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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Technoeconomic aspects of next-generation telecommunications including the Internet service

Unknown Date (has links)
This research is concerned with the technoeconomic aspects of modern and next-generation telecommunications including the Internet service. The goal of this study thereof is tailored to address the following: (i) Reviewing the technoeconomic considerations prevailing in telecommunication (telco) systems and their implicating futures; (ii) studying relevant considerations by depicting the modern/next-generation telecommunications as a digital ecosystem viewed in terms of underlying complex system evolution (akin to biological systems); (iii) pursuant to the digital ecosystem concept, co-evolution modeling of competitive business structures in the technoeconomics of telco services using dichotomous (flip-flop) states as seen in prey-predator evolution; (iv) specific to Internet pricing economics, deducing the profile of consumer surplus versus pricing model under DiffServ QoS architecture pertinent to dynamic- , smart- and static-markets; (v) developing and exemplifying decision-making pursuits in telco business under non-competitive and competitive markets (via gametheoretic approach); (vi) and modeling forecasting issues in telco services addressed in terms of a simplified ARIMA-based time-series approach, (which includes seasonal and non-seasonal data plus goodness-fit estimations in time- and frequency-domains). Commensurate with the topics indicated above, necessary analytical derivations/models are proposed and computational exercises are performed (with MatLabTM R2006b and other software as needed). Extensive data gathered from open literature are used thereof and, ad hoc model verifications are performed. Lastly, results are discussed, inferences are made and open-questions for further research are identified. / by Renata Cristina Tourinho Sardenberg. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
72

Spreading factor optimization and random access stability control for IMT-2000.

January 2000 (has links)
Ho Chi-Fong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 63-[64]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- The 2.5G Systems --- p.3 / Chapter 1.2.1 --- HSCSD --- p.3 / Chapter 1.2.2 --- GPRS --- p.3 / Chapter 1.2.3 --- EDGE --- p.4 / Chapter 1.2.4 --- IS-136 --- p.4 / Chapter 1.3 --- The Evolution from 2G/2.5G to 3G --- p.4 / Chapter 1.3.1 --- GSM Data Evolution --- p.4 / Chapter 1.3.2 --- TDMA Data Evolution --- p.5 / Chapter 1.3.3 --- CDMA Data Evolution --- p.6 / Chapter 1.4 --- UTRA --- p.7 / Chapter 1.4.1 --- UTRA FDD --- p.8 / Chapter 1.4.2 --- UTRA TDD --- p.18 / Chapter 1.4.3 --- Transport Channels --- p.25 / Chapter 2 --- Spreading Factor Optimization for FDD Downlink --- p.27 / Chapter 2.1 --- The Optimal Channel Splitting Problem --- p.28 / Chapter 2.2 --- Spreading Factor Optimization for FDD Downlink Dedicated Chan- nel --- p.30 / Chapter 3 --- Random Access Channel Stability Control --- p.33 / Chapter 3.1 --- Random Access Slotted Aloha --- p.33 / Chapter 3.1.1 --- System model --- p.33 / Chapter 3.1.2 --- Probability of Code-Collision --- p.34 / Chapter 3.1.3 --- Throughput Analysis of Random Access in TD/CDMA System --- p.37 / Chapter 3.1.4 --- Retransmission --- p.42 / Chapter 3.1.5 --- System Delay --- p.42 / Chapter 3.2 --- Random Access Channel Stability Control --- p.43 / Chapter 3.2.1 --- System Model --- p.43 / Chapter 3.2.2 --- Random Access Procedure --- p.44 / Chapter 3.3 --- Random Access Channel Stability Control Alogrithm --- p.47 / Chapter 3.3.1 --- Simulation --- p.49 / Chapter 3.4 --- Multi-class Model --- p.55 / Chapter 4 --- Conclusions and Topics for Future Study --- p.60 / Chapter 4.1 --- Thesis Conclusions --- p.60 / Chapter 4.2 --- Future Work --- p.61 / Chapter 4.2.1 --- Downlink and Uplink resource allocation in TDD --- p.61 / Chapter 4.2.2 --- Resource Unit Packing in TDD --- p.62 / Chapter 4.2.3 --- Other Topics --- p.62 / Bibliography --- p.63
73

