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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.
1

Technology spillovers from foreign direct investment (FDI): the case of the Republic of Korea

Ha, Yoo Jung January 2012 (has links)
This thesis investigates conditions under which the activities of multinational enterprises (MNEs) impact upon innovation performance in host-country firms. Three specific sub-questions are addressed: 1) Do MNE subsidiary characteristics influence FDI spillovers on host-country firms? 2) Does the external technological environment in individual industries influence spillover effects? 3) Do such technology spillovers follow a linear relation with the scale of FDI? Individual empirical analyses, using firm-level data extracted from two waves (2002 and 2005) of the Korean Innovation Survey (KIS) in the Republic of Korea (South Korea), are used to examine these questions. The first finding is that FDI spillovers vary depending on the subsidiary’s heterogeneous role. In this regard, we build on recent theoretical contributions made by the network-based view of MNEs, distinguishing heterogeneous subsidiary roles into either competence-creating (CC) or competence-exploiting (CE). Our results show that CC subsidiaries generate negative horizontal and positive backward spillovers, but no forward spillovers. Against this, CE subsidiaries generate positive horizontal and forward spillovers and negative backward spillovers. The second finding concerns the moderating role assumed by the type of business environment in the host country during foreign entry, especially in terms of environment velocity. We build on strategic management literature that the behaviour and performance of a firm is influenced by environment velocity, finding that environment velocity affects backward (negatively) and forward spillovers (positively), but not horizontal spillovers. The third finding concerns non-linear (linear) impacts of FDI spillover across different scales of FDI in a sector, building on existing studies predicting a changing marginal effect of horizontal spillovers. We took this a step further by comparing horizontal spillovers on local rivals and vertical spillovers on local partners, either suppliers or clients. The key contributions are two-fold: firstly, this thesis proposes revising implicit assumptions in the extant literature by identifying conditions of FDI spillovers concerning subsidiary heterogeneity and business environment type, and also by confirming the non-linear effect of horizontal and backward FDI spillovers. Secondly, it provides a glimpse of FDI spillovers in a technologically capable host country in East Asia. The findings stress various implications, including the usefulness of international business theories for assessing the role of MNE activities in host economies.
2

Ultra-high-Q SiC photonic nanocavities / 超高Q値SiCフォトニック結晶ナノ共振器に関する研究

Jeon, Seung Woo 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19723号 / 工博第4178号 / 新制||工||1644(附属図書館) / 32759 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 野田 進, 教授 木本 恒暢, 教授 川上 養一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
3

Génération de sources optiques fibrées très hautes cadences et caractérisation de fibres optiques microstructurées en verre de Chalcogénure / High bit rate optical pulses sources generation and microstructured chalcogenide fibers characterizations

Balme, Coraline 19 January 2011 (has links)
Ce mémoire de thèse s'inscrit dans le contexte du projet FUTUR financé par l'ANR et concernant le développement de Fonctions optiques pour les Transmissions à très haut débit dans le Réseau coeur et porte sur la génération de sources optiques fibrées très hautes cadences et la caractérisation de fibres optiques microstructurées en verre de Chalcogénure. A cet effet, nous étudions les caractéristiques linéaires et non-linéaires au sein de fibres microstructurées en verre de chalcogénures conçue et réaliser via différentes collaborations dans le cadre du projet de l'ANR FUTUR. Pour cela un grand nombre de méthodes de caractérisations ont été mises au point donnant une comparaison entre une fibre SMF standard et ces fibres microstructurées chalcogénures. Par exemple, un montage interférométrique pour la mesure de la dispersion chromatique pour échantillon court, ou encore de nombreux banc expérimentaux permettant la caractérisation des propriétés non-linéaires de ces fibres (diffusion Raman, diffusion Brillouin, Coefficient non linéaire Kerr...). La seconde partie de ce mémoire présente la mise au point de méthode de conversion d'un battement sinusoïdal en un train d'impulsions hautement cadencé. Il est montré dans ce manuscrit que cette technique a été exploitée au plus prêt de ses limites, par l'obtention d'impulsions extrêmement courtes et par des débits très élevés. Les trains d'impulsions à très hautes cadences ont été caractérisés par un dispositif expérimental SHG-FROG. Une démonstration de la multiplication du débit par deux a été démontrée par l'effet Talbot. / This memory of thesis s' registered voter in the context of the FUTUR project financed by l'ANR and concerning the development of optical finctions fot the high bit-rate transmissions in the Network heart and carries on very high rates optical fibers sources generation and the optical chalcogenide microstructured fiber charaterization. For this purpose, we study the linear and non-linear characteristics of microstructured chalcogenide fibers conceived and realized in various collaborations within the framework of the ANR FUTUR project. For that a great number of characterizations methods were developed giving a comparison between a standard single mode fiber and there microstructured chalcogenide fibers. For exemple, an interferometric setup for the chromatic dispersion measurement for short sample, or many experimental setup allowing the nonlinear properties characterizations as of these fibers (Raman scattering, nonlinear Kerr Coefficient). The second part of this memory presents the settling of sinusoidal beat conversion into a high bit rate generation method. It is shown in this manuscript that this technique was exploited with readiest of its limits, by obtaining extremely short pulses and by very high bit-rate. The pulses train at very high rates were characterized by an experimental device SHG-FROG. A demonstration of the multiplication of the bit-rate by two at summer shown by Talbot effect.
4

