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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.
101

Comparing Android Runtime with native : Fast Fourier Transform on Android / Jämförelse av Android Runtime och native : Fast Fourier Transform på Android

Danielsson, André January 2017 (has links)
This thesis investigates the performance differences between Java code compiled by Android Runtime and C++ code compiled by Clang on Android. For testing the differences, the Fast Fourier Transform (FFT) algorithm was chosen to demonstrate examples of when it is relevant to have high performance computing on a mobile device. Different aspects that could affect the execution time of a program were examined. One test measured the overhead related to the Java Native Interface (JNI).  The results showed that the overhead was insignificant for FFT sizes larger than 64.  Another test compared matching implementations of FFTs between Java and native code. The conclusion drawn from this test was that, of the converted algorithms, Columbia Iterative FFT performed the best in both Java and C++. A third test, evaluating the performance of vectorization, proved to be an efficient option for native optimization. Finally, tests examining the effect of using single-point precision (float) versus double-point precision (double) data types were covered. Choosing float could improve performance by using the cache in an efficient manner. / I denna studie undersöktes prestandaskillnader mellan Java-kod kompilerad av Android Runtime och C++-kod kompilerad av Clang på Android. En snabb Fourier Transform (FFT) användes under experimenten för att visa vilka användningsområden som kräver hög prestanda på en mobil enhet. Olika påverkande aspekter vid användningen av en FFT undersöktes. Ett test undersökte hur mycket påverkan Java Native Interface (JNI) hade på ett program i helhet. Resultaten från dessa tester visade att påverkan inte var signifikant för FFT-storlekar större än 64. Ett annat test undersökte prestandaskillnader mellan FFT-algoritmer översatta från Java till C++. Slutsatsen kring dessa tester var att av de översatta algoritmerna var Columbia Iterative FFT den som presterade bäst, både i Java och i C++. Vektorisering visade sig vara en effektiv optimeringsteknik för arkitekturspecifik kod skriven i C++. Slutligen utfördes tester som undersökte prestandaskillnader mellan flyttalsprecision för datatyperna float och double. float kunde förbättra prestandan genom att på ett effektivt sätt utnyttja processorns cache.
102

holiness and other hauntings

Armstrong, Julia Diane 16 May 2023 (has links)
holiness and other hauntings is a poetry collection that seeks to understand other people. Armstrong uses her poems to track herself back through time to her cousins, her parents, her grandparents, her teachers, and friends. Her work explores queerness and Catholicism, family fraught and family found, love and grief and guilt and ghosts. Her poems lean towards music; internal rhyme, assonance and consonance, alliteration, and long strings of rhymed vowels that sit like pearls in the mouth. Her poems beg forgiveness in shouts; she writes as remembrance, as prayer, as missive, as an engine for hope. / Master of Fine Arts / holiness and other hauntings is a poetry collection.
103

