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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.
61

Convergence vers IP des systèmes de télécommunication par satellite / IP conververgence of satellite communication systems

Hobaya, Fabrice 30 September 2011 (has links)
Dans un contexte de convergence vers IP du monde des télécommunications, les systèmes de communication par satellite se doivent de suivre la tendance pour rester compétitifs et s'intégrer efficacement au monde Internet. Après avoir rappelé les enjeux d'une convergence dans les systèmes satellite et dressé un panorama des architectures de convergence envisageables, nous avons identifié les limites des systèmes actuels en termes de convergence vers IP. Notre choix se porte alors sur l'architecture IP/GSE pour la voie aller. Nous spécifions ensuite le protocole d'encapsulation GSE-Alt, inspiré de GSE mais adapté à la voie retour. Le déploiement de nouveaux services et l'évolution de services existants sont assurés et rendus plus aisés grâce à la couche IP. Les couches GSE et GSE-Alt optimisent le transport d'IP. Pour offrir un support de communication répondant à la diversité des exigences de qualité des services applicatif, nous définissons ensuite plusieurs mécanismes autorisant la mise en cohérence du traitement de la qualité de service (QoS) aux différents niveaux protocolaires dans les systèmes de communication par satellite. Enfin, pour permettre une interconnexion et une intégration du monde satellite au monde Internet, nous étudions les besoins en termes de déploiement du routage IP. Nous définissons alors une architecture permettant au satellite de réaliser de la commutation de niveau IP. Cette convergence vers un système « tout IP » du segment de communication par satellite est le fondement nécessaire à son insertion transparente au reste du monde des télécommunications. / The world of telecommunications converging towards IP, the telecommunication satellite systems have to follow the trend to stay competitive and to be integrated to the Internet world. We first remind the issues of convergence in satellite communications, then we list the different convergence architectures conceivable in satellite systems and describe the limits of current systems in term of IP convergence. Our choice is devoted to the IP/GSE architecture for the forward link. Then, we specify the GSE-Alt protocol, inspired from GSE but adapted to the return link. The deployment of new services and the evolution of existing services are possible and made easier thanks to the IP layer. Both layers GSE and GSE-Alt optimize the transport of the IP packets. In order to propose a communication support allowing various quality of service (QoS) needs, we specify several mechanisms allowing a great coherence of the quality of service treatments at the different protocol levels. Finally, to allow an interconnection and an integration of the satellite world to the Internet world, we study the requirements in term of IP routing deployment. Therefore, we specify an architecture allowing the satellite to make the switching at the IP level. This convergence of the satellite towards an "all IP" system is the base required to its transparent insertion to the rest of the telecommunication world.
62

Multiscale analysis of emulsions and suspensions with surface effects

Nika, Grigor 22 April 2016 (has links)
The better understanding of the behavior of emulsions and suspensions is important in many applications. In general, emulsions allow the delivery of insoluble agents to be uniformly distributed in a more efficient way. At the same time suspensions of rigid particles are used as “smart materialsâ€� as their properties can be changed by the interaction with a magnetic or electric field. In the first part of the talk we consider a periodic emulsion formed by two Newtonian fluids in which one fluid is dispersed under the form of droplets of arbitrary shape, in the presence of surface tension. We assume the droplets have fixed centers of mass and are only allowed to rotate. We are interested in the time-dependent, dilute case when the characteristic size of the droplets aε, of arbitrary shape, is much smaller than the period length ε. We obtain a Brinkman type of fluid flow for the critical size aε = O(ε3) as a replacement of the Stokes flow of the emulsion. Additionally, using Mosco convergence and semigroup theory we extend the convergence to the parabolic case. For the case when the droplets convect with the flow, it can be shown again using Mosco-convergence that, as the size of the droplets converges to zero faster than the distance between the droplets, the emulsion behaves in the limit like the continuous phase and no “strangeâ€� term appears. Moreover, we determine the rate of convergence of the velocity field for the emulsion to that of the velocity for the one fluid problem in both the H1 and L2 norms. Additionally, a second order approximation is determined in terms of the bulk and surface polarization tensors for the cases of uniform and non-uniform surface tension. The second part of the talk is devoted to the study of MR fluids. We consider a suspension of rigid magnetizable particles in a non-conducting, viscous fluid with an applied external magnetic field. Thus, we use the quasi-static Maxwell equations coupled with the Stokes equations to capture the magnetorheological effect. We upscale using two scale asymptotic expansions to obtain the effective equations consisting of a coupled nonlinear system in a connected phase domain as well as the new constitutive laws. The proposed model generalizes the model of Rosenweig by coupling the velocity of the fluid and the magnetic field intensity. Using the finite element method we compute the effective coefficients for the MR fluid. We analyze the resulting MR model for Poiseuille and Couette flows and compare with experimental data for validation.
63

