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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.
11

Practical and efficient internet routing with competing interests /

Mahajan, Ratul. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 123-135).
12

NETWORK-BASED DISTRIBUTED DATA ACQUISITION AND RECORDING FOR SMALL SYSTEMS

Hildin, John 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Some of the first applications of network-based data acquisition systems have been for large aircraft. These systems contained numerous network nodes including data acquisition units, switches, recorders, network management units, and others. One of the desirable aspects of a networked-based system is the ability to scale such a system to meet increasing test requirements. Similarly, these systems lend themselves to scaling down, as well, to meet the testing needs of smaller test articles. These needs may include fewer nodes and/or physically smaller components. The testing of smaller vehicles places slightly different requirements on the testing process. In general, there is a greater need for real-time analysis, flexibility and ad-hoc testing. This paper will attempt to show how a small to medium sized test article can benefit from the same powerful, feature-rich network-based data acquisition and recording system as used on larger programs. The paper will also show how a smaller system can deliver on this promise without sacrificing performance and functionality.
13

Network Management and Signalling Standards for CCSDS Advanced Orbiting System Communication Systems

Pietras, John 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The Consultative Committee for Space Data Systems (CCSDS) is an international organization chartered to develop and adopt communications protocols and data processing standards suitable for use in space-related communication and data processing systems. Among its ongoing activities, CCSDS is in the final stages of approving recommendations for communications services and protocols to be used by "advanced orbiting systems" (AOS) typified by the international Space Station Freedom Program. As a companion activity to the development of the AOS protocols, CCSDS is in the process of defining the network management functions that are necessary to realize the full capabilities of the AOS services. CCSDS is also concerned with communicating management information among distributed network management systems, an environment that will be typical of multi-national space ventures. These network management systems are envisioned to be automated, resulting in a need for standard network management protocols and data structures. This paper briefly describes the CCSDS network management environment, and reviews the current status of CCSDS recommendations for network management functional capability, use of international standards for network management, and composition of signalling systems in support of the AOS services. The paper concludes with a timetable for future work in this area.
14

Case studies of opportunities for improving GSM BSS network performance

Abbadessa, Daniele January 1998 (has links)
No description available.
15

New optimal power flow techniques to improve integration of distributed generation in responsive distribution networks

Robertson, James George January 2015 (has links)
Climate change has brought about legally-binding targets for Scotland, the U.K. and the E.U. to reduce greenhouse gas emissions and source a share of overall energy consumption from renewable energy resources by 2020. With severe limitations in the transport and heating sectors the onus is on the electricity sector to provide a significant reduction in greenhouse gas emissions and introduce a substantial increase in renewable energy production. The most attractive renewable energy resources are located in the geographic extremes of the country, far from the large population densities and high voltage, high capacity transmission networks. This means that the majority of renewable generation technologies will need to connect to the conventionally passive, lower voltage distribution networks. The integration of Distributed Generation (DG) is severely restricted by the technical limitations of the passively managed lower voltage infrastructure. Long lead times and the capital expenditure of traditional electricity network reinforcement can significantly delay or make the economics of some renewable generation schemes unviable. To be able to quickly and cost-effectively integrate significant levels of DG, the conventional fit-and-forget approach will have to be evolved into a ‘connect-and-manage’ system using active network management (ANM) techniques. ANM considers the real-time variation in generation and demand levels and schedules electricity network control settings to alleviate system constraints and increase connectable capacity of DG. This thesis explores the extent to which real time adjustments to DG and network asset controller set-points could allow existing networks to accommodate more DG. This thesis investigates the use of a full AC OPF technique to operate and schedule in real time variables of ANM control in distribution networks. These include; DG real and reactive power output and on-load-tap-changing transformer set-points. New formulations of the full AC OPF problem including multi-objective functions, penalising unnecessary deviation of variable control settings, and a Receding-Horizon formulation are assessed. This thesis also presents a methodology and modelling environment to explore the new and innovative formulations of OPF and to assess the interactions of various control practices in real time. Continuous time sequential, single scenario, OPF analyses at a very short control cycle can lead to the discontinuous and unnecessary switching of network control set-points, particularly during the less onerous network operating conditions. Furthermore, residual current flow and voltage variation can also gave rise to undesirable network effects including over and under voltage excursion and thermal overloading of network components. For the majority of instances, the magnitude of constraint violation was not significant but the levels of occurrence gave occasional cause for concern. The new formulations of the OPF problem were successful in deterring any extreme and unsatisfactory effects. Results have shown significant improvements in the energy yield from non-firm renewable energy resources. Initial testing of the real time OPF techniques in a simple demonstration network where voltage rise restricted the headroom for installed DG capacity and energy yield, showed that the energy yield for a single DG increased by 200% from the fit-and-forget scenario. Extrapolation of the OPF technique to a network with multiple DGs from different types of renewable energy resources showed an increase of 216% from the fit-and-forget energy yield. In a much larger network case study, where thermal loading limits constrained further DG capacity and energy yield, the increase in energy yield was more modest with an average increase of 45% over the fit-and-forget approach. In the large network where thermal overloading prevailed there was no immediate alternative to real power curtailment. This work has demonstrated that the proposed ANM OPF schemes can provide an intelligent, more cost effective and quicker alternative to network upgrades. As a result, DNOs can have a better knowledge and understanding of the capabilities and technical limitations of their networks to absorb DG safely and securely, without the expense of conventional network reinforcement.
16

