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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Five Kingdoms

Groom, Kelle 01 January 2008 (has links)
Five Kingdoms. (Under the direction of Don Stap.) Five Kingdoms is a collection of 55 poems in three sections. The title refers to the five kingdoms of life, encompassing every living thing. Section I explores political themes and addresses subjects that reach across a broad expanse of time--from the oldest bones of a child and the oldest map of the world to the bombing of Fallujah in the current Iraq war. Connections between physical and metaphysical worlds are examined. The focus narrows from the world to the city in section II. The theme of shelter is important to these poems, as is the act of being a flâneur. The search for shelter, physical and spiritual, is explored. The third section of Five Kingdoms narrows further to the individual. Political themes recur, as do ekphrastic elements, in the examination of individual lives and the search for physical and metaphysical shelter. The title poem "Five Kingdoms," was written on the 60th anniversary of the atomic bombing of Hiroshima on August 6, 1945. This non-narrative poem is composed of a series of questions for the reader regarding personal and national security. It is a political poem that uses a language of fear and superstition to question what we are willing to sacrifice to be safe and what "safety" means. The poem ends with a call to action: "Before you break in two, categorize/the five kingdoms, count all the living things." The poems in this manuscript are a kind of counting that pays attention to the things of the world through praise and elegy. The poems in Five Kingdoms are indebted to my reading of many poets, in particular Michael Burkard, Carolyn Forché, Brenda Hillman, Tony Hoagland, Kenneth Koch, Philip Levine, Denise Levertov, Jane Mead, W.S. Merwin, Pablo Neruda, Frank O'Hara, Mary Oliver, Adrienne Rich, and Mark Strand.
72

David Amram (b. 1930): Analysis of Selected Works for Wind Band: <i>King Lear Variations</i>, <i>Andante and Variations on a Theme for Macbeth</i>, <i>Ode to Lord Buckley</i>

Romer, Wayne 13 April 2010 (has links)
No description available.
73

Deep Learning for Ordinary Differential Equations and Predictive Uncertainty

Yijia Liu (17984911) 19 April 2024 (has links)
<p dir="ltr">Deep neural networks (DNNs) have demonstrated outstanding performance in numerous tasks such as image recognition and natural language processing. However, in dynamic systems modeling, the tasks of estimating and uncovering the potentially nonlinear structure of systems represented by ordinary differential equations (ODEs) pose a significant challenge. In this dissertation, we employ DNNs to enable precise and efficient parameter estimation of dynamic systems. In addition, we introduce a highly flexible neural ODE model to capture both nonlinear and sparse dependent relations among multiple functional processes. Nonetheless, DNNs are susceptible to overfitting and often struggle to accurately assess predictive uncertainty despite their widespread success across various AI domains. The challenge of defining meaningful priors for DNN weights and characterizing predictive uncertainty persists. In this dissertation, we present a novel neural adaptive empirical Bayes framework with a new class of prior distributions to address weight uncertainty.</p><p dir="ltr">In the first part, we propose a precise and efficient approach utilizing DNNs for estimation and inference of ODEs given noisy data. The DNNs are employed directly as a nonparametric proxy for the true solution of the ODEs, eliminating the need for numerical integration and resulting in significant computational time savings. We develop a gradient descent algorithm to estimate both the DNNs solution and the parameters of the ODEs by optimizing a fidelity-penalized likelihood loss function. This ensures that the derivatives of the DNNs estimator conform to the system of ODEs. Our method is particularly effective in scenarios where only a set of variables transformed from the system components by a given function are observed. We establish the convergence rate of the DNNs estimator and demonstrate that the derivatives of the DNNs solution asymptotically satisfy the ODEs determined by the inferred parameters. Simulations and real data analysis of COVID-19 daily cases are conducted to show the superior performance of our method in terms of accuracy of parameter estimates and system recovery, and computational speed.</p><p dir="ltr">In the second part, we present a novel sparse neural ODE model to characterize flexible relations among multiple functional processes. This model represents the latent states of the functions using a set of ODEs and models the dynamic changes of these states utilizing a DNN with a specially designed architecture and sparsity-inducing regularization. Our new model is able to capture both nonlinear and sparse dependent relations among multivariate functions. We develop an efficient optimization algorithm to estimate the unknown weights for the DNN under the sparsity constraint. Furthermore, we establish both algorithmic convergence and selection consistency, providing theoretical guarantees for the proposed method. We illustrate the efficacy of the method through simulation studies and a gene regulatory network example.</p><p dir="ltr">In the third part, we introduce a class of implicit generative priors to facilitate Bayesian modeling and inference. These priors are derived through a nonlinear transformation of a known low-dimensional distribution, allowing us to handle complex data distributions and capture the underlying manifold structure effectively. Our framework combines variational inference with a gradient ascent algorithm, which serves to select the hyperparameters and approximate the posterior distribution. Theoretical justification is established through both the posterior and classification consistency. We demonstrate the practical applications of our framework through extensive simulation examples and real-world datasets. Our experimental results highlight the superiority of our proposed framework over existing methods, such as sparse variational Bayesian and generative models, in terms of prediction accuracy and uncertainty quantification.</p>
74

