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1
Holmström, Maria. "End-to-end monitoring of mobile services". Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1671.
Testo completoAbstract (sommario):
The growing market of mobile services through SMS, MMS, WAP and soon also for 3G protocols, requires efficient test methods to ensure that the customers get what they are paying for and in a reasonable time. Preferably, these tests should be done automatically and come as close to real conditions as possible. It would be valuable to be able to make tests from end to end, i.e. requesting and receiving the mobile services on a real mobile phone and combine that with a system that controls and evaluates the tests.
This thesis presents a solution to how the part of an end-to-end monitoring system for mobile services that runs on a mobile phone can be designed and implemented. The phone is made to interpret commands from a control process on a remote server and turn them into mobile service requests in a proper format (e.g. SMS or MMS). When it receives the reply from a mobile service provider, it forwards the relevant result information to the control process.
The monitoring system is based on Symbian OS, an operating system developed to suit handheld devices like mobile phones. The current implementation supports tests for SMS and MMS services.
The system is to be used by mobile operators or other providers of mobile services, which want to test and monitor their services.
2
Soudais, Guillaume. "End-to-End Service Guarantee for High-Speed Optical Networks". Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAT027.
Testo completoAbstract (sommario):
Poussée par un besoin croissant de bande passante et de performance, le réseau informatique s’est développé de telle sorte que les réseaux OT et de télécommunications cherchent à exploiter cette infrastructure pour leur expansion. Ces trois secteurs ont historiquement été séparés en raison de différentes exigences entre autres en matière de latence, de sa variation et de fiabilité. Pour répondre aux besoins des applications temps critiques, le groupe de travail Time Sensitive Network a développé de nouveaux ensembles de protocoles qui commencent à être mis en œuvre dans des produits commerciaux. D’autres groupes ont proposé des architectures novatrices avec contrôle du temps pour permettre des performances garanties, entre et à l’intérieur des centres de données périphériques. Dans ma thèse, je propose une solution pour transporter les applications temps critiques dans les réseaux existants, car elle ne nécessite pas de changer toute l’architecture. Je montre les avantages de sa mise en œuvre dans les réseaux TSN pour une solution pérenne avec une utilisation améliorée des ressources. Pour transporter le trafic temps critique dans les réseaux existants, je propose de créer un chemin en isolant et en planifiant le trafic temps critique sur un canal avec une latence garantie. Avec cette construction, je développe un algorithme pour effectuer une compensation de la variation de latence, permettant une transmission à la latence constante pour le trafic temps critique. Dans un second temps, je propose une méthode de synchronisation et mets en œuvre un réseau de mesure principalement utilise ici pour la mesure de la latence, m’aidant à obtenir des informations sur la distribution de la latence que mon protocole créé. Enfin, avec un algorithme de compensation de variation de latence amélioré, je démontre de meilleures performances en matière de gigue et étudie le temps de mise en service de notre protocole, permettant l’utilisation des ressources uniquement lorsque le trafic temps critique est présent. Dans ma thèse, je démontre, avec une implémentation FPGA, la réduction de la variation de latence, permettant aux applications des réseaux OT et de télécommunications de fonctionner sur les réseaux existants et augmentés par des normes TSNDriven by an ever-growing bandwidth and performance need, the IT network has grown such that OT and telecommunications networks are looking to exploit this infrastructure for their expansion. These three sectors have historically been separated due to different requirements, on latency, its variation and on reliability. To answer to time critical application needs, the Time Sensitive Network taskforce has developed new sets of protocols that are starting to be implemented in commercial products. Other groups have proposed novel architecture with time control to enable guaranteed performances between and inside edge datacenters. In my PhD I propose a solution to carry time critical application in legacy networks as it does not require to change the whole architecture. I show the benefits of its implementation in TSN networks for a future-proof solution with improved resource usage. To carry time critical traffic in legacy I propose to create a path by isolating and scheduling time critical traffic on a channel with guaranteed latency. With this construction, I build an algorithm to perform latency variation compensation enabling a constant latency transmission for time critical traffic. In a second time, propose a synchronization scheme and implemented a monitoring network primarily used here for latency monitoring, helping me gain insights on the distribution of latency that my protocol creates. Lastly, with an improved latency compensation algorithm, I demonstrate better jitter performances and study the turn-up time for our protocol enabling resource usage only when time-critical traffic is present. In my PhD I demonstrate, with an FPGA implementation and commercial product, latency variation reduction enabling OT and telecommunications network applications to run on legacy and TSN augmented network
3
Kyusakov, Rumen. "Efficient Web Services for End-To-End Interoperability of Embedded Systems". Doctoral thesis, Luleå tekniska universitet, EISLAB, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18129.
Testo completoAbstract (sommario):
As the number of Internet-connected devices rapidly grows, it has become ever more challenging to develop and maintain purpose-made tightly integrated distributed embedded systems. Instead, the Internet of Things (IoT) approach, based on standardized interfaces and open communication protocols, enables support for various applications with the possibility of extension to provide additional services that were not necessarily available at the initial deployment.This thesis presents methods and tools for the development of standard-based Web services for the Internet of Things. Some of the key challenges in using Web services on resource-constrained devices are due to the overhead of the communication protocols, which leads to the need for greater network bandwidth, processing power, and memory usage. A common solution to these problems is to use gateways that translate between the protocols used on one end of the connection (i.e. low-capability devices) and those on the other end (i.e. powerful Web servers). However, this increases the overall complexity of the system. The work presented herein answers the following research questions: 1) Is it feasible to deploy standard Web services on IoT systems without using application layer gateways? 2) What are the trade-offs in using Web services for end-to-end interoperability of resource-constrained embedded systems? 3) What levels of efficiency and functionality can be achieved using binary coding schemes for XML data exchange?The research questions are tested by building and evaluating several prototype IoT systems. These evaluations show that the use of Web services requires more powerful hardware (i.e. CPU and RAM) and a larger form factor in exchange for better interoperability compared to the use of ad hoc application protocols. The main challenge in employing embedded Web services is the large size of the messages, which is due to the use of verbose data formats such as XML. Although it is shown that it is possible to deploy XML-based Web services on low-capability devices without application layer gateways, this approach has severe performance limitations. Using the Efficient XML Interchange (EXI) binary coding scheme overcomes some of these limitations by substantially reducing the size of the XML messages. The main outcome of this thesis is the design and implementation of a software toolkit, called EXIP, for building EXI-based embedded Web services.The trade-offs in the use of embedded Web services are likely to change in the near future as the importance of application layer interoperability increases and IoT devices become faster, more energy efficient, and equipped with more memory. The dominating importance of interoperability can be seen in highly heterogeneous systems such as energy management systems (i.e. smart grids), where embedded Web services are already in use today. With this in mind, future research directions and extensions of this work include the development of performance optimization strategies for the EXIP toolkit to foster the expansion of embedded Web services to an even wider range of IoT applications.Godkänd; 2014; 20140909 (rumkyu); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Rumen Kyusakov Ämne: Industriell elektronik/Industrial Electronics Avhandling: Efficient Web Services for End-To-End Interoperability of Embedded Systems Opponent: Dr Frank Golatowski, Institute of Applied Microelements and CE, University of Rostock, Rostock-Warnemüende, Germany Ordförande: Biträdande professor Jens Eliasson, EISLAB, Institutionen för system- och rymdteknik, Luleå tekniska universitetet, Luleå Tid: Tisdag den 4 november 2014, kl. 13:00 Plats: A109, Luleå tekniska universitet
Embeddable EXI implementation in C, Architecture for Service-Oriented Process – Monitoring and Control, Arrowhead
4
Papageorgiou, Pavlos. "The measurement manager modular and efficient end-to-end measurement services /". College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8900.
Testo completoAbstract (sommario):
Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
5
VIZZARRI, ALESSANDRO. "End to end quality of service quality of experience evaluation for HTTP based services over LTE". Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2014. http://hdl.handle.net/2108/203507.
Testo completo
6
Salz, Jonathan Michael 1979. "TESLA : a transparent, extensible session-layer framework for end-to-end network services". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87292.
Testo completoAbstract (sommario):
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 69-73).
by Jonathan Michael Salz.
M.Eng.
7
Moyo, Thamsanqa. "An investigation into interoperable end-to-end mobile web service security". Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1137/.
Testo completo
8
Yoro, Wilfried. "Modeling the correlation between the energy consumption and the end-to-end traffic of services in large telecommunication networks". Thesis, Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0005/document.
