Tesi sul tema "Network performance (Telecommunication)"
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1
Hoepner, Brian. "Methods of managing network user expectations". Menomonie, WI : University of Wisconsin--Stout, 2005. http://www.uwstout.edu/lib/thesis/2005/2005hoepnerb.pdf.
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Dheram, Meher Vinay. "Network performance evaluation and simulation studies on backbone traffic aggregation". Diss., Online access via UMI:, 2006.
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Carter, Steven Michael. "Implementation and analysis of the IP measurement protocol (IPMP)". Master's thesis, Mississippi State : Mississippi State University, 2001. http://library.msstate.edu/etd/show.asp?etd=etd-11152001-090121.
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Zhao, Qi. "Towards Ideal Network Traffic Measurement: A Statistical Algorithmic Approach". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19821.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Computing, Georgia Institute of Technology, 2008.Committee Chair: Xu, Jun; Committee Member: Ammar, Mostafa; Committee Member: Feamster, Nick; Committee Member: Ma, Xiaoli; Committee Member: Zegura, Ellen.
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Kumar, Abhishek. "Network Data Streaming: Algorithms for Network Measurement and Monitoring". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11172005-143837/.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2006.Dr. Mostafa Ammar, Committee Member ; Dr. Mark Crovella, Committee Member ; Dr. Constantinos Dovrolis, Committee Member ; Dr. Ellen Zegura, Committee Chair ; Dr. Jun Xu, Committee Chair. Vita. Includes bibliographical references.
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Albarrán, Munoz Isaac, e Ruiz De Azúa Manuel Parras. "Telecommunication Services’ Migration to the Cloud : Network Performance analysis". Thesis, KTH, Kommunikationssystem, CoS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93841.
Testo completoAbstract (sommario):
Nowadays, telecommunication services are commonly deployed in private networks, which are controlled and maintained by the telecommunication operators themselves, by co-location services providers, or, to some extent, by their hardware and software providers. However, with the present development of cloud computing resources, one might consider if these services could and should be implemented in the Cloud, thus taking advantage of cloud computing’s high availability, geographic distribution, and ease of usage. Additionally, this migration could reduce the telecommunication operators’ concerns in terms of hardware and network maintenance, leaving those to the Cloud computing providers who will need to supply a highly available and consistent service, to fulfill the telecommunication services’ requirements. Furthermore, virtualization provides the possibility of easily and rapidly changing the Cloud network topology facilitating the addition and removal of machines and services, allowing telecommunication services providers to adapt to their demands on the fly. The aim of this thesis project is to analyze and evaluate the level of performance, from the network point of view, that can be achieved when using Cloud computing resources to implement a telecommunication service, carrying out practical experiments both in laboratory and real environments. These measurements and analyses were conducted using an Ericsson prototype mobile switching center server (MSC-S) application, although the results obtained could be adapted to other applications with similar requirements. In order to potentially test this approach in a real environment, a prior providers’ survey was utilized to evaluate their services based on our requirements in terms of hardware and network characteristics, and thus select a suitable candidate environment for our purposes. One cloud provider was selected and its service was further evaluated based on the MSC-S application requirements. We report the results of our bench-marking process in this environment and compare them to the results of testing in a laboratory environment. The results of both sets of testing were well correlated and indicate potential for hosting telecommunication services in a Cloud environment, providing the Cloud meets the requirements imposed by the telecom services.Actualmente, los servicios de telecomunicaciones se implementan comúnmente en redes privadas, controladas y mantenidas por los operadores de telecomunicaciones, por proveedores de servicios de colocación o, hasta cierto punto, por proveedores de hardware y software. Sin embargo, con el presente desarrollo de la tecnología de ’Cloud computing’, se puede considerar la posibilidad de implementar servicios de telecomunicaciones en la nube, aprovechando su alta disponibilidad, distribución geográfica y facilidad de uso. Además, este cambio puede reducir las preocupaciones de los operadores en relación al mantenimiento del hardware y de la red, delegando en los proveedores del servicio de ’Cloud computing’, los cuáles deberán proporcionar un servicio consistente, cumpliendo así con los requisitos de los servicios de telecomunicaciones. Por otra parte, la virtualización propociona la posibilidad de cambiar rápida y fácilmente la topología de la red, facilitando la adición y supresión de maquinas y servicios, y, por tanto, permitiendo a los operadores adaptarse a sus necesidades sobre la marcha. El objetivo de esta tésis es analizar y evaluar en nivel de rendimiento, desde el punto de vista de la red, que se puede conseguir usando recursos de ’Cloud computing’ para implementar un servicio de telecomunicaciones, llevando a cabo experimentos tanto en el laboratorio como en un entorno real. Estos análisis fueron realizados utilizando un prototipo de un servidor de conmutación móvil (MSC-S) de Ericsson, aunque los resultados pueden adaptarse a otras aplicaciones con unos requisitos similares. Para probar esta propuesta en un entorno real, se realizó una encuesta de proveedores de servicios de ’Cloud computing’, con el objetivo de evaluar sus servicios teniendo en cuenta nuestros requisitos de hardware y red. Finalmente, un proveedor fue escogido y su servicio evaluado basándonos en los requisitos de la aplicación MSC-S. En este documento proporcionamos los resultados de esa evaluación y los comparamos con los obtenidos en el laboratorio. Los resultados de ambas evaluaciones fueron satisfactorios e indican la posibilidad de implementar servicios de telecomunicaciones en la nube, siempre que la nube cumpla los requisitos impuestos por dichos servicios de telecomunicaciones.
Nuförtiden är telekommunikationstjänster ofta uppsatta i privata nätverk, som kontrolleras och underhålls av teleoperatörerna själva, av samlokaliserande tjänsteleverantörer eller i viss utsträckning av deras hårdvaruoch programvaru-leverantörer. Med den nuvarande utvecklingen av Cloud Computing-resurser kan man dock överväga om dessa tjänster kan och bör genomföras i ett Cloud, vilket drar fördel av Cloud Computings höga tillgänglighet, geografiska spridning, och enkla användning. Denna migration minskar även teleoperatörernas oro angående hårdvaru- och nätverks-underhåll genom att överlåta detta till Cloud Computing-leverantörerna, som kommer att behöva leverera en hög tillgänglighet och konsekvent service för att uppfylla telekommunikationstjänsternas krav. Dessutom ger virtualisering möjlighet att enkelt och snabbt ändra ett Clouds nätverkstopologi, vilket underlättar tillägg och borttagning av maskiner och tjänster, vilket hjälper teleoperatörer att snabbt anpassa sig till deras krav. Målet med examensarbetet är att analysera och uppskatta prestandan, från nätets perspektiv, som kan uppnås vid användning av Cloud Computingresurser för att genomföra en teletjänst, genom praktiska experiment både i laboratorium och i verkligheten. Dessa mätningar och analyser utfördes med en prototyp av en Ericsson mobilomkopplingscentralserverapplikation (MSCS), även om de erhållna resultaten skulle kunna anpassas till andra program med liknande krav. För att potentiellt kunna testa denna metod i en verklig miljö användes en tidigare leverantörs undersökning för att utvärdera deras tjänster baserat på våra krav på hårdvara och nätverksegenskaper, och genom detta välja en lämplig kandidatmiljö för våra syften. En Cloud-leverantör valdes och dess tjänster utvärderades vidare baserat på MSC-Ss applikationskrav. Vi redovisar resultatet av vår testprocess i den här miljön och jämför det med resultaten av tester i laboratoriemiljö. Resultaten från båda uppsättningarna av tester var väl korrelerade och visar på potentialen av att implementera telekommunikationstjänster i en Cloud-miljö, om detta Cloud uppfyller de kraven som ställs av telekommunikationtjänsterna.