Desterritorialización y reterritorialización de Tyger de Blake y Nightingale de Keats en la obra de Jorge Luis Borges: ¿diálogo interdiscursivo e intercultural entre el romanticismo inglés y la Argentina postmoderna?

Barra van Treek, Erika de la January 2008 (has links)
Tesis para optar al grado de Doctor en Literatura Hispanoamericana y Chilena / Como es sabido y Borges (1899-1986) mismo lo señala, pasó su niñez “detrás de una verja con lanzas, y en una biblioteca de ilimitados libros ingleses. Palermo del cuchillo y de la guitarra andaba (me aseguran) por las esquinas” Esta pequeña cita instala una problemática no menor en su obra y que contiene la relación siempre en tensión entre Latinoamérica (periferia) y Europa (centro). La investigación examina especialmente el diálogo interdiscursivo e intercultural entre Borges y dos románticos ingleses: William Blake (1757-1827) y John Keats (1795-1821) a través de la desterritorialización de Tyger y Nightingale del contexto romántico inglés decimonónico y su reterritorialización en la Argentina borgeana moderna / postmoderna del siglo XX. Metodológicamente, se ha realizado un análisis del poema “The Tyger” de Blake y del poema “Ode to a Nightingale” de Keats para dilucidar su significación o significaciones románticas. Posteriormente se ha examinado la obra ensayística, cuentística, lírica de Borges en búsqueda de los significados que él atribuye a tyger y nightingale descubriéndose una polisemia compleja otorgada por sus acercamientos serios o jocosos. En otras palabras, Borges desestabiliza la relación significante /significado de tyger y nightingale y su contexto romántico. Tanto tyger como nightingale diseminan rizomáticamente por la obra de Borges a través de los principios de conexión y heterogeneidad que permiten unirlos a nuevos significados diversos sin que se llegue jamás a un significado definitivo. Borges instalaría una postergación infinita del significado que asemeja un deslizamiento, un rodar, un nomadismo con múltiples entradas y salidas entre los discursos involucrados. (Kristeva, 1980; Derrida, 1975; Deleuze/Guattari, 1997; Barthes, 1974). Aunque la investigación se encuentra aún en progreso, la recodificación que hace Borges de los significantes románticos ingleses tyger y nightingale parece tener importantes implicancias desde la perspectiva del postcolonialismo, ya que el juego literario conducido por Borges establece una relación de paridad con el centro que cuestiona la sujeción periférica de América Latina al centro Europeo.
75

Simulation for LEGO Mindstorms robotics

Tian, Yuan January 2008 (has links)
The LEGO® MINDSTORMS® toolkit can be used to help students learn basic programming and engineering concepts. Software that is widely used with LEGO MINDSTORMS is ROBOLAB, developed by Professor Chris Rogers from Tufts University, Boston, United States. It has been adopted in about 10,000 schools in the United States and other countries. It is used to program LEGO MINDSTORMS robotics in its icon-based programming environment. However, this software does not provide debug features for LEGO MINDSTORMS programs. Users cannot test the program before downloading it into LEGO robotics hardware. In this project, we develop a simulator for LEGO MINDSTORMS to simulate the motions of LEGO robotics in a virtual 3D environment. We use ODE (Open Dynamic Engine) and OpenGL, combined with ROBOLAB. The simulator allows users to test their ROBOLAB program before downloading it into the LEGO MINDSTORMS hardware. For users who do not have the hardware, they may use the simulator to learn ROBOLAB programming skills which may be tested and debugged using the simulator. The simulator can track and display program execution as the simulation runs. This helps users to learn and understand basic robotics programming concepts. An introduction to the overall structure and architecture of the simulator is given and is followed by a detailed description of each component in the system. This presents the techniques that are used to implement each feature of the simulator. The discussions based on several test results are then given. This leads to the conclusion that the simulator is able to accurately represent the actions of robots under certain assumptions and conditions.
76

Mathematical models for the control of Argulus foliaceus in UK stillwater trout fisheries

