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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.
361

Quelques problèmes liés à la dynamique des équations de Gross-Pitaevskii et de Landau-Lifshitz

de Laire, André 21 November 2011 (has links) (PDF)
Cette thèse est consacrée à l'étude des équations de Gross-Pitaevskii et de Landau-Lifshitz, qui présentent d'importantes applications en physique. L'équation de Gross-Pitaevskii modélise des phénomènes de l'optique non linéaire, de la superfluidité et de la condensation de Bose-Einstein, tandis que l'équation de Landau-Lifshitz décrit la dynamique de l'aimantation dans des matériaux ferromagnétiques. Lorsqu'on modélise la matière à très basse température, on fait l'hypothèse que l'interaction des particules est ponctuelle. L'équation de Gross-Pitaevskii classique s'en déduit alors en prenant comme interaction une masse de Dirac. Cependant, différents types de potentiels non locaux probablement plus réalistes ont aussi été proposés par des physiciens pour modéliser des interactions plus générales. Dans un premier temps, on s'intéressera à donner des conditions suffisantes couvrant une variété assez large d'interactions non locales et telles que le problème de Cauchy associé soit globalement bien posé avec des conditions non nulles à l'infini. Par la suite, on étudiera les ondes progressives de ce modèle non local et on donnera des conditions telles que l'on puisse déterminer les vitesses pour lesquelles il n'existe pas de solution non constante d'énergie finie. Concernant l'équation de Landau-Lifshitz, on s'intéressera aussi aux ondes progressives d'énergie finie. On montrera la non existence d'ondes progressives non constantes d'énergie petite en dimensions deux, trois et quatre, sous l'hypothèse que l'énergie soit inférieure au moment dans le cas de la dimension deux. En outre, on donnera aussi dans le cas bidimensionnel la description d'une courbe minimisante qui pourrait donner une approche variationnelle pour construire des solutions de l'équation de Landau-Lifshitz. Finalement, on décrira le comportement à l'infini des ondes progressives d'énergie finie.
362

Galerkin-truncated dynamics of ideal fluids and superfluids: cascades, thermalization and dissipative effects

Krstulovic, Giorgio 19 March 2010 (has links) (PDF)
Cette thèse regroupe des études portant sur la dynamique de relaxation de différents systèmes conservatifs ayant tous une troncature de Galerkin sur les modes de Fourier. On montre que, de façon très générale, ces systèmes relaxent lentement vers l'équilibre thermodynamique avec une thermalisation partielle à petite échelle qui induit une dissipation effective à grande échelle, tout en conservant les invariants globaux. La première partie de ce travail est consacrée à l'étude de la viscosité effective dans l'équation d'Euler incompressible tronquée. L'utilisation des méthodes de Monte-Carlo et de la théorie EDQNM permet la construction d'un modèle à deux fluides de ce système. Cette étude est ensuite généralisée au cas des écoulements hélicitaires. La dynamique de relaxation des écoulements décrits par les équations de la magnétohydrodynamique et des fluides compressibles tronqués est finalement caractérisée. Dans une deuxième partie, nous généralisons l'étude de la thermalisation au cas de l'équation de Gross-Pitaevski tronquée. On trouve que des effets existant dans les superfluides à température finie, comme la friction mutuelle et le ''counterflow'', sont naturellement présents dans ce modèle. On propose ainsi l'équation de Gross-Pitaevskii tronquée comme un modèle simple et riche de la dynamique superfluide à température finie. La radiation produite par le mouvement de vortex ponctuels décrits par l'équation de Gross-Pitevskii 2D est finalement caractérisée analytiquement et numériquement.
363

La théorie de Gross-Pitaevskii pour un condensat de Bose-Einstein en rotation : vortex et transitions de phase