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Kiss, Zoltan. "Predictive Mobility Management for future mobile telecommunication networks". Thesis, De Montfort University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391858.
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Saple, Avdhoot Kishore Yilmaz Levent. "Agent-based simulation of behavioral anticipation in computer networks a comparative study of anticipatory fault management /". Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/SAPLE_AVDHOOTKISHORE_37.pdf.
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Agarwal, Shweta S. "Search for an optimal network reporting threshold". Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1091451063.
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Krithikaivasan, Balaji Medhi Deepankar. "Forecasting models and adaptive quantized bandwidth provisioning for nonstationary network traffic". Diss., UMK access, 2006.
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Thesis (Ph. D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2006."A dissertation in computer networking and telecommunication networking." Advisor: Deep Medhi. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Oct. 31, 2007. Includes bibliographical references (leaves 168-172). Online version of the print edition.
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Wang, Kongxun. "Performance optimization with integrated consideration of routing, flow control, and congestion control in packet-switched networks". Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/8305.
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Dzalilov, Zari. "Mathematical models of dynamic reconfiguration of telecommunication networks". Thesis, University of Ballarat, 2004. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/58707.
Testo completoAbstract (sommario):
In this thesis we examine mathematical models for dynamical reconfiguration of telecommunication networks. Dynamical configuration is one of the most important problems in the field of network management. In the case of some part of the network being damaged the system should maintain its operations, taking into account the new conditions. This can be achieved by using the residual capacity of the system if it is available. If there were not enough residual capacity, the managers of the system need to involve some of the unaffected traffic in order to reorganize traffic. A prolonged breakdown will push some customers to change their provider; there is also a lost [sic] of profit because of breakdowns, that can be considered as a certain implicit penalty. To reorganize traffic by using new routes we should have a flexible routing system.Doctor of Philosophy
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Hong, Jun, e 洪珺. "Impact of information on wireless network performance". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46585989.
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Cheng, Luwei, e 程芦伟. "Network performance isolation for virtual machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47753183.
Testo completoAbstract (sommario):
Cloud computing is a new computing paradigm that aims to transform computing
services into a utility, just as providing electricity in a “pay-as-you-go”
manner. Data centers are increasingly adopting virtualization technology for the
purpose of server consolidation, flexible resource management and better fault
tolerance. Virtualization-based cloud services host networked applications in virtual
machines (VMs), with each VM provided the desired amount of resources
using resource isolation mechanisms.
Effective network performance isolation is fundamental to data centers, which
offers significant benefit of performance predictability for applications. This research
is application-driven. We study how network performance isolation can be
achieved for latency-sensitive cloud applications. For media streaming applications,
network performance isolation means both predicable network bandwidth
and low-jittered network latency. The current resource sharing methods for VMs
mainly focus on resource proportional share, whereas ignore the fact that I/O latency
in VM-hosted platforms is mostly related to resource provisioning rate. The
resource isolation with only quantitative promise does not sufficiently guarantee
performance isolation. Even the VM is allocated with adequate resources such as
CPU time and network bandwidth, problems such as network jitter (variation in
packet delays) can still happen if the resources are provisioned at inappropriate
moments. So in order to achieve performance isolation, the problem is not only
how many/much resources each VM gets, but more importantly whether the resources are provisioned in a timely manner. How to guarantee both requirements
to be achieved in resource allocation is challenging.
This thesis systematically analyzes the causes of unpredictable network latency
in VM-hosted platforms, with both technical discussion and experimental
illustration. We identify that the varied network latency is jointly caused by
VMM CPU scheduler and network traffic shaper, and then address the problem
in these two parts. In our solutions, we consider the design goals of resource
provisioning rate and resource proportionality as two orthogonal dimensions. In
the hypervisor, a proportional share CPU scheduler with soft real-time support
is proposed to guarantee predictable scheduling delay; in network traffic shaper,
we introduce the concept of smooth window to smooth packet delay and apply
closed-loop feedback control to maintain network bandwidth consumption.
The solutions are implemented in Xen 4.1.0 and Linux 2.6.32.13, which are
both the latest versions when this research was conducted. Extensive experiments
have been carried out using both real-life applications and low-level benchmarks.
Testing results show that the proposed solutions can effectively guarantee network
performance isolation, by achieving both predefined network bandwidth and low-jittered
network latency.published_or_final_version
Computer Science
Master
Master of Philosophy
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Draai, Kevin. "A model for assessing and reporting network performance measurement in SANReN". Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/16131.
Testo completoAbstract (sommario):
The performance measurement of a service provider network is an important activity. It is required for the smooth operation of the network as well as for reporting and planning. SANReN is a service provider tasked with serving the research and education network of South Africa. It currently has no structure or process for determining network performance metrics to measure the performance of its network. The objective of this study is to determine, through a process or structure, which metrics are best suited to the SANReN environment. This study is conducted in 3 phases in order to discover and verify the solution to this problem. The phases are "Contextualisation", "Design",and "Verification". The "Contextualisation" phase includes the literature review. This provides the context for the problem area but also serves as a search function for the solution. This study adopts the design science research paradigm which requires the creation of an artefact. The "Design" phase involves the creation of the conceptual network performance measurement model. This is the artefact and a generalised model for determining the network performance metrics for an NREN. To prove the utility of the model it is implemented in the SANReN environment. This is done in the "Verification" phase. The network performance measurement model proposes a process to determine network performance metrics. This process includes getting NREN requirements and goals, defining the NRENs network design goals through these requirements, define network performance metrics from these goals, evaluating the NRENs monitoring capability, and measuring what is possible. This model provides a starting point for NRENs to determine network performance metrics tailored to its environment. This is done in the SANReN environment as a proof of concept. The utility of the model is shown through the implementation in the SANReN environment thus it can be said that it is generic.The tools that monitor the performance of the SANReN network are used to retrieve network performance data from. Through understanding the requirements, determining network design goals and performance metrics, and determining the gap the retrieving of results took place. These results are analysed and finally aggregated to provide information that feeds into SANReN reporting and planning processes. A template is provided to do the aggregation of metric results. This template provides the structure to enable metrics results aggregation but leaves the categories or labels for the reporting and planning sections blank. These categories are specific to each NREN. At this point SANReN has the aggregated information to use for planning and reporting. The model is verified and thus the study’s main research objective is satisfied.