Testo completoAbstract (sommario):
D’après Cisco, le trafic mobile de données augmentera d’un facteur 7 entre 2016 et 2021. Pour faire face à l’augmentation du trafic, les opérateurs mobile dimensionnent le réseau, ce qui s’accompagne d’une augmentation de sa consommation d’énergie et de son empreinte Carbonne. En outre, les marges financières des opérateurs baissent. Ainsi, le revenu global généré par le secteur des télécommunications a connu une baisse de 4% entre 2014 et 2015 d’après l’union internationale des télécommunications (UIT). Ces préoccupations ont suscité l’intérêt de la communauté scientifique pour la réduction de la consommation électrique des réseaux. Des études dans la littérature estiment l’énergie consommée par les services sur les équipements réseaux en se focalisant sur la consommation variable. La consommation énergétique d’un équipement réseau est composée d’une composante fixe et d’une composante variable. Dans cette thèse, nous partageons la responsabilité des catégories de service dans la consommation fixe du réseau en utilisant la valeur de Shapley. Dans un premier temps, nous considérons un réseau d’accès mobile et partageons la responsabilité des catégories de service qu’il fournit dans la consommation fixe. Nous définissons 5 catégories de service, à savoir, le «Streaming», le Web, le téléchargement, la voix et les autres services de données. En outre, nous traitons le cas de figure où certaines catégories de service sont obligatoires. Etant donné la complexité algorithmique de la valeur de Shapley, nous en proposons une forme approchée qui permet d’en réduire considérablement le temps de calcul. Ensuite, nous considérons le réseau de bout-en-bout, c’est-à-dire, l’accès mobile, l’accès fixe, la collecte, le coeur IP, le coeur mobile, les registres et les plateformes de service. Pour chaque segment, nous partageons la responsabilité des catégories de service dans la consommation fixe en appliquant notre modèle de partage basé sur la valeur de Shapley. L’analyse des résultats montre que le service «Streaming» consomme le plus d’énergie quel que soit le segment de réseau considéré, à l’exception des registres. Pour finir, nous traitons de la modélisation de l’efficacité énergétique des catégories de service. Dans un premier temps, nous calculons l’efficacité énergétique des catégories de service étant donné une station de base avec et sans «sleep mode». Ensuite, nous calculons l’efficacité énergétique des catégories de service étant donné un réseau d’accès mobile et considérant les cas avec et sans catégories de service obligatoires. Aussi étudions-nous les conditions pour ne pas détériorer l’efficacité énergétique du réseau au cours du temps en fonction des scénarios de dimensionnementInternet traffic is growing exponentially. According to Cisco, mobile data traffic will increase sevenfold between 2016 and 2021, growing at a compound annual growth rate (CAGR) of 47%. In order to improve or keep up with users quality of experience (QoE), mobile carriers upgrade the network with additional equipment. As a consequence, the network carbon footprint increases over time, alongside with its energy consumption. In addition, mobile carriers margins are decreasing. Global telecommunication revenues declined by 4% between 2014 and 2015 based on the international telecommunication union (ITU) figures. These concerns fostered a great interest in the research community for reducing networks energy consumption. In this regard, many works in the literature investigate the energy consumed by services on network equipment for optimization purposes notably, focusing on the variable component of energy consumption. Energy consumption of a network equipment is composed of a variable and a fixed components. The variable component is consumed to serve traffic. The fixed component is consumed irrespective of traffic. In this thesis, our objective is to share the responsibility of service categories in the fixed energy consumption. To do so, we use the Shapley value. First, we consider a radio access network and share the responsibility of the service categories it delivers in the fixed energy consumption. The services are classified into five categories, namely, Streaming, Web, Download, Voice and other data services. In addition, we consider the case when some service categories are mandatory to be provided, such as Voice due to legal constraints for instance. Because the Shapley value has a huge computational complexity, we introduce closed-form expressions in order to significantly reduce it. Next, we consider the end-to-end network and all its segments, that is, the mobile access, the fixed access, the collect, the mobile core, the registers, the IP core and the service platforms. For each segment, we share the responsibility of the service categories in the fixed energy consumption with the Shapley-based model introduced in the preceding chapter. We find that Streaming is the service that consumes the most whatever the network segment, except for registers, as it represents the vast majority of Internet traffic. Eventually, we focus on the service categories energy efficiency. First, we consider a base station and compute the services energy efficiency for the cases with and without sleep mode. Then, we consider a radio access network and compute the services energy efficiency with and without a mandatory player. Moreover, we discuss the conditions to not deteriorate the network energy efficiency over time following different upgrade scenarios
9
Yoro, Wilfried. "Modeling the correlation between the energy consumption and the end-to-end traffic of services in large telecommunication networks". Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0005.
Testo completoAbstract (sommario):
D’après Cisco, le trafic mobile de données augmentera d’un facteur 7 entre 2016 et 2021. Pour faire face à l’augmentation du trafic, les opérateurs mobile dimensionnent le réseau, ce qui s’accompagne d’une augmentation de sa consommation d’énergie et de son empreinte Carbonne. En outre, les marges financières des opérateurs baissent. Ainsi, le revenu global généré par le secteur des télécommunications a connu une baisse de 4% entre 2014 et 2015 d’après l’union internationale des télécommunications (UIT). Ces préoccupations ont suscité l’intérêt de la communauté scientifique pour la réduction de la consommation électrique des réseaux. Des études dans la littérature estiment l’énergie consommée par les services sur les équipements réseaux en se focalisant sur la consommation variable. La consommation énergétique d’un équipement réseau est composée d’une composante fixe et d’une composante variable. Dans cette thèse, nous partageons la responsabilité des catégories de service dans la consommation fixe du réseau en utilisant la valeur de Shapley. Dans un premier temps, nous considérons un réseau d’accès mobile et partageons la responsabilité des catégories de service qu’il fournit dans la consommation fixe. Nous définissons 5 catégories de service, à savoir, le «Streaming», le Web, le téléchargement, la voix et les autres services de données. En outre, nous traitons le cas de figure où certaines catégories de service sont obligatoires. Etant donné la complexité algorithmique de la valeur de Shapley, nous en proposons une forme approchée qui permet d’en réduire considérablement le temps de calcul. Ensuite, nous considérons le réseau de bout-en-bout, c’est-à-dire, l’accès mobile, l’accès fixe, la collecte, le coeur IP, le coeur mobile, les registres et les plateformes de service. Pour chaque segment, nous partageons la responsabilité des catégories de service dans la consommation fixe en appliquant notre modèle de partage basé sur la valeur de Shapley. L’analyse des résultats montre que le service «Streaming» consomme le plus d’énergie quel que soit le segment de réseau considéré, à l’exception des registres. Pour finir, nous traitons de la modélisation de l’efficacité énergétique des catégories de service. Dans un premier temps, nous calculons l’efficacité énergétique des catégories de service étant donné une station de base avec et sans «sleep mode». Ensuite, nous calculons l’efficacité énergétique des catégories de service étant donné un réseau d’accès mobile et considérant les cas avec et sans catégories de service obligatoires. Aussi étudions-nous les conditions pour ne pas détériorer l’efficacité énergétique du réseau au cours du temps en fonction des scénarios de dimensionnementInternet traffic is growing exponentially. According to Cisco, mobile data traffic will increase sevenfold between 2016 and 2021, growing at a compound annual growth rate (CAGR) of 47%. In order to improve or keep up with users quality of experience (QoE), mobile carriers upgrade the network with additional equipment. As a consequence, the network carbon footprint increases over time, alongside with its energy consumption. In addition, mobile carriers margins are decreasing. Global telecommunication revenues declined by 4% between 2014 and 2015 based on the international telecommunication union (ITU) figures. These concerns fostered a great interest in the research community for reducing networks energy consumption. In this regard, many works in the literature investigate the energy consumed by services on network equipment for optimization purposes notably, focusing on the variable component of energy consumption. Energy consumption of a network equipment is composed of a variable and a fixed components. The variable component is consumed to serve traffic. The fixed component is consumed irrespective of traffic. In this thesis, our objective is to share the responsibility of service categories in the fixed energy consumption. To do so, we use the Shapley value. First, we consider a radio access network and share the responsibility of the service categories it delivers in the fixed energy consumption. The services are classified into five categories, namely, Streaming, Web, Download, Voice and other data services. In addition, we consider the case when some service categories are mandatory to be provided, such as Voice due to legal constraints for instance. Because the Shapley value has a huge computational complexity, we introduce closed-form expressions in order to significantly reduce it. Next, we consider the end-to-end network and all its segments, that is, the mobile access, the fixed access, the collect, the mobile core, the registers, the IP core and the service platforms. For each segment, we share the responsibility of the service categories in the fixed energy consumption with the Shapley-based model introduced in the preceding chapter. We find that Streaming is the service that consumes the most whatever the network segment, except for registers, as it represents the vast majority of Internet traffic. Eventually, we focus on the service categories energy efficiency. First, we consider a base station and compute the services energy efficiency for the cases with and without sleep mode. Then, we consider a radio access network and compute the services energy efficiency with and without a mandatory player. Moreover, we discuss the conditions to not deteriorate the network energy efficiency over time following different upgrade scenarios
10
Bou, Diab Wafaa. "End-to-security of real-time services over beyond third generation networks". Versailles-St Quentin en Yvelines, 2010. http://www.theses.fr/2010VERS0011.
Testo completoAbstract (sommario):
La sécurité représente un grand défi pour la transmission du trafic temps-réel sur les réseaux IP, l'objectif est d'acquérir le même niveau de sécurité offert par la téléphonie standard sans affecter la performance et la qualité de service. Sécuriser les services multimédia temps-réel sur un réseau IP est un processus complexe; les solutions de sécurité doivent prendre en compte les contraintes temps-réel des services voix et multimédia et leurs mécanismes doivent traiter les attaques possibles et l’overhead associé. La nécessité d’offrir un certain niveau de qualité de service (QoS) résulte souvent de l’utilisation des faibles mécanismes de sécurité. Le problème d’appliquer les mécanismes de sécurité pour les applications sensibles en temps-réel est que la sécurité et l'efficacité sont des exigences contradictoires ; les mécanismes de sécurité dégradent la performance et la QoS de telles applications, c’est principalement car ces mécanismes peuvent être responsables de l'augmentation de la latence et de la perte de paquets ; si la latence est trop élevée elle peut être la contrainte la plus dégénérant de la qualité des communications multimédia temps-réel. D'autre part, l'un des défis majeurs pour les applications temps-réel sur des réseaux mobiles de prochaine génération ou les réseaux au-delà de troisième génération (B3G) est le handover vertical sans-couture (seamless vertical handover). Ces applications sensibles aux latences et à la perte de paquets nécessitent un contrôle de handover rapide et efficace sur les diverses technologies sans fil pour réaliser la continuité de service et la mobilité sans coupure tout en préservant la sécurité et la qualité de service. L'objectif de cette thèse est de fournir une solution de sécurité robuste sans compromis sur la qualité de service et la performance des applications multimédia temps réel. À cause de la nature temps-critique des applications multimédia et leur faible tolérance au délai et à la perte de paquet, de nombreux mécanismes de sécurité mis en oeuvre dans les réseaux de données ne sont pas applicables aux services temps réel. D'abord, nous étudions les mécanismes de sécurité utilisés actuellement pour la protection des applications IP et examinons les différentes solutions de sécurité VPN en présentant leurs avantages et inconvénients. Ensuite, nous analysons les mécanismes de sécurité supportant les services temps réel et permettant de protéger les signalisations et les trafics médias et comparons les différentes solutions afin de trouver une solution de sécurité robuste supportant des applications multimédia sur des réseaux d’accès hétérogènes. Ensuite, nous présentons une nouvelle solution VPN basé sur IPSec permettant d’offrir une sécurité de bout-en-bout pour les applications temps-réel tout en préservant la performance et la Qualité de Service. La solution est basée sur le protocole de sécurité IPSec et travaille indépendamment du réseau sous-jacent, elle offre de chiffrement de bout-en-bout et donc évite les bouchons (bottlenecks) des files d'attente au niveau des routeurs et protège les utilisateurs et les communications multimédia des attaquants de l'intérieur. La méthode de signalisation permet d’établir le tunnel VPN de bout-en-bout sans délai. Nous proposons une nouvelle méthode de routage du trafic média sécurisé sur les réseaux IP, cette méthode réduit l’overhead de traitement à chaque routeur dans le chemin et minimise la latence et la perte de paquet multimédia. Après cela, nous décrivons le défi de la sécurité et les exigences des applications temps réel durant le handover vertical. Les applications temps réel ont besoin d'une solution de gestion de la mobilité qui réalise le handover aussi rapide que possible et offre un handover sans couture sécurisé sans perception du point de vue d’utilisateur. Ensuite, nous présentons la nouvelle solution de gestion de mobilité offrant un handover sans-couture, rapide et sécurisé pour les applications temps réel durant la mobilité entre les réseaux d’accès hétérogènes. Cette solution effectue l’authentification et la protection de l'intégrité durant le processus de handover anticipé, ce qui minimise l’overhead de signalisation et entraîne une réduction significative de la latence de handover et la perte de paquet. La solution permet aussi de résoudre le problème de désynchronisation entre les utilisateurs dû au mécanisme de compression. Un nouveau module entre les domaines E-IDM (Enhanced Inter-Domain Module) est introduit pour assurer la qualité de service et la sécurité de bout-en-bout des applications multimédia temps réel, tout en offrant de handover sécurisé entre les réseaux d'accès hétérogènesSecurity presents a big challenge for transmitting real-time traffic over IP networks; the goal is to acquire the same security level offered by the standard telephony without affecting the performance and the quality of service. Securing real-time multimedia services over IP networks is a complex process; the security solutions must take into account the real-time constraints of voice and multimedia services and their mechanisms should address possible attacks and overhead associated with it. The need to provide certain level of Quality of Service (QoS) often results with weak security mechanisms. The problem of applying security mechanism for real-time sensitive applications is that security and efficiency are conflicting requirements and the security mechanisms may degrade the performance and the QoS of such applications. This is mainly because security mechanisms can be responsible for the increased latency and the packet loss; if latency is too high, it can be the most deteriorating constrain for the quality of the real-time multimedia communications. On the other hand, one of the major challenges for real-time applications over extgeneration mobile networks or the Beyond Third Generation Networks (B3G) is the seamless vertical handoff. Such latency and loss sensitive applications require fast and efficient handover control over various wireless technologies to realize service continuity and seamless mobility while preserving the security and the QoS. The aim of this thesis is to provide a robust security solution without compromising the QoS and the performance of the real-time multimedia applications. Because of the timecritical nature of multimedia applications and their low tolerance for disruption and packet loss, many security mechanisms implemented in data networks are not applicable to real-time services. We first investigate the different security mechanisms applying nowadays for protecting IP applications, and examine the various VPN security solutions presenting their advantages and drawbacks. Then, we analyze the mechanisms supporting real-time services and enabling to protect both the signaling and the media traffic, and compare the different
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Laverton, Christian. "Social Tagging of Services to Support End User Development in Ubiquitous Collaborative Environments". Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9581.