Active network management and uncertainty analysis in distribution networks

Zhou, Lin January 2015 (has links)
In distribution networks, the traditional way to eliminate network stresses caused by increasing generation and demand is to reinforce the primary network assets. A cheaper alternative is active network management (ANM) which refers to real-time network control to resolve power flow, voltage, fault current and security issues. However, there are two limitations in ANM. First, previous ANM strategies investigated generation side and demand side management separately. The generation side management evaluates the value from ANM in terms of economic generation curtailment. It does not consider the potential benefits from integrating demand side response such as economically shifting flexible load over time. Second, enhancing generation side management with load shifting requires the prediction of network stress whose accuracy will decrease as the lead time increases. The uncertain prediction implies the potential failure of reaching expected operational benefits. However, there is very limited investigation into the trade-offs between operational benefit and its potential risk. In order to tackle the challenges, there are two aspects of research work in this thesis. 1) Enhanced ANM. It proposes the use of electric vehicles (EVs) as responsive demand to complement generation curtailment strategies in relieving network stress. This is achieved by shifting flexible EV charging demand over time to absorb excessive wind generation when they cannot be exported to the supply network. 2) Uncertainty management. It adopts Sharpe Ratio and Risk Adjust Return On Capital concepts from financial risk management to help the enhanced ANM make operational decisions when both operational benefit and its associated risk are considered. Copula theory is applied to further integrate correlations of forecasting errors between nodal power injections (caused by wind and load forecasting) into uncertainty management. The enhanced ANM can further improve network efficiency of the existing distribution networks to accommodate increasing renewable generation. The cost-benefit assessment informs distribution network operators of the trade-off between investment in ANM strategy and in the primary network assets, thus helping them to make cost-effective investment decisions. The uncertainty management allows the impact of risks that arise from network stress prediction on the expected operational benefits to be properly assessed, thus extending the traditional deterministic cost-benefit assessment to cost-benefit-risk assessment. Moreover, it is scalable to other systems in any size with low computational burden, which is the major contribution of this thesis.
17

An adaptive distributed algorithm for path aggregation.

January 2008 (has links)
Zhang, Zhenyi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 55-[58]). / Abstracts in Chinese and English. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Problem Formulation --- p.4 / Chapter 3 --- Examples --- p.7 / Chapter 3.1 --- Examples of Undirected Graph --- p.7 / Chapter 3.1.1 --- Example 1: SPF Routing --- p.7 / Chapter 3.1.2 --- Example 2: rings --- p.7 / Chapter 3.1.3 --- Example 3: grid --- p.8 / Chapter 3.1.4 --- Example 4: cube --- p.9 / Chapter 3.1.5 --- Example 5: random graph X --- p.10 / Chapter 3.1.6 --- Example 6: random graph Y --- p.10 / Chapter 3.2 --- An Example for Directive Graph --- p.11 / Chapter 4 --- The Framework --- p.13 / Chapter 4.1 --- The distributed algorithm --- p.13 / Chapter 4.2 --- The modules --- p.14 / Chapter 4.3 --- Path control --- p.15 / Chapter 4.4 --- The forwarding module --- p.18 / Chapter 4.5 --- The routing module --- p.19 / Chapter 4.5.1 --- Non-weighted Routing (NWR) --- p.19 / Chapter 4.5.2 --- Weighted Routing (WR) --- p.20 / Chapter 4.6 --- Packet Aggregation (PKA) --- p.21 / Chapter 5 --- Experiments of Path Aggregation --- p.23 / Chapter 5.1 --- System Setup --- p.24 / Chapter 5.2 --- Experiment Results --- p.25 / Chapter 6 --- Convergence --- p.28 / Chapter 6.1 --- Simulation study --- p.34 / Chapter 6.2 --- Optimality --- p.34 / Chapter 6.3 --- Speed of Convergence --- p.37 / Chapter 7 --- The adaptive property --- p.41 / Chapter 7.1 --- Adapting to new links --- p.42 / Chapter 7.2 --- Adapting to topology changing --- p.43 / Chapter 7.3 --- Adapting to interference and congestion --- p.45 / Chapter 7.4 --- Adapting to traffic flows --- p.45 / Chapter 7.5 --- Adapting to capacity --- p.46 / Chapter 8 --- Related works --- p.48 / Chapter 8.1 --- Spanning Tree --- p.48 / Chapter 8.2 --- Minimum Equivalent Directed Graph Problem --- p.49 / Chapter 8.3 --- Topology Control --- p.50 / Chapter 8.4 --- The Relationship with our problem --- p.53 / Chapter 9 --- Conclusion --- p.54
18