McPherson, Nicola J. January 2013 (has links)
Species of Argulus are macro-, ecto-parasites known to infect a wide variety of fish, but in the UK mainly cause problems in rainbow (Oncorhynchus mykiss) and brown trout (Salmo trutta). Argulus foliaceus is estimated to have caused problems in over 25% of stillwater trout fisheries in the UK. While A. foliaceus does not usually cause high levels of mortality, the parasite affects fish welfare, and also makes fish harder to catch due to morbidity and reduced appetite. This can cause severe economic problems for the fishery, resulting in reduced angler attendance due to poor capture rates and the reduced aesthetic appearance of fish; in the worst-case scenario this can result in the closure of the fishery. Current methods of control include chemical treatment with chemotherapeutant emamectin benzoate (Slice), physical intervention with egg-laying boards which are removed periodically and cleaned in order to reduce the number of parasites hatching into the environment, and the complete draining and liming of the lake to remove all free-living and egg stages of the parasite. While these treatments have all been shown to reduce parasite numbers, none are known to have resulted in permament eradication of the parasite. There is evidence to suggest that A. foliaceus will eventually develop resistance to Slice - the only currently available chemical treatment against the infection - and egg-laying boards and the draining and liming of the lake are both time- and labour-intensive. Previous studies have shown that slow fish turnover is a risk factor with respect to A. foliaceus infections, and with a wide variety of stocking practices occurring in the UK one of the first aims of this project was to determine their impact on the host-parasite dynamics. Mathematical models provide a cost-effective way of examining the impact of such practices, and after a literature review (chapter one), in chapter two a three-compartment mathematical model was adapted for use in the A. foliaceus-trout system. Four generalised stocking methods were then incorporated and analysed, and a minimum threshold host density was found to be necessary to sustain the parasite. Including a function which reduced the capture rate as the parasite burden increased allowed the parasite to survive at a lower host density, as susceptible fish were removed from the water at a slower rate, and attached parasites also remained in the water for longer. This resulted in hysteresis in the model, as the invasion threshold for the parasite remained the same, but once established the parasite became harder to eradicate, requiring significant reductions in the host density. In chapter three the model was further developed in order to improve its biological real- ism. Several features were added and these included: natural host mortalities, a separate compartment for the parasite egg population, and parasite survival after the natural or parasite-induced mortality of its host. In chapter four seasonality was added by incorporating temperature-dependent egg-laying rates and an over-wintering period during which the parasite was unable to reproduce. The model was then fit to the available data, and estimates for the rate of parasite-induced host mortalities and the parasite’s rate of attachment to a host were found. In chapter five we returned to stocking methods, this time looking at the frequency and timing of stocking events and the impact of imposing a rod limit (whereby anglers are only permitted to capture four fish per visit); it was concluded that while current guidelines suggest that very frequent trickle stocking is recommended when dealing with Argulus spp. infections, monthly stocking does not appear to worsen the infection, and if the fish capture rate is high then less-frequent stocking may also be permissable - particularly if stocking occurs towards the end of the year when the parasite is no longer active. This practice may, however, be detrimental to the fishery due to low fish densities in the summer months. In chapter six treatment with Slice was included in the model, and it was demonstrated that with constant treatment, and in the absence of reservoir hosts and a withdrawal period from the drug prior to stocking treated fish into the fishery, the parasite was eradicated. Under current veterinary cascade guidelines, however, trout are required to undergo a withdrawal period of 500 degree days prior to being made available for human consumption. When this was included in the model the drug still decreased parasite abundance, but did not eradicate it - this is in agreement with results reported by communications with fishery managers currently treating fish with Slice. A reduction in the withdrawal period of 25% was shown to further decrease parasite abundance, but still did not result in parasite extinction. As constant treatment with Slice is not advisable due to the potential for resistance build-up, we then sought to find time at which to apply a single treatment of Slice, and found that this was in August when the temperature was highest and the parasite was reproducing and attaching to hosts quickly. Egg-laying boards were also incorporated into the model and similarly to findings by Fenton et al. [11] the success of this treatment was mostly dependent on the proportion of eggs being laid on the boards (as opposed to natural substrates). In contrast with the A. coregoni system, however, the boards would have to be cleaned and replaced more frequently that once per year, as several cohorts of A. foliaceus emerge during a single year.
77

The personal mythology of Peter III Feodorovich as deployed in Russian panegyrics of 1742, 1743, and 1762

Kutuzov, Maria Unknown Date
No description available.
78

A metapopulation model for mass gatherings Application: global travel, Hajj and the spread of measles

