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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.
31

Um controle de versões refinado e flexível para artefatos de software / Flexible and fine-grained version control for software artifacts

Junqueira, Daniel Carnio 07 January 2008 (has links)
As atividades de controle de versões são consideradas essenciais para a manutenção de sistemas de computador. Elas começaram a ser realizadas na década de 1950 de forma manual. As primeiras ferramentas de controle de versões, que surgiram nos anos setenta, não evoluíram significativamente desde sua criação e, até hoje, o controle de versões de arquivos é geralmente realizado em arquivos ou mesmo módulos completos, utilizando os conceitos que foram lançados há mais de três décadas. Com a popularização da utilização de sistemas computacionais, ocorreu um sensível aumento no número de sistemas existentes e, também, na complexidade dos mesmos. Além disso, muitas alterações ocorreram nos ambientes de desenvolvimento de software, e existe demanda por sistemas que permitam aos desenvolvedores ter cada vez mais controle automatizado sobre o que está sendo desenvolvido. Para isso, algumas abordagens de controle de versões refinados para artefatos de software foram propostas, mas, muitas vezes, não oferecem a exibilidade de utilização exigida pelos ambientes de desenvolvimento de software. Neste trabalho, é apresentado um sistema que visa a fornecer suporte ao controle de versões refinado e flexível para artefatos de software, tendo por base um modelo bem definido para representação das informações da estrutura dos arquivos que compõem determinado projeto de software, sejam eles código-fonte dos programas de computador, documentação criada em Latex, arquivos XML, entre outros. O sistema apresentado foi projetado para ser integrado com outras soluções utilizadas em ambientes de desenvolvimento de software / Version control tasks are considered essential for the maintenance of computers systems. They have been done since beginning of 50\'s in a by hand manner. First tools, which were released in 70\'s, didn\'t evolve significantly since its creation, and, in general, version control systems still work with entire files or even modules of software, having the same concepts that were launched more than three decades ago. With the popularization of computers systems there had been a sensible increase in the number of existing systems and also in the complexity of these systems. Besides that many changes have taken place in the software development environments, and there is demand for systems which allow developers to have more automated control about what is being developed. Regard to this demand some approaches of fine-grained version control have been proposed, but they usually do not provide the required exibility for its use in the real software development environments. In this work its presented a system which aims at providing support for exible and fine-grained version control of software artifacts, using a well defined model to represent the logical structure of the files which compose a software project, independently of its type - they can be XML files, source-code files, Latex files and others. The system has been designed to be integrated with other software solutions used in software development environments
32

Resource variation and the evolution of phenotypic plasticity in fishes

Ruehl, Clifton Benjamin 30 September 2004 (has links)
Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation. One successful evolutionary strategy to mitigate environmental variation is phenotypic plasticity: the production of alternative phenotypes in response to environmental variation. Phenotypic plasticity yields multiple characters that may enable organisms to better optimize phenotypic responses across environmental gradients. In this thesis, I trace the development of thought on phenotypic plasticity and present two empirical studies that implicate phenotypic plasticity in producing morphological variation in response to resource variation. The first empirical study addresses trophic plasticity, population divergence, and the effect of fine-scale environmental variation in western mosquitofish (Gambusia affinis). Offspring from two populations were fed either attached or unattached food items offered in three orientations: (1) water surface, (2) mid-water, (3) benthic, and (4) a daily rotation of the former three (fine-grained variation). Attached food induced wide heads, blunt snouts and rounded pectoral fins relative to morphology in the unattached treatment. Mid-water feeding induced elongated heads and deeper mid-bodies relative to benthic and surface feeding induced morphologies. The rotating treatment produced intermediate morphologies. Population divergence seemed related to both trophic and predation ecology. Ecomorphological consequences of induced morphologies and the need for inclusion of greater ecological complexity in studies of plasticity are discussed. The second study examines induced morphological plasticity and performance in red drum (Sciaenops ocellatus). I fed hatchery fish either hard or soft food for two months. Performance trials were designed to measure their ability to manipulate and consume hard food items. External morphology and the mass of pharyngeal crushing muscles were assessed for variation among treatments. A hard food diet induced deeper bodies and larger heads, more massive pharyngeal muscles, and initially more efficient consumption of hard food than fish receiving soft food. The observed morphological variation is in accordance with variation among species. Determining evolutionary mechanisms operating within red drum populations should eventually aid in developing and optimizing conservation efforts and ease the transition from hatchery facilities to estuaries.
33