Testo completoAbstract (sommario):
Tailorability in ubiquitous computing systems is needed at different levels, depending on the targeted end users. For inexperienced end users lacking computer competency, high level mechanisms for tailoring are needed. Systems such as ASTRA, which use a service oriented architecture, can provide such high level tailorability through service composition. With service composition, services can be combined and configured to form applications. However, using service composition introduces new challenges for end users. To find appropriate services, users need mechanisms for searching and browsing services. Equally important is it that users are able to understand how services work and what functionality they offer. Service descriptions can ease this task, but the problem with existing approaches to service descriptions is that they are not intended for end users and are hard to understand. This work looks at social tagging, which is a collaborative process where users attach labels or tags to items. This leads to user created metadata, as opposed to metadata created by experts. By introducing social tagging in ASTRA to describe services, users are provided with a framework for sharing their understanding of services with fellow users. To create a solution for social tagging for service descriptions, a thorough problem analysis was performed. The analysis considered the design space of tagging systems to find appropriate design choices in the problem context. Providing several tag visibility levels was identified as important, especially community tagging. The quality of tags as seen from the community members' perspective is likely to increase, as members of communities often share similar opinions and understandings. An important difference identified between existing tagging systems and tagging of services is that services can be embedded in physical devices. Thus, services can be discovered and accessed physically, which means that physical access to the services' tags should be supported. A requirements specification for a tagging system was specified, focusing on the platform requirements for basic tagging mechanisms, tag based navigation, and searching. The requirements lead to a design of platform architecture, aiming at extending the UbiCollab platform with social tagging functionality. The architecture uses a client/server solution, where the server service is shared among a network of users and handles public and community level tags. The client service is a local service which handles private tags, and acts as an intermediary between end user tools and the server service. A prototype of the platform services and an end user tool was implemented. The implementation is demonstrated through scenarios, showing possible uses of the tagging system.
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Thomas, Rosemary Hellen. "Access to health care services : East-End Montreal (Quebec) English-speaking elderly experience". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111557.
Testo completoAbstract (sommario):
To better understand Anglophone elderly experience in accessing health care services in a Francophone area, it is important to look beyond availability of healthcare services near their homes. This study explored factors such as language competence, preference, motivation, reaching and waiting times, as contributors to elderly people's choice.A questionnaire designed for this study was administered to 199 males and females, aged 55 years and older, recruited from the only Anglophone Seniors' Centre in East-End Montreal. It was found that elderly people with limited French proficiency were more likely to travel out of their area for healthcare services, resulting in significantly longer average travel and waiting times. Of those who would have liked an interpreter, very few were actually able to get one. The most frequently expressed need was for more English or bilingual workers and services.
To improve access and enhance elderly people's quality of life, training and intervention programs need to be developed in collaboration with the government.
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AVINO, GIUSEPPE. "Development and Performance Evaluation of Network Function Virtualization Services in 5G Multi-Access Edge Computing". Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2875737.
Testo completo
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Hou, Wu-Nan [Verfasser]. "An approach to the machine front-end services for the CIM-Open System Architecture (CIM-OSA) / Wu-Nan Hou". Karlsruhe : KIT-Bibliothek, 1993. http://d-nb.info/1138708399/34.
Testo completo
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Reid, Shenee J. "Geographic differences in accessibility to renal treatment among black and white populations within Network 6 of the End Stage Renal Disease Networks". Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/reid.pdf.
Testo completo
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Duarte, Rafael Luiz. "Provisionamento baseado em web services de conexões fim-a-fim em redes opticas GMPLS". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259637.
Testo completoAbstract (sommario):
Orientador: Mauricio Ferreira MagalhãesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-07T01:33:38Z (GMT). No. of bitstreams: 1 Duarte_RafaelLuiz_M.pdf: 1020338 bytes, checksum: 55a286156672abedc8e5b20a444d8a7c (MD5) Previous issue date: 2006
Resumo: Para o provisionamento de conexões fim-a-fim em domínios ópticos é desejável uma solução de arquitetura que permita o estabelecimento automático destas conexões: A tecnologia GMPLS oferece um plano de controle que especifica mecanismos que estendem o roteamento e a sinalização do mundo IP contribuindo para a configuração automática de conexões em domínios ópticos. Este trabalho propõe uma arquitetura para o provisionamento de conexões fim-a-fim em redes ápticas GMPLS. Tal arquitetura é baseada na tecnologia Web services e permite o estabelecimento de dois tipos de conexões. A primeira, conhecida como SPC (Soft Permanent Connection), é utilizada pelo gerente do domínio óptico. O SPC conecta dois elementos de rede pertencentes ao mesmo domínio. A segunda, é uma conexão fim-a-fim na qual um usuário cliente pode enviar dados através de múltiplos domínios. Neste último caso, o cliente precisa negociar com cada domínio para verificar a disponibilidade de recursos. Para tal arquitetura foram criados módulos responsáveis pelo provisionamento e gerenciamento das conexões além da utilização do simulador GLASS para validação da arquitetura proposta
Abstract: For the provisioning of end-to-end connections in optical domains it is desirable to have an architecture that supports the automatic establishment of such connections. The GMPLS technology offers a control plan that specifies mechanisms which extend the routing and the signalling of IP world contributing for the automatic configuration of end-to-end connections in optical domains. This work proposes an architecture for the provisioning of end-to-end connections in GMPLS optical networks. Such architecture is based on the Web services technology and allows the establishment of two kinds of connections. The first one, known as SPC (Soft Permanent Connection), is used by the manager of the optical domain. The SPC connects two network elements belonging to the same domain. The second one is an end-to-end connection by which a given client can send data across multiple domains. In this last case the client needs to negotiate with each domain to verify the availability of resources. For such architecture we defined modules responsibIe for the provisioning and management of the connections. The GLASS simulator was used for validation ofthe proposed architecture
Mestrado
Engenharia de Computação
Mestre em Engenharia Elétrica
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Ho, I.-Van. "The role of tele-ophthalmology as part of a community health service to remote top end Northern Territory communities cost-effectiveness study of diabetic retinopathy screening, monitoring and management /". Connect to full text, 2006. http://hdl.handle.net/2123/5432.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Sydney, 2006.Title from title screen (viewed Oct. 7, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine. Includes bibliography. Also available in print form.
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Ho, I.-Van. "The role of tele-ophthalmology as part of a community health service to remote top end Northern Territory communities : cost-effectiveness study of diabetic retinopathy screening, monitoring and management". Phd thesis, Faculty of Medicine - Discipline of Clinical Ophthalmology and Eye Health, 2006. http://hdl.handle.net/2123/5432.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Sydney, 2006.Title from title screen (viewed Oct. 7, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine. Includes bibliography. Also available in print form.
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Serra, Ana Paula Gonçalves. "Método para identificação de parâmetros de qualidade de serviços aplicados a serviços móveis e interativos". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-26072007-175442/.