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Stapelberg, Dieter. "Link failure recovery among dynamic routes in telecommunication networks". Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2591.
Testo completoAbstract (sommario):
Thesis (MSc (Mathematical Sciences. Computer Science))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Since 2002 data tra c has overtaken voice tra c in volume [1]. Telecom / Network operators still generate most of their income carrying voice tra c. There is however a huge revenue potential in delivering reliable guaranteed data services. Network survivability and recovery from network failures are integral to network reliability. Due to the nature of the Internet, recovery from link failures needs to be distributed and dynamic in order to be scalable. Link failure recovery schemes are evaluated in terms of the survivability of the network, the optimal use of network resources, scalability, and the recovery time of such schemes. The need for recovery time to be improved is highlighted by real-time data tra c such as VoIP and video services carried over the Internet. The goal of this thesis is to examine existing link failure recovery schemes and evaluate the need for their extension, and to evaluate the performance of the proposed link failure recovery schemes. i
AFRIKAANSE OPSOMMING: Sedert 2002 het data verkeer die stem verkeer in volume verbygesteek [1]. Telekommunikasie / netwerk operateurs genereer egter steeds die meeste van hul inkomste met stem verkeer. Netwerk oorlewing en die herstel van netwerk mislukkings is integraal tot netwerk stabiliteit. Die samestelling van die Internet noodsaak dat die herstel van skakel mislukkings verspreid en dinamies van natuur moet wees. Die herstel-skema van skakel mislukkings word evalueer in terme van die oorleefbaarheid van die netwerk, die mees e ektiewe benutting van network bronne, aanpasbaarheid, en die herstel tydperk van die skema. Die vinnig moontlikste herstel tydperk word genoodsaak deur oombliklike data verkeer soos VoIP en beeld dienste wat oor die Internet gedra word. The doel van hierdie tesis is om bestaande skakel mislukking herstel skemas te evalueer, en dan verder ondersoek in te stel na hul uitbreiding. Daarna word die voorgestelde skakel mislukking skema se e ektiwiteit gemeet.
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McCaskey, Harold Orr. "Performance analysis of an integrated voice and data network". Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/32966.
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Qiang, Qiang. "Network efficiency/performance measurement with vulnerability and robustness analysis with application to critical infrastructure". Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3372272/.
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Hamdoun, Hassan. "Practical network coding schemes for energy efficient long term evolution radio access networks". Thesis, Swansea University, 2013. https://cronfa.swan.ac.uk/Record/cronfa42828.
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Geng, Yanhui, e 耿彦辉. "A framework to model the relationship between information and network performance". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43223977.
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Geng, Yanhui. "A framework to model the relationship between information and network performance". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43223977.
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Al-Fuqaha, Ala Isam Chaudhry Ghulam M. "Routing and wavelength assignment in all-optical DWDM networks with sparse wavelength conversion capabilities". Diss., UMK access, 2004.
Cerca il testo completoAbstract (sommario):
Thesis (Ph. D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2004."A dissertation in engineering and computer networking." Advisor: Ghulam Chaudhry. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Feb. 22, 2006. Includes bibliographical references (leaves 135-157). Online version of the print edition.
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Dahal, Subharoj. "Implementing a redundant solution to improve network system reliability at XYZ Hospital". Online version, 2009. http://www.uwstout.edu/lib/thesis/2009/2009dahals.pdf.
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Baruani, Atumbe Jules. "Network engineering using multi-objective evolutionary algorithms". Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/21548.
Testo completoAbstract (sommario):
Thesis (MSc)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: We use Evolutionary Multi-Objective Optimisation (EMOO) algorithms to optimise objective functions that reflect situations in communication networks. These include functions that optimise Network Engineering (NE) objective functions in core, metro and wireless sensor networks. The main contributions of this thesis are threefold. Routing and Wavelength Assignment (RWA) for IP backbone networks. Routing and Wavelength Assignment (RWA) is a problem that has been widely addressed by the optical research community. A recent interest in this problem has been raised by the need to achieve routing optimisation in the emerging generation multilayer networks where data networks are layered above a Dense Wavelength Division Multiplexing (DWDM) network. We formulate the RWA as both a single and a multi-objective optimisation problem which are solved using a two-step solution where (1) a set of paths are found using genetic optimisation and (2) a graph coloring approach is implemented to assign wavelengths to these paths. The experimental results from both optimisation scenarios reveal the impact of (1) the cost metric used which equivalently defines the fitness function (2) the algorithmic solution adopted and (3) the topology of the network on the performance achieved by the RWA procedure in terms of path quality and wavelength assignment. Optimisation of Arrayed Waveguide Grating (AWG) Metro Networks. An Arrayed Waveguide Grating (AWG) is a device that can be used as a multiplexer or demultiplexer in WDM systems. It can also be used as a drop-and-insert element or even a wavelength router. We take a closer look at how the hardware and software parameters of an AWG can be fine tuned in order to maximise throughput and minimise the delay. We adopt a multi-objective optimisation approach for multi-service AWG-based single hop metro WDM networks. Using a previously proposed multi-objective optimisation model as a benchmark, we propose several EMOO solutions and compare their efficiency by evaluating their impact on the performance achieved by the AWG optimisation process. Simulation reveals that (1) different EMOO algorithms can exhibit different performance patterns and (2) good network planning and operation solutions for a wide range of traffic scenarios can result from a well selected EMOO algorithm. Wireless Sensor Networks (WSNs) Topology (layout) Optimisation. WSNs have been used in a number of application areas to achieve vital functions in situations where humans cannot constantly be available for certain tasks such as in hostile areas like war zones, seismic sensing where continuous inspection and detection are needed, and many other applications such as environment monitoring, military operations and surveillance. Research and practice have shown that there is a need to optimise the topology (layout) of such sensors on the ground because the position on which they land may affect the sensing efficiency. We formulate the problem of layout optimisation as a multi-objective optimisation problem consisting of maximising both the coverage (area) and the lifetime of the wireless sensor network. We propose different algorithmic evolutionary multi-objective methods and compare their performance in terms of Pareto solutions. Simulations reveal that the Pareto solutions found lead to different performance patterns and types of layouts.
