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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.
631

Contribución al control de admisión en redes móviles celulares multiservicio

García Roger, David 06 May 2008 (has links)
El trabajo contenido en esta tesis trata de contribuir en la caracterización, comprensión y desarrollo de mecanismos para la apropiada gestión de los recursos en las redes móviles celulares. En concreto, la aportación que comprende este esfuerzo incluye el desarrollo de modelos, algoritmos y métodos para estudiar el control de admisión desde una perspectiva estacionaria, y el desarrollo de esquemas que optimicen el comportamiento del control de admisión de manera adaptativa con respecto a las situaciones no estacionarias de los sistemas reales. / García Roger, D. (2007). Contribución al control de admisión en redes móviles celulares multiservicio [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1845 / Palancia
632

Mécanismes de contrôle de la qualité de services dans les réseaux WiMAX relais / Quality of Services Control Mechanisms in WiMAX Multihop Relay Networks

Brahmia, Mohamed El Amine 26 November 2012 (has links)
Nous assistons ces dernières années à une émergence constante de nouvelles applications, notamment pour les services audiovisuels. Ces applications imposent au réseau un certain nombre de contraintes pour qu’elles puissent fonctionner correctement. Le développement de mécanismes permettant d’offrir une garantie à ces contraintes, est donc devenu un objectif crucial. La norme IEEE 802.16j est l’une des solutions sans fil qui propose plus de ressources afin de supporter les nouveaux services de télécommunications. Dans la présente thèse, nous focalisons notre étude sur la problématique de la qualité de service dans les réseaux WiMAX relais. Nos contributions se regroupent à travers les étapes ci-dessous : Nous proposons un protocole de routage multicast pour les services IPTV (HDTV, SD-TV, Web-TV et Mobile-TV). Ce protocole repose d’une part sur un nouveau mécanisme de construction de l’arbre multicast basé sur les nombres premiers et d’autre part, sur une nouvelle méthode d’agrégation basée sur le standard de compression Vidéo «SVC». L’objectif est de supporter l’hétérogénéité des utilisateurs tout en optimisant la consommation des ressources. Par ailleurs, nous étudions le problème d’ordonnancement dans les réseaux WiMAX. Nous proposons un algorithme d’ordonnancement adaptatif AWRR, ce dernier se base sur une technique à charge pondérée. L’objectif est d’ajuster dynamiquement le poids de chaque classe de service, en prenant en compte la charge de la file d’attente et les contraintes de la QoS. Enfin, nous nous intéressons à l’étude de la problématique du chemin optimal contraint. Nous proposons une solution déterministe basée sur une fonction de coût. Notre fonction permet aussi d’assurer le contrôle d’admission, elle se base sur deux fonctions de coût élémentaires qui prennent en compte quatre critères de QoS. / Over recent years, new applications steadily developed in a tremendous space, especially in audiovisual services area. The present applications have some of constraints to work properly. The developments of mechanism which enable to overcome these constraints become a critical issue in this area. The IEEE 802.16j standard is one of wireless communication technology which offering more resources to support new telecommunication services. In this thesis, we focus our research on the problem of quality of service (QoS) inWiMAX relay networks. Our contributions are classified as follows : we proposed a multicast routing protocol for IPTV services (such as HD-TV, SD-TV, Web-TV and Mobile-TV). This proposed protocol used a new multicast tree construction mechanism based-on prime numbers. We also developed a new aggregation method based on standard video compression called Scalable Video Coding (SVC). Our goal is to support user’s heterogeneity while optimizing resources consumption. In addition, we studied the problem of scheduling inWiMAX networks.We proposed an adaptive scheduling algorithm AWRR for IPTV services. The aim of this method is to support QoS constraints by using two schedulers, and assigning a dynamic value to each service queue. Finally, we interested to study about the problem of path selection. We proposed a solution based on a deterministic cost function. This function also ensures admission control based on two basic cost functions which include four QoS criteria. This thesis has been prepared in the MIPS/GRTC laboratory, University of Haute Alsace, under a research contract external (CRE) framework with France Telecom R&D. All proposed mechanisms were evaluated by the simulator QualNet, Matlab and mathematical analysis.
633

A QoE Model for Digital Twin Systems in the Era of the Tactile Internet

Alja'Afreh, Mohammad 25 October 2021 (has links)
The idiom by Thomas Fuller fantasizes the fact that seeing is believing, but the feeling is the truth. This ideology has fired the vision and innovation of the Mulsemedia, multiple-sensorial media, and Internet of Skills (IoS) which enable the exchange of control, skills, and expertise anytime/everywhere across the Internet. With the emergence of the new generation of mobile network (5G), Tactile Internet, as well as the deployment of Industry 4.0 and Health 4.0, multimedia systems are moving towards immersed haptic enabled human-machine interaction systems such as the Digital Twin (DT). Specifically, Industry 4.0 will be using DT and robots on a large scale. This will increase human-machine and interaction to a great extent. There will be multimodal communications used to interact with digital twins and robots, specially haptics. Hence, tactile internet will replace the conventional internet today. In fact, a DT system can also be extended in Health 4.0 domain to act as a COVID-19 early warning system. Tracking a person’s temperature and other symptom data in real-time can signal if as well as when it’s time to see a doctor or take a COVID test. Link to a COVID tracing app, the digital twin might help get more information about the virus relative to the person itself. Since there are currently no well-recognized models to evaluate the performance of these systems, to address this research lacuna, we proposed a Quality-of-Experience (QoE) model for DT systems containing multi-levels of subjective, objective, and physiopsychological influencing factors. The model is itemized through a fully detailed taxonomy that deduces the perceived user’s emotional and physical states during and after consuming spatial, temporal, proximal, and abstracted multi-modality media between humans and machines. Further, the taxonomy was modelled using the best practice of machine learning methods to show how QoE for digital twin applications can be inferred and predicted from interactions and biosignals in this class of applications. Furthermore, the taxonomy was applied to two use cases. The first one addresses the objective quality optimization for transmission in a large scale immersed haptic virtual reality over the Internet while the second one aims to objectively infer an important DT QoE physiological aspect i.e, fatigue.
634