Testo completoAbstract (sommario):
Atualmente, os usuários desejam obter, fornecer, compartilhar e interagir com informações e serviços com conteúdo multimídia em qualquer lugar, a qualquer momento e com qualquer dispositivo. Para que isso seja possível, um dos grandes desafios é assegurar a QoS (Quality of Service) fim a fim (entre o usuário final e a organização provedora de serviço) para a disponibilização de serviços móveis e interativos com conteúdo multimídia para os usuários finais. Em geral esse tipo de serviço têm maior exigência de QoS, pois além dos parâmetros de redes, possuem parâmetros específicos para áudio, imagem e vídeo, além de exigirem sincronização de áudio e vídeo, e a QoS fim a fim deve considerar parâmetros de QoS sob a percepção do usuário final. Com isso, o objetivo deste trabalho é propor um método para o levantamento de parâmetros de QoS para o estabelecimento de USLAs (User Service Level Agreements - Acordo do Nível de Serviço do Usuário) entre a organização provedora de serviço e o usuário final para serviços móveis e interativos com conteúdo multimídia em um ambiente de convergência tecnológica. O método consiste em quatro passos: 1. identificação do serviço a ser oferecido ao usuário final e elaboração de um grafo em árvore, que tem como objetivo identificar outros serviços que podem compor o serviço a ser oferecido ao usuário final; 2. mapeamento dos parâmetros de QoS em um metamodelo; 3. validação do metamodelo, para que se possa extrair do metamodelo os parâmetros de QoS; 4. elaboração do USLA. Este trabalho propõe um primeiro passo para solucionar a falta de métodos padronizados para o estabelecimento de USLA para serviços móveis e interativos com conteúdo multimídia sob a percepção do usuário final. Além de facilitar a identificação e composição de serviços e parâmetros, por meio de um metamodelo que proporciona a integração de classes de serviços que podem ser facilmente reutilizadas e customizadas, de acordo, com o tipo de serviço oferecido pela organização provedora de serviço e pela necessidade do usuário final.In these days the final users wish to obtain, to furnish and to interact using interactive services with multimedia content anywhere, anytime and with any kind of user device. One of the biggest challenges is to assure the End-to End Quality of Service (E2E QoS) in the delivering of the interactive and multimedia services for moving users. In general, this kind of users have more strict requirements needs, because, besides of the computer network parameters, they need specify specific parameters like sound, image and video and their synchronization, on the users\' point of the view - perceived QoS. The main objective of this thesis is to present the application of a method for eliciting the E2E QoS parameters aiming the establishment of the User Service Level Agreement - USLA between the service provider and the final user applied to interactive and mobile services with multimedia content, inserted on a technological convergence environment. The method is a four steps method that consists of (1) an identification of the service to be offered to the final user and the elaboration of a tree graph aiming the identification of the composition of the service by other services (2) mapping the QoS parameters in a metamodel (3) validation of the metamodel, and extraction of the E2E QoS parameters (4) elaboration the USLA. This thesis proposes a first step to solve the lack of standardized methods for the establishment of the USLA for interactive and mobile services with multimedia content under the users\' perception. Besides of facilitating the identification and the composition of services and parameters, using a metamodel, that provides the integration of classes of services, that can be easily reused and customized, according, with the type of service offered for the service provider to the final user.
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McLaughlin, Dorry. "A study to develop and evaluate a multi-media resource in palliative and end-of-life care for specialist palliative care and learning disability services : promoting collaborative working". Thesis, University of Ulster, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558777.
Testo completoAbstract (sommario):
Background The literature highlights concerns regarding the quality of palliative care offered to people with learning disabilities (Michael, 2008). It is also recognised that better collaboration between learning disability and specialist palliative care services is essential to develop this area of practice and to provide quality palliative and end-of-life care to this population (Tuffrey- Wijne et ai, 2007b; Read and Morris, 2008; Ryan et ai, 2011). Aim: This study aimed to develop and evaluate a multi-media resource for specialist palliative care and learning disability services which promoted collaborative working Methods: A sequential, exploratory mixed methods research approach involving three phases was used. The study used a unique combined perspective of service users and health and social care professionals. In Phase 1 two focus groups took place with people with learning disabilities and semi structured interviews with five family carers and thirty health and social care professionals. This informed Phase 2 which involved a regional scoping study of end-of-life care service provision based on the structure of the National Gold Standard Framework for end-of-life care. From the findings of Phase 1 and 2, and in consultation with an expert reference group, a multi- media educational resource (DVD and Manual) was developed. An explorative evaluation of the resource took place with twelve professionals who had taken part in interviews in Phase 1. Findings: The findings of the study show that people with learning disabilities and family carers can inform the design and delivery of professional education and service provision in palliative and end-of-life care. Examples of good practice and areas needing service improvement have been identified. It is apparent that there are a range of unmet learning needs across learning disab.lity and specialist palliative care services which can be effectively met through joint working and learning. The study has provided greater insights into the rationale for and concepts of joint working and learning between learning disability and specialist palliative care services and a partnership framework has emerged from the findings of the study. Conclusions: This study has shown the value of involving a robust service user perspective in the development and delivery of a multi-media resource, which has demonstrated transferability of learning to practice. The resource promoted partnership working and the partnership framework which has emerged from the study demonstrates that the perceived barriers to joint working and learning are challenges that can be worked through. Most importantly the person with learning disability, and those who matter to them, have their place at the centre as they are also part of the joint working and learning that goes on in the partnership.
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Kayayurt, Barış Tuğlular Tuğkan. "End-to-end security for mobile devices/". [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/bilgisayaryazilimi/T000492.pdf.
Testo completo
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Chen, Xiaobao. "An end-to-end communication support architecture for multi-service applications". Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245146.
Testo completo
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Dobslaw, Felix. "End-to-End Quality of Service Guarantees for Wireless Sensor Networks". Doctoral thesis, Mittuniversitetet, Avdelningen för data- och systemvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-26289.
Testo completoAbstract (sommario):
Wireless sensor networks have been a key driver of innovation and societal progressover the last three decades. They allow for simplicity because they eliminate ca-bling complexity while increasing the flexibility of extending or adjusting networksto changing demands. Wireless sensor networks are a powerful means of fillingthe technological gap for ever-larger industrial sites of growing interconnection andbroader integration. Nonetheless, the management of wireless networks is difficultin situations wherein communication requires application-specific, network-widequality of service guarantees. A minimum end-to-end reliability for packet arrivalclose to 100% in combination with latency bounds in the millisecond range must befulfilled in many mission-critical applications.The problem addressed in this thesis is the demand for algorithmic support forend-to-end quality of service guarantees in mission-critical wireless sensor networks.Wireless sensors have traditionally been used to collect non-critical periodic read-ings; however, the intriguing advantages of wireless technologies in terms of theirflexibility and cost effectiveness justify the exploration of their potential for controland mission-critical applications, subject to the requirements of ultra-reliable com-munication, in harsh and dynamically changing environments such as manufactur-ing factories, oil rigs, and power plants.This thesis provides three main contributions in the scope of wireless sensor net-works. First, it presents a scalable algorithm that guarantees end-to-end reliabilitythrough scheduling. Second, it presents a cross-layer optimization/configurationframework that can be customized to meet multiple end-to-end quality of servicecriteria simultaneously. Third, it proposes an extension of the framework used toenable service differentiation and priority handling. Adaptive, scalable, and fast al-gorithms are proposed. The cross-layer framework is based on a genetic algorithmthat assesses the quality of service of the network as a whole and integrates the phys-ical layer, medium access control layer, network layer, and transport layer.Algorithm performance and scalability are verified through numerous simula-tions on hundreds of convergecast topologies by comparing the proposed algorithmswith other recently proposed algorithms for ensuring reliable packet delivery. Theresults show that the proposed SchedEx scheduling algorithm is both significantlymore scalable and better performing than are the competing slot-based schedulingalgorithms. The integrated solving of routing and scheduling using a genetic al-vvigorithm further improves on the original results by more than 30% in terms of la-tency. The proposed framework provides live graphical feedback about potentialbottlenecks and may be used for analysis and debugging as well as the planning ofgreen-field networks.SchedEx is found to be an adaptive, scalable, and fast algorithm that is capa-ble of ensuring the end-to-end reliability of packet arrival throughout the network.SchedEx-GA successfully identifies network configurations, thus integrating the rout-ing and scheduling decisions for networks with diverse traffic priority levels. Fur-ther, directions for future research are presented, including the extension of simula-tions to experimental work and the consideration of alternative network topologies.Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 4 (manuskript inskickat för granskning), delarbete 5 (manuskript inskickat för granskning)
At the time of the doctoral defence the following papers were unpublished: paper 4 (manuscript under review), paper 5 (manuscript under review)
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Deshpande, Jayram A. "Satisfying End to End Quality of Service Requirements in DTN Environments". Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1163644692.
Testo completo
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Singaravelu, Lenin. "End-to-End Security of Information Flow in Web-based Applications". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16142.
Testo completoAbstract (sommario):
Web-based applications and services are increasingly being used in security-sensitive tasks. Current security protocols rely on two crucial assumptions to protect the confidentiality and integrity of information: First, they assume that end-point software used to handle security-sensitive information is free from vulnerabilities. Secondly, these protocols assume point-to-point communication between a client and a service provider. However, these assumptions do not hold true with large and complex vulnerable end point software such as the Internet browser or web services middleware or in web service compositions where there can be multiple value-adding service providers interposed between a client and the original service provider.
To address the problem of large and complex end-point software, we present the AppCore approach which uses manual analysis of information flow, as opposed to purely automated approaches, to split existing software into two parts: a simplified trusted part that handles security-sensitive information and a legacy, untrusted part that handles non-sensitive information without access to sensitive information. Not only does this approach avoid many common and well-known vulnerabilities in the legacy software that compromised sensitive information, it also greatly reduces the size and complexity of the trusted code, thereby making exhaustive testing or formal analysis more feasible. We demonstrate the feasibility of the AppCore approach by constructing AppCores for two real-world applications: a client-side AppCore for https-based applications and an AppCore for web service platforms. Our evaluation shows that security improvements and complexity reductions (over a factor of five) can be attained with minimal modifications to existing software (a few tens of lines of code, and proxy settings of a browser) and an acceptable performance overhead (a few percent).
To protect the communication of sensitive information between the clients and service providers in web service compositions, we present an end-to-end security framework called WS-FESec that provides end-to-end security properties even in the presence of misbehaving intermediate services. We show that WS-FESec is flexible enough to support the lattice model of secure information flow and it guarantees precise security properties for each component service at a modest cost of a few milliseconds per signature or encrypted field.
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Ma, Kun. "Resource management in the cloud: An end-to-end Approach". University of Western Cape, 2020. http://hdl.handle.net/11394/7886.
Testo completoAbstract (sommario):
Philosophiae Doctor - PhDCloud Computing enables users achieve ubiquitous on-demand , and convenient access to a variety of shared computing resources, such as serves network, storage ,applications and more. As a business model, Cloud Computing has been openly welcomed by users and has become one of the research hotspots in the field of information and communication technology. This is because it provides users with on-demand customization and pay-per-use resource acquisition methods.
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Luo, Zongyang. "Routing and End-to-End Quality of Service in Satellite IP Networks". Thesis, University of Surrey, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486077.