AFRIKAANSE OPSOMMING: Ons gebruik ”Evolutionary Multi-Objective Optimisation (EMOO)” algoritmes om teiken funksies, wat egte situasies in kommunikasie netwerke voorstel, te optimiseer. Hierdie sluit funksies in wat ”Network Engineering” teiken funksies in kern, metro en wireless sensor netwerke optimiseer. Die hoof doelwitte van hierdie tesis is dus drievuldig. RWA vir IP backbone netwerke ”Routing and Wavelength Assignment (RWA)” is ’n probleem wat al menigte kere in die optiese navorsings kringe aangespreek is. Belangstelling in hierdie veld het onlangs ontstaan a.g.v. die aanvraag na die optimisering van routering in die opkomende generasie van veelvuldige vlak netwerke waar data netwerke in ’n vlak ho¨er as ’n ”Dense Wavelength Division Multiplexing (DWDM)” netwerk gele is. Ons formuleer die RWA as beide ’n enkele and veelvuldige teiken optimiserings probleem wat opgelos word deur ’n 2-stap oplossing waar (1) ’n stel roetes gevind word deur genetiese optimisering te gebruik en (2) ’n grafiek kleuring benadering geimplementeer word om golflengtes aan hierdie roetes toe te ken. Die eksperimentele resultate van beide optimiserings gevalle vertoon die impak van (1) die koste on wat gebruik word wat die ekwalente fitness funksie definieer , (2) die algoritmiese oplossing wat gebruik word en (3) die topologie van die netwerk op die werkverrigting van die RWA prosedure i.t.v. roete kwaliteit en golflengte toekenning. Optimisering van AWG Metro netwerk ’n ”Arrayed Waveguide Grating (AWG)” is ’n toestel wat gebruik kan word as ’n multipleksor of demultipleksor in WDM sisteme. Dit kan ook gebruik word as ’n val-en-inplaas element of selfs ’n golflengte router. Kennis word ingestel na hoe die hardeware en sagteware parameters van ’n AWG ingestel kan word om die deurset tempo te maksimeer en vertragings te minimiseer. Ons neem ’n multi-teiken optimiserings benadering vir multi diens, AWG gebaseerde, enkel skakel, metro WDM netwerke aan. Deur ’n vooraf voorgestelde multi teiken optimiserings model as ”benchmark” te gebruik, stel ons ’n aantal EMOO oplossings voor en vergelyk ons hul effektiwiteit deur hul impak op die werkverrigting wat deur die AWG optimiserings proses bereik kan word, te vergelyk. Simulasie modelle wys dat (1) verskillende EMOO algoritmes verskillende werkverrigtings patrone kan vertoon en (2) dat goeie netwerk beplanning en werking oplossings vir ’n wye verskeidenheid van verkeer gevalle kan plaasvind a.g.v ’n EMOO algoritme wat reg gekies word. ”Wireless Sensor Network” Topologie Optimisering WSNs is al gebruik om belangrike funksies te verrig in ’n aantal toepassings waar menslike beheer nie konstant beskikbaar is nie, of kan wees nie. Voorbeelde van sulke gevalle is oorlog gebiede, seismiese metings waar aaneenlopende inspeksie en meting nodig is, omgewings meting, militˆere operasies en bewaking. Navorsing en praktiese toepassing het getoon dat daar ’n aanvraag na die optimisering van die topologie van sulke sensors is, gebaseer op gronde van die feit dat die posisie waar die sensor beland, die effektiwiteit van die sensor kan affekteer. Ons formuleer die probleem van uitleg optimisering as ’n veelvuldige vlak optimiserings probleem wat bestaan uit die maksimering van beide die bedekkings area en die leeftyd van die wireless sensor netwerk. Ons stel verskillende algoritmiese, evolutionˆere, veelvuldige vlak oplossings voor en vergelyk hul werkverrigting i.t.v Pareto oplossings. Simulasie modelle wys dat die Pareto oplossings wat gevind word lei na verskillende werkverrigtings patrone en uitleg tipes.
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Yoon, Janghyun. "A network-aware semantics-sensitive image retrieval system". Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180459/unrestricted/yoon%5fjanghyun%5f200312%5fphd.pdf.
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He, Rongsen. "Indirect interconnection networks for high performance routers/switches". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Summer2007/R_He_072307.pdf.
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Combrink, J. J. (Jacobus Johannes). "A bandwidth market for traffic engineering in telecommunication networks". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49808.
Testo completoAbstract (sommario):
Thesis (MSc)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Traffic engineering determines the bandwidth allocation required to meet the traffic loads in a network. Similarly an economic market determines the resource allocation required to meet the demand for resources. The term bandwidth market denotes traffic engineering methods that use economic market methodology to determine the bandwidth allocation required to meet the traffic loads. A bandwidth market is an attractive traffic engineering method because of its distributed nature and ability to respond quickly to changes in network architecture or traffic loads. Network terminology is frequently used to define bandwidth markets. Our approach is to use the concepts of microeconomics to define a bandwidth market. The result is that our bandwidth markets are similar to economic markets, which is advantageous for applying economic principles correctly. This thesis presents the theoretical basis for two bandwidth markets. The first bandwidth market is a framework for building bandwidth markets. The second bandwidth market represents a society of cooperating individuals. The society distributes resources via a mechanism based on economic principles. An implementation of the bandwidth market is presented in the form of an optimisation algorithm, followed by its application to several test networks. We show that, in the test networks examined, the optimisation algorithm reduces the network loss. For all test networks, the network loss achieved by the optimisation algorithm compares well with the network loss achieved by a centralised optimisation algorithm.
AFRIKAANSE OPSOMMING: Verkeersingenieurswese bepaal die nodige bandwydtetoekenning om die verkeersvolume in 'n netwerk te dra. Op 'n soortgelyke wyse bepaal 'n ekonomiese mark die nodige hulpbrontoekenning om die aanvraag vir hulpbronne te bevredig. Die terme bandwydtemark stel verkeersingenieurswesetegnieke voor wat ekonomiese-mark metodes gebruik om die bandwydtetoekenning vir die verkeersvolume in 'n netwerk te bepaal. 'n Bandwydtemark is 'n aantreklike verkeersingenieurswesetegniek omdat dit verspreid van aard is en vinnig kan reageer op veranderinge in netwerk argitektuur en verkeersvolume. Netwerkterminologie word gereeld gebruik om bandwydtemarkte te definieer. Ons benadering is om mikro-ekonomiese begrippe te gebruik om 'n bandwydtemark te definieer. Die resultaat is dat ons bandwydtemarkte soortgelyk aan ekonomiese markte is, wat voordelig is vir die korrekte toepassing van ekonomiese beginsels. Hierdie tesis lê die teoretiese grondwerk vir twee bandwydtemarkte. Die eerste bandwydtemark is 'n raamwerk vir die ontwikkeling van bandwydtemarkte. Die tweede bandwydtemark stel 'n vereniging van samewerkende individue voor. Die vereniging versprei bandwydte deur middel van 'n meganisme wat gebasseer is op ekonomiese beginsels. 'n Implementasie van hierdie bandwydtemark word voorgestel in die vorm van 'n optimeringsalgoritme, gevolg deur die toepassing van die optimeringsalgoritme op 'n aantal toetsnetwerke. Ons wys dat die bandwydtemark die netwerkverlies verminder in die toetsnetwerke. In terme van netwerkverlies vaar die bandwydtemark goed vergeleke met 'n gesentraliseerde optimeringsalgoritme.
28
Ng, Hwee Ping. "Performance analysis of management techniques for SONET/SDH telecommunications networks". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FNg.pdf.
Testo completo
29
Thompson, Richard. "Evaluating TCP/IP performance over satellite networks". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49954.