Extensions of Skorohods almost sure representation theorem

Hernandez Ceron, Nancy 11 1900 (has links)
A well known result in probability is that convergence almost surely (a.s.) of a sequence of random elements implies weak convergence of their laws. The Ukrainian mathematician Anatoliy Volodymyrovych Skorohod proved the lemma known as Skorohods a.s. representation Theorem, a partial converse of this result. In this work we discuss the notion of continuous representations, which allows us to provide generalizations of Skorohods Theorem. In Chapter 2, we explore Blackwell and Dubinss extension [3] and Ferniques extension [10]. In Chapter 3 we present Cortissozs result [5], a variant of Skorokhods Theorem. It is shown that given a continuous path inM(S) it can be associated a continuous path with fixed endpoints in the space of S-valued random elements on a nonatomic probability space, endowed with the topology of convergence in probability. In Chapter 4 we modify Blackwell and Dubins representation for particular cases of S, such as certain subsets of R or R^n. / Mathematics
64

The Study of Convergence of Telecom service company in Taiwan ¡Ð the View of sustainable competitive advantage

Cheng, Hung-yang 01 August 2008 (has links)
There are telecommunication industry and information industry to cost altogether, that is to communicate with each other according to industry development and technological gradual progress and fit Technological standardization, make the industry must use the fast development in the manufacturer, make the convergence of each boundary-less.Moreover different operation key different from resource foundation to can form difficult entry-barrier that cross over also ability way accumulated. Taiwan¡¦s ICT with the technological follower type, but with pursuing while growing up under large ship of the fast gradual progress of technology, how to adjust strategic resources, Represent brand-new institutional framework to create biggest customer's value with the business activity, it is a key topic.This research probes the mobile telecommunication industry, and base on digital-converge progression, focus on the enterprise behaviors produced under the third generation of mobile telecommunication data services and innovated. And Selected Key companies to analyze separately under the extension environment from competition advantage and Merger & Acquisition, and study through the description of the case. The result of study is found as follows: 􀁺 Three kind of convergence triggering business model changed. 􀁺 New technology of telecommunication created new mobile services. 􀁺 Strategical merger and acquisition changed telecommunication industrial structure.
65

G-Convergence and Homogenization of some Monotone Operators

Olsson, Marianne January 2008 (has links)
In this thesis we investigate some partial differential equations with respect to G-convergence and homogenization. We study a few monotone parabolic equations that contain periodic oscillations on several scales, and also some linear elliptic and parabolic problems where there are no periodicity assumptions. To begin with, we examine parabolic equations with multiple scales regarding the existence and uniqueness of the solution, in view of the properties of some monotone operators. We then consider G-convergence for elliptic and parabolic operators and recall some results that guarantee the existence of a well-posed limit problem. Then we proceed with some classical homogenization techniques that allow an explicit characterization of the limit operator in periodic cases. In this context, we prove G-convergence and homogenization results for a monotone parabolic problem with oscillations on two scales in the space variable. Then we consider two-scale convergence and the homogenization method based on this notion, and also its generalization to multiple scales. This is further extended to the case that allows oscillations in space as well as in time. We prove homogenization results for a monotone parabolic problem with oscillations on two spatial scales and one temporal scale, and for a linear parabolic problem where oscillations occur on one scale in space and two scales in time. Finally, we study some linear elliptic and parabolic problems where no periodicity assumptions are made and where the coefficients are created by certain integral operators. Here we prove results concerning when the G-limit may be obtained immediately and is equal to a certain weak limit of the sequence of coefficients.
66

Lietuvos ekonominės konvergencijos, siekiant visateisės narystės ekonominėje ir valiutinėje sąjungoje, tyrimas / Research on Lithuanian economic convergence seeking full rights membership in Economic and Monetary Union