Rougerie, Nicolas 09 December 2010 (has links) (PDF)
Lorsqu'un gaz de bosons est suffisament refroidi, une transition de phase apparaît : toutes les particules se concentrent dans le m^eme état d'énergie. On appelle l'objet résultant de ce phénomène un condensat de Bose-Einstein. On peut le décrire par une fonction d'onde macroscopique, minimisant à l'équilibre la fonctionnelle d'énergie de Gross-Pitaevskii. Une des propriétés remarquables des condensats est leur superfluidité. Elle peut se manifester par l'apparition de vortex (tourbillons) dans un condensat mis en rotation. Dans cette thèse nous étudions le comportement asymptotique des minimiseurs de la fonctionnelle de Gross-Pitaevskii bi-dimensionelle et des énergies associées dans différents régimes de paramètres rendant compte de situations physiquement intéressantes. Nous cherchons à identifier certaines transitions de phase caractérisées par l'organisation des vortex du condensat. Dans une première partie nous étudions une situation où il est justié physiquement de considérer un problème simplifié. La minimisation de la fonctionnelle d'énergie est alors restreinte au premier espace propre de l'opérateur de Ginzburg-Landau (le plus bas niveau de Landau, lié à l'espace de Fock-Bargmann). Nous étudions théoriquement et numériquement le modèle simplifié dans un régime où le condensat est annulaire et contient un réseau de vortex déformé. Une seconde partie est consacrée à un régime de rotation extrême où le problème limite devient linéaire. Nous montrons que ce problème limite décrit correctement les asymptotiques d'énergie et de densité de matière. Sous une hypothèse supplémentaire nous démontrons qu'un vortex géant se forme, c'est-à-dire un condensat annulaire dont tous les vortex se rassemblent dans la zone centrale de faible densité de matière. Les deux dernières parties de la thèse sont consacrées à l'évaluation de la vitesse critique pour l'apparition du vortex géant. Nous montrons d'abord que le vortex géant apparaît au dessus d'un certain seuil que nous calculons en fonction des autres paramètres du problème, ce qui fournit une borne supérieure de la vitesse critique. Dans une quatrième partie nous montrons que cette borne supérieure est en fait optimale en considérant des vitesses proches du seuil par valeur inférieure. Nous montrons alors que des vortex sont présents dans le condensat et qu'ils se répartissent uniformément le long d'un cercle.
364

Une approche hybride de l'extraction d'information : sous-langages et lexique-grammaire

Watrin, Patrick 25 October 2006 (has links)
L'extraction d'information consiste habituellement à remplir, au départ d'un ensemble de documents, les champs d'un formulaire préalablement établi et articulé autour d'un scénario précis. Dans ce travail, nous cherchons à étudier la pertinence des bases de données syntaxiques du lexique-grammaire afin de répondre aux questions et enjeux posés par ce domaine d'application (adaptabilité, performance,...). La phrase élémentaire (couple <prédicat, compléments essentiels>) est l'unité significative minimale de cette théorie linguistique (M. Gross, 1975) qui réunit lexique et syntaxe en un unique formalisme. Chacune de ces phrases dessine le sens d'un prédicat au moyen de critères tant distributionnels que transformationnels. Dans un cadre générique, on ne peut malheureusement pas prétendre caractériser davantage ces phrases. Il convient en effet que l'analyse syntaxico-sémantique qui dérive de l'utilisation du formalisme s'adapte à toute situation d'énonciation. Toutefois, si on limite l'analyse dont il est question à un contexte ou sous-langage particulier, celui d'un scénario d'extraction par exemple, en d'autres termes, si nous bornons la situation d'énonciation, il est envisageable de préciser la sémantique du prédicat et de ses compléments essentiels. Les phrases élémentaires peuvent ainsi être appréhendées comme autant de motifs d'extraction.
365

Essays on Regional Growth, Comparative Advantages and Foreign Direct Investments

Thulin, Per January 2010 (has links)
This thesis consists of four essays, covering four different topics. The first essay investigates the relationship between inter-firm labor mobility and regional productivity growth. Previous studies have shown that density is positively correlated with growth. I claim that it is not density in itself, but rather the attributes associated with it that drives economic growth. One such attribute is the increased possibility for labor mobility and knowledge diffusion that follows when firms and individuals locate in close proximity to each other. This hypothesis is tested using density as an instrument for labor mobility. The result shows that labor mobility increases regional growth rates. The second essay examines the relationship between agglomeration economies and relative wage costs in influencing location of multinational corporations. An inflow of firms to certain regions and industries is likely to increase demand for labor. If mobility of labor is low increased costs can be expected to deter additional inflows of firms, albeit agglomeration economies may compensate for higher wages. The empirical analysis finds that FDI has become increasingly sensitive to differences in wage costs across industrialized countries, but also that agglomeration economies related to knowledge externalities positively influences higher costs. The third essay looks at the impact of FDI on home country investments. Previous research has been inconclusive as regards the effects on domestic investments. In this article, we show that this inconclusiveness can be explained at a disaggregated level as a function of the way industries are organized. We argue that a complementary relationship can be expected to prevail in vertically integrated industries, whereas a substitutionary relationship can be expected in horizontally organized production. The empirical analysis confirms a significant difference between the two categories of industry as regards the impact of outward FDI on domestic investment. The fourth, and final, essay of this thesis analyses how increased R&amp;D expenditures and market size influence the distribution of comparative advantage. Previous studies report ambiguous results and also refer to periods when markets were much more segmented and production factors less mobile. The empirical analysis comprises 19 OECD-countries and spans the period 1981 to 1999. It is shown how an increase in R&amp;D-expenditures by one percentage point implies a three-percentage point increase in high-technology exports, whereas market size fails to attain significance. In addition, institutional factors influence the dynamics of comparative advantage.
366