Path integral Monte Carlo. Algorithms and applications to quantum fluids

Brualla Barberà, Llorenç 11 July 2002 (has links)
Path integral Monte Carlo (PIMC) is a method suitable for quantum liquid simulations at finite temperature. We present in this thesis a study of PIMC dealing with the theory and algorithms related to it, and then two applications of PIMC to current research problems of quantum fluids in the Bolzmann regime. The first part encompasses a study of the different ingredients of a PIMC code: action, sampling and physical property estimators. Particular attention has been paid to Li-Broughton's higher order approximation to the action. Regarding sampling, several collective movement methods have been derived, including the bisection algorithm, that has been thoroughly tested. We also include a study of estimators for different physical properties, such as, the energy (through the thermodynamic and virial estimators), the pair distribution function, the structure factor, and the momentum distribution. In relation to the momentum distribution, we have developed a novel algorithm for its estimation, the trail method. It surmounts some of the problems exposed by previous approaches, such as the open chain method or McMillan's algorithm.The Richardson extrapolation used within PIMC simulations, is another contribution of this thesis. Up until now, this extrapolation has not been used in this context. We present studies of the energy dependence on the number of "beads", along with the betterment provide by the Richardson extrapolation. Inasmuch as our goal is to perform research of quantum liquids at finite temperature, we have produced a library of codes, written from scratch, that implement most of the features theoretically developed. The most elaborated parts of these codes are included in some of the appendixes.The second part shows two different applications of the algorithms coded. We present results of a PIMC calculation of the momentum distribution of Ne and normal 4He at low temperatures. In the range of temperatures analysed, exchanges can be disregarded and both systems are considered Boltzmann quantum liquids. Their quantum character is well reflected in their momentum distributions witch show clear departures from the classical limit. The PIMC momentum distributions which show clear departures from the classical limit. The PIMC momentum distributions are sampled using the trail method. Kinetic energies of both systems, as a function of temperature and at a fixed density, are also reported. Finally, the solid-liquid neon phase transition along the 35 K isotherm has been characterized.While thermodynamic properties of the solid phase are well known the behaviour of some properties, such as the energy or the dessity, during the trasition presen6 some uncertainties For example, experimental data for the place diagram, which determines solid and liquid boundaries, present sizeable differences. The temperature chosen is high enough so that Bose or Fermi statistics corrections are small, although the system is strongly quantum mechanical. The results obtained show a discontinuity in the kinetic energy during the transition.
104

Measurement of the beta-neutrino correlation in laser trapped {sup 21}Na

Scielzo, Nicholas David January 2003 (has links)
Thesis (Ph.D.); Submitted to Univ. of California, Berkeley, CA (US); 1 Jun 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--54350" Scielzo, Nicholas David. USDOE Director. Office of Science. Nuclear Physics (US) 06/01/2003. Report is also available in paper and microfiche from NTIS.
105

Monte Carlo quântico aplicado ao estudo do comportamento quântico-clássico do Neônio / Monte carlo qapplied to study quantum-classic behavior of nein

CARVALHO, Thiago Milograno de 20 February 2009 (has links)
Made available in DSpace on 2014-07-29T15:07:09Z (GMT). No. of bitstreams: 1 Dissertacao Thiago Milograno.pdf: 1110506 bytes, checksum: 08596b9630b30f983f7a8e9f0777f92d (MD5) Previous issue date: 2009-02-20 / In this work we have applied Quantum Monte Carlo method at finite temperature known as Path Integral Monte Carlo (PIMC) to study the quantum-classical behavior of the Neon. We have calculated the one body density matrix as well as the atomic momentum distribution which have shown to be significantly different from the classical Maxwell- Boltzmman distribution in the range of densities and temperatures studied. The deviations from a classical gaussian are substantial but it decreases as one goes to temperatures above T = 35 K or densities below p = 20 nm−3. Furthermore, at low temperature the results show that there are more low momentum atoms than in a classical gaussian distribution. / Neste trabalho aplicamos o método de Monte Carlo Quântico à temperatura finita conhecido como Path Integral Monte Carlo (PIMC) a fim de estudar o comportamento quântico-clássico do Neônio. Calculamos a matriz densidade de um corpo, bem como a distribuição de momento atômica que mostrou ser significativamente diferente da distribuição clássica de Maxwell-Boltzmann nos intervalos de densidade e temperatura estudados. Os desvios de uma gaussiana clássica são substanciais porém esses desvios diminuem para temperaturas acima de T = 35 K ou densidades abaixo de p= 20 nm−3. Além disso, para baixas temperaturas os resultados mostram que há mais átomos com momentos menores do que na distribuição clássica gaussiana.
106

Correlation of Watershed NDVI Values to Benthic Macroinvertebrate Biodiversity in Eight North American Wadeable Streams