Montvilaitė, Kristina 04 June 2007 (has links)
Magistro darbe, siekiant ištirti Lietuvos ekonominę konvergenciją integracijos į EVS kontekste, apibrėžta konvergencijos koncepcija, nusakant galimus jos pažinimo ir įvertinimo būdus makroekonomikos teorijos bei Mastrichto sutarties atžvilgiais. Tyrimo metu apibūdintos Lietuvos ekonomikos ir ekonominės politikos tendencijos po nepriklausomybės atkūrimo 1990 m. kovo 11 d. iki šių dienų, įgalinančios detaliau įvertinti ekonominės konvergencijos tvarumą. Atliekant Lietuvos ekonominės konvergencijos analizę statistiniais tyrimo metodais, išanalizuotas ekonominis suartėjimas su visateisėmis EVS šalimis narėmis, remiantis BVP parametrais; išnagrinėtas tam tikrų makroekonominių rodiklių atitikimas Mastrichto konvergencijos kriterijams, atskleidžiant jų raidą 1999-2006 m., įtakojusius esminius veiksnius, numatant ateities tendencijas bei probleminių aspektų sprendimo būdus; patvirtintos suformuluotos mokslinio tyrimo hipotezės: (1) Lietuvos ekonominė konvergencija su visateisėmis EVS šalimis, remiantis BVP parametrais, vyksta ir yra tvari; (2) vienalaikiškas visų konvergencijos kriterijų tenkinimas dėl kai kurių iš jų tarpusavio nesuderinamumo yra sunkiai įgyvendinamas; (3) infliacijos rodiklis nebūtų tapęs kliūtimi 2007 m. sausio 1 d. įsivesti eurą, jei nedarbo lygis būtų buvęs bent 1 proc. punktu didesnis (iki to momento, kai buvo vertinamas Lietuvos konvergencijos tvarumas 2006 m. gegužės mėn.), kitoms sąlygoms nekintant. Magistro darbo tema perskaitytas pranešimas Šiaulių... [toliau žr. visą tekstą] / In Master’s Thesis on purpose of Lithuania’s economical convergence’s exploration in the context of the integration in the EMS, the concept of convergence by defining its possible cognition’s and evaluation’s ways in respect of Macro-economical theory and Maastricht Treaty is defined. During the research the tendencies of Lithuania’s economics and economical politics from the independence’s re-establishment on 11 of March 1990 until nowadays are described which can enable evaluating the longevity of economical convergence. During the fulfilling of the analysis of Lithuania’s economical convergence with the statistical methods of research, referring to the GDP parameters economical approach to EMS countries was analyzed, the execution and longevity of the convergence’s indicators were analyzed uncovering their development in the period of 1999-2006 year, which had influenced the essential factors and for providing the future’s tendencies and possible ways of resoling problematical aspects, the formulated hypothesizes of scientific research were supported, that (1) Lithuania’s economic convergence with EMS full rights countries in accordance with the GDP parameters is enacting and stable; (2) contemporaneous meeting of all the criteria of convergence for the incompatibility inter some of them is hardly executed; (3) having the level of unemployment at least by 1 percent point higher (until that moment when the longevity of Lithuania’s convergence was being evaluated... [to full text]
67

Extensions of Skorohod’s almost sure representation theorem

Hernandez Ceron, Nancy Unknown Date
No description available.
68

Enterprise network convergence : path to cost optimization /

Sridharan, Vidhumana. January 2007 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 97-102).
69

Modélisation mathématique de quelques problèmes de mécanique par homogénéisation / Mathematical modeling of some mechanics problems by homogenization

Sontichai, Nuttawat 15 December 2010 (has links)
On étudie quelques problèmes singuliers d'homogénéisation en élasticité linéarisée ou électricté non-linéaire où, en plus de la période de distribution des hétérogénéités, apparaissent d'autres paramètres comme la très forte (ou faible) rigidité ou permittivité d'une des phases et la taille relative de celle-ci. Sont visés des milieux fibrés ou stratifiés et des maçonneries planes et minces. / We study some singular problems of homogenization in linearized elasticity or nonlinear electricty where, in addition to the period of distribution of heterogenities, other parameters do appear as the very high (or low) stiffness or permittivity of one phase and its the relative size. Fibered media, stratified media and flat and thin masonries are considered.
70

Convergence across the four Central and Eastern European states: Panel Data Approaches

Akhmetov, Daniyar January 2010 (has links)
The aim of the work is to analyze the convergence in the Czech Republic for the period of 1996- 2006. The paper is based primarily on the Barro and Sala-i-Martin's theories of convergence of sub-national territorial units. The regression results proved assumptions to be realistic. The main model concentrates on a panel data approach that captures the extent to which new transport infrastructure influences within-nation regional convergence. This paper developed a regional approach to evaluate the impact of transport infrastructure, human capital and migration in four Central and Eastern European countries - the Czech Republic, Hungary, Poland and the Slovak Republic. The aim is to present an overview of the convergence process of the Czech regions between 1996 and 2006. A neoclassical growth model is used as a framework to study convergence across the 14 administrative units of the Czech Republic. Data on gross value added per capita are exploited. 1

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