Market Potential Analysis of Producer Services : A Study of Jönköping County

Kantola, Jan January 2007 (has links)
The purpose of this thesis is to investigate the market potential of producer services in Jönköping County. In relation to the main purpose, the idea is to examine which factors that have a positive impact on the development of a long run qualitative producer service industry in the region. The favourable location of Jönköping County is one of the main factors for why the county has one of the highest densities of manufacturing firms in Sweden. Moreover, the region has comparative advantages in several products, for an example; wood, rubber, machinery and electronically goods. Earlier research and comparisons with other international manufacturing clusters indicates that these areas tend to contain highly developed producer service industries. The thesis gives a case example of how the beneficial, mutual interaction between the manufacturing and producer service industries works in the car industry in Germany. However, to be able to establish a successful and close relationship between the above mentioned industries, the theoretical framework distinguishes several important factors; for instance, education and infrastructure are assumed to be the two most vital ingredienses. Nonetheless, also the firms’ production milieu and technology affects the successful development of a cluster district. Furthermore,when relating the theoretical assumptions to the descriptive statistics, with the intention to elucidate the industrial structure of Jönköping County, one can differentiate three major producer service sectors, namely; “Transport and mail”, “Consulting, marketing, law” and finally “Rentals of premises, labour and machinery”. Nevertheless, several alarming observations can be noticed concerning the wage level, education intensity, productivity and gross profit percentage within the county’s producer service industry; where all these features are below the domestic average. Nevertheless, the empirical analysis indicates that the region has a varying, but yet a positive market potential in the majority of the county’s municipalities. With correct priorities, Jönköping County has good future prospects to reach a high competitive position, but to accomplish this; the education intensity has to be improved. / Syftet med denna uppsats är att utreda om Jönköpings län besitter marknadspotential inom närindustriella tjänster. I relation till syftet är avsikten också att ta reda på vilka faktorer som kan underlätta utvecklingen av en långsiktig kvalitativ service industri i länet. Den fördelaktiga geografiska positionen är en av faktorerna till varför Jönköpings län har blivit ett av Sveriges industritätaste områden; där regionen har komparativa fördelar i trä, gummi, maskin och elektroniska produkter. Genom tidigare forskning och vid jämförelser med andra internationella tillverkningskluster hävdas det att det finns tydliga tecken på att dessa områden bör innerhålla starkt utvecklade centra för närindustriella tjänster. I uppsatsen nämns framförallt den tyska bilindustrin som ett exempel på hur nära samarbetet mellan tillverkning och service industrin kan bedrivas. För att kunna nå en nära samverkan mellan de nämnda industrierna så pekar teoridelen ut flera viktiga ståndpunkter, där bland annat utbildning och infrastruktur är av allra högsta vikt. Men även företagens produktionsmiljö och teknologi reflekterar hur ett framgångsrikt klusterområde utvecklas. När man därefter relaterar dessa utgångspunkter till den deskriptiva statistiken med syfte att klargöra Jönköpings läns industristruktur, kan man konstatera att den största industritjänsten utgörs av transport och logistik. Därefter följer marknadsföring,redovisning och juridisk rådgivning, medan den tredje och sista tjänsten är uthyrning av lokaler, maskiner och personal. Dock påträffas flera oroväckande iakttagelser gällande lönenivåer, utbildningsintensitet, produktivitet och bruttovinstandelar inom produktionstjänster i länet, då samtliga faktorer hamnar under riksgenomsnittet. Vidare indikerar de empiriska resultaten och analysen på att det finns en varierande men positiv marknadspotential i majoriteten av länets kommuner. Med rätta prioriteringar så finns det således goda framtidsutsikter för att regionen skall kunna skaffa sig en hög konkurrenskraft i framtiden. Men då krävs det framförallt en högre utbildningsgrad bland den arbetsföra befolkningen i länet.
367