Resource variation and the evolution of phenotypic plasticity in fishes

Ruehl, Clifton Benjamin 30 September 2004 (has links)
Resource variation and species interactions require organisms to respond behaviorally, physiologically, and morphologically within and among generations to compensate for spatial and temporal environmental variation. One successful evolutionary strategy to mitigate environmental variation is phenotypic plasticity: the production of alternative phenotypes in response to environmental variation. Phenotypic plasticity yields multiple characters that may enable organisms to better optimize phenotypic responses across environmental gradients. In this thesis, I trace the development of thought on phenotypic plasticity and present two empirical studies that implicate phenotypic plasticity in producing morphological variation in response to resource variation. The first empirical study addresses trophic plasticity, population divergence, and the effect of fine-scale environmental variation in western mosquitofish (Gambusia affinis). Offspring from two populations were fed either attached or unattached food items offered in three orientations: (1) water surface, (2) mid-water, (3) benthic, and (4) a daily rotation of the former three (fine-grained variation). Attached food induced wide heads, blunt snouts and rounded pectoral fins relative to morphology in the unattached treatment. Mid-water feeding induced elongated heads and deeper mid-bodies relative to benthic and surface feeding induced morphologies. The rotating treatment produced intermediate morphologies. Population divergence seemed related to both trophic and predation ecology. Ecomorphological consequences of induced morphologies and the need for inclusion of greater ecological complexity in studies of plasticity are discussed. The second study examines induced morphological plasticity and performance in red drum (Sciaenops ocellatus). I fed hatchery fish either hard or soft food for two months. Performance trials were designed to measure their ability to manipulate and consume hard food items. External morphology and the mass of pharyngeal crushing muscles were assessed for variation among treatments. A hard food diet induced deeper bodies and larger heads, more massive pharyngeal muscles, and initially more efficient consumption of hard food than fish receiving soft food. The observed morphological variation is in accordance with variation among species. Determining evolutionary mechanisms operating within red drum populations should eventually aid in developing and optimizing conservation efforts and ease the transition from hatchery facilities to estuaries.
34

Μηχανισμός πρόσβασης για υπηρεσίες ιστού (web services) για βιομηχανικές εφαρμογές

Κατσαρού, Κατερίνα 22 January 2009 (has links)
Η διπλωματική εργασία ασχολείται με την ανάγκη για έναν προηγμένο μηχανισμό ασφάλειας που θα παρέχει προστασία πληροφοριών από τους μη εξουσιοδοτημένους χρήστες. Τα περισσότερα συστήματα σε εταιρικό και βιομηχανικό επίπεδο χρησιμοποιούν την απλή εξουσιοδότηση (simple authorization) ή all-or-nothing όπου έχουμε παραχώρηση πρόσβασης στους πόρους του συστήματος εάν ο χρήστης είναι εξουσιοδοτημένος ή εάν δεν είναι άρνηση πρόβλεψης χωρίς να έχει προβλεφθεί κάποια ενδιάμεση λύση. Στην περίπτωση του ελέγχου πρόσβασης για υπηρεσίες Ιστού (web services) –που είναι εφαρμογές που παρέχονται μέσω Διαδικτύου όπως φαίνεται και από το όνομά τους- δεν είναι ικανοποιητική η παραχώρηση πρόσβασης σε ολόκληρη την υπηρεσία Ιστού δηλαδή η πρόσβαση στο υψηλότερο επίπεδο (coarse-grained access control) αλλά απαιτείται και η πρόσβαση σε κάποια ή κάποιες από τις μεθόδους την υπηρεσίας Ιστού δηλαδή η διαβαθμισμένη πρόσβαση (fine-grained access control). Η πολιτική ελέγχου πρόσβασης που χρησιμοποιήσαμε είναι ο έλεγχος πρόσβασης βασισμένος σε ρόλους (Role-based Access Control) όπου οι χρήστες αποκτούν πρόσβαση στους προστατευόμενους πόρους (μια ολόκληρη υπηρεσία Ιστού ή μέθοδο) συνδεόμενοι με ρόλους με τις κατάλληλες άδειες πρόσβασης δηλαδή μόνο εξουσιοδοτημένοι χρήστες έχουν πρόσβαση στους προστατευόμενους πόρους. Τέλος υποθέσαμε μία βιομηχανική υποδομή που παρέχει σε πελάτες πρόσβαση μέσω ενός OPC XML-DA server όπου το OPC είναι ένα σύνολο από ανοικτά πρότυπα που παρέχουν δια-λειτουργικότητα (interoperability) και συνδεσιμότητα (connectivity) μεταξύ βιομηχανικού αυτοματισμού και επιχειρησιακών συστημάτων. / -
35

FieSta: An approach for Fine-Grained Scope Definition, Configuration and Derivation of Model-Driven Software Product Lines