Deflection routing in buffered binary hypercube switches

Mukhopadhyaya, Utpal Kanti 01 January 1998 (has links)
The growing acceptance of B-ISDN (Broadband Integrated Services Digital Network) requires entirely new switching support a wide range of service demands including voice, video and data. At the same time, advances in the field of VLSI have enabled new principles to the design and architecture high-performance switching fabrics. Direct binary switch fabrics are a suitable candidate for future B- switches. Binary hypercubes have regular topology, are highly fault and have multiple paths for routing cells which help avoid performance penalties due to congestion and faults. In addition, these switches can adopt the novel, distributed, and adaptive routing scheme called 'deflection routing'. In normal routing, cells are routed along shortest paths to their destinations; in case of multiple cells contending for a single outgoing channel, the rest of the contending cells are either buffered or dropped to avoid congestion. In the case of deflection routing, cells can be routed along non-shortest paths. As a result, deflection routing helps avoid dropping cells. The scheme may be implemented with and without queuing buffers at the routers. In order to properly provision, control, and design these hypercube switches, it is essential that their performance capabilities be completely understood. Researchers have used both analytical model and simulations to evaluate performance of hypercube switches. The presence of distributed logic, multi-path routing, deflection routing, and queuing buffers make modeling tasks highly challenging. Building a reasonably accurate model of a hypercube switch with queuing buffers and deflection routing and using that model to gain practical insights into some of the important design parameters of the switch has been the major motivation of this thesis. An approximate Markov model of a single switching element is built to capture the behavior of a d-dimension switch. The numerical model is solved iteratively. Accuracy of the model is established by validating against simulation results. One disadvantage of having multiple paths, queuing buffers, and deflection motion of cells in hypercube switches is that the cells belonging to a particular traffic stream may not be delivered at their destinations in sequence. This phenomenon is known as 'out-of-orderness' of cells. An additional goal of this thesis has been development of a model to capture out-of-orderness phenomenon. The model is validated by comparing model results against simulation. Results show that the model is accurate and reveals significant insight into switch's behavior that can be used to design and engineer d-dimension hypercube switches.
74

DiffServ/MPLS Network Design and Management

Anjali, Tricha 09 April 2004 (has links)
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.
75

MPEG-4 AVC traffic analysis and bandwidth prediction for broadband cable networks

Lanfranchi, Laetitia I. January 2008 (has links)
Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Bing Benny; Committee Co-Chair: Fred B-H. Juang; Committee Member: Gee-Kung Chang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
76

Approaches for traffic classification and the optimisation of radio resources in cellular networks : application to South Africa

Kurien, Anish Mathew. January 2012 (has links)
D. Tech. Electrical Engineering. / Objectives of the study is to propose a suitable feature extraction and classication approach that is capable of adapting to the non-linear nature and the noise contained in the time series data. The end goal of subscriber classication in this study is to utilise the subscriber information extracted for a new radio resource optimisation model that focuses on the Channel Allocation Problem CAP. Although there they have been various models proposed in literature for solving of the CAP problem, the utilisation of subscriber related information in the CAP has not been directly considered.
77

Multiple ring networks in clustered traffic environments.

Green, Breton. January 1998 (has links)
Ring networks are appropriate for the full range of network levels, including multiprocessor systems, local area computer networks and high speed backbones. The most well known and widely implemented examples are the IBM token ring and FDDI networks. Ring networks have the advantages of high channel utilisation and bounded delay if an n-limited service policy is used. The packet transfer delay, defined as the average time a packet spends in the network from the time it is generated until the time it is received at its destination node, improves with the number of rings on which a node is connected. However, many ring connections are not economically feasible since the cost of the ring interface increases with the number of rings. There has been an abundance of previous work on single token ring networks. A number of papers on slotted rings, register insertion rings and more complex ring architectures have also been published. However, there is very little existing literature on multiple ring networks as well as ring networks in clustered traffic environments, i.e. where nodes from the same cluster tend to communicate more with each other than with other nodes in the network. This thesis focuses on two network topologies that make use of multiple rings and are well suited to clustered traffic environments: the two-connected multiple ring (2-MR) and the destination removal double ring (DRDR). For the 2-MR network, three different practical token-based protocols are investigated in an attempt to optimise performance. It is further shown that significant performance improvements can be achieved by employing a slotted ring protocol rather than the token ring protocol. The DRDR network is also examined and its performance compared to the aforementioned architectures. For each of the six cases, both random and clustered traffic patterns are considered and compared. Analytical results are derived which are verified by results obtained from computer simulations. Furthermore, we look at exact methods of analysing ring networks. A mean value analysis of a single token ring network with a I-limited service discipline is performed, which clearly shows the complexity exact methods introduce. Finally, although it has been stated in the literature that an exact analysis of a multiple symmetrical token ring network is intractable, we present a novel Markov chain approach that gives exact results for near zero loads. / Thesis (M.Sc.-Electronic Engineering)-University of Natal, 1998.
78

