Дисертації: "Construction of telecommunication systems"

1

Umuhoza, Denise. "Metric of trust for mobile ad hoc networks using source routing algorithms." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8946_1183465240.

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This thesis proposed and presented technical details of new probabilistic metrics of trust in the links wireless ad hoc networks for unobservable communications. In covert communication networks, only the end nodes are aware of the communication characteristics of the overall path. The most widely used protocols of ad hoc networks was overviewed. The routing protocols of ad hoc networks with trust considerations and select Destination Sequence Routing, a protocol that can be used in distributed ad hoc network settings for path discovery, was also reviewed. It establishes a path through which all packets sent by a source must pass to the destination. The end nodes are responsible for examining the statistics of the received packets and deriving inferences on path feature variations which are used for computing new trust metrics. When a path is judged not trustworthy based on the metrics, the Destination Sequence Routing is informed to undertake a new trusted path discovery between the end points. The thesis added a new feature based on the quality of service parameters of the path to create trust in the links in recognition of attacks.

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2

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.

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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).

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3

Payandehjoo, Kasra. "Study of nonlinear transmission lines and their applications." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99785.

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With the increasing market demand for wideband multifunctional electronic systems, real-time broadband measurement systems with few picoseconds switching rates are essential. Furthermore, stable millimeter wave sources are required to drive these wideband electronic systems. Nonlinear transmission lines (NLTLs) are high impedance transmission lines periodically loaded with reverse biased diode serving as varactors. Extremely high bandwidths are achievable because of the possibility to fabricate these structures monolithically, which is why pulses with ultra short transitions can be generated using NLTLs. Also, efficient wideband frequency conversion is made possible by NLTL technology.
In this thesis, a comprehensive study of NLTLs and their applications is presented. Sharpening of the edges of electrical pulses, voltage dependent true time delay, and harmonic generation in NLTLs are investigated through analytical studies as well as circuit simulations and experimental measurements. Designing the best possible mixers, frequency doublers, and edge sharpeners and optimizing them are not the objects of this thesis. The main objective is to study an alternative design approach by using NLTLs. To this end, analytical solution for the magnitude of the third harmonic along a nonlinear transmission line is derived for the first time. Also, for the first time the lowpass nature of the NLTL is combined with the solutions for the magnitudes of harmonics in order to improve the validity range of the predicted harmonics. An NLTL harmonic generator is fabricated and measurement results are reported.
Inspired by the distributed nature of nonlinear transmission lines, a novel filtering method is introduced for the suppression of the unwanted signals in different NLTL applications. The filtering method is applied to a nonlinear transmission line frequency multiplier in order to filter the third harmonic. The distributed filtering is also used to suppress the image signal in an NLTL mixer. The proposed filtering method is general and can be applied to other periodic structure as well (such as distributed amplifiers and distributed mixers). For implementing the filtering, compact complementary split ring resonators are proposed and designed for an NLTL frequency doubler.

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4

Van, Wyk Hendrik Petrus Daniel. "Design and construction of a modem for satellite use." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86580.

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Thesis (MScEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: In this thesis the design and testing of the baseband components of a modem intended for use as a telemetry and control link for a low earth orbit satellite is presented. This includes parts of the physical layer as well as a basic data-link layer. Binary phase-shift keying (BPSK) is used as the modulation scheme and is realised by making use of software defined radio on a standard x86 computer with digital to analogue and analogue to digital converters that use a universal serial bus (USB) connection. The data-link layer makes use of a basic framing scheme and provides bit synchronisation, an automatic repeat request (ARQ) system and Bose Chaudhuri Hocquenghem (BCH) forward error correction (FEC). The ARQ system ensures that data is delivered reliably and the FEC improves the system’s performance in noisy conditions. A prototype system was developed to test the performance of the individual layers as well as the system as a whole. For testing purposes the Linux Internet Protocol (IP) stack is used as higher network layers. Radio frequency hardware developed by Verschaeve [1] modulates the signal away from baseband, transmits it over the air and receives it.
AFRIKAANSE OPSOMMING: In hierdie tesis word die ontwerp en toetsing van die basisband komponente van ‘n modem, bedoel vir gebruik op ‘n satelliet in ‘n lae-aarde wentelbaan, bespreek. Die ontwerp sluit dele van die fisiese vlak sowel as ‘n verbindingsvlak in. Binêre faseskuifsleuteling word gebruik as die modulasieskema en word verwesenlik deur gebruik te maak van sagteware gedefinieerde radio. Dit voer uit op ’n standaard x86 rekenaar wat deur middel van USB gekoppel is aan ’n digitaal-na-analoog- en ’n analoog-na-digitaal-omsetter. Die verbindingsvlak het ‘n eenvoudige ramingskema. Dit voorsien bis sinkronisasie, die hersending van verlore rame en Bose Chaudhuri Hocquenghem (BCH) voorwaartse foutverbetering. Die hersending van verlore rame verseker dat data betroubaar oorgedra kan word en foutverbetering verbeter die stelsel se vermoëns in ruiserige toestande. ‘n Prototipe stelsel is ontwikkel om die vermoëns van die individuele vlakke, sowel as die stelsel as ’n geheel, te toets. Tydens toetsing is die Linux Internet Protokol stapel gebruik vir die hoër netwerk vlakke. Radio komponente wat deur Verschaeve [1] ontwikkel was is gebruik om die sein uit te saai en te ontvang.