Testo completoAbstract (sommario):
Thesis (MScEng) -- Stellenbosch University, 2004.ENGLISH ABSTRACT: Interest in TCP/IP as a communication protocol for use in space communication has increased substantially with the growth of the world wide web (WWW). TCP/IP is a relevant communication protocol for space based communication systems that need to access the broader terrestrial communication network. Low Earth Orbit(LEO) satellites have very short delay times between themselves and the ground, and correspondingly very short connection times. Staying in contact with a LEO satellite continuously through a space-based network requires large constellations of satellites and complex routing strategies. Connectivity with the world wide web using a widely accepted protocol such as TCP/IP is desirable because it would make communication with the satellite over a terrestrial station possible, were it to route communication onto the WWW. This thesis looks at the expected TCP/IP performance over satellite network links, identifies problem areas for current TCP/IP technologies, and makes suggestions for optimizing TCP/IP over such links. The thesis also introduces a new performance benchmark, the equivalence level, allowing for the simplified description of TCP throughput behaviour over a broad range of network parameters. The performance of the Linux kernel release 2.4.18 TCP/IP stack is also evaluated.
AFRIKAANSE OPSOMMING: Die belangstelling in TCP/IP as ’n kommunikasie protokol vir gebruik in die ruimte het kenmerklik toegeneem met die groei van die wereld wye web (WWW). TCP/IP is ’n relevante protokol vir kommunikasie stelsels in die ruimte, veral met die doel om toegang tot land gebaseerde kommunikasie netwerke te kry. Lae wentelbaan sateliete het baie kort vertragingstye tussen die aarde en die sateliet, en gevolglik baie kort verbindingstye. Groot sateliet konstelasies en komplekse verbintenis strategie word benodig om ’n lae wentelbaan sateliet deurentyd in kontak te hou met ’n ruimtegebaseerde netwerk. Verbinding met die wereld wye web deur die gebruik van ’n wyd aanvaarde protokol, soos TCP/IP, is wenslik, want dit sal kommunikasie met die sateliet oor ’n aardgebaseerde stasie moontlik maak, sou dit kommunikasie oor die wereld wye web stuur. Hierdie tesis kyk na die verwagte werking van TCP/IP oor sateliet netwerk konneksies, identifiseer probleme met huidiglike TCP/IP tegnologie, en maak voorstellings vir die optimale funtionering van TCP/IP oor sulke konneksies. Hierdie tesis stel ook ’n nuwe werkverrigtings maatstaf, die gelykheidsvlak, wat die vereenvoudige beskrywing van TCP/IP data tempo gedrag oor ’n groot variasie van netwerk parameters toelaat. Die werking van die Linux Kernel 2.4.18 TCP/IP stapel word ook geevalueer.
30
Lo, Chor Wing. "Voice over IP performance using expedited forwarding and assured forwarding on differentiated services enabled network /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?COMP%202002%20LO.
Testo completoAbstract (sommario):
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.Includes bibliographical references (leaves 57-59). Also available in electronic version. Access restricted to campus users.
31
Anjali, Tricha. "DiffServ/MPLS Network Design and Management". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5191.
Testo completoAbstract (sommario):
The MultiProtocol Label Switching (MPLS) framework is used in many networks to provide efficient load balancing which distributes the traffic for efficient Quality of Service (QoS) provisioning in the network. If the MPLS framework is combined with Differentiated Services (DiffServ) architecture, together they can provide aggregate-based service differentiation and QoS. The combined use of DiffServ and MPLS in a network is called DiffServ-aware Traffic Engineering (DS-TE). Such DiffServ-based MPLS networks demand development of efficient methods for QoS provisioning. In this thesis, an automated manager for management of these DiffServ-based MPLS networks is proposed. This manager, called Traffic Engineering Automated Manager (TEAM), is a centralized authority for adaptively managing a DiffServ/MPLS domain and it is responsible for dynamic bandwidth and route management. TEAM is designed to provide a novel and unique architecture capable of managing large scale MPLS/DiffServ domains without any human interference. TEAM constantly monitors the network state and reconfigures the network for efficient handling of network events. Under the umbrella of TEAM, new schemes for Label Switched Path (LSP) setup/teardown, traffic routing, and network measurement are proposed and evaluated through simulations. Also, extensions to include Generalized MPLS (GMPLS) networks and inter-domain management are proposed.
32
Lam, Lai-lan. "Gain-scheduled PID controllers in networked control systems". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B44193725.
Testo completo
33
Lam, Lai-lan, e 林麗蘭. "Gain-scheduled PID controllers in networked control systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B44193725.
Testo completo
34
Hanratty, Joseph M. "Performance analysis of hybrid ARQ protocols in a slotted code division multiple-access network". Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/15690.
Testo completo
35
Kim, Young Yong. "A study on traffic and channel dynamics for wireless multimedia network performance analysis /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
Testo completo
36
Erjongmanee, Supaporn. "Study of network-service disruptions using heterogeneous data and statistical learning". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43601.
Testo completoAbstract (sommario):
The study of network-service disruptions caused by large-scale disturbances has mainly focused on assessing network damage; however, network-disruption responses, i.e., how the disruptions occur depending on social organizations, weather, and power resources, have been studied little. The goal of this research is to study the responses of network-service disruptions caused by large-scale disturbances with respect to (1) temporal and logical network, and (2) external factors such as weather and power resources, using real and publicly available heterogeneous data that are composed of network measurements, user inputs, organizations, geographic locations, weather, and power outage reports. Network-service disruptions at the subnet level caused by Hurricanes Katrina in 2005 and Ike in 2008 are used as the case studies. The analysis of network-disruption responses with respect to temporal and logical network shows that subnets became unreachable dependently within organization, cross organization, and cross autonomous system. Thus, temporal dependence also illustrates the characteristics of logical dependence. In addition, subnet unreachability is analyzed with respect to the external factors. It is found that subnet unreachability and the storm are weakly correlated. The weak correlation motivates us to search for root causes and discover that the majority of subnet unreachability reportedly occurred because of power outages or lack of power generators. Using the power outage data, it is found that subnet unreachability and power outages are strongly correlated.
37
Mascarenhas, da Veiga Alves Manoel Eduardo. "Characterisation of end-to-end performance for web-based file server respositories". Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09ENS/09ensm395.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 128-135. Investigates the behaviour of TCP bulk file transfer application sessions in a broadband access environment. Introduces some concepts for evaluating network behaviour: a path instability parameter for analyzing different TCP connections; a minimum RTT delay and a minimum typical path for estimating path characteristics between a client and application servers.
38
Gustavsson, Jonas. "Automated Performance Optimization of GSM/EDGE Network Parameters". Thesis, Linköping University, Linköping University, Communication Systems, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-52565.
Testo completoAbstract (sommario):
The GSM network technology has been developed and improved during several years which have led to an increased complexity. The complexity results in more network parameters and together with different scenarios and situations they form a complex set of configurations. The definition of the network parameters is generally a manual process using static values during test execution. This practice can be costly, difficult and laborious and as the network complexity continues to increase, this problem will continue to grow.This thesis presents an implementation of an automated performance optimization algorithm that utilizes genetic algorithms for optimizing the network parameters. The implementation has been used for proving that the concept of automated optimization is working and most of the work has been carried out in order to use it in practice. The implementation has been applied to the Link Quality Control algorithm and the Improved ACK/NACK feature, which is an apart of GSM EDGE Evolution.