Gallagher, Denice Lynne 05 1900 (has links)
Water quality of a stream or river is influenced by the surrounding landscape and vegetation. The Normalized Difference Vegetation Index (NDVI) is commonly used to characterize landcover and vegetation density. Benthic macroinvertebrates are ubiquitous in freshwater streams and are excellent indicators of the quality of freshwater habitats. Data from one NDVI remote sensing flight and one macroinvertebrate sampling event for eight wadeable stream study sites in the National Ecological Observatory Network (NEON) were acquired. Proportions of high, moderate, and sparse vegetation were calculated for each stream watershed using ArcGIS. Functional feeding groups and tolerance values were assigned to macroinvertebrate taxa. The Fourth-corner and RLQ methods of analysis, available in the ade4 package for R software, were used to evaluate the relationships of macroinvertebrate traits with environmental variables. Hypothesis testing using Model 6 in the ade4 package resulted in p-values of 0.066 and 0.057 for global (overall) significance. Mean NDVI values of moderately vegetated areas and proportion of sparse vegetation were found to be significant to percent shredders at alpha ≤ 0.05. Results of these methods of analysis, when combined with traditional macroinvertebrate sampling metrics, show that NDVI can be a useful, additional tool to characterize a watershed and its effects on macroinvertebrate community composition and structure.
107

<i>Sekai-kei</i> as Existentialist Narrative: Positioning <i>Xenosaga</i> within the Genre Framework.

Thomas, Stefanie 09 July 2014 (has links)
No description available.
108

Décélération Zeeman-Stern Gerlach d’un jet supersonique de particules paramagnétiques par une onde de champ magnétique progressive / Zeeman-Stern Gerlach deceleration of supersonic beams of paramagnetic particles with traveling waves of magnetic field

Trimeche, Azer 17 December 2013 (has links)
Ce travail porte sur l’étude et la réalisation d’une nouvelle technique de décélération d’un jet supersonique de particules paramagnétiques en utilisant une onde de champ magnétique progressive co-mobile. Cette technique repose sur une méthode de ralentissement basée sur les forces de type Stern Gerlach agissant sur un système paramagnétique en mouvement en présence d’un champ magnétique co-propageant. Cette méthode très innovatrice a l’avantage de pouvoir s’appliquer à une grande palette d’espèces ouvrant ainsi de nouvelles possibilités d’applications. On décrit une approche théorique adaptée qui permet de faire un lien direct entre la théorie, la programmation des paramètres expérimentaux, les résultats obtenus et ce d’une manière systématique, rationnelle et prédictive.Ce mémoire est composé de trois parties. La première porte sur les forces décélératrices et le calcul des différentes forces, de type Stern Gerlach, utilisées dans nos expériences. Les formules établies dans cette partie sont essentielles pour l’interprétation des résultats expérimentaux. La deuxième partie porte sur le dispositif expérimental : le jet supersonique pré-refroidi, la zone d’interaction et la détection. On donne le détail de la réalisation des circuits créant les champs magnétiques nécessaires au guidage et à la décélération du jet. La troisième partie porte sur les résultats des expériences réalisées et leur interprétation directement à partir des équations du mouvement de l’effet Stern Gerlach. Des simulations sont présentées pour étayer les interprétations. On présente les résultats de décélération obtenus récemment sur l’argon et le néon métastables. Ces résultats valident clairement l’importance de l’ajout d’un champ magnétique uniforme qui définit un axe de quantification adiabatique global pour toutes les particules du jet et permet le découplage entre la précession des moments magnétiques et l’action des forces de gradient. Ces résultats mettent en évidence, aussi, l’effet de polarisation du jet qui dépend du sens relatif du champ magnétique uniforme ajouté par rapport à l’onde de champ magnétique progressive.Enfin, la compréhension et le contrôle de la dynamique du piégeage à une vitesse donnée, de l’accélération et de la décélération nécessitent le découplage entre les effets transverses et les effets longitudinaux de l’onde. Ces derniers sont clairement visibles quand le champ magnétique uniforme ajouté vient limiter les effets transverses de l’onde de champ magnétiques progressive. Les perspectives pour ce nouveau décélérateur Zeeman Stern Gerlach sont grandes. Un premier résultat de piégeage du di-azote métastable à 560m/s est présenté et ceci ouvre la voie pour décélérer les molécules paramagnétiques en jet supersonique pulsé. La décélération des radicaux libres et des neutrons est aussi envisageable. / This work focuses on the study and implementation of a new technique of deceleration of a supersonic beam of paramagnetic particles using a co-moving progressive wave of magnetic field. This technique relies on a method of slowing based on Stern-Gerlach forces acting on a paramagnetic system in motion in the presence of a co-propagating magnetic field. This highly innovative approach has the advantage of being applicable to a wide range of species and opens up new opportunities. A suitable theoretical approach is followed, that allows for a direct link between theory, programming of experimental parameters, and experimental results in a systematic, rational and predictive manner.This thesis is composed of three parts. The first concerns the calculation of the various Stern Gerlach forces used in our experiments to decelerate the paramagnetic particles. Formulas established in this section are essential for the interpretation of experimental results. The second part is devoted to the experimental device: the creation of the cooled supersonic beam, interaction zone and detection. A separate chapter is devoted to the detailed description of the different setups of coils used to create the magnetic fields necessary to guide and to decelerate the particles of the beam.The third part is devoted to the experimental results and their direct interpretation using the equations of motion in Stern Gerlach forces. Simulations are presented to embody the interpretations. We present results about the deceleration of metastable argon and neon atoms. These results validate the significance of the addition of a uniform magnetic field defining a global adiabatic quantization axis for all the particles in the beam. This realizes the decoupling between the precession of the magnetic moments and Stern Gerlach forces. The results demonstrate the polarization effect of the beam that depends on the direction of the added uniform magnetic field relative to the progressive wave of the magnetic field.Finally, the understanding and control of the dynamics of trapping at a given speed, acceleration and deceleration require decoupling between the transverse and longitudinal effects of the wave. These effects are clearly visible when the added uniform magnetic field limits the transverse effects of the progressive wave of magnetic field. The outlooks for the new Zeeman Stern Gerlach decelerator are numerous. A first result of trapping di-nitrogen metastable at 560m/s is presented and the road is open to decelerate paramagnetic molecules in pulsed supersonic jet. Deceleration free radicals and neutrons are also possible.
109