Testo completoAbstract (sommario):
This thesis presents the studies of end-to-end quality of service (QoS) in satellite networks. The end-to-end QoS is affected by r0U:ting algorithms at the Internet Protocol (IP) networking layer and transmission control protocol/ user datagram protocol (TCPIUDP) protocols at the transport layer. In particular, this thesis investigates multi-constrained routing algorithm in low earth orbit (LEO) satellite networks and transport layer performance enhancements via reliable link layer support in satellite IP networks. Firstly, the routing algorithms/protocols for LEO satellite networks are investigated. A novel QoS routing algorithm is proposed for LEO satellite networks. A weighted graph model is used to analyse the QoS routing problem in LEO satellite networks. Based on this model, a Delay Constrained Longest lifeTime (DCLT) routing algorithm is proposed for LEO satellite networks. The novelty of this work is that the algorithm proposed tries to fmd the paths that fulfil the delay constraint of users' requests using heuristic methodology and at the same time, it tries to fmd a path that has longest lifetime to make sure the connection lasts as long as possible. This algorithm is more efficient particularly for LEO satellite networks since the re-routing attempts are reduced. Both theoretical analysis and simulation methods have been used to evaluate the performance of the algorithm. Secondly, the TCP performance with different link layer frame sizes and link layer retransmission mechanisms over geostationary earth orbit (GEO) satellite networks is investigated. TCP' performance decreases over satellite link with poor channel condition and long propagation delay. This work is mainly focused on how to eliminate the effect ofthe poor channel conditions on TCP performance. An analytical model is proposed to study the effect of different link layer frame sizes and retransmission mechanisms. Then, a link layer relay mechanism is proposed to enhance the TCP performance. From both the mathematical analysis and simulation results, it can be found that link layer frame with small sizes and link layer automatic repeat request (ARQ) can enhance TCP performance. Furthermore, with the proposed link layer relay mechanism, TCP throughput can be enhanced substantially especially under the very poor channel condition. Finally, the TCP performance with different link layer frame sizes and link layer frame retransmission mechanism is investigated over low earth orbit! medium earth orbit (LEO/MEO) multi-hop satellite networks. A LEOIMEO satellite network can be considered as a wireless multi-hop network with lower propagation delay compared with a GEO satellite network. With the analytical model proposed, the TCP performance with link layer retransmission mechanisms and different link layer frame sizes over multi-hop satellite networks is studied. In addition, a novel hop-by-hop link layer relay mechanism is proposed. From the results .. of modelling and simulation, it shows that rcp throughput can also be improved under poor channel condition. Key words: Quality of Service (QoS), QoS Routing, End-to-End QoS, rcp, Satellite IP Networks.
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Sallabi, Farag M. "End-to-end quality of service support for multimedia applications in the Internet". Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6376.
Testo completoAbstract (sommario):
Quality of Service (QoS) in the Internet is one of the most active research areas in recent years. With the introduction of sophisticated multimedia applications, researchers have concentrated in finding solutions to make the Internet a suitable environment for such applications. The obvious solution is to enable applications reserve network resources according to their QoS needs. Researchers have also suggested enhancing the existing routing protocols for handling QoS. In this thesis, we present an end-to-end QoS architecture based on resource reservations. The architecture proposes the introduction of domain agencies in network domains. The domain agency is responsible for managing the resources in its domain and reserve resources according to the received requests from the users. It handles immediate and advance resource reservations and adapts the reserved resources according to user interactions. It contains a QoS routing agent to construct a QoS intra-domain path. The QoS routing agent uses a modification of Dijkstra's algorithm to find a shortest-narrowest path that accommodates the requested QoS. We present the analytical study and implementation of the main components proposed in this thesis. Then we present implementation of the architecture in an agent environment, which provides a good opportunity to test and analyze the system.
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Pletka, Roman [Verfasser]. "Adaptive End-to-End Quality of Service Guarantees in IP Networks / Roman Pletka". Aachen : Shaker, 2004. http://d-nb.info/1181603889/34.
Testo completo
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de, Oliveira Jaudelice C. "New techniques for end-to-end quality of service provisioning in DiffServ/MPLS networks". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/14790.
Testo completo
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Baranda, Hortigüela Jorge. "End-to-end network service orchestration in heterogeneous domains for next-generation mobile networks". Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/672782.
Testo completoAbstract (sommario):
5G marks the beginning of a deep revolution in the mobile network ecosystem, transitioning to a network of services to satisfy the demands of new players, the vertical industries. This revolution implies a redesign of the overall mobile network architecture where complexity, heterogeneity, dynamicity, and flexibility will be the rule. Under such context, automation and programmability are essential to support this vision and overcome current rigid network operation processes. Software Defined Networking (SDN), Network Function Virtualization (NFV) and Network slicing are key enabling techniques to provide such capabilities. They are complementary, but they are still in its infancy and the synergies between them must be exploited to realise the mentioned vision.
The aim of this thesis is to further contribute to its development and integration in next generation mobile networks by designing an end-to-end (E2E) network service orchestration (NSO) architecture, which aligned with some guidelines and specifications provided by main standardization bodies, goes beyond current management and orchestration (MANO) platforms to fulfil network service lifetime requirements in heterogeneous multi-technology/administrative network infrastructures shared by concurrent instances of diverse network services.
Following a bottom-up approach, we start studying some SDN aspects related to the management of wireless network elements and its integration into hierarchical control architectures orchestrating networking resources in a multi-technology (wireless, optical, packet) infrastructure. Then, this work is integrated in an infrastructure manager module executing the joint resource abstraction and allocation of network and compute resources in distributed points of presence (PoPs) connected by a transport network, aspect which is not (or lightly) handled by current MANO platforms. This is the module where the integration between NFV and SDN techniques is executed. This integration is commanded by a Service Orchestrator module, in charge of automating the E2E lifecycle management of network services implementing network slices (NS) based on the vertical requirements, the available infrastructure resources, and, while fulfilling service level agreement (SLA) also during run-time operation. This architecture, focused on single administrative domain (AD) scenarios, constitutes the first group of contributions of this thesis.
The second group of contributions evolves this initial architecture to deal with the orchestration and sharing of NS and its network slice subnet instances (NSSIs) involving multiple ADs. The main differential aspect with current state-of-the-art solutions is the consideration of resource orchestration aspects during the whole orchestration process. This is fundamental to achieve the interconnection of NSSIs, hence making the E2E multi-domain orchestration and network slicing a reality in practice. Additionally, this work also considers SLA management aspects by means of scaling actions during run-time operation in such complex scenarios.
The third group of contributions demonstrate the validity and applicability of the resulting architectures, workflows, and interfaces by implementing and evaluating them in real experimental infrastructures featuring multiple ADs and transport technologies interconnecting distributed computing PoPs. The performed experimentation considers network service definitions close to real vertical use cases, namely automotive and eHealth, which help bridging the gap between network providers and vertical industries stakeholders. Experimental results show that network service creation and scaling times in the order of minutes can be achieved for single and multi-AD scenarios, in line with 5G network targets. Moreover, these measurements serve as a reference for benchmarking the different operations involved during the network service deployment. Such analysis are limited in current literature.5G marca el inicio de una gran revolución en las redes móviles, convirtiéndose en redes orientadas a servicios para satisfacer las demandas de nuevos actores, las industrias verticales. Esta revolución supone un rediseño total de la arquitectura de red donde la complejidad, heterogeneidad, dinamicidad y flexibilidad serán la norma. En este contexto, la automatización y programabilidad serán esenciales para superar los rígidos procesos actuales de operación de red. Las redes definidas por software (SDN), la virtualización de funciones de red (NFV) y el particionamiento de redes son técnicas clave para proporcionar dichas capacidades. Éstas son complementarias, pero aún recientes y sus sinergias se deben explotar para realizar la nueva visión. El objetivo de esta tesis es contribuir a su desarrollo e integración en la nuevas generaciones de redes móviles mediante el diseño de una arquitectura de orquestación de servicios de red (NSO) extremo a extremo (E2E), que alineada con algunas pautas y especificaciones de los principales organismos de estandarización, va más allá de los actuales sistemas de gestión y orquestación (MANO) para instanciar y garantizar los requisitos de los diversos servicios de red desplegados concurrentemente en infraestructuras heterogéneas compartidas que combinan múltiples tecnologías y dominios administrativos (AD). Siguiendo un enfoque ascendente, comenzamos a estudiar aspectos de SDN relacionados con la gestión de elementos de red inalámbricos y su integración en arquitecturas jerárquicas de orquestación de recursos de red en infraestructuras multi tecnología (inalámbrica, óptica, paquetes). Luego, este trabajo se integra en un módulo de administración de infraestructura que ejecuta de forma conjunta la abstracción y la asignación de recursos de red y computación en múltiples puntos de presencia (PoP) distribuidos conectados por una red de transporte, aspecto que no está (o ligeramente) considerado por los actuales sistemas MANO. Este módulo ejecuta la integración de las técnicas NFV y SDN. Esta integración está dirigida por el módulo Orquestador de Servicios, que automatiza la gestión E2E del ciclo de vida de los servicios de red implementando las diferentes particiones de red en base a los requisitos de los verticales, los recursos de infraestructura disponibles y mientras cumple los acuerdos de nivel de servicio (SLA) durante la operación del servicio. Esta arquitectura, centrada en escenarios con un único AD, forma el primer grupo de contribuciones de esta tesis. El segundo grupo de contribuciones evoluciona esta arquitectura abordando la orquestación y compartición de particiones de red y sus componentes (NSSIs) en escenarios con múltiples AD. La consideración detallada de aspectos de orquestación de recursos es el principal aspecto diferencial con la literatura. Esto es fundamental para la interconexión de NSSIs, haciendo realidad la orquestación E2E y el particionamiento de red en escenarios con múltiples AD. Además, se considera la gestión de SLA mediante acciones de escalado durante la operación del servicio en los escenarios mencionados. El tercer grupo de contribuciones valida las arquitecturas, procedimientos e interfaces resultantes pues se han implementado y evaluado sobre infraestructuras experimentales reales que presentan múltiples AD y tecnologías de transporte interconectando PoP distribuidos. Esta experimentación considera definiciones de servicios de red cercanos a casos de uso de verticales reales, como automoción y eHealth, ayudando a cubrir la brecha entre los proveedores de red y los verticales. Los resultados experimentales muestran que la creación y el escalado de servicios de red se pueden realizar en pocos minutos en escenarios con un único o múltiples ADs, en línea con los indicadores de red objetivos de 5G. Estas medidas, escasas en la literatura actual, sirven como referencia para caracterizar las diferentes operaciones involucradas durante el despliegue de servicios.