The Application of the Charlop-Atwell Scale of Motor Coordination to Children With Autism: An Objective and Subjective Measure of Gross Motor Functioning

Colton, Reny A 01 January 2013 (has links)
Recent research has investigated the prevalence of gross motor deficits in children diagnosed with Austim Spectrum Disorder (ASD), however these studies typically utilize the Bruininks-Oserestsky Test of Motor Proficiency, the Movement Assessment Battery for Children, the Peabody Developmental Motor Scales, or the Test of Gross Motor Development for assessment. These scales are expensive, require specialized equipment, are difficult to administer, and contain numerous test items that lead to long test administration times. The current research applied the Charlop-Atwell Scale of Motor Coordination to measure gross motor function deficits in children with autism and compared the data against scores from neurotypical children to determine the degree of delay of motor development. The Charlop-Atwell scale proved to be an effective measure of motor deficits and the study had high interobservor reliability. Children with ASD scored significantly lower than neurotypical children half their age on the objective subtest and total scale score. Looking at scores on separated test items, individual motor deficits were identified and results can be referred to an occupational or physical therapist for remedial treatment program development.
368

El delito de conducción temeraria del artículo 380 del Código Penal

Muñoz Ruiz, Josefa 31 May 2013 (has links)
Statistics show that motor vehicle driving is a risky activity when combined with other factors such as alcohol consumption, excessive speed and road conditions, what make undisputed the necessary incriminating of risky behaviors. In the same way, it could generate specific dangerous situations to pedestrians´ life or physical integrity, drivers or attendants who daily are involved in road traffic. This kind of dangerous driving is the backbone of this Thesis which aims to provide an analysis dogmatic about the recklessly driving and the concrete danger to the life or integrity of persons. Attention is focuses on the doctrinal debate generated about the legally determination and establishment of the criteria coined by forensic practice in the specification of its constitutive elements, concluding a critical view of the current regulatory framework in our Legislation. / Las cifras que arrojan los datos estadísticos demuestran que la conducción de vehículos a motor es una actividad de riesgo que cuando se combina con otros factores como el consumo de alcohol, velocidad excesiva y el estado de las vías, hace indiscutible la necesaria incriminación de comportamientos peligrosos que generan situaciones de riesgo concreto para la vida o integridad física de peatones, conductores o acompañantes que a diario intervienen en el tráfico rodado. Es precisamente esta forma de conducción peligrosa la que constituye el eje de estudio de esta tesis doctoral que tiene como objetivo ofrecer un análisis dogmático del delito de conducción con temeridad manifiesta y concreto peligro para la vida o integridad de las personas, prestando especial interés al debate doctrinal que genera la determinación del bien jurídico y la fijación de los criterios acuñados por la práctica forense en la determinación de los elementos constitutivos del mismo, para concluir con una visión crítica al actual marco normativo.
369

Debt and deficit in the Czech Republic and France

Huneau, Mathieu, Doktor, Petr January 2012 (has links)
This thesis is analyzing the development of debt and deficit situation in the Czech Republic and France. Our main research questions are: why the Czech Republic and France have different debt and deficit? What are the effects and causes of debt and deficit? How Czech Republic and France wants to reduce the level of debt and deficit? These are the central questions we try to answer in this thesis. To pursue a systematic analysis, we start with a theoretical section on we described different theories of debt/deficit and budgetary rules effects on the economy in order to understand characteristics of debt issues. From these findings, we have resulted causes and differences of debt situations in our countries, which is part of empirical analysis. This is done by evolution of debt/deficit and factors that affect level of debt/deficit. We analyzed three mains factors and due to this factors that influence debt/deficit we can clearly see why our countries have different levels in debt problem. Regarding this we can say our countries are different in many respects. The major difference is monetary policy due to French member of Eurozone. Also the way how to get from debt issue and find a compromise between government reforms and interests of citizens will vary in the future.
370