Arboleda, Hugo 28 October 2009 (has links) (PDF)
We present an approach based on Model-Driven Development ideas to create Software Product Lines(SPLs). In Model-Driven SPL approaches, the derivation of a product starts from a domain application model. This model is transformed through several stages reusing model transformation rules until a product is obtained. Transformations rules are selected according to variants included in configurations created by product designers. Configurations include variants from variation points, which are relevant characteristics representing the variability of a product line. Our approach (1) provides mechanisms to improve the expression of variability of Model-Driven SPLs by allowing designers to create fine-grained configurations of products, and (2) integrates a product derivation process which uses decision models and Aspect-Oriented Programming facilitating the reuse, adaptation and composition of model transformation rules. We introduce constraint models which make it possible for product line architects to capture the scope of product lines using the concepts of constraint, cardinality property and structural dependency property. To configure products, we create domain models and binding models, which are sets of bindings between model elements and variants and satisfy the constraint models. We define a decision model as a set of aspects. An aspect maintains information of what and when transformations rules that generate commonalities of products must be intercepted (joinpoints) and what transformation rules (advices) that generate variable structures must be executed instead. Our strategy maintains uncoupled variants from model transformation rules. This solves problems related to modularization, coupling, flexibility and maintainability of transformations rules because they are completely separated from variants; thus, they can evolve independently.
36

Efficient graph algorithm execution on data-parallel architectures

Bangalore Lakshminarayana, Nagesh 12 January 2015 (has links)
Mechanisms for improving the execution efficiency of graph algorithms on Data-Parallel Architectures were proposed and identified. Execution of graph algorithms on GPGPU architectures, the prevalent data-parallel architectures was considered. Irregular and data dependent accesses in graph algorithms were found to cause significant idle cycles in GPGPU cores. A prefetching mechanism that reduced the amount of idle cycles by prefetching a data-dependent access pattern found in graph algorithms was proposed. Storing prefetches in unused spare registers in addition to storing them in the cache was shown to be more effective by the prefetching mechanism. The design of the cache hierarchy for graph algorithms was explored. First, an exclusive cache hierarchy was shown to be beneficial at the cost of increased traffic; a region based exclusive cache hierarchy was shown to be similar in performance to an exclusive cache hierarchy while reducing on-chip traffic. Second, bypassing cache blocks at both the level one and level two caches was shown to be beneficial. Third, the use of fine-grained memory accesses (or cache sub-blocking) was shown to be beneficial. The combination of cache bypassing and fine-grained memory accesses was shown to be more beneficial than applying the two mechanisms individually. Finally, the impact of different implementation strategies on algorithm performance was evaluated for the breadth first search algorithm using different input graphs and heuristics to identify the best performing implementation for a given input graph were also discussed.
37

Komplexní studium jemnozrnných polykrystalů Cu a slitiny CuZr připravených metodami equal channel angular pressing a high pressure torsion / Complex investigation of fine-grained polycrystals of Cu and CuZr alloy processed by equal channel angular pressing a high pressure torsion

Srba, Ondřej January 2012 (has links)
Title: Complex investigation of fine-grained polycrystals of Cu and CuZr alloy processed by equal channel angular pressing and high pressure torsion Author: RNDr.Ondřej Srba Department: Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University Prague Supervisor: Doc. RNDr. Miloš Janeček, CSc. Abstract: In the thesis the microstructure development, mechanical, elastic and corrosion properties of deformed specimens of pure Cu and binary alloy CuZr processed by equal channel angular pressing (ECAP) are investigated. Several properties of pure Cu processed by ECAP are compared with properties of the same material processed by high pressure torsion (HPT). The microstructure development is characterized in detail by several experimental techniques (light and electron microscopy, electron back scatter diffraction, positron annihilation spectroscopy, etc.). The microstructure development in specimens processed by ECAP is characterized by the continuous fragmentation of the initial coarse grain structure and the formation of new grains having the sizes in the submicrocrystalline range (of 460 nm and 260 nm in Cu and CuZr alloy, respectively). During the deformation by ECAP the fraction of high-angle grain boundaries, the dislocation density and the concentration of vacancies are...
38

Formation des chondres et relation avec leurs auréoles de matrice à grains fins / Chondrule formation and relation with their fine-grained rims

Soulié, Camille 10 December 2014 (has links)
Les météorites les plus primitives, appelées chondrites, sont les témoins privilégiés de la formation des premiers solides du système solaire et des processus qui ont conduit à la naissance des premiers corps planétaires. Les chondres, qui sont des sphérules ferromagnésiennes ignées, et leur matrice finement cristallisée constituent l’essentiel du volume des chondrites primitives. L’origine des chondres comme celle de la matrice est encore largement débattue. Cette thèse interroge les relations qui existent entre les chondres et la matrice à grains fins qui les auréole fréquemment, notamment dans les chondrites carbonées. En prenant l’exemple de la chondrite Vigarano (CV3) nous explorons la piste d’un continuum des conditions physico-chimiques pour former les chondres et leurs auréoles de matrice à grain fin. La thèse aborde cette problématique par une double approche : une approche expérimentale consacrée à la quantification des vitesses de dissolution de l’olivine dans des liquides silicatés caractéristiques des chondres de type I et une approche de caractérisation détaillée de la minéralogie, des fabriques et de la composition isotopique de l’oxygène des chondres et de leurs auréoles de matrice à grains fins dans Vigarano. Ces travaux suggèrent que chondre et matrice pourraient enregistrer une continuité d’interaction avec le gaz environnant, d’abord de type liquide/gaz (solubilité) pour la formation des chondres, puis de type solide/gaz (condensation) à plus basse température pour la formation des auréoles de matrice à grains fins / The most primitive meteorites, the chondrites, are our best witnesses of solar system birth and formation of first solids as well as processes that formed the first planetary bodies. Both chondrules, which are ferromagnesian igneous spherules, and fine-grained matrix, constitute the largest volume fraction of primitive chondrites. Their origin still constitutes a matter of debate. This thesis questions the relationship between chondrules and fine-grained matrix, called fine-grained rims, that frequently overlay chondrules in primitive carbonaceous chondrites. By taking the example of Vigarano (CV3), we explore the idea that chondrules and fine-grained rims could form in a continuum of physical and chemical conditions. This thesis combines both experimental and characterization approaches, with an experimental determination of olivine dissolution rates in molten silicates representative of type I chondrule melts and a detailed petrographic characterization of mineralogy, fabrics and oxygen isotopic composition of chondrules and their fine-grained rims in Vigarano. This work suggests that chondrules and their fine-grained rims could register a continuous interaction with surrounding gas, with first, chondrule formation from liquid/gas interaction (solubility) and then fine-grained rim formation, at lower temperature and from solid/gas interaction (condensation)
39

Um controle de versões refinado e flexível para artefatos de software / Flexible and fine-grained version control for software artifacts

Daniel Carnio Junqueira 07 January 2008 (has links)
As atividades de controle de versões são consideradas essenciais para a manutenção de sistemas de computador. Elas começaram a ser realizadas na década de 1950 de forma manual. As primeiras ferramentas de controle de versões, que surgiram nos anos setenta, não evoluíram significativamente desde sua criação e, até hoje, o controle de versões de arquivos é geralmente realizado em arquivos ou mesmo módulos completos, utilizando os conceitos que foram lançados há mais de três décadas. Com a popularização da utilização de sistemas computacionais, ocorreu um sensível aumento no número de sistemas existentes e, também, na complexidade dos mesmos. Além disso, muitas alterações ocorreram nos ambientes de desenvolvimento de software, e existe demanda por sistemas que permitam aos desenvolvedores ter cada vez mais controle automatizado sobre o que está sendo desenvolvido. Para isso, algumas abordagens de controle de versões refinados para artefatos de software foram propostas, mas, muitas vezes, não oferecem a exibilidade de utilização exigida pelos ambientes de desenvolvimento de software. Neste trabalho, é apresentado um sistema que visa a fornecer suporte ao controle de versões refinado e flexível para artefatos de software, tendo por base um modelo bem definido para representação das informações da estrutura dos arquivos que compõem determinado projeto de software, sejam eles código-fonte dos programas de computador, documentação criada em Latex, arquivos XML, entre outros. O sistema apresentado foi projetado para ser integrado com outras soluções utilizadas em ambientes de desenvolvimento de software / Version control tasks are considered essential for the maintenance of computers systems. They have been done since beginning of 50\'s in a by hand manner. First tools, which were released in 70\'s, didn\'t evolve significantly since its creation, and, in general, version control systems still work with entire files or even modules of software, having the same concepts that were launched more than three decades ago. With the popularization of computers systems there had been a sensible increase in the number of existing systems and also in the complexity of these systems. Besides that many changes have taken place in the software development environments, and there is demand for systems which allow developers to have more automated control about what is being developed. Regard to this demand some approaches of fine-grained version control have been proposed, but they usually do not provide the required exibility for its use in the real software development environments. In this work its presented a system which aims at providing support for exible and fine-grained version control of software artifacts, using a well defined model to represent the logical structure of the files which compose a software project, independently of its type - they can be XML files, source-code files, Latex files and others. The system has been designed to be integrated with other software solutions used in software development environments
40

Genetické algoritmy – implementace paralelního zpracování / Genetic Algorithms - Implementation of Multiprocessing

Tuleja, Martin January 2018 (has links)
Genetic algorithms are modern algorithms intended to solve optimization problems. Inspiration originates in evolutionary principles in nature. Parallelization of genetic algorithms provides not only faster processing but also new and better solutions. Parallel genetic algorithms are also closer to real nature than their sequential counterparts. This paper describes the most used models of parallelization of genetic algorithms. Moreover, it provides the design and implementation in programming language Python. Finally, the implementation is verified in several test cases.

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