminist Performance Poetry Creates Havens for Activism and ChangeKyser, Tiffany S. 19 July 2010 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / My thesis examines the ways in which female performance poets deliver their messages and how those messages inspire, affirm, and encourage their audiences. From the traditions of outsider art—Beat poetry, feminist poetry, jazz, folk, punk, and rap—feminist performance poets choose the public sphere as a platform to witness to social injustices. In naming inequality, these poets challenge patriarchal foundations of gender roles, question academia’s criteria as to what constitutes “good” poetry, and expose social injustices. In this thesis, I examine the work of feminist performance poets Ani Difranco, Alix Olson, Andrea Gibson, Ursula Rucker, and Jessica Care Moore as examples of a new way of reading. Their work is significant in that they continue the tradition of feminist poetry by challenging the patriarchal status quo through a re-socializing and accessible style. Their work allows audiences to commune together in shared experience and promotes social change by demystifying cultural norms and gender codes in order to expose the exclusivity in patriarchal ideologies. These poets draw on a woman-centered spirituality, subvert misogynistic feminine archetypes, pay homage to ancestors and foremothers, and address issues of the body—naming oppression yet making room for pleasure.
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Systemanalyse und Entwicklung Six-Port basierter Funkempfängerarchitekturen unter Berücksichtigung analoger StöreffekteMailand, Marko 09 January 2008 (has links) (PDF)
Due to the increasing demand of broadband capability and reconfigurability for mobile applications, there is an enormous interest to develop appropriate analog receiver front-ends. In this respect, one promising candidate group is the Six-Port-based direct conversion receiver. The presented work focuses on the investigation of Six-Port-based mobile receiver front-ends with their specific systematical signal processing. Thereby, issues of spurious interfering signals which are generated within the down conversion process of such receivers are of special interest. Based on a comprehensive description of the analog signal processing within additive frequency conversion, a reason could be identified why existing Six-Port receivers have not found any practical application in mobile communication yet – the dynamic DC-offset. With this insight compensation techniques were developed to overcome the negative influences of the dynamic DC-offset. Furthermore, this work presents novel Six-Port-based receiver architectures which, on the one hand, keep the advantages of additive mixing systems like: low power consumption, broadband capability and simplicity of implementation especially for mm-wave transmissions. On the other hand, these novel architectures comprise compensation techniques such that systematically generated spurious signals are inherently compensated in the analog part of the receiver. Moreover, the influence of impairments of phase and amplitude within the IQ-branches of a receiver was investigated. The resulting, unwanted IQ-imbalance was shown to be a mixing method (multiplicative or additive) independent spurious effect. It is suggested to compensate for IQ-imbalance in the digital part of the receiver system. This can be realized with the use of adaptive algorithms. The comparison with conventional analog receiver architectures (especially homodyne receivers) with respect to the reception of today’s and future digitally modulated transmission signals indicate the proposed Six-Port-based receiver architectures to be suitable candidates to fulfill the difficult tasks of modern mobile communication.
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Systemanalyse und Entwicklung Six-Port basierter Funkempfängerarchitekturen unter Berücksichtigung analoger StöreffekteMailand, Marko 22 October 2007 (has links)
Due to the increasing demand of broadband capability and reconfigurability for mobile applications, there is an enormous interest to develop appropriate analog receiver front-ends. In this respect, one promising candidate group is the Six-Port-based direct conversion receiver. The presented work focuses on the investigation of Six-Port-based mobile receiver front-ends with their specific systematical signal processing. Thereby, issues of spurious interfering signals which are generated within the down conversion process of such receivers are of special interest. Based on a comprehensive description of the analog signal processing within additive frequency conversion, a reason could be identified why existing Six-Port receivers have not found any practical application in mobile communication yet – the dynamic DC-offset. With this insight compensation techniques were developed to overcome the negative influences of the dynamic DC-offset. Furthermore, this work presents novel Six-Port-based receiver architectures which, on the one hand, keep the advantages of additive mixing systems like: low power consumption, broadband capability and simplicity of implementation especially for mm-wave transmissions. On the other hand, these novel architectures comprise compensation techniques such that systematically generated spurious signals are inherently compensated in the analog part of the receiver. Moreover, the influence of impairments of phase and amplitude within the IQ-branches of a receiver was investigated. The resulting, unwanted IQ-imbalance was shown to be a mixing method (multiplicative or additive) independent spurious effect. It is suggested to compensate for IQ-imbalance in the digital part of the receiver system. This can be realized with the use of adaptive algorithms. The comparison with conventional analog receiver architectures (especially homodyne receivers) with respect to the reception of today’s and future digitally modulated transmission signals indicate the proposed Six-Port-based receiver architectures to be suitable candidates to fulfill the difficult tasks of modern mobile communication.
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THE BRONX COCKED BACK AND SMOKING MULTIFARIOUS PROSE PERFORMANCEAvila, Alex 01 June 2016 (has links)
The Bronx Cocked Back And Smoking is a collection of multifarious prose performances recounting the historical, personal, social, political and cultural constructs of a city birthed by violence. This body of work is accompanied by video, audio, photography, and theatre performance texts. St. Mary’s Housing project, in the Bronx, is the foundation where most of this literary work takes place. The modern day Griot (storyteller) is a Poet, guiding his audience through the social inequalities and disparities that plague St. Mary’s community. The Poet shares personal traumatic insights while simultaneously utilizing writing as a form of survival to the conditions of the Bronx. This multi-platform performance highlights the metaphorical and physical concerns with the cycle of violence. This question is answered through the Poet’s choice by selecting the pen over the gun.
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