Desenvolvimento de uma metodologia baseada no modelo de Duas-Regiões e em técnicas de análise de ruído microscópico para a medida absoluta dos parâmetros cinéticos &beta;eff, &Lambda; e &beta;eff/&Lambda; do reator IPEN/MB-01

Kuramoto, Renato Yoichi Ribeiro 02 April 2007 (has links)
Uma nova metodologia para a medida absoluta da fração efetiva de nêutrons atrasados &beta;eff, baseada em técnicas de análise de ruído microscópico e no modelo de Duas- Regiões, foi desenvolvida no reator IPEN/MB-01. Diferentemente das demais técnicas, tais como o Método de Bennet Modificado, o Método do Número de Nelson e o Método da fonte de 252Cf, a principal vantagem da metodologia proposta é a obtenção de &beta;eff de um modo puramente experimental, sem a necessidade de quaisquer outros parâmetros, sejam estes calculados ou provenientes de outros experimentos. Com a finalidade de validar este novo método, uma série de experimentos Rossi-&alpha; e Feynman-&alpha; foram realizados no reator IPEN/MB-01. De acordo com a metodologia proposta, &beta;eff foi estimado com uma incerteza de 0.67%, a qual atende aos requisitos de precisão almejados. Além disso, o tempo de geração de nêutrons prontos , dentre outros parâmetros, também foi obtido experimentalmente via esta metodologia. Em geral, os parâmetros medidos estão em acordo com resultados provenientes de experimentos de análise de ruído macroscópico. Nas comparações teoria-experimento, os valores de &beta;eff medidos neste trabalho mostram que a biblioteca JENDL3.3 apresenta a melhor performance (dentro de 1%). Esta concordância justifica a redução no yield de fissão do 235U proposta por Sakurai e Okajima. / A new method for absolute measurement of the effective delayed neutron fraction, &beta;eff , based on microscopic noise experiments and the Two-Region Model was developed at the IPEN/MB-01 Research Reactor facility. In contrast with other techniques like the Modified Bennet Method, Nelson-Number Method and 252Cf-Source Method, the main advantage of this new methodology is to obtain the effective delayed neutron parameters in a purely experimental way, eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-&alpha; and Feynman-&alpha; experiments for validation of this method were performed at the IPEN/MB-01 facility, and adopting the present approach, &beta;eff was measured with a 0.67% uncertainty. In addition, the prompt neutron generation time, , and other parameters were also obtained in an absolute experimental way. In general, the final results agree well with values from frequency analysis experiments. The theory-experiment comparison reveals that JENDL-3.3 shows deviation for &beta;eff lower than 1% which meets the desired accuracy for the theoretical determination of this parameter. This work supports the reduction of the 235U thermal yield as proposed by Okajima and Sakurai.
110