Detecção de anomalias em redes de computadores / Anomaly detection in computer networks

Zarpelão, Bruno Bogaz 16 August 2018 (has links)
Orientadores: Leonardo de Souza Mendes, Mario Lemes Proença Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T19:18:19Z (GMT). No. of bitstreams: 1 Zarpelao_BrunoBogaz_D.pdf: 5089650 bytes, checksum: 281e7d926aae4a7e05a2e94347a06179 (MD5) Previous issue date: 2010 / Resumo: Anomalias em redes de computadores são desvios súbitos e acentuados que ocorrem no tráfego em consequência de diversas situações como defeitos em softwares, uso abusivo de recursos da rede, falhas em equipamentos, erros em configurações e ataques. Nesta tese, é proposto um sistema de detecção de anomalias em redes de computadores baseado em três níveis de análise. O primeiro nível de análise é responsável por comparar os dados coletados em um objeto SNMP (Simple Network Management Protocol) com o perfil de operações normais da rede. O segundo nível de análise correlaciona os alarmes gerados no primeiro nível de análise utilizando um grafo de dependências que representa as relações entre os objetos SNMP monitorados. O terceiro nível de análise reúne os alarmes de segundo nível utilizando informações sobre a topologia de rede e gera um alarme de terceiro nível que reporta a propagação da anomalia pela rede. Os testes foram realizados na rede da Universidade Estadual de Londrina, utilizando situações reais. Os resultados mostraram que a proposta apresentou baixas taxas de falsos positivos combinadas a altas taxas de detecção. Além disso, o sistema foi capaz de correlacionar alarmes gerados para diferentes objetos SNMP em toda a rede, produzindo conjuntos menores de alarmes que ofereceram ao administrador de redes uma visão panorâmica do problema / Abstract: Anomalies in computer networks are unexpected and significant deviations that occur in network traffic due to different situations such as software bugs, unfair resource usage, failures, misconfiguration and attacks. In this work, it is proposed an anomaly detection system based on three levels of analysis. The first level of analysis is responsible for comparing the data collected from SNMP (Simple Network Management Protocol) objects with the profile of network normal behavior. The second level of analysis correlates the alarms generated by the first level of analysis by using a dependency graph, which represents the relationships between the SNMP objects. The third level of analysis correlates the second level alarms by using network topology information. The third level generates a third level alarm that presents the anomaly propagation path through the network. Tests were performed in the State University of Londrina network, exploring real situations. Results showed that the proposal presents low false positive rates and high detection rates. Moreover, the proposed system is able to correlate alarms that were generated for SNMP objects at different places of the network, producing smaller sets of alarms that offer a wide-view of the problem to the network administrator / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica
79