Menjivar, Liliana 12 September 2013 (has links)
Mass gatherings stress local and global health care systems as they bring together individuals from all over the world that have very different health conditions. We firstly provide an overview of the concepts and results of mathematical epidemiology and public health. Secondly, we present an introduction to the mathematical modelling of measles using deterministic and stochastic approaches for both single and multiple populations. Lastly, we develop a model for mass gatherings and present an application to measles during the Hajj by studying an SIR deterministic metapopulation model with residency and its stochastic analogue. The models incorporate real world country data and time dependent movement and transmission rates, accounting for realistic volume of international travel and seasonality of measles activity. Numerical results for the deterministic system are presented. We conclude with a discussion on further work.
79

Paprastųjų diferencialinių lygčių sistemų su ypatuma kraštiniai uždaviniai / The boundary value problems for a system of ordinary differential equations with singularity

Statkevičiūtė, Odeta 08 August 2012 (has links)
Magistro darbe nagrinėjami paprastųjų tiesinių antros eilės diferencialinių lygčių sistemos su ypatuma kraštiniai uždaviniai. Ištirta sprendinių asimptotika ypatingojo taško aplinkoje. Surasti lygčių sistemos sprendinio įverčiai. Nagrinėjamų diferencialinių uždavinių sprendiniai, konstruojami naudojant integralinius operatorius. Įrodyta sprendinių vienatis. / In this paper the some boundary value problems for a system of ordinary second order differential equations with singularity are considered. The asymptotic of solutions in the neighborhood of singular point are discussed. The estimates of the solution are given. The solutions of considered differential problems are constructed using some integral operators. The uniqueness of the solutions is proved.
80

A mathematical model of Phospholipid Biosynthesis

Behzadi, Mahsa 12 July 2011 (has links) (PDF)
A l'heure de l'acquisition de donn'ees 'a haut d'ebit concernant le m'etabolisme cellulaire et son 'evolution, il est absolument n'ecessaire de disposer de mod'eles permettant d'int'egrer ces donn'ees en un ensemble coh'erent, d'en interpr'eter les variations m'etaboliques r'ev'elatrice, les 'etapes clefs o'u peuvent s'exercer des r'egulations, voire mˆeme d'en r'ev'eler des contradictions apparentes met- tant en cause les bases sur lesquelles le mod'ele lui-mˆeme est construit. C'est ce type de travail que j'ai entrepris 'a propos de donn'ees exp'erimentales obtenues dans le laboratoire biologique sur le m'etabolisme de cellules tu- morales en r'eponse 'a un traitement anti-canc'ereux. Je me suis attach'ee 'a la mod'elisation d'un point particulier de ce m'etabolisme. Il concerne le m'etabolisme des glyc'erophospholipides qui sont de bons marqueurs de la prolif'eration cellulaire. Les phospholipides constituent l'essentiel des mem- branes d'une cellule et l''etude de leur synth'ese (en particulier chez les cellules de mammif'eres) est de ce fait un sujet important. Ici, nous avons pris le parti de mettre en place un mod'ele math'ematique par 'equations diff'erentielles ordinaires, qui est essentiellement bas'e sur des 'equations hyperboliques (Michaelis-Menten), mais aussi sur des cin'etiques type loi d'action de masse et diffusion. Le mod'ele, compos'e de 8 'equations diff'erentielles, donc de 8 substrats d'int'erˆet, comporte naturellementdes param'etres inconnus in vivo, et certains d'ependents des conditions cellulaires (diff'erentiations de cellules, pathologies, . . .). Le mod'ele s'epare la structure du r'eseau m'etabolique, l''ecriture de la matrice de stoechiom'etrie, celles des 'equations de vitesse et enfin des 'equations diff'erentielles. Le mod'ele choisi est le mod'ele murin (souris/rat), parce qu'il est lui-mˆeme un mod'ele de l'homme. Plusieurs con- ditions sont successivement consid'er'ees pour l'identification des param'etres, afin d''etudier les liens entre la synth'ese de phospholipides et le cancer : - le foie sain du rat, - le m'elanome B16 et le carcinome de la lign'ee 3LL chez la souris, respectivement sans traitement, en cours de traitement 'a la Chloro'ethyl-nitrosour'ee et apr'es traitement, - enfin le m'elanome B16 chez la souris sous stress de privation de m'ethionine. En r'esum'e, ce tra- vail fourni une interpr'etation nouvelle des donn'ees exprimentales en mon- trant le rˆole essentiel de la PEMT et la nature superstable de l''etat sta- tionnaire de fonctionnement du r'eseau m'etabolique des phospholipides lors de la canc'erog'en'ese et du traitement des cancers. Il montre bien l'avantage de l'utilisation d'un mod'ele math'ematique dans l'interpr'etation de donn'ees m'etaboliques complexes.

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