Desenvolvimento de um WebLab para estudo de efeitos não-lineares em fibras ópticas

Pessôa Filho, Joaquim 20 August 2007 (has links)
Made available in DSpace on 2016-04-18T21:39:45Z (GMT). No. of bitstreams: 2 Joaquim Pessoa Filho1.pdf: 2407971 bytes, checksum: 0f6a298a559015177c4035cc2d83dc77 (MD5) Joaquim Pessoa Filho2.pdf: 2335540 bytes, checksum: 646d7c73d08bbfeccbd03d5a30419c7c (MD5) Previous issue date: 2007-08-20 / The advent f the Internet and the development of Information and Communication Technologies generated new spaces for communication and collaboration between groups of people in geographically distinct regions. The association of Web Technology with instrument automation and control by computer has made possible the development of the so called Remote Laboratories or WebLabs distributed environments that allow to access and control experiments remotely through a network or the Internet in real time and with the sensation of presence. In this work, a WebLab was developed for the study of non-linear effects in optical fibers, aiming to support and complement activities in face-to-face and distance courses on Optical Communications. Applications and graphic user interfaces were developed for instrument control and data acquisition in a remote experiment for measuring the non-linear coefficient of an optical fiber using the Continuous Wave Self-Phase Modulation Method. An application integrated to the user interface was also developed for the numerical simulation of the measurement through the integration of the Non-linear Schrödinger Equation by the Split-Step Fourier Method as well as a component based on Java Media Framework for audio and video transmission during the remote execution of the experiment. This work is part of the activities related to the participation of the Mackenzie Photonics Laboratory in the KyaTera Project of FAPESP´s TIDIA Program. / O advento da Internet e o desenvolvimento das Tecnologias da Informação e Comunicação (TIC´s) geraram novos espaços para a comunicação e colaboração entre grupos de pessoas localizadas em regiões geograficamente distintas. A associação da tecnologia Web com a automação e controle de instrumentos por computador tornou possível o desenvolvimento dos chamados Laboratórios Remotos ou WebLabs - ambientes distribuídos que permitem o acesso e controle remoto de experimentos através de uma rede de comunicação ou da Internet em tempo real e com sensação de presença. Neste trabalho, foi desenvolvido um WebLab para o estudo de efeitos não-lineares em fibras ópticas, destinado a apoiar e complementar atividades em cursos de Comunicações ópticas presenciais e a distância. Foram desenvolvidos aplicativos e interfaces gráficas de usuário para o controle e aquisição de dados dos instrumentos utilizados em um experimento remoto de medida do coeficiente não-linear de uma fibra óptica pelo método da Auto-Modulação de Fase com Onda Contínua. Também foi desenvolvido um aplicativo integrado à interface de usuário para simulação numérica da medida através da integração da Equação de Schrödinger Não-linear pelo método Split-Step Fourier, bem como um componente baseado em Java Media Framework para transmissão de áudio e vídeo durante a execução remota do experimento. O trabalho é parte das atividades relacionadas à participação do Laboratório de Fotônica Mackenzie no Projeto KyaTera do Programa TIDIA da FAPESP.
5