GSM-nätsteknologin har utvecklats och förbättrats under lång tid, vilket har lett till en ökad komplexitet. Denna ökade komplexitet har resulterat i fler nätverksparameterar, tillstånd och standarder. Tillsammans utgör de en komplex uppsättning av olika konfigurationer. Dessa nätverksparameterar har hittills huvudsakligen bestämts med hjälp av en manuell optimeringsprocess. Detta tillvägagångssätt är både dyrt, svårt och tidskrävande och allt eftersom komplexiteten av GSM-näten ökar kommer problemet att bli större.Detta examensarbete presenterar en implementering av en algoritm för automatiserad optimering av prestanda som huvudsakligen använder sig av genetiska algoritmer för att optimera värdet av nätverksparametrarna. Implementeringen har använts för att påvisa att konceptet med en automatiserad optimering fungerar och det mesta av arbetet har utförts för att kunna använda detta i praktiken. Implementeringen har tillämpats på Link Quality Control-algoritmen och Improved ACK/NACK-funktionaliteten, vilket är en del av GSM EDGE Evolution.
39
Nurubhashu, Mabusubhan Vali. "OPNET Based Design and Performance Evaluation of ZigBee Networks". Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062853/.
Testo completoAbstract (sommario):
ZigBee is a substandard of IEEE 802.15 family that is specially designed to take care of factors such as power, data rate and area that primarily affect network performance. This has controlling and monitoring capability, which finds potential applications in different sectors. ZigBee allows the concept of hybrid networks and mobility. A comprehensive analysis of ZigBee networks was carried out by constructing and simulating the networks to evaluate the performance in terms of throughput, delay, network load, and packets dropped. This research is aimed at evaluating the effect of network topology on the system performance. A careful review of simulation platforms brought the conclusion of using OPNET Modeler which has the required frame work. Different network topologies of simple and hybrid were built and simulated. Throughout the simulations, the best-case scenarios were drawn to the conclusion by the graphical analysis of parameters of evaluation. Mobile networks were constructed and simulated to investigate the effect of mobility on communication.
40
Yuen, Kwan Hung. "TCP performance over satellite networks /". View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20YUEN.
Testo completoAbstract (sommario):
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 68-71). Also available in electronic version. Access restricted to campus users.
41
Henkle, Thomas Grove III. "Performance characteristics of a multiple use Ku-band satellite network". Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44646.
Testo completoAbstract (sommario):
Construction of a Ku-band earth station was completed in August 1989 at the teleport in the
Corporate Research Center of Virginia Polytechnic Institute and State University. At that time
specific applications for the terminal were being determined. Several satellite networks which can
use the Ku-band earth station are explored in this thesis. System level designs are presented for
each network. The anticipated performance of the network during clear sky conditions and during
periods of rain fade conditions are calculated. To aid in these calculations the software package
LAMP was developed.
detailed system design of a VSAT network is given in later chapters. The development of
VSAT networks considers multiple access and data traffic control protocols. VSAT network
performance under various traffic conditions also is determined.
Master of Science
42
Jia, Long University of Ballarat. "Optimization based methods for solving some problems in telecommunications and the internet". University of Ballarat, 2005. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/12802.
Testo completoAbstract (sommario):
The purpose of this thesis is to develop some new algorithms based on optimization techniques for solving some problems in some areas of telecommunications and the Internet. There are two main parts to this thesis. In the first part we discuss optimization based stochastic and queueing models in telecommunications network corrective maintenance. In the second part we develop optimization based clustering (OBC) algorithms for network evolution and multicast routing. The most typical scenario encountered during mathematical optimization modelling in telecommunications, for example, is to minimize the cost of establishment and maintenance of the networks subject to the performance constraints of the networks and the reliability constraints of the networks as well. Most of these optimization problems are global optimization, that is, they have many local minima and most of these local minima do not provide any useful information for solving these problems. Therefore, the development of effective methods for solving such global optimization problems is important. To run the telecommunications networks with cost-effective network maintenance,we need to establish a practical maintenance model and optimize it. In the first part of the thesis, we solve a known stochastic programming maintenance optimization model with a direct method and then develop some new models. After that we introduce queue programming models in telecommunications network maintenance optimization. The ideas of profit, loss, and penalty will help telecommunications companies have a good view of their maintenance policies and help them improve their service. In the second part of this thesis we propose the use of optimization based clustering (OBC) algorithms to determine level-constrained hierarchical trees for network evolution and multicast routing. This problem is formulated as an optimization problem with a non-smooth, non-convex objective function. Different algorithms are examined for solving this problem. Results of numerical experiments using some artifiicial and real-world databases are reported.Doctor of Philosophy
43
Jia, Long. "Optimization based methods for solving some problems in telecommunications and the internet". Thesis, University of Ballarat, 2005. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/44593.
Testo completoAbstract (sommario):
The purpose of this thesis is to develop some new algorithms based on optimization techniques for solving some problems in some areas of telecommunications and the Internet. There are two main parts to this thesis. In the first part we discuss optimization based stochastic and queueing models in telecommunications network corrective maintenance. In the second part we develop optimization based clustering (OBC) algorithms for network evolution and multicast routing. The most typical scenario encountered during mathematical optimization modelling in telecommunications, for example, is to minimize the cost of establishment and maintenance of the networks subject to the performance constraints of the networks and the reliability constraints of the networks as well. Most of these optimization problems are global optimization, that is, they have many local minima and most of these local minima do not provide any useful information for solving these problems. Therefore, the development of effective methods for solving such global optimization problems is important. To run the telecommunications networks with cost-effective network maintenance,we need to establish a practical maintenance model and optimize it. In the first part of the thesis, we solve a known stochastic programming maintenance optimization model with a direct method and then develop some new models. After that we introduce queue programming models in telecommunications network maintenance optimization. The ideas of profit, loss, and penalty will help telecommunications companies have a good view of their maintenance policies and help them improve their service. In the second part of this thesis we propose the use of optimization based clustering (OBC) algorithms to determine level-constrained hierarchical trees for network evolution and multicast routing. This problem is formulated as an optimization problem with a non-smooth, non-convex objective function. Different algorithms are examined for solving this problem. Results of numerical experiments using some artifiicial and real-world databases are reported.Doctor of Philosophy
44
Jia, Long. "Optimization based methods for solving some problems in telecommunications and the internet". University of Ballarat, 2005. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/14637.