Arquitectura de computadors
32
Javadtalab, Abbas. "An End-to-End Solution for High Definition Video Conferencing over Best-Effort Networks". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/31954.
Testo completoAbstract (sommario):
Video streaming applications over best-effort networks, such as the Internet, have become very popular among Internet users. Watching live sports and news, renting movies, watching clips online, making video calls, and participating in videoconferences are typical video applications that millions of people use daily. One of the most challenging aspects of video communication is the proper transmission of video in various network bandwidth conditions. Currently, various devices with different processing powers and various connection speeds (2G, 3G, Wi-Fi, and LTE) are used to access video over the Internet, which offers best-effort services only. Skype, ooVoo, Yahoo Messenger, and Zoom are some well-known applications employed on a daily basis by people throughout the world; however, best-effort networks are characterized by dynamic and unpredictable changes in the available bandwidth, which adversely affect the quality of the video. For the average consumer, there is no guarantee of receiving an exact amount of bandwidth for sending or receiving video data. Therefore, the video delivery system must use a bandwidth adaptation mechanism to deliver video content properly. Otherwise, bandwidth variations will lead to degradation in video quality or, in the worst case, disrupt the entire service. This is especially problematic for videoconferencing (VC) because of the bulkiness of the video, the stringent bandwidth demands, and the delay constraints. Furthermore, for business grade VC, which uses high definition videoconferencing (HDVC), user expectations regarding video quality are much higher than they are for ordinary VC. To manage network fluctuations and handle the video traffic, two major components in the system should be improved: the video encoder and the congestion control.
The video encoder is responsible for compressing raw video captured by a camera and generating a bitstream. In addition to the efficiency of the encoder and compression speed, its output flow is also important. Though the nature of video content may make it impossible to generate a constant bitstream for a long period of time, the encoder must generate a flow around the given bitrate.
While the encoder generates the video traffic around the given bitrate, congestion management plays a key role in determining the current available bandwidth. This can be done by analyzing the statistics of the sent/received packets, applying mathematical models, updating parameters, and informing the encoder. The performance of the whole system is related to the in-line collaboration of the encoder and the congestion management, in which the congestion control system detects and calculates the available bandwidth for a specific period of time, preferably per incoming packet, and informs rate control (RC) to adapt its bitrate in a reasonable time frame, so that the network oscillations do not affect the perceived quality on the decoder side and do not impose adverse effects on the video session.
To address these problems, this thesis proposes a collaborative management architecture that monitors the network situation and manages the encoded video rate. The goal of this architecture is twofold: First, it aims to monitor the available network bandwidth, to predict network behavior and to pass that information to the encoder. So encoder can encode a suitable video bitrate. Second, by using a smart rate controller, it aims for an optimal adaptation of the encoder output bitrate to the bitrate determined by congestion control.
Merging RC operations and network congestion management, to provide a reliable infrastructure for HDVC over the Internet, represents a unique approach. The primary motivation behind this project is that by applying videoconference features, which are explained in the rate controller and congestion management chapter, the HDVC application becomes feasible and reliable for the business grade application even in the best-effort networks such as the Internet.
33
Wyngaard, Lisa Jade. "How can the rights of paying consumers to electricity be squared with the rights of Eskom to be paid?'". University of the Western Cape, 2018. http://hdl.handle.net/11394/6379.
Testo completoAbstract (sommario):
Magister Legum - LLM (Public Law and Jurisprudence)Electricity supply can be classified into three stages namely: generation, transmission and distribution, with the functions of generation and transmission being carried out by Eskom. In 2001, Eskom was converted from a statutory body into a public company having a share capital with its entire share capital held by the State. It is a major public entity and therefore an Organ of State and albeit that Eskom is classified as a public company, it is still a State-owned Enterprise. Municipalities purchase electricity from Eskom in bulk in order to carry out the distribution function and manage bulk supply of electricity to end-users in terms of the Local Government: Municipal Structures Act 117 of 1998 (Structures Act). Municipalities re-sell electricity purchased from Eskom to end-users as well as provide free basic electricity to indigent consumers.
34
Mulkijanyan, Nina. "Evaluation Procedure for QoS of Short Message Service : International SMS Route Analysis". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49828.
Testo completoAbstract (sommario):
Due to its ubiquitous availability, Short Message Service (SMS), first introduced in the 1980s, became not only the most popular way of communication, but also stimulated the development of SMS-based value added services. This application-to-person traffic is delivered to end users through SMS aggregators who provide the link between service providers and mobile carriers. In order to perform optimal traffic routing, the aggregators need to estimate the quality of each potential international route to the specified destination. The evaluation criteria include end-to-end delivery time, as well as correct verification of delivered data. This thesis suggests a method of quality of service (QoS) assessment for international SMS service which combines two types of tests, end-to-end delay measurements and various verification tests. A prototype of the testing system for international SMS service was developed to generate SMS traffic, collect and analyze results, and evaluate the experienced QoS of the SMS route used in accordance with the proposed approach. As a part of end-to- end delay measurement tests, SMS traffic was sent to Singtel network in Singapore along two routes. The verification tests were executed via different routes to two mobile networks: Singtel and Tele2 (Sweden). The results of the performed measurements determined the route with the highest QoS, i.e. the one with bigger bottleneck bandwidth and lower data loss rate. The prototype of the SMS testing system can be used by SMS aggregators to verify delivery of a SMS message, check the integrity of the message, figure out interconnection type of the route supplier with the destination carrier and to identify the presence of load balancers in the path. The prototype also makes it possible to compare end-to-end delay times of several routes and compute bottleneck values for each of the tested routes.
35
Fredriksson, Desireé. "End-to-end latency and cost impact of function segregation and customized memory allocation in FaaS environments". Thesis, Umeå universitet, Institutionen för datavetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184634.
Testo completoAbstract (sommario):
Function as a service (FaaS) is a type of serverless cloud computing intended to facilitate development by abstracting away infrastructural management, and offer a more flexible, pay-as-you-go billing model based on execution time and memory allocation. FaaS functions are deployed to the cloud provider as either single units, or chained to form a pipeline of multiple functions that call each other. As each step in the pipeline might have different requirements, it could be beneficial to split larger functions into smaller parts. This would enable customized provisioning according to each function's needs, and potentially result in a lower rate. However, decreased memory entails a lower CPU performance, which directly correlates to computation time. A test application was created and executed on Google Cloud services to investigate what impact function segregation, and provisioning accommodated to each sub-function requirement, have on end-to-end latency and total cost. In conclusion, no trivial relation between cost and performance was found. Segregating and adjusting provisioning to required memory was in this experiment cheaper in some cases, but not all; however, always significantly slower. In addition to price and workload behavior being considered and balanced, it was found that aspects such as level of control over management and hardware configuration has to be weighed in when deciding if FaaS is a suitable alternative for a given situation.
36
Ghorbanzadeh, Mohammad. "Resource Allocation and End-to-End Quality of Service for Cellular Communications Systems in Congested and Contested Environments". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/64390.
Testo completoAbstract (sommario):
This research addresses the concept of radio resource allocation for cellular communications systems operating in congested and contested environments with an emphasis on end-to-end quality of service (QoS). The radio resource allocation is cast under a proportional fairness formulation which translates to a convex optimization problem. Moreover, the resource allocation scheme considers subscription-based and traffic differentiation in order to meet the QoS requirements of the applications running on the user equipment in the system. The devised resource allocation scheme is realized through a centralized and a distributed architecture and solution algorithms for the aforementioned architectures is derived and implemented in the mobile devices and the base stations. The sensitivity of the resource allocation scheme to the temporal dynamics of the quantity of the users in the system is investigated. Furthermore, the sensitivity of the resource allocation scheme to the temporal dynamics in the application usage percentages is accounted for. In addition, a transmission overhead of the centralized and distributed architectures for the resource allocation schemes is performed. Furthermore, the resource allocation scheme is modified to account for a possible additive bandwidth done through spectrum sharing in congested and contested environments, in particular spectrally coexistent radar systems. The radar-spectrum additive portion is devised in a way to ensure fairness of the allocation, high bandwidth utilization, and interference avoidance. In order to justify the aforesaid modification, the interference from radar systems into the Long Term Evolution (LTE) as the predominant 4G technology is studies to confirm the possibility of the spectrum sharing. The preceding interference analysis contains a detailed simulation of radar systems, propagation path loss models, and a third generation partnership project compliant LTE system. The propagation models are Free Space Path Loss (FSPL) and Irregular Terrain Model (ITM). The LTE systems under consideration are macro cell, outdoor small cells, and indoor small cells. Furthermore, the resource allocation under channel consideration is formalized such that the resources are allocated under a congested environment and based on the quality of channel the users have in the network as well as the quality of service requirements of the applications running on the mobile devices.Ph. D.
37
Abbasi, Munir A. "Interoperability of wireless communication technologies in hybrid networks : evaluation of end-to-end interoperability issues and quality of service requirements". Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5562.
Testo completoAbstract (sommario):
Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation.
38
Zhang, Peilin Verfasser], Oliver [Akademischer Betreuer] Theel, Oliver [Akademischer Betreuer] [Kramer e Olaf [Akademischer Betreuer] Landsiedel. "Improving end-to-end quality of service in low-power wireless sensor networks / Peilin Zhang ; Oliver Theel, Oliver Kramer, Olaf Landsiedel". Oldenburg : BIS der Universität Oldenburg, 2020. http://d-nb.info/121965311X/34.
Testo completo
39
Zhang, Peilin [Verfasser], Oliver [Akademischer Betreuer] Theel, Oliver [Akademischer Betreuer] Kramer e Olaf [Akademischer Betreuer] Landsiedel. "Improving end-to-end quality of service in low-power wireless sensor networks / Peilin Zhang ; Oliver Theel, Oliver Kramer, Olaf Landsiedel". Oldenburg : BIS der Universität Oldenburg, 2020. http://d-nb.info/121965311X/34.
Testo completo
40
Geyer, Fabien [Verfasser], Georg [Akademischer Betreuer] Carle e Jörg [Akademischer Betreuer] Liebeherr. "End-to-End Flow-Level Quality-of-Service Guarantees for Switched Networks / Fabien Geyer. Gutachter: Georg Carle ; Jörg Liebeherr. Betreuer: Georg Carle". München : Universitätsbibliothek der TU München, 2015. http://d-nb.info/1075317282/34.