Approche micromécanique du comportement d'un matériau fissuré non saturé / Micromechanical approach of behaviour of a cracked unsaturated material

Tran, Bao Viet 12 January 2010 (has links)
On s'intéresse plus particulièrement à la modélisation du comportement d'un matériau hétérogène méso-fissuré (béton, roche,...), soumis à une sollicitation thermo-hydro-mécanique avec prise en compte du couplage géométrique. Pour conduire cette étude, on s'appuie notamment sur les approches micro-mécaniques du comportement des milieux méso-fissurés non saturés développées depuis quelques années au Laboratoire des Matériaux et des Structures du Génie Civil - Ur Navier - Université Paris Est. Le milieu fissuré non saturé traité ici est constitué d'une matrice solide homogène élastique linéaire et de fissures connectées saturées par deux fluides immiscibles : un liquide et un gaz séparés par une surface capillaire. La fissure est traditionnellement considérée comme une cavité ellipsoïdale (cas 3D) ou elliptique (cas 2D) dont le rapport d'aspect tend vers zéro. Deux morphologies typiques de matériau sont considérés dans ce travail : la situation où les fissures sont toutes orientées dans la même direction et la situation où les fissures possèdent des orientations aléatoires. Dans une première étape, on rappelle brièvement les résultats disponibles concernant la modélisation des fissures non saturées par des cavités ellipsoïdales aplaties. A la fin de cette première partie, on complète les résultats déjà disponibles en étudiant l'influence de l'histoire de chargement sur la réponse de matériau. Dans une deuxième étape, on s'attache à valider une partie des résultats obtenus en utilisant une description des efforts capillaires dans les fissures par une précontrainte homogène en seréférant aux solutions analytiques exactes disponibles dans la littérature permettant de décrire le comportement d'une fissure isolée au sein d'une matrice élastique. Dans une troisième étape, on s'intéresse aux phénomènes de propagation des fissures en condition non saturée. Les lois de propagation sous critique et le phénomène de branchement des fissures sont également prises en compte dans cette approche. La dernière partie de la thèse concerne l'influence de la température sur le comportement des milieux poreux non saturés / The main topic of my work is the development of a micromechanical model for the behaviour of unsaturated mesocracks in media (concrete, rock...) in which the thermo-hydro-mechanical loadingsand thermo-hydro-mechanical couplings are taken into account. For this, we used the micromechanical approach model of behaviour of cracked porous media recently developed at LMSGC. My thesis is focused on the equilibrium configurations of a porous material whose pore space is saturated by a vapour and a liquid phase. The behaviour of an elastic medium containing unsaturated mesocracks is studied in the framework of a micromechanical approach. The cracks are filled by two immiscible fluids, namely a liquid and a gas, separated by a capillary interface. Furthermore, it is assumed that the set of cracks constitutes a connected network ; the capillary pressure is uniform over a representative elementary volume. The cracks are modelled as flat oblate spheroid cavities. Several geometrical configurations of cracks in porous media are considered in the framework of Eshelby-based homogenization methods (parallel cracks, randomly oriented cracks). First, a previously developed model showed that when coupling between the deformation of the cracks and the capillary forces is taken into account, there is no more a one-to-one relationship between the loading parameters and the state-variables. Thus, we describe the loading history prescribed to the material in order to compute its response. Second, we validate these results referring to the exact solutions available in the literature to describe the behaviour of a unsaturated crack within an elastic matrix. Third, the description of crack propagation in unsaturated media is considered in the framework of linear elastic fracture mechanics. The phenomenon of subcritical crack growth due to stress corrosion cracking is taken into account in this approach. Mixed mode fracture in the plane is also examined. Finally, we are interested in the influence of the temperature on the behavior of unsaturated porous media in the framework of the micromechanical approach

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