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5

Chen, Lyu-Shi 1958. "EXPERT SYSTEM FOR BROADBAND NETWORK CABLE PLANT DESIGN." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276490.

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This thesis implements the expert system technology in broadband network cable plant design to provide an automated design tool for the design engineer. Under this scheme, the knowledge of the cable plant design engineer can be captured and adapted into a manageable form. The various processes of this system include design rule checking, automatically blueprint layout, signal quality analysis and report generator. As we know, the broadband cable plant design shares 50% of the installation budget at the same time, it is a critical issue in the reliability, the extendability, and the manageability of the network system. It is important that the design can be verified before beginning installation. This is the goal of broadband cable plant design expert system tries to address.

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6

Nguyen, Son. "Capacity and Throughput Optimization in Multi-cell 3G WCDMA Networks." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc4948/.

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User modeling enables in the computation of the traffic density in a cellular network, which can be used to optimize the placement of base stations and radio network controllers as well as to analyze the performance of resource management algorithms towards meeting the final goal: the calculation and maximization of network capacity and throughput for different data rate services. An analytical model is presented for approximating the user distributions in multi-cell third generation wideband code division multiple access (WCDMA) networks using 2-dimensional Gaussian distributions by determining the means and the standard deviations of the distributions for every cell. This model allows for the calculation of the inter-cell interference and the reverse-link capacity of the network. An analytical model for optimizing capacity in multi-cell WCDMA networks is presented. Capacity is optimized for different spreading factors and for perfect and imperfect power control. Numerical results show that the SIR threshold for the received signals is decreased by 0.5 to 1.5 dB due to the imperfect power control. The results also show that the determined parameters of the 2-dimensional Gaussian model match well with traditional methods for modeling user distribution. A call admission control algorithm is designed that maximizes the throughput in multi-cell WCDMA networks. Numerical results are presented for different spreading factors and for several mobility scenarios. Our methods of optimizing capacity and throughput are computationally efficient, accurate, and can be implemented in large WCDMA networks.

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7

Zuo, Yiying 1974. "Design, analysis, and implementation of multi-port refraction based electro-optic switches." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103035.

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Electro-optic (EO) beam deflectors are voltage-controlled devices widely used for scanning and switching applications. For example, high-speed, low-loss optical switches aimed at future optical networks can be built on EO deflectors. Novel EO deflectors distinguish themselves with a much-improved steering performance, high-speed response and simple fabrication requirements. Patterned ferroelectric crystals such as LiTaO3 are first poled to provide the required prism shaped domain structures. The application of an electrical field across the entire crystal can then be used to drive the trajectory of the beam as it travels through the poled wafer. The electric field induces an index change of opposite magnitude on the adjacent domain regions in the EO device, causing the optical beam to refract at the interfaces.
Although rectangular geometry is extensively employed in EO devices, nonrectangular scanners have demonstrated better deflection performance. Two new nonrectangular geometries capable of further enhancing the deflection performance of EO beam scanners, proposed in this dissertation, were constructed. Their parabola and half-horn geometries provide 2-3 degrees of steering, which is 2-3 times greater than the steering provided by rectangular deflectors.
EO deflectors based on the parabola and the half-horn geometries, which can provide larger deflection angles, were built. These devices demonstrated a deflection angle of 3.1°, less than 5 dB of insertion loss from fiber to fiber, and -40 dB of crosstalk.
Two packaged optical switches using rectangular EO deflectors were demonstrated. By combining these EO deflectors with fiber collimators and high voltage packaging, high speed optical switches were built and characterized. The switch design was based on a 500mum z-cut LiTaO3 single crystal wafer fabricated using the domain inversion method. The 1x2 switch had a maximum deflection angle of 1.22° with an applied voltage of 1.1 kV and the 1x4 switch had a maximum deviation angle of 2.14°, with an applied voltage of 1 kV. The average insertion loss and crosstalk figures were 2.36 dB and -36 dB, respectively. The worst case switching time was 86 ns.

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8

Altunbasak, Hayriye Celebi. "Layer 2 security inter-layering in networks." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11172006-130414/.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.
Wardi, Yorai, Committee Member ; Abler, Randy, Committee Member ; Copeland, John, Committee Member ; Owen, Henry, Committee Chair ; Ahamad, Mustaque, Committee Member.

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9

Kilicoglu, Nezaket. "Construction Of An Experimental Radar System." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612760/index.pