• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 102
  • 39
  • 29
  • 28
  • 22
  • 19
  • 7
  • 6
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • Tagged with
  • 309
  • 49
  • 39
  • 26
  • 24
  • 20
  • 19
  • 18
  • 17
  • 17
  • 17
  • 17
  • 16
  • 16
  • 15
  • 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.
121

Ensaio clínico comparando os usos de heparina e MEDTA como selo de cateter de hemodiálise / Clinical trial comparing the use of heparin and MEDTA as a hemodialysis catheter lock

Miltersteiner, Diego da Rosa January 2010 (has links)
Introdução: Sepse relacionada ao cateter é a principal causa de hospitalizações e a segunda causa de morte em pacientes com insuficiência renal crônica em hemodiálise. O uso de medicações que possam diminuir a incidência de bacteremia relacionada ao cateter parece uma alternativa para diminuir o número de eventos. Objetivo: Comparação do uso de heparina contra minociclina e edetato dissódico (MEDTA) como selo de cateter de longa permanência em pacientes com insuficiência renal crônica em hemodiálise, comparando desfecho de sobrevida de cateter em relação ao tempo livre de bacteremias, alterações de fluxo, necessidade de trombolítico e cultura positiva de material de descarte. Método: Ensaio clínico, randomizado, multicêntrico, aberto, controlado, comparativo entre heparina e MEDTA. Resultados: 28 pacientes foram incluídos no total do estudo (14 no grupo heparina e 14 no grupo MEDTA). Os grupos não apresentaram diferenças estatisticamente significativas em relação à idade, sexo, níveis de albumina e hemoglobina, tempo de permanência de cateter, alterações de fluxo do cateter (fluxo < 250mL/min) e necessidade de uso de trombolítico. O grupo MEDTA apresentou significativamente menos episódios de bacteremia e menor número de culturais de material de descarte positivos (P< 0,05). Conclusões: O uso de MEDTA como selo parece diminuir a incidência de bacteremias em pacientes com insuficiência renal crônica em hemdiálise emuso de acesso vascular por cateter, apresentando índices semelhantes de patência de cateter. / Introduction: Catheter-related sepsis is the leading cause of hospitalization and the second cause of death in patients with chronic renal failure undergoing hemodialysis. The use of medications that can reduce the incidence of catheter-related bacteremia seems as an alternative to reduce the number of events. Objective: Comparison of heparin against minocycline and disodium edetate (MEDTA) as a tunneled catheter lock in patients with chronic renal failure on hemodialysis, comparing outcome of catheter survival over time free survival time of bacteremia, flow alterations, need of thrombolytic therapy and positive culture of material from discard. Method: Clinical trial, randomized, multicenter, open, controlled comparative between heparin and MEDTA. Results: 28 patients were included in the overall study (14 in the heparin group and 14 in MEDTA group). The groups showed no statistically significant differences regarding age, sex, albumin and hemoglobin levels, length of catheter, catheter flow changes (flow <250mL/min) and required use of thrombolytic therapy. MEDTA group had significantly fewer episodes of bacteremia and fewer positive cultural of discarded material (P <0.05). Conclusions: The use of MEDTA as a catheter lock appears to decrease the incidence of bacteremia in patients with chronic renal failure in hemdiálise inuse vascular access catheter, showing similar rates of patency of the catheter.
122

Molntjänster och molnleverantörer : En uppsats om leverantörsinlåsningar

Hajdarevic, Demir, Frimanson, Per January 2014 (has links)
Det finns många fördelar med att använda molntjänster och molnmarknaden har växt fort de senaste åren. Men när molnleverantörsmarknaden är så pass konkurrens utsatt är det inte lätt att välja vem man vill vända sig till, och det finns ofta anledningar till att vilja byta leverantör. Det finns många saker som kan låsa in en kund hos en leverantör, ofta på grund av att det skulle bli alldeles för dyrt att flytta, kanske för att ditt system inte är kompatibelt med någon annan leverantör, eller för att ett avtal hindrar dig från att flytta delar av systemet. Detta är vad man brukar kalla för leverantörsinlåsningar (vendor lock-ins). Många vill idag flytta system till molnet, men få är tillräckligt kunniga i vad det innebär och vad som kommer krävas från kunden. I den här studien vill vi belysa problemet och erbjuda vägledning till hur man kan minimera leverantörsinlåsningar.
123

Modéliser l’effet des biais cognitifs sur les dynamiques industrielles : innovation orpheline et architecte de l’inconnu / Modeling the impact of cognitive biases on industrial dynamics : Orphaninnovation and architect of the unknown

Agogué, Marine 15 October 2012 (has links)
L'objet de la thèse est l'étude des dynamiques industrielles, en particulier des biais cognitifs qui conduisent au blocage de ces dynamiques. Si les processus d'innovation dépassant le cadre de l'entreprise ont fait l'objet de diverses recherches, les dynamiques industrielles sont restées peu étudiées sous l'angle du blocage cognitif dans les activités de conception. Pour approfondir cette question, la thèse se focalise sur l'étude d'une phénoménologie nouvelle, l'innovation orpheline, définie comme une innovation très attendue par la société, mais qu'aucun acteur ou consortium d'acteurs n'est capable de générer, alors que les conditions traditionnelles pour favoriser son émergence sont réunies. L'enjeu de la thèse est de répondre à trois questions: Quelle modélisation pour cerner les facteurs causaux de l'innovation orpheline ? ; Quel outil pour diagnostiquer les biais cognitifs dans une situation empirique ? ; Quelles modalités organisationnelles pour sortir de l'innovation orpheline ?Cette démarche a permis de dégager trois résultats principaux :1) un modèle de la fixation cognitive collective, soulignant l'impact fort que peut avoir l'interaction entre les imaginaires singuliers au sein d'un collectif.2) un outil, le référentiel C-K pour identifier la fixation collective et pour diagnostiquer l'innovation orpheline.3) un modèle d'action pour un nouvel acteur, baptisé l'architecte de l'inconnu, en charge de stimuler les capacités de conception innovante de l'écosystème d'acteurs. / The purpose of the thesis is the study of industrial dynamics, in particular cognitive biases that lead to the lock-in of these dynamics. If innovation processes beyond the scope of the firm have been the subject of various studies, little has been done on the study of industrial dynamics from the perspective of cognitive lock in design activities. To explore this question, the thesis focuses on the study of a new phenomenology, orphan innovation, which is defined as orphan innovation as an innovation highly expected by society, but one which no actor or consortium of actors can manage to process with their current innovation capabilities, although all of the institutional conditions to foster it are gathered. The aim of the thesis is to answer three questions: How to model industrial dynamics and to identify causal factors of orphan innovation? How to build a tool to diagnose cognitive biases and orphan innovation in empirical situations? What are the organizational levers to overcome orphan innovation situations?The thesis then is based on three main results:1) a model of collective cognitive fixation, underlying the impact of imaginaries and their interactions among a collective action.2) a methodology to identify collective fixation and therefore to diagnose orphan innovation.3) a model of action for a new actor, called the architect of the unknown, in charge of stimulating innovative design capacities of the actors among the industry.
124

Choix d’investissement sous incertitude des gestionnaires des réseaux de distribution (GRD) en Europe à l’horizon 2030 / European Distribution System Operators’ (DSOs) investments choices under incertitude by 2030

Andaluz-Alcàzar, Alvaro 31 October 2012 (has links)
La distribution reste le segment du secteur de l’électricité le moins étudié. Mais les débats s’animent autour d’elle depuis deux ou trois ans quant aux changements structurels possibles du fait notamment de l’émergence amorcée ou annoncée des smart technologies: ils pourraient en effet remettre en cause dans les prochaines années les modèles d’affaires actuels des GRD et leur mode de régulation. Mais de nombreuses incertitudes pèsent sur leurs choix d’investissements. La thèse vise à anticiper les évolutions des modèles d’affaires des GRD en Europe à l’horizon 2030 en tenant compte des paramètres technologiques, macroéconomiques et géographiques. Elle propose une vision théorique et analytique originale, en introduisant tout d’abord la notion de « technologies à potentiel naturel » pour étudier le développement optimal de différentes technologies par contexte géographique et par scénario de référence. A partir de ces résultats, elle définit alors différentes évolutions possibles des activités de la distribution. Le croisement de ces futurs avec les différentes stratégies d’investissement envisageables pour les GRD permet de définir les futurs modèles d’affaires des GRD européens en fonction des combinaisons de smart technologies déployées et des contextes géographiques contrastés. Dans sa dernière partie, la thèse s’intéresse tout particulièrement aux changements prévisibles dans la relation GRD / régulateur sectoriel via une formalisation par la théorie des jeux. Enfin, en s’appuyant notamment sur les études théoriques de Brian Arthur, la thèse identifie les différents effets lock-in qui pourraient entraver l’émergence des smart technologies et les solutions possibles / Distribution activities have been the least studied domain of the electricity sector; over the last few years though, strong debates emerged with regards to the future. Indeed, this activity might soon undergo some deep structural changes, particularly as smart technologies are deployed: theses technologies could strongly impact the current business cases of the DSOs, along with the regulation now in effect, at a time when numerous uncertainties weigh on the distributors choices of investments. This thesis investigates the distributors’ business models evolutions in Europe for the next 20 years, based on technological, macroeconomic and geographical parameters. It proposes an original approach, both theoretical and analytical, to better understand the future world of DSOs. At first, it introduces the notion of “technologies with natural potential” in order to study the optimal development of the different technologies, by geographical context and macroeconomic scenarios. From these results, it then defines various possible evolutions of the distribution activities. Crossing these futures with the various possible investment strategies for the DSOs makes it possible to define the future business models of the European DSOs, according to various combinations of smart technologies displayed and contrasted geographical contexts. In its last part, the thesis studies the predictable changes in the relation DSO / regulator, using a formalization based on the Games Theory; this work is complemented by identifying the different lock-in effects (using the approach described in Brian Arthur’s studies) that could hinder the emergence of smart technologies, and the possible solutions
125

Modélisation hydromécanique du bois : application au sapin blanc du Massif Central / Hydromechanical modeling of wood : application to silver fir of the Massif Central

Nguyen, Sung Lam 12 July 2016 (has links)
Le présent travail porte sur la modélisation 3D du comportement hydromécanique du bois en général et du sapin blanc en particulier, avec la prise en compte des couplages entre les effets orthotrope, hydrique, élastique, viscoélastique et mécanosorptifs, y compris l’effet hygroverrou qui est un phénomène de blocage temporaire de la déformation en phase de séchage sous contrainte. Ce mémoire est scindé en trois grandes parties découpées en sept chapitres. La première partie examine le contexte et la problématique du comportement hydromécanique du bois. Les aspects traités vont de la structure, du phénomène hygroscopique et de l’effet de retrait/gonflement, aux divers aspects du comportement hydromécanique du bois sous humidité constante ou variable comme l’orthotropie, la viscoélasticité et les effets mécanosorptifs qui traduisent l’interaction complexe entre le chargement mécanique et les variations d’humidité. Les bases pour la modélisation sont présentées dans le deuxième chapitre, telles que la formulation incrémentale à pas de temps fini pour modéliser le comportement viscoélastique orthotrope 3D et les modèles mécanosorptifs intéressants de la littérature. A partir de cette étude bibliographique, on propose une voie pour modéliser dans ce travail l’effet mécanosorptif comme la somme de trois effets élémentaires : effet mécanosorptif irréversible, fluage mécanosorptif et effet hygroverrou. Les deux premiers effets sont modélisés par des modèles existants tandis que la modélisation de l’effet hygroverrou est l’objet d’une démarche originale dans ce travail. La deuxième partie, décomposée en deux chapitres, est consacrée à la construction du modèle de comportement 3D. Le premier chapitre présente les développements mathématiques pour l’élaboration d’un modèle analytique. Ce modèle est basé sur l’hypothèse de partition de la déformation totale en une somme de six déformations élémentaires : hydrique, élastique instantanée, viscoélastique pure, hygroverrou, mécanosorptive irréversible et de fluage mécanosorptif. Les variations de ces déformations élémentaires sont établies de manière séparée. En particulier, la loi d’évolution de la déformation hygroverrou construite sur la base d’observations expérimentales, est différente en phase de séchage et d’humidification. Une contrainte auxiliaire, introduite en respectant les principes thermodynamiques, permet de résoudre le problème de la récupération de la déformation hygroverrou en phase d’humidification en cas de contrainte nulle ou insuffisante. En parallèle, un nouveau modèlerhéologique est également proposé pour modéliser le comportement viscoélastique à humidité variable. Ce modèle, équivalent à un modèle de Maxwell généralisé et/ou à un modèle de Kelvin-Voigt généralisé, est capable de décrire le fluage aussi bien que la relaxation. Le deuxième chapitre de cette partie est consacré à la transformation du modèle analytique en une forme incrémentale à pas de temps fini. La contribution de chaque partie élémentaire est établie par résolution exacte à partir d’équations différentielles ou d’intégrales de Boltzmann. La somme des formes élémentaires ainsi obtenues conduit à la loi de comportement du modèle complet qui est similaire à celle d’un comportement thermo-élastique équivalent. Du fait de la procédure d’intégration, le pas de temps de calcul est fini mais pas nécessairement petit. Cette propriété est très importante car elle permet de réduire considérablement le temps de calcul tout en préservant une très bonne précision. La dernière partie est divisée en trois chapitres. Elle présente la mise en œuvre numérique du modèle hydromécanique à l’aide du code d’éléments finis Cast3m, suivie de la validation et d’applications à diverses classes de problèmes. L’algorithme numérique est organisé en modules indépendants. Des procédures élémentaires sont construites pour réaliser des fonctions spécifiques ; elles sont appelées selon un ordre précis par un programme principal. (...) / This work concerns 3D modeling of hydro-mechanical behavior of wood in general and the silver fir (Abies alba Mill.) in particular with taking account of the couplings between the effects: orthotropie, hydric, elastic, viscoelastic and mechano-sorptive including hydro-lock effect that is a temporary locking of the mechanical strain during a period of drying under stress. This memory is divided into three parts divided into seven chapters. The first part examines the background and the problem of hydro-mechanical behavior of wood. The aspects go from the structure, hygroscopic phenomenon and the effect of swelling/shrinkage, to various aspects of the hydro-mechanical behavior of wood under constant or variable moisture as orthotropie, viscoelasticity and mechano-sorptive effects that is the interaction complex between mechanical loading and moisture variations. The bases for modeling are presented in the second chapter, such as incremental formulation on finite time step to model the 3D orthotropic viscoelastic behavior and interesting mechano-sorptive models of literature. From this literature review, we propose a way to model in this work mechano-sorptive effect as the sum of three elementary effects: irrecoverable mechanosorptive, mechano-sorptive creep and hydro-lock effect. The first and the second effects are modeled by existing models while modeling hygroverrou effect is an original subject in this work. The second part, divided into two chapters, is dedicated to building the 3D model of behavior. The first chapter presents the mathematical developments for the development of an analytical model. This model is based on the assumption partition of the total strain by a sum of six elementary strains: hydric, instant elastic, viscoelastic pure, hydro-lock, irrecoverable mechano-sorptive and mechano-sorptive creep. Variations of these elementary strains are established separately. In particular, the evolution law of the hydro-lock strain constructed on the basis of experimental observations is different in phase of drying and moistening. An auxiliary stress introduced in accordance with thermodynamic principles, solves the problem of recovering the hydro-lock strain in the moistening phase in case with zero or little stress. In parallel, a new rheological model is proposed to model the viscoelastic behavior at variable humidity. This model, equivalent to a generalized Maxwell model and / or a generalized Kelvin-Voigt model, is able to describe the creep as well as relaxation. The second chapter of this part is devoted to the transformation of the analytical model in an incremental form on finite time step. The contribution of each elementary part is established by exact resolutionfrom differential equations or Boltzmann’s integrals. The sum of elementary forms thus obtained leads to the complete model behavior law which is similar to that of an equivalent thermo-elastic behavior. Because of the integration process, the time step calculation is finished but not necessarily small. This property is very important because it significantly reduces the computation time while maintaining very good accuracy. The last part is divided into three chapters. It presents numerical implementation of hydro- mechanical model using the finite element code Cast3m, followed by validation and applications to various classes of problems. The numerical algorithm is organized into independent modules. Elementary procedures are built to perform specific functions; they are called in a specific order by the main program. Model validation is made by comparison between simulated results and experimental data available in tension and bending. The last chapter of the thesis presents applications of solid wood reconstituted silver fir. They show the ability of the model to predict the states of stress and strain in timber structures under mechanical loading and variable humidity.
126

Software lock elision for x86 machine code

Roy, Amitabha January 2011 (has links)
More than a decade after becoming a topic of intense research there is no transactional memory hardware nor any examples of software transactional memory use outside the research community. Using software transactional memory in large pieces of software needs copious source code annotations and often means that standard compilers and debuggers can no longer be used. At the same time, overheads associated with software transactional memory fail to motivate programmers to expend the needed effort to use software transactional memory. The only way around the overheads in the case of general unmanaged code is the anticipated availability of hardware support. On the other hand, architects are unwilling to devote power and area budgets in mainstream microprocessors to hardware transactional memory, pointing to transactional memory being a 'niche' programming construct. A deadlock has thus ensued that is blocking transactional memory use and experimentation in the mainstream. This dissertation covers the design and construction of a software transactional memory runtime system called SLE_x86 that can potentially break this deadlock by decoupling transactional memory from programs using it. Unlike most other STM designs, the core design principle is transparency rather than performance. SLE_x86 operates at the level of x86 machine code, thereby becoming immediately applicable to binaries for the popular x86 architecture. The only requirement is that the binary synchronise using known locking constructs or calls such as those in Pthreads or OpenMPlibraries. SLE_x86 provides speculative lock elision (SLE) entirely in software, executing critical sections in the binary using transactional memory. Optionally, the critical sections can also be executed without using transactions by acquiring the protecting lock. The dissertation makes a careful analysis of the impact on performance due to the demands of the x86 memory consistency model and the need to transparently instrument x86 machine code. It shows that both of these problems can be overcome to reach a reasonable level of performance, where transparent software transactional memory can perform better than a lock. SLE_x86 can ensure that programs are ready for transactional memory in any form, without being explicitly written for it.
127

Možnosti vývoje vícevláknových aplikací na platformě Java 8 / Development of Multithreaded Applications on the Java 8 platform

Souček, Dan January 2014 (has links)
This master thesis is a programmer's guide book of a concurrent programming on the Java 8 platform. Concurrency brings additional issues that cannot occur in single-threaded ap-plications. One of the thesis' objectives is to analyze these issues and introduce several principles that, in case they are properly followed, help to create flawless and well-behaving concurrent applications. Another goal of this thesis is to describe the Java con-currency programming from the theoretical point of view. Firstly, the thesis is focused on basic thread development and synchronization issues. Later, it introduces the features and instruments that are provided by Java 5 and higher versions. The theoretical passages are enriched by practical examples that perform discussed features and help to clarify some specific issues. The thesis is written in Czech language and covers large set of concurrency topics from the very basics through the utility libraries to modern instruments present in Java 8.
128

RESPONSE PREDICTION AND DAMAGE ASSESSMENT OF FLEXIBLE RISERS / フレキシブルライザーの応答予測と損傷評価に関する研究 / フレキシブル ライザー ノ オウトウ ヨソク ト ソンショウ ヒョウカ ニ カンスル ケンキュウ

Riveros Jerez, Carlos Alberto 24 September 2008 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第14135号 / 工博第2969号 / 新制||工||1441(附属図書館) / 26441 / UT51-2008-N452 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 杉浦 邦征, 准教授 白土 博通, 准教授 宇都宮 智昭 / 学位規則第4条第1項該当 / Doctor of Engineering / Kyoto University / DFAM
129

Diagnostika kovových materiálů / Diagnosis of metallic materials

Buday, Matej January 2010 (has links)
This thesis deals with non-destructive testing (NDT). It Describes two basic thermographic methods, lock-in and pulse thermography. Different types of measurements using Fluke Ti55, points to the possibility of applying these methods in practice. Pulse thermography issue is a substantial part of this work, due to its good applicability. Also, it compares visual testing methods (VIS) and pulse thermography due to measurement with die-casting alloy AC-AlSi9Cu3 (Fe).
130

Vícepásmový mikrovlnný vysílač pro studium šíření elektromagnetických vln v atmosféře / Multiband Microwave Transmitter for Electromagnetic Waves Propagation Study

Poslušný, Marek January 2013 (has links)
Master’s thesis describes the design of multi-band microwave transmitters to study the propagation of electromagnetic waves in the atmosphere with the possibility of modulation of the transmitted signal. Based transmitters are synchronized phase lock loop, frequency multipliers, double balanced diode mixers.

Page generated in 0.039 seconds