Testo completoAbstract (sommario):
The purpose of this thesis is to develop some new algorithms based on optimization techniques for solving some problems in some areas of telecommunications and the Internet. There are two main parts to this thesis. In the first part we discuss optimization based stochastic and queueing models in telecommunications network corrective maintenance. In the second part we develop optimization based clustering (OBC) algorithms for network evolution and multicast routing. The most typical scenario encountered during mathematical optimization modelling in telecommunications, for example, is to minimize the cost of establishment and maintenance of the networks subject to the performance constraints of the networks and the reliability constraints of the networks as well. Most of these optimization problems are global optimization, that is, they have many local minima and most of these local minima do not provide any useful information for solving these problems. Therefore, the development of effective methods for solving such global optimization problems is important. To run the telecommunications networks with cost-effective network maintenance,we need to establish a practical maintenance model and optimize it. In the first part of the thesis, we solve a known stochastic programming maintenance optimization model with a direct method and then develop some new models. After that we introduce queue programming models in telecommunications network maintenance optimization. The ideas of profit, loss, and penalty will help telecommunications companies have a good view of their maintenance policies and help them improve their service. In the second part of this thesis we propose the use of optimization based clustering (OBC) algorithms to determine level-constrained hierarchical trees for network evolution and multicast routing. This problem is formulated as an optimization problem with a non-smooth, non-convex objective function. Different algorithms are examined for solving this problem. Results of numerical experiments using some artifiicial and real-world databases are reported.Doctor of Philosophy
45
Heidari, Fariba. "Quality of service routing using decentralized learning". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115672.
Testo completoAbstract (sommario):
This thesis presents several decentralized, learning-based algorithms for on-line routing of bandwidth guaranteed paths. The presented routing algorithms do not need any a-priori knowledge of traffic demand; they use only their locally observed events and update their routing policy using learning schemes. The employed learning algorithms are either learning automata or the multi-armed bandit algorithms. We investigate the asymptotic behavior of the proposed routing algorithms and prove the convergence of one of them to the user equilibrium. Discrete event simulation results show the merit of these algorithms in terms of improving the resource utilization and increasing the network admissibility compared with shortest path routing.We investigate the performance degradation due to decentralized routing as opposed to centralized optimal routing policies in practical scenarios. The system optimal and the Nash bargaining solutions are two centralized benchmarks used in this study. We provide nonlinear programming formulations of these problems along with a distributed recursive approach to compute the solutions. An on-line partially-decentralized control architecture is also proposed to achieve the system optimal and the Nash bargaining solution performances. Numerical results in some practical scenarios with well engineered networks, where the network resources and traffic demand are well matched, indicate that decentralized learning techniques provide efficient, stable and scalable approaches for routing the bandwidth guaranteed paths.
In the context of on-line learning, we propose a new algorithm to track the best action-selection policy when it abruptly changes over time. The proposed algorithm employs change detection mechanisms to detect the sudden changes and restarts the learning process on the detection of an abrupt change. The performance analysis of this study reveals that when all the changes are detectable by the change detection mechanism, the proposed tracking the best action-selection policy algorithm is rate optimal. On-line routing of bandwidth guaranteed paths with the potential occurrence of network shocks such as significant changes in the traffic demand is one of the applications of the devised algorithm. Simulation results show the merit of the proposed algorithm in tracking the optimal routing policy when it abruptly changes.
46
Poellabauer, Christian. "Q-Fabric: System Support for Continuous Online Quality Management". Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-04082004-134256/unrestricted/poellabauer%5Fchristian%5F200405%5Fphd.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2004.Pande, Santosh, Committee Member ; Pu, Calton, Committee Member ; Schwan, Karsten, Committee Chair ; Franke, Hubertus, Committee Member ; Eisenhauer, Greg, Committee Member. Vita. Includes bibliographical references (leaves 158-169).
47
Kim, Jonghyun. "Realistic mobility modeling and simulation for mobile wireless network in urban environments". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.67Mb, 81 p, 2005. http://wwwlib.umi.com/dissertations/fullcit/1428178.
Testo completo
48
Sathyanarayana, Supreeth. "Characterizing the effects of device components on network traffic". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47640.
Testo completoAbstract (sommario):
When a network packet is formed by a computer's protocol stack, there are many components (e.g., Memory, CPU, etc.) of the computer that are involved in the process. The objective of this research is to identify, characterize and analyze the effects of the various components of a device (e.g., Memory, CPU, etc.) on the device's network traffic by measuring the changes in its network traffic with changes in its components. We also show how this characterization can be used to effectively perform counterfeit detection of devices which have counterfeit components (e.g., Memory, CPU, etc.).
To obtain this characterization, we measure and apply statistical analyses like probability distribution fucntions (PDFs) on the interarrival
times (IATs) of the device's network packets (e.g., ICMP, UDP, TCP, etc.). The device is then modified by changing just one component (e.g., Memory, CPU, etc.) at a time while holding the rest constant and acquiring the IATs again. This, over many such iterations provides an understanding of the effect of each component on the overall device IAT statistics. Such statistics are captured for devices (e.g., field-programmable gate arrays (FPGAs) and personal computers (PCs)) of different types. Some of these statistics remain stable across different IAT captures for the same device and differ for different devices (completely different devices or even the same device with its components changed). Hence, these statistical variations can be used to detect changes in a device's composition, which lends itself well to counterfeit detection.
Counterfeit devices are abundant in today's world and cause billions of dollars of loss in revenue. Device components are substituted with inferior quality components or are replaced by lower capacity components. Armed with our understanding of the effects of various device components on the device's network traffic, we show how such substitutions or alterations of legitimate device components can be detected and hence perform effective counterfeit detection by statistically analyzing the deviation of the device's IATs from that of the original legitimate device. We perform such counterfeit detection experiments on various types of device configurations (e.g., PC with changed CPU, RAM, etc.) to prove the technique's efficacy. Since this technique is a fully network-based solution, it is also a non-destructive technique which can quickly, inexpensively and easily verify the device's legitimacy. This research also discusses the limitations of network-based counterfeit detection.
49
Kassa, Debassey Fesehaye. "Analytic models of TCP performance". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/16608.
Testo completoAbstract (sommario):
Thesis (MSc)--University of Stellenbosch, 2005.ENGLISH ABSTRACT: The majority of tra c on the Internet uses the Transmission Control Protocol (TCP) as a transport layer protocol for the end-to-end control of information transfer. Measurement, simulation and analytical models are the techniques and tools that can be used to understand and investigate the Internet and its performance. Measurements can only be used to explore existing network scenario or otherwise become costly and in exible with the growth and complexity of the Internet. Simulation models do not scale with the growth of network capacities and the number of users. Computationally e cient analytical models are therefore important tools for investigating, designing, dimensioning and planning IP (Internet Protocol) networks. Existing analytical models of TCP performance are either too simple to capture the internal dynamics of TCP or are too complex to be used to analyze realistic network topologies with several bottleneck links. The literature shows that the xed point algorithm (FPA) is a very useful way of solving analytical models of Internet performance. This thesis presents fast and accurate analytical models of TCP performance with the FPA used to solve them. Apart from what is observed in experimental literature, no comprehensive proof of the convergence and uniqueness of the FPA is given. In this thesis we show how the FPA of analytical models of reliable Internet protocols such as TCP converges to a unique xed point. The thesis speci es the conditions necessary in order to use the FPA for solving analytical models of reliable Internet protocols. We also develop a general implementation algorithm of the FPA of analytical models of TCP performance for realistic and arbitrary network topologies involving heterogenous TCP connections crossing many bottleneck links. The models presented in this thesis give Internet performance metrics, assuming that only basic network parameters such as the network topology, the number of TCP connections, link capacity, distance between network nodes and router bu er sizes are known. To obtain the performance metrics, TCP and network sub{models are used. A closed network of :=G=1 queues is used to develop each TCP sub-model where each queue represents a state of a TCP connection. An M=M=1=K queue is used for each network sub{model which represents the output interface of an IP router with a bu er capacity of K ��������1 packets. The two sub-models are iteratively solved. We also give closed form expressions for important TCP performance values and distributions. We show how the geometric, bounded geometric and truncated geometric distributions can be used to model reliable protocols such as TCP. We give models of the congestion window cwnd size distribution by conditioning on the slow start threshold ssthresh distribution and vice-versa. We also present models of the probabilities of TCP timeout and triple duplicate ACK receptions. Numerical results based on comparisons against ns2 simulations show that our models are more accurate, simpler and computationally more e cient than another well known TCP model. Our models can therefore be used to rapidly analyze network topologies with several bottlenecks and obtain detailed performance metrics.