Online traffic engineering for MPLS networks

Botha, Marlene 4 1900 (has links)
Thesis (MSc) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT: The Internet is fast evolving into a commercial platform that carries a mixture of narrow- and broadband applications such as voice, video, and data. Users expect a certain level of guaranteed service from their service providers and consequently the need exists for efficient Internet traffic engineering to enable better Quality of Service (QoS) capabilities. Multi-protocol Label Switching (MPLS) is a label switching protocol that has emerged as an enabling technology to achieve efficient traffic engineering for QoS management in IP networks. The ability of the MPLS protocol to create explicit virtual connections called Label Switched Paths (LSPs) to carry network traffic significantly enhances the traffic engineering capabilities of communication networks. The MPLS protocol supports two options for explicit LSP selection: offline LSP computation using an optimization method and dynamic route selection where a single node makes use of current available network state information in order to compute an explicit LSP online. This thesis investigates various methods for the selection of explicit bandwidth guaranteed LSPs through dynamic route selection. We address the problem of computing a sequence of optimal LSPs where each LSP can carry a specific traffic demand and we assume that no prior information regarding the future traffic demands are available and that the arrival sequence of LSP requests to the network is unknown. Furthermore, we investigate the rerouting abilities of the online LSP selection methods to perform MPLS failure restoration upon link failure. We propose a new online routing framework known as Least Interference Optimization (LIO) that utilizes the current bandwidth availability and traffic flow distribution to achieve efficient traffic engineering. We present the Least Interference Optimization Algorithm (LIOA) that reduces the interference among competing network flows by balancing the number and quantity of flows carried by a link for the setup of bandwidth guaranteed LSPs in MPLS networks. The LIOA routing strategy is evaluated and compared against well-known routing strategies such as the Minimum Hop Algorithm (MHA), Minimum Interference Routing Algorithm (MIRA), Open Shortest Path First (OSPF) and Constraint Shortest Path First (CSPF) by means of simulation. Simulation results revealed that, for the network topologies under consideration, the routing strategies that employed dynamic network state information in their routing decisions (LIOA, CSPF and MIRA) generally outperformed the routing strategies that only rely on static network information (OSPF and MHA). In most simulation experiments the best performance was achieved by the LIOA routing strategy while the MHA performed the worse. Furthermore we observed that the computational complexity of the MIRA routing strategy does not translate into equivalent performance gains. We employed the online routing strategies for MPLS failure recovery upon link failure. In particular we investigated two aspects to determine the efficiency of the routing strategies for MPLS rerouting: the suitability of the LSP configuration that results due to the establishment of LSPs prior to link failure and the ability of the online routing strategy to reroute failed LSPs upon link failure. Simulation results revealed similar rerouting performance for all online routing strategies under investigation, but a LSP configuration most suitable for online rerouting was observed for the LIOA routing strategy. / AFRIKAANSE OPSOMMING:Die Internet is voordurend besig om te evoleer in 'n medium wat 'n wye reeks moderne kommunikasietegnologiee ondersteun, insluitende telefoon, video en data. Internet gebruikers verwag gewaarborgde diens van hul diensverskaffers en daar bestaan dus 'n vraag na doeltreffende televerkeerbeheer vir gewaarborgde Internet diensgehalte. Multiprotokol Etiketskakeling (MPLS) is 'n etiketskakeling protokol wat doeltreffende televerkeerbeheer en diensgehalte moontlik maak deur die eksplisiete seleksie van virtuele konneksies vir die transmissie van netwerkverkeer in Internetprotokol (IP) netwerke. Hierdie virtuele konneksies staan bekend as etiketgeskakelde paaie. Die MPLS protokol ondersteun tans twee moontlikhede vir eksplisiete seleksie van etiketgeskakelde paaie: aflyn padberekening met behulp van optimeringsmetodes en dinamiese aanlyn padseleksie waar 'n gekose node 'n eksplisiete pad bereken deur die huidige stand van die netwerk in ag te neem. In hierdie tesis word verskeie padseleksiemetodes vir die seleksie van eksplisiete bandwydte-gewaarborgde etiketgeskakelde paaie deur mid del van dinamiese padseleksie ondersoek. Die probleem om 'n reeks optimale etiketgeskakelde paaie te bereken wat elk 'n gespesifeerde verkeersaanvraag kan akkommodeer word aangespreek. Daar word aanvaar dat geen informasie in verband met die toekomstige verkeersaanvraag bekend is nie en dat die aankomsvolgorde van etiketgeskakelde pad verso eke onbekend is. Ons ondersoek verder die herroeteringsmoontlikhede van die aanlyn padseleksiemetodes vir MPLS foutrestorasie in die geval van skakelonderbreking. Vir hierdie doel word 'n nuwe aanlyn roeteringsraamwerk naamlik Laagste Inwerking Optimering (LIO) voorgestel. LIO benut die huidige beskikbare bandwydte en verkeersvloeidistribusie van die netwerk om doeltreffende televerkeerbeheer moontlik te maak. Ons beskryf 'n Laagste Inwerking Optimering Algoritme (LIOA) wat die inwerking tussen kompeterende verkeersvloei verminder deur 'n balans te handhaaf tussen die aantal en kwantiteit van die verkeersvloeistrome wat gedra word deur elke netwerkskakel. Die LIOA roeteringstrategie word geevalueer met behulp van simulasie en die resultate word vergelyk met ander bekende roeteringstrategiee insluitende die Minimum Node Algorithme (MHA), die Minimum Inwerking Algoritme (MIRA), die Wydste Kortste Pad Eerste Algoritme (OSPF) en die Beperkte Kortste Pad Eerste Algoritme (CSPF). Die resultate van die simulasie-eksperimente to on dat, vir die netwerk topologiee onder eksperimentasie, die roeteringstratgiee wat roeteringsbesluite op dinamiese netwerk informasie baseer (LIOA, MIRA, CSPF) oor die algemeen beter vaar as die wat slegs staatmaak op statiese netwerkinformasie (MHA, OSPF). In die meeste simulasie-eksperimente vaar die LIOA roeteringstrategie die beste en die MHA roeteringstrategie die slegste. Daar word verder waargeneem dat die komputasiekomplesiteit van die MIRA roeteringstrategie nie noodwendig weerspieel word in die sukses van roeteringsuitkoms nie. In die geval waar die aanlyn roeteringstrategiee aangewend word vir MPLS foutrestorasie, toon die resultate van simulasie-eksperimente dat al die roeteringstrategiee min of meer dieselfde uitkoms lewer ten opsigte van herroetering van onderbreekte verkeersvloei. Die konfigurasie van etiketgeskakelde paaie deur die LIOA roeteringstrategie voor skakelonderbreking is egter die geskikste vir televerkeer herroetering na skakelonderbreking
80