Metody měření výkonnostních a kvalitativních parametrů datových sítí / Methods for measurement of data network performance and quality parameters

Sukup, Luboš January 2012 (has links)
Master thesis involves the development of quality measurement issues and performance parameters in data networks. It describes the main technologies as they affect the quality and performance parameters and the effect of these parameters for voice, video and data services. Next are listed some methods for measuring parameters of the data network.In the practical part is selected one method of measuring network parameters and properties of this method are demonstrated by illustrative examples.
635

Implementace QoS v přístupové síti / QoS Implementation in Access Network

Adámek, David January 2008 (has links)
This diploma thesis deals with computer networks which play a key role in present society. More and more demands are placed on these networks (especially on quality of services and throughput) because of fast-growing developement of services such as voice and video real-time transmissions. All the packets in typical Ethernet networks are equal. Therefore it is sometimes impossible for the application to maintain required throughput speed of a network. For this case it is useful to take some mechanisms into the consideration. These mechanisms (sometimes called QoS) are able to distinguish different types of transmissions and traffic, analyze them and then prioritize them according to some pre-defined set of rules. The most famous mechanisms are Integrated Services and Differentiated Services. The implementation of Differentiated Services is the goal of this thesis.
636

Zajištění kvality služeb pomocí protokolu MPLS / Quality of service assurance using the MPLS protocol

Henzl, Václav January 2010 (has links)
The aim of this semestral thesis is to create a MPLS network model using OPNET Modeler program and consecutive simulation of this network behavior with focus on quality of service assurance. This project contains also theoretical introduction to the MPLS network problematic and quality of service assurance - hereafter it is focused on simulation and analysis of data flows in extended communication network model with focus on Voice Over IP parameters. This thesis is discovering attributes of MPLS with respect to network traffc.
637

Návrh laboratorních úloh v simulačním prostředí NS3 / Creation of laboratory exercises in the NS3 enviroment

Štefančík, Matej January 2015 (has links)
Diploma thesis provides an introduction to the ns-3 network simulator. It describes the basic abstactions and components of the instrument. This work further discusses the theory, which was applied during simulation creation. The concept of unicast, the issue of IP addressing and routing in networks are specificaly analyzed. The practical part is focused on the creation of four laboratory tasks within the scope of Advanced Communication Techniques. The first task is dedicated to the the issue of static unicast routing in the network. It clarifies the impact of metrics on the process of routing. The following task compares the different types of ICMPv4 and ICMPv6 messages. The third task discusses additional functions of the ICMPv6. Specifically, it focuses on five different types of ICMPv6 messages defined by NDP (Neighbor Discovery Protocol) and their role in the network traffic. The last task focuses on ensuring the quality of services (QoS) in wireless networks, by setting priorities and thereby dividing the traffic into different classes. Attention is focused on parameters such as throughput, delay and jitter.
638

Kritické parametry pro bezdrátové sítě WiFi a WiMAX / Critical Parameters for Wireless Networks WiFi and WiMAX

Grenar, Milan January 2015 (has links)
My thesis will be aimed at problems of wireless networks WiFi and WiMAX. A modelling of network will be put into effect onto which the measurement will be implemented and the impacts of network load on the data transfer Quality of Service (QoS) will be examined with aiming at VoIP. On this network model a power failure will be simulated and the impacts of this failure after restoring the power supply will be monitored. The aim of this thesis is to check the rate of network throughput while preserving a providing service quality and to suggest an economica1ly acceptable solution of the problems relating to feeding tension outage of the access point (AP) for a practical usage in these networks.
639

Softwarově definované sítě / Software defined networks

Flimel, Peter January 2016 (has links)
This diploma work describes the software-defined network focusing on optical networks. Subsequently designed their own software network that is implemented in the environment OMNeT ++. This work deals with SDN (software-defined network), and impact on current communications environment in the world of telecom-munications services.
640

Metody měření výkonnostních a kvalitativních parametrů datových sítí / Methods for measurement of data network performance and quality parameters

Sukup, Luboš January 2013 (has links)
Master thesis involves the development of quality measurement issues and performance parameters in data networks. It describes the main technologies as they affect the quality and performance parameters and the effect of these parameters for voice, video and data services. Next are listed some methods for measuring parameters of the data network.In the practical part is selected one method of measuring network parameters and properties of this method are demonstrated by illustrative examples.

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