Testo completo
41
Chung, Edward Chi-Fai. "Quality of service analysis for distributed multimedia systems in a local area networking environment". Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1174610545.
Testo completo
42
Chen, Tao. "Development and simulation of hard real-time switched-ethernet avionics data network". Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6995.
Testo completoAbstract (sommario):
The computer and microelectronics technologies are developing very quickly nowadays. In the mean time, the modern integrated avionics systems are burgeoning unceasingly. The modern integrated modular architecture more and more requires the low-latency and reliable communication databus with the high bandwidth. The traditional avionics databus technology, such as ARINC429, can not provide enough high speed and size for data communication, and it is a problem to achieve transmission mission successfully between the advanced avionic devices with the sufficient bandwidth.
AFDX(Avionics Full Duplex Switched Ethernet) is a good solution for this problem, which is the high-speed full duplex switched avionic databus, on the basis of the Ethernet technology. AFDX can not only avoid Ethernet conflicts and collisions, but also increase transmission rate with a lower weigh of the databus. AFDX is now adopted by A380,B787 aircraft successfully.
The avionics data must be delivered punctualy and reliablely, so it is very essential to validate the real-time performance of AFDX during the design process. The simulation is a good method to acquire the network performance, but it only happends in some given set of scenarios, and it is impossible to consider every case. So a sophisticatd network performance method for the worst-case scenario with the pessimistic upper bound requires to be deduced. The avionic design engineers have launched many researches in the AFDX simulation and methods study. That is the goal that this thesis is aimming for.
The development of this project can been planned in the following two steps.
In the first step, a communication platform plans to be implemented to simulate the AFDX network in two versions – the RTAI realtime framework and Linux user space framework. Ultimately, these frameworks need to be integrated into net-ASS, which is an integrated simulation and assessment platform in the cranfield’s lab.The second step deduces an effective method to evaluate network performance, including three bounds(delay,backlog and output flow), based on the NC. It is called Network Calculus. It is an internet theory keeping the network system in determistic way. It is also used in communication queue management. This mathematics method is planed to be verified with simulation results from the AFDX simuation communication platform, in order to assure its validity and applicability.
All in all, the project aims to assess the performance of different network topologies in different avionic architectures, through the simulation and the mathematical assessment. The technologies used in this thesis benefit to find problems and faults in the beginning stage of the avionics architecture design in the industrial project, especially, in terms of guarantee the lossless service in avionics databus.
43
Anna, Kiran Babu. "A NEW FRAMEWORK FOR QOS PROVISIONING IN WIRELESS LANS USING THE P-PERSISTENT MAC PROTOCOL". Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2381.
Testo completoAbstract (sommario):
The support of multimedia traffic over IEEE 802.11 wireless local area networks (WLANs) has recently received considerable attention. This dissertation has proposed a new framework that provides efficient channel access, service differentiation and statistical QoS guarantees in the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e. In the first part of the dissertation, the new framework to provide QoS support in IEEE 802.11e is presented. The framework uses three independent components, namely, a core MAC layer, a scheduler, and an admission control. The core MAC layer concentrates on the channel access mechanism to improve the overall system efficiency. The scheduler provides service differentiation according to the weights assigned to each Access Category (AC). The admission control provides statistical QoS guarantees. The core MAC layer developed in this dissertation employs a P-Persistent based MAC protocol. A weight-based fair scheduler to obtain throughput service differentiation at each node has been used. In wireless LANs (WLANs), the MAC protocol is the main element that determines the efficiency of sharing the limited communication bandwidth of the wireless channel. In the second part of the dissertation, analytical Markov chain models for the P-Persistent 802.11 MAC protocol under unsaturated load conditions with heterogeneous loads are developed. The Markov models provide closed-form formulas for calculating the packet service time, the packet end-to-end delay, and the channel capacity in the unsaturated load conditions. The accuracy of the models has been validated by extensive NS2 simulation tests and the models are shown to give accurate results. In the final part of the dissertation, the admission control mechanism is developed and evaluated. The analytical model for P-Persistent 802.11 is used to develop a measurement-assisted model-based admission control. The proposed admission control mechanism uses delay as an admission criterion. Both distributed and centralized admission control schemes are developed and the performance results show that both schemes perform very efficiently in providing the QoS guarantees. Since the distributed admission scheme control does not have a complete state information of the WLAN, its performance is generally inferior to the centralized admission control scheme. The detailed performance results using the NS2 simulator have demonstrated the effectiveness of the proposed framework. Compared to 802.11e EDCA, the scheduler consistently achieved the desired throughput differentiation and easy tuning. The core MAC layer achieved better delays in terms of channel access, average packet service time and end-to-end delay. It also achieved higher system throughput than EDCA for any given service differentiation ratio. The admission control provided the desired statistical QoS guarantees.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science PhD
44
Li, Ruogu. "Principles and Methods of Adaptive Network Algorithm Design under Various Quality-of-Service Requirements". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354642003.
Testo completo
45
Stenström, Simon, e Victor Pege. "Högpristjänster mot lägre marknadssegment : En kvalitativ studie av SaaS-företag och dess ompositionering mot lägre marknadssegment". Thesis, Södertörns högskola, Företagsekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-36013.
Testo completoAbstract (sommario):
Företag använder marknadssegmentering för att dela in kunder i grupper utefter liknande karaktäristika, som exempelvis betalningsvilja. Företag kan i sinom tid möta en mättad marknad inom dess segment, och behöver då ompositionera strategier mot nya segment för fortsatt kundtillväxt. För företag som valt en positionering mot segment med hög betalningsvilja (high-end), är en möjlighet för fortsatt kundtillväxt istället ompositionering mot lägre segment (low-end). Syftet med studien var att kartlägga och identifiera hur företag besittande en högpristjänst, kan nå kunder med lägre betalningsvilja genom nedåtgående segmentering. Detta utan att skada varumärket och riskera förluster av befintliga kunder. Utifrån syftet fastslogs följande frågeställning: • Hur kan SaaS-företag som besitter en high-end tjänst, använda nedåtgående segmentering utan att skada varumärket och förlora befintliga kunder? Studiens avgränsning begränsades till SaaS-företag, en delbransch inom IT-branschen. Detta med anledning av dess unika, relativt obefintliga, marginalkostnad. Studien har genomförts genom att använda en kvalitativ forskningsmetodik, i form av fem semistrukturerade intervjuer med fyra företag ståendes inför det problem som berörs. Studien består genomgående av en struktur baserad på blocken segmentering, tillväxt, lönsamhet samt varumärke. Studiens resultat, baserad på insamlad empiri och analys, har lett till en slutsats som påvisat fyra stycken beståndsdelar. Dessa ter sig vara faktorer som en high-end tjänst bör inneha, för en lyckad strategiförändring mot lägre marknadssegment. Dessa fyra kriterier är marknadsmedvetenhet, skalbar tjänst, flerstegig prismodell samt varumärkesmedvetenhet.Companies use market segmentation to divide customers into groups along similar characteristics, such as willingness to pay. Companies could eventually meet a saturated market within its segments, and would then need to reposition towards new segments for continued customer growth. For companies that choose to position themselves against segments with high willingness to pay (high-end), a possibility of continued customer growth is to position segments with lower willingness to pay (low- end). The purpose of this thesis was to plot and identify how companies, proprietors of a high-end solution, can use downward segmentation to reach customers with lower willingness to pay. This without damaging the brand and risking losses of existing customers. Based on the purpose of the thesis, the following research question has been established: • How can SaaS-companies that have a high-end service, use downward segmentation without damaging their brand and losing existing customers? The delimitation of the study was limited to SaaS companies, a sub-sector in the IT industry. This is due to its unique, relatively non-existent, marginal cost. The study has been conducted using a qualitative research method, in the form of five semi structured interviews with four companies facing the problem concerned. The study is continuously conducted through a structure based on segmentation, growth, profitability and brand. The results of the study, based on collected empirical data and the analysis, have led to a conclusion containing four specific components. These appear to be factors that a high-end service should hold for a successful strategy change towards lower market segments. These four criteria are market awareness, scalable service, multi-pricing model and brand awareness. This thesis is written in Swedish.
46
Nguyen, Huu-Nghi. "Estimation de l’écart type du délai de bout-en-bout par méthodes passives". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1044/document.
Testo completoAbstract (sommario):
Depuis l'avènement du réseau Internet, le volume de données échangées sur les réseaux a crû de manière exponentielle. Le matériel présent sur les réseaux est devenu très hétérogène, dû entre autres à la multiplication des "middleboxes" (parefeux, routeurs NAT, serveurs VPN, proxy, etc.). Les algorithmes exécutés sur les équipements réseaux (routage, “spanning tree”, etc.) sont souvent complexes, parfois fermés et propriétaires et les interfaces de supervision peuvent être très différentes d'un constructeur/équipement à un autre. Ces différents facteurs rendent la compréhension et le fonctionnement du réseau complexe. Cela a motivé la définition d'un nouveau paradigme réseaux afin de simplifier la conception et la gestion des réseaux : le SDN (“Software-defined Networking”). Il introduit la notion de contrôleur, qui est un équipement qui a pour rôle de contrôler les équipements du plan de données. Le concept SDN sépare donc le plan de données chargés de l'acheminement des paquets, qui est opéré par des équipements nommés virtual switches dans la terminologie SDN, et le plan contrôle, en charge de toutes les décisions, et qui est donc effectué par le contrôleur SDN. Pour permettre au contrôleur de prendre ses décisions, il doit disposer d'une vue globale du réseau. En plus de la topologie et de la capacité des liens, des critères de performances comme le délai, le taux de pertes, la bande passante disponible, peuvent être pris en compte. Cette connaissance peut permettre par exemple un routage multi-classes, ou/et garantir des niveaux de qualité de service. Les contributions de cette thèse portent sur la proposition d'algorithmes permettant à une entité centralisée, et en particulier à un contrôleur dans un cadre SDN, d'obtenir des estimations fiables du délai de bout-en-bout pour les flux traversant le réseau. Les méthodes proposées sont passives, c'est-à-dire qu'elles ne génèrent aucun trafic supplémentaire. Nous nous intéressons tout particulièrement à la moyenne et l'écart type du délai. Il apparaît que le premier moment peut être obtenu assez facilement. Au contraire, la corrélation qui apparaît dans les temps d'attentes des noeuds du réseau rend l'estimation de l'écart type beaucoup plus complexe. Nous montrons que les méthodes développées sont capables de capturer les corrélations des délais dans les différents noeuds et d'offrir des estimations précises de l'écart type. Ces résultats sont validés par simulations où nous considérons un large éventail de scénarios permettant de valider nos algorithmes dans différents contextes d'utilisationSince the early beginning of Internet, the amount of data exchanged over the networks has exponentially grown. The devices deployed on the networks are very heterogeneous, because of the growing presence of middleboxes (e.g., firewalls, NAT routers, VPN servers, proxy). The algorithms run on the networking devices (e.g., routing, spanning tree) are often complex, closed, and proprietary while the interfaces to access these devices typically vary from one manufacturer to the other. All these factors tend to hinder the understanding and the management of networks. Therefore a new paradigm has been introduced to ease the design and the management of networks, namely, the SDN (Software-defined Networking). In particular, SDN defines a new entity, the controller that is in charge of controlling the devices belonging to the data plane. Thus, in a SDN-network, the data plane, which is handled by networking devices called virtual switches, and the control plane, which takes the decisions and executed by the controller, are separated. In order to let the controller take its decisions, it must have a global view on the network. This includes the topology of the network and its links capacity, along with other possible performance metrics such delays, loss rates, and available bandwidths. This knowledge can enable a multi-class routing, or help guarantee levels of Quality of Service. The contributions of this thesis are new algorithms that allow a centralized entity, such as the controller in an SDN network, to accurately estimate the end-to-end delay for a given flow in its network. The proposed methods are passive in the sense that they do not require any additional traffic to be run. More precisely, we study the expectation and the standard deviation of the delay. We show how the first moment can be easily computed. On the other hand, estimating the standard deviation is much more complex because of the correlations existing between the different waiting times. We show that the proposed methods are able to capture these correlations between delays and thus providing accurate estimations of the standard deviation of the end-to-end delay. Simulations that cover a large range of possible scenariosvalidate these results
47
Shi, Xiaohan. "A reliable real-time transport protocol for networked control systems over wireless networks". Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/60160/1/Xiaohan_Shi_Thesis.pdf.