Security in Wireless Mesh Network

GHUMMAN, SHAKEEL AHMAD January 2009 (has links)
<p>The Master’s thesis report describes the wireless mesh networks functions,</p><p>characteristics, network management and finally different protocols with security issues and applications. Wireless Networks (WMNs) are replacing wireless Infrastructure networks in many areas because of their lower and higher flexibility. The wireless mesh networks (WMNs) provides network access for both mesh and conventional clients through mesh routers and mesh clients. Communication across the network is formed via the bridge functions. Mesh router also provides the minimal mobility and form the backbone of WMNs.</p><p>Wireless mesh network has resolved the limitation of ad hoc networks which is ultimately improves the performance of Ad hoc networks. Security is a very important issue which can be resolve through proper management of network. The improvment of 802.11i security has greatly improved the network perfomance and increase the encryption and integrity security capabilities. The key points which are being addressed in this report are security issues and threats and their counter measures. Attacks which can come on diffent layers are being discussed in this survey. Security of wireless mesh network is still under consideration. Wireless mesh network are attracting more attention due to its enhanced features.</p><p>Wireless mesh network topology technology is being discussed in this report. Then network management of WMNs is explained and in the concluding chapters security issues are discussed. Threats, attacks and challenges of WMNs are discussed in this survey.</p>
19

Security in Wireless Mesh Network

GHUMMAN, SHAKEEL AHMAD January 2009 (has links)
The Master’s thesis report describes the wireless mesh networks functions, characteristics, network management and finally different protocols with security issues and applications. Wireless Networks (WMNs) are replacing wireless Infrastructure networks in many areas because of their lower and higher flexibility. The wireless mesh networks (WMNs) provides network access for both mesh and conventional clients through mesh routers and mesh clients. Communication across the network is formed via the bridge functions. Mesh router also provides the minimal mobility and form the backbone of WMNs. Wireless mesh network has resolved the limitation of ad hoc networks which is ultimately improves the performance of Ad hoc networks. Security is a very important issue which can be resolve through proper management of network. The improvment of 802.11i security has greatly improved the network perfomance and increase the encryption and integrity security capabilities. The key points which are being addressed in this report are security issues and threats and their counter measures. Attacks which can come on diffent layers are being discussed in this survey. Security of wireless mesh network is still under consideration. Wireless mesh network are attracting more attention due to its enhanced features. Wireless mesh network topology technology is being discussed in this report. Then network management of WMNs is explained and in the concluding chapters security issues are discussed. Threats, attacks and challenges of WMNs are discussed in this survey.
20

Study on Architecture-Oriented Network Management Model

Huang, Hsin-Wei 16 January 2008 (has links)
In the past several years, the usage of network is getting more and more popular and various types of network applications also have vigorous advancement. Because the benefits which network applications produced obtain a lot of enterprise's attention, each enterprise is eager to introduce the network to unify each kind of information system, and expects to achieve the synthesis effect as well. At present, the network system has been an indispensable infrastructure in the enterprise, but how to make it effective becomes a tough issue in an enterprise¡¦s business plan. In 1997, the International Standard Organization proposed the OSI Network Management Model, is also named FCAPS Model, to apply on the data network. FCAPS Model is mainly to define the functional scope of the network management system. Though it is easy to understand, it does not have the deeper explanations how to achieve these functions. Also, FCAPS fails to tell who should do what in a network system. As a result of such deficiencies, the enterprise often doesn¡¦t know how to do to apply FCAPS into the planning of a network management system. This research develops a network management architecture description language (NMADL) by using the concept of system architecture to construct an architecture-oriented network management model (AONMM). AONMM is an integrated model which consists of the viewpoint of structure and behavior. By integrating the structure and behavior into one unity, it clearly and completely describes the network management system. Furthermore, this research analyzes the problems of FCAPS Model and compares it with AONMM to verify AONMM¡¦s superiority. AONMM is a valuable referenced model for planning, analyzing and designing network management systems.

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