Traffic engineering label switched paths

Bagula, Bigomokero Antoine 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The Internet is evolving into a commercial platform requiring enhanced protocols and an expanded physical infrastructure allowing a better delivery from IP. Multi-protocol Label Switching (MPLS) is a technology enabling traffic engineering and virtual private network (VPN) provisioning. MPLS achieves traffic engineering by carrying the traffic over virtual connections called Label Switched Paths (LSPs) which are engineered based on QoS requirements such as delay, jitter and packet loss minimization or throughput maximization. This thesis proposes path finding and traffic distribution methods to be deployed in MPLS networks for traffic engineering LSPs. A flow optimization model based on a pre-planned routing approach separating path finding and traffic distribution is presented. This model is augmented by a threshold routing approach which routes the traffic based on thresholds expressing the maximum load level reached by network links. This routing approach moves the traffic away from thresholdmarked links to achieve low-utilized links/paths. The performance and routing capabilities of these methods are evaluated through designed software. A routing architecture implementing a two-layer signalling model for MPLS network is proposed and evaluated through simulation. v / AFRIKAANSE OPSOMMING:Die verandering van die Internet in 'n kommersiele platform met verbeterde protokolle en 'n uitgebreide fisieke infrastruktuur stel die internetprotokol (IP) in staat tot beter lewering. Multiprotokol- etiketskakeling (MPLS), is 'n tegnologie vir die voorsiening van televerkeerbeheer en virtuele privaatnetwerke (VPN). MPLS verskaf televerkeerbeheer deur die verkeer te dra oar virtuele konneksies, wat bekend staan as etiketgeskakelde paaie, waarvan die ontwerp gebaseer is op vereistes vir diensgehalte soos vertraging, ritteling en die minimering van pakketverlies of maksimering van deurvoer. Hierdie tesis stel nuwe padvind- en verkeerdistribusiemetodes voor wat aangewend word in MPLSnetwerke om etiketgeskakelde paaie te beheer. 'n Model vir vloei-optimering-gebaseer op voorafbeplande roetering wat padvinding en verkeerdistribusie skei-word aangebied. Hierdie model word uitgebrei deur 'n benadering van drempelroetering wat die verkeer roeteer en gebaseer is op drempels wat die maksimum ladingsvlak voorstel wat bereik kan word deur netwerkskakels. Hierdie roeteringsbenadering skuif die verkeer weg van drempelgemerkte skakels en bereik daardeur laaggebruikte skakelsjpaaie. Die prestasie en roeteringsvaardigheid van hierdie metodes word gevalueer deur selfontwikkelde programmatuur. 'n Argitektuur vir roetering wat 'n dubbellaagseinmodel implementeer vir 'n MPLS-netwerk, word aangebied en gevalueer met simulasie.

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