Testo completoAbstract (sommario):
Deploying wireless networks in networked control systems (NCSs) has become more and more popular during the last few years. As a typical type of real-time control systems, an NCS is sensitive to long and nondeterministic time delay and packet losses. However, the nature of the wireless channel has the potential to degrade the performance of NCS networks in many aspects, particularly in time delay and packet losses. Transport layer protocols could play an important role in providing both reliable and fast transmission service to fulfill NCS’s real-time transmission requirements. Unfortunately, none of the existing transport protocols, including the Transport Control Protocol (TCP) and the User Datagram Protocol (UDP), was designed for real-time control applications. Moreover, periodic data and sporadic data are two types of real-time data traffic with different priorities in an NCS. Due to the lack of support for prioritized transmission service, the real-time performance for periodic and sporadic data in an NCS network is often degraded significantly, particularly under congested network conditions.
To address these problems, a new transport layer protocol called Reliable Real-Time Transport Protocol (RRTTP) is proposed in this thesis. As a UDP-based protocol, RRTTP inherits UDP’s simplicity and fast transmission features. To improve the reliability, a retransmission and an acknowledgement mechanism are designed in RRTTP to compensate for packet losses. They are able to avoid unnecessary retransmission of the out-of-date packets in NCSs, and collisions are unlikely to happen, and small transmission delay can be achieved. Moreover, a prioritized transmission mechanism is also designed in RRTTP to improve the real-time performance of NCS networks under congested traffic conditions. Furthermore, the proposed RRTTP is implemented in the Network Simulator 2 for comprehensive simulations. The simulation results demonstrate that RRTTP outperforms TCP and UDP in terms of real-time transmissions in an NCS over wireless networks.
48
Li, Ding. "Localised Routing Algorithms with Quality of Service Constraints. Development and performance evaluation by simulation of new localised Quality of Service routing algorithms for communication networks using residual bandwidth and mean end-to-end delay as metrics". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4912.
Testo completoAbstract (sommario):
Localised QoS routing is a relatively new, alternative and viable approach to solve the problems of traditional QoS routing algorithms which use global state information resulting in the imposition of a large communication overhead and route flapping. They make use of a localised view of the network QoS state in source nodes to select paths and route flows to destination nodes. Proportional Sticky Routing (PSR) and Credit Based Routing (CBR) have been proposed as localised QoS routing schemes and these can offer comparable performances. However, since network state information for a specific path is only updated when the path is used, PSR and CBR operate with decision criteria that are often stale for paths that are used infrequently. The aim of this thesis is to focus on localised QoS routing and contribute to enhancing the scalability of QoS routing algorithms. In this thesis we have developed three new localised QoS routing schemes which are called Score Based QoS Routing (SBR), Bandwidth Based QoS Routing (BBR) and Delay Based Routing (DBR). In some of these schemes, the path setup procedure is distributed and uses the current network state to make decisions thus avoiding problems of staleness. The methods also avoid any complicated calculations. Both SBR and BBR use bandwidth as the QoS metric and mean delay is used as the QoS metric in DBR. Extensive simulations are applied to compare the performance of our proposed algorithms with CBR and the global Dijkstra's algorithm for different update intervals of link state, different network topologies and using different flow arrival distributions under a wide range of traffic loads. It is demonstrated by simulation that the three proposed algorithms offer a superior performance under comparable conditions to the other localised and global algorithms.
49
Fornasa, Martino. "Network Access Capacity Estimation through Passive Traffic Measurement". Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3425622.
Testo completoAbstract (sommario):
This work proposes models, techniques and tools aimed at passively estimating the maximum achievable downlink network-layer bandwidth (capacity) of an access link to the Internet from inside a network. The Internet access capacity estimation by mean of passive measurements is an interesting issue from a scientific and from an industrial perspective.
From a scientific perspective the problem, still open, is of interest because of the packet based and best effort based nature of the TCP/IP, that makes the user perceived rate depend not only on the access rate but also on the backbone performance and on the endpoint server performance. Extracting the access rate from TCP/IP observations requires the development of appropriate models, algorithms and techniques.
From an industrial perspective the problem is relevant considering the Internet’s evolution is at a point at where the TCP/IP suite protocols best effort nature needs to be paired with appropriate provisioning policies based on enforceable service level agreements (SLA) between service providers and service users and/or between different types of service providers. The availability of widely accepted techniques to measure the service levels is fundamental to such an evolution.
This thesis proposes a method that extends the well-known packet-pair approach to network capacity estimation by considering longer TCP packet sequences to minimize the impact of measurement noise and to obtain reliable estimation without the need of a large amount of data. In order to obtain such a result, the method augments the traditional packet timing analysis with a model driven data analysis, similar to what is done in pattern recognition to extract known items from large data sets (for example to recognize known objects in images). A two layer process is proposed, in which the first layer performs packet timing analysis, based on statistical techniques, to extract the main traffic features, while the second layer combines the features extracted through appropriate heuristics, to compute the access capacity. The second layer takes advantage of the knowledge of the application environment (i.e. the way TCP/IP networks behave) to analyze the features in a global way, so as to eliminate the false features, i.e. those deriving from noise or artifacts, and identify the true features, i.e. those deriving from the known and expected network behaviour.L’utente di una linea di accesso a Internet (ad es. l’utente di una ADSL) è sensibile alla qualità del servizio, che è determinata da vari aspetti, tra cui la banda disponibile. La stima per mezzo di misure passive della massima banda ottenibile a livello IP (capacity) su un link di accesso ad una rete TCP/IP è un problema interessante sia dal punto di vista scientifico che considerando le sue applicazioni industriali. Dal punto di vista scientifico, il problema è interessante perché l’estrazione della capacity a partire da osservazioni passive sul TCP/IP richiede lo sviluppo di modelli e algoritmi appropriati. Dal punto di vista industriale, la stima della banda di accesso è uno strumento fondamentale per la verifica delle condizioni minime di servizio che possono essere stipulate tra un internet service provider ed un utente finale o tra il fornitore dell’accesso (access service provider) e il fornitore della connettività Internet (network service provider). La tesi propone dei modelli e delle tecniche aventi lo scopo di stimare dall’interno della rete e in maniera passiva la capacity di un link di accesso a Internet. Il metodo proposto estende i tradizionali approcci basati sulle tecniche packet-pair considerando sequenze di pacchetti TCP più lunghe di due elementi allo scopo di minimizzare l’impatto del rumore di misura. Lo scopo è quello di ottenere una stima affidabile senza il bisogno di raccogliere grandi moli di dati su cui applicare tecniche statistiche.
50
Neil, Marjorie H. "Mapping the ethical journey of experienced nurses now practising in rural and remote hospitals in central and south-west Queensland and in domiciliary services in Brisbane : a grounded theory approach". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/41844/1/Marjorie_Neil_Thesis-.pdf.
Testo completoAbstract (sommario):
The aim of this thesis has been to map the ethical journey of experienced nurses now practising in rural and remote hospitals in central and south-west Queensland and in domiciliary services in Brisbane. One group of the experienced nurses in the study were Directors of Nursing in rural and remote hospitals. These nurses were “hands on”, “multi-skilled “ nurses who also had the task of managing the hospital. Also there were two Directors of Nursing from domiciliary services in Brisbane.
A grounded theory method was used. The nurses were interviewed and the data retrieved from the interviews was coded, categorised and from these categories a conceptual framework was generated. The literature which dealt with the subject of ethical decision making and nurses also became part of the data. The study revealed that all these nurses experienced moral distress as they made ethical decisions.
The decision making categories revealed in the data were: the area of financial management; issues as end of life approaches; allowing to die with dignity; emergency decisions; experience of unexpected death; the dilemma of providing care in very difficult circumstances. These categories were divided into two chapters: the category related to administrative and financial constraints and categories dealing with ethical issues in clinical settings. A further chapter discussed the overarching category of coping with moral distress. These experienced nurses suffered moral distress as they made ethical decisions, confirming many instances of moral distress in ethical decision making documented in the literature to date.
Significantly, the nurses in their interviews never mentioned the ethical principles used in bioethics as an influence in their decision making. Only one referred to lectures on ethics as being an influence in her thinking. As they described their ethical problems and how they worked through them, they drew on their own previous experience rather than any knowledge of ethics gained from nursing education. They were concerned for their patients, they spoke from a caring responsibility towards their patients, but they were also concerned for justice for their patients.
This study demonstrates that these nurses operated from the ethic of care, tempered with the ethic of responsibility as well as a concern for justice for their patients. Reflection on professional experience, rather than formal ethics education and training, was the primary influence on their ethical decision making.