The Study on Management of Financial Problems among Taiwan Travel Industry

Chang, King-Ming 26 June 2012 (has links)
Operation scales of the travel agencies can be giant or tiny in term of sizes. No matter in Taiwan or abroad, most trvel agents are SMEs (small and medium enterprises), while some large-scale foreign or mainland travel agencies are even bigger than ordinary banks or airlines. Travel agents play a role as an important channel for travelers. They collect a considerable huge amount of money from travelers and pay to the suppliers just like a temporary God of Wealth. Airline tickets and tour fares end up to some hundred millions or even some billions of turn over (in total amount counting method) commonly. This is an industry which charges in advance before providing services. In addition to the shorter term of airline credit, six elements of travel - meals, accommodations, transportations, sightseeing, shopping, and entertainments, are allowed routinely credited periodically, especially tours fares often accumulated to an astronomical figures. This sevice industry is quite different from other manufacture suffered from the "inventories" problem, but with something in common, it has a huge amount of outstanding accounts remain unsettled, or even worse to cause the phoenomenon of financial black hole with "assets virtually inflated and liabilities virtually reduced". Several large tours wholesalers in Taiwan went bankruptcy might be owing to these reasons. Even the subsidiary of TUI, the world's largest tours group, outbroke similar news incident in early 2011. It was not singly but in pairs, Reuters reported that Europe's second largest travel company Thomas Cook facing financial crisis in late 2011, were forced to acquire ¢G 2 billion loan from banks to survive in the coming low winter season. A great amount of accumulated money often causes a crisis of credit expansion, if any ambitious entrepreneur seeks to gain more profits from other reinvestments, intends to get real estates, accquitions, mergers, and other risky investments, possibly resulted in large scale damage with both investments and foreign currency exchange losses, when facing an economy downturn or political turmoils. "Financial management" is always the primary course of business running. Emphasis on the "financial problems management" is not just a slogon, and not just to watch bank deposits closely, but also to realize how and what sholuld be seriously paid attention to. Revenue increasing and cost cutting are always the true value of financial management on business development. The differences of corporate finance from time to time are as same as different figures of human pulse, blood presure, or blood suguar that varies at diffent times or in different conditions. Financial management of a company is just like personal health management, such as people in different stages faces different situations and needs. So companies must grasp the pulse of business development in different stages to plan for the future direction. Many companies seek to maximize profits at the same time, yet ignoring the strong managing and decision-guiding functions of financial management. Newspapers and magazines often report how many employees and consumers are impacted by the closing of plants or travel agencies, many of them are wellknown enterprises. Although the global economic downturns, the failure of business diversification or reinvestment hold-up losses and other factors might take the blames. But as the old saying: "There is no sunset industry but only sunset enterprises." How to survive in the harsh environment? We must strengthen to master financial management, through analysis and control of "financial problems management" to generate necessary resources and to cut the costs to enhance the business performance. "The management of financial problems among travel industry" is really the weakest point of this industry. Practical financial management books or informations for travel agencies are not easy to be found in stores or other resources. In past decades we have seen the rotation of rises and falls in the industry, we strongly believe "Accounting and Financial Management" is the basis for all kinds of management. This thesis contains the examples of Phoenix Tours International and other travel agents among Taiwan travel industry. The real experiences of daily practices are the most important contents. I attempt to integrate academic theories into daily practices, a little theoretical but more practical argument, to provide better healthy informations for the industry. Despite the company accounting system, I had also tried to establish a basic financial training material for my management team. Wish all our colleagues will not repeat the same financial errors of their predecessors. Under the guideline of Taiwan Tourism Bureau which is committed to developing tourism with ¡§Vanguard for excellences and piloting for all projects¡¨, I tried to do my best to write down personal experiences and researches knowledge as basic works. Hope to bring up some echoes and brainstormings, to lead a brighter future and better progress for the industry. All the appendixes to this thesis are important references to the main text. Many of them are also my writings in the past. At last, IFRSs regulations will soon be implemented, we have to find out its impacts on the enterprises that should not be underestimated. Not only affect financial and accounting areas, information system, performance reward systems, investor relations, tax and legal aspects will also have significant impacts. IFRSs conversion or convergence may not only be an easy task, but provides an excellent opportunity for companies to re-examine the existing financial strategies, accounting policies, management systems, process efficiencies, risk managements, internal controls, system functions, corporate governances and investor relations practices, such as whether to meet current and future needs, and take this opportunity to enhance their strengths by improving inadequacies.

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