Desenvolvimento de uma metodologia baseada no modelo de Duas-Regiões e em técnicas de análise de ruído microscópico para a medida absoluta dos parâmetros cinéticos &beta;eff, &Lambda; e &beta;eff/&Lambda; do reator IPEN/MB-01

Renato Yoichi Ribeiro Kuramoto 02 April 2007 (has links)
Uma nova metodologia para a medida absoluta da fração efetiva de nêutrons atrasados &beta;eff, baseada em técnicas de análise de ruído microscópico e no modelo de Duas- Regiões, foi desenvolvida no reator IPEN/MB-01. Diferentemente das demais técnicas, tais como o Método de Bennet Modificado, o Método do Número de Nelson e o Método da fonte de 252Cf, a principal vantagem da metodologia proposta é a obtenção de &beta;eff de um modo puramente experimental, sem a necessidade de quaisquer outros parâmetros, sejam estes calculados ou provenientes de outros experimentos. Com a finalidade de validar este novo método, uma série de experimentos Rossi-&alpha; e Feynman-&alpha; foram realizados no reator IPEN/MB-01. De acordo com a metodologia proposta, &beta;eff foi estimado com uma incerteza de 0.67%, a qual atende aos requisitos de precisão almejados. Além disso, o tempo de geração de nêutrons prontos , dentre outros parâmetros, também foi obtido experimentalmente via esta metodologia. Em geral, os parâmetros medidos estão em acordo com resultados provenientes de experimentos de análise de ruído macroscópico. Nas comparações teoria-experimento, os valores de &beta;eff medidos neste trabalho mostram que a biblioteca JENDL3.3 apresenta a melhor performance (dentro de 1%). Esta concordância justifica a redução no yield de fissão do 235U proposta por Sakurai e Okajima. / A new method for absolute measurement of the effective delayed neutron fraction, &beta;eff , based on microscopic noise experiments and the Two-Region Model was developed at the IPEN/MB-01 Research Reactor facility. In contrast with other techniques like the Modified Bennet Method, Nelson-Number Method and 252Cf-Source Method, the main advantage of this new methodology is to obtain the effective delayed neutron parameters in a purely experimental way, eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-&alpha; and Feynman-&alpha; experiments for validation of this method were performed at the IPEN/MB-01 facility, and adopting the present approach, &beta;eff was measured with a 0.67% uncertainty. In addition, the prompt neutron generation time, , and other parameters were also obtained in an absolute experimental way. In general, the final results agree well with values from frequency analysis experiments. The theory-experiment comparison reveals that JENDL-3.3 shows deviation for &beta;eff lower than 1% which meets the desired accuracy for the theoretical determination of this parameter. This work supports the reduction of the 235U thermal yield as proposed by Okajima and Sakurai.

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