AFRIKAANSE OPSOMMING: Die meerderheid van die verkeer op die Internet gebruik die Transmission Control Protocol (TCP) as `n vervoer laag protokol vir die einde-tot-einde kontrole van inligting oordrag. Meting, simulasie en analitiese modelle is die tegnieke en gereedskap wat gebruik kan word om die Internet te ondersoek en verstaan. Meting kan slegs gebruik word om bestaande netwerke scenarios te verken. Meting is duur en onbuigsaam met die groei en samegesteldheid van die Internet. Simulasie modelle skaal nie met die groei van netwerk kapasiteit en gebruikers nie. Analitiese modelle wat berekening e ektief is is dus nodige gereedskap vir die ondersoek, ontwerp, afmeting en beplanning van IP (Internet Protocol) netwerke. Bestaande analitiese TCP modelle is of te eenvoudig om die interne dinamiek van die TCP saam te vat of hulle is te ingewikkeld om realistiese netwerk topologie met heelwat bottelnek skakels te analiseer. Literatuur toon dat die xed point algorithm (FPA) baie handig is vir die oplos van analitiese modelle van Internet verrigting. In hierdie tesis word vinnige en akkurate analitiese modelle van TCP verrigting opgelos deur FPA weergegee. Buiten wat deur eksperimentele literatuur aangedui word is daar geen omvattende bewyse van die konvergensie en uniekheid van die FPA nie. In hierdie tesis word aangedui hoe die FPA van analitiese modelle van betroubare Internet protokolle soos die TCP konvergeer na `n unieke vaste punt. Hierdie tesis spesi seer die voorwaardes benodig om die FPA te gebruik vir die oplos van analitiese modelle van realistiese Internet protokolle. `n Algemene uitvoer algoritme van die FPA van analitiese modelle van TCP vir realistiese en arbitr^ere netwerk topogra e insluitende heterogene TCP konneksies oor baie bottelnek skakels is ontwikkel. Die model in hierdie tesis gee Internet verrigting metodes met die aanname dat slegs basiese netwerk parameters soos netwerk topologie, die aantal TCP konneksies, die konneksie kapasiteit, afstand tussen netwerk nodusse en die roete bu er grotes bekend is. Om die verrigting metodes te verkry, word TCP en netwerk sub-modelle gebruik. `n Geslote netwerk van :=G=1 rye is gebruik om elke TCP sub-model, waar elke ry 'n toestand van `n TCP konneksie voorstel, te ontwikkel. `n M=M=1=K ry is gebruik vir elke netwerk sub-model wat die uitset koppelvlak van `n IP roetemaker met `n bu er kapasiteit van K ������� 1 pakkies voorstel. Die twee submodelle word iteratief opgelos. Geslote vorm uitdrukkings vir belangrike TCP verrigting waardes en verspreidings word gegee. Daar word getoon hoe geometriese, begrensde geometriese en geknotte geometriese verspreidings gebruik kan word om betroubare protokolle soos die TCP te modelleer. Modelle van die kongestie venster cwnd grootte verspreiding word gegee deur die kondisionering van die stadige aanvang drempel ssthresh verspreiding en andersom. Modelle van die voorspelling van TCP tyduit en trippel duplikaat ACK resepsie word weergegee. Numeriese resultate gebaseer op vergelykings met ns2 simulasies wys dat ons modelle meer akkuraat, eenvoudiger en berekeningsgewys meer e ektief is as ander wel bekende TCP modelle. Ons modelle kan dus gebruik word vir vinnig analise van netwerk topologie met verskeie bottelnekke en om gedetailleerde verrigting metodes te bekom.
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Lee, Myounghwan. "Quality of service with DiffServ architecture in hybrid mesh/relay networks". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34694.
Testo completoAbstract (sommario):
The objective of this research is to develop an optimized quality of service (QoS) assurance algorithm with the differentiated services (DiffServ) architecture, and a differentiated polling algorithm with efficient bandwidth allocation for QoS assurance in the hybrid multi-hop mesh/relay networks. These wide area networks (WANs), which will employ a connection-based MAC protocol, along with QoS-enabled wireless local area networks (WLANs) that use a contention-based MAC protocol, need to provide an end-to-end QoS guarantee for data communications, particularly QoS-sensitive multimedia communications.
Due to the high cost of construction and maintenance of infrastructure in wireless networks, engineers and researchers have focused their investigations on wireless mesh/relay networks with lower cost and high scalability. For current wireless multi-hop networks, an end-to-end QoS guarantee is an important functionality to add, because the demand for real-time multimedia communications has recently been increasing. For real-time multimedia communication in heterogeneous networks, hybrid multi-hop mesh/relay networks using a connection-based MAC protocol, along with QoS-enabled WLANs that use a contention-based MAC protocol can be an effective multi-hop network model , as opposed to multi-hop networks with a contention-based MAC protocol without a QoS mechanism. To provide integrated QoS support for different QoS mechanisms, the design of the cross-layer DiffServ architecture that can be applied in wireless multi-hop mesh/relay networks with WLANs is desirable.
For parameterized QoS that requires a specific set of QoS parameters in hybrid multi-hop networks, an optimized QoS assurance algorithm with the DiffServ architecture is proposed here that supports end-to-end QoS through a QoS enhanced WAN for multimedia communications.
For a QoS assurance algorithm that requires a minimum per-hop delay, the proper bandwidth to allow the per-hop delay constraint needs to be allocated. Therefore, a polling algorithm with a differentiated strategy at multi-hop routers is proposed here. The proposed polling algorithm at a router differentially computes and distributes the polling rates for routers according to the ratio of multimedia traffic to overall traffic, the number of traffic connections, and the type of polling service.
By simulating the architecture and the algorithms proposed in this thesis and by analyzing traffic with the differentiated QoS requirement, it is shown here that the architecture and the algorithms produce an excellent end-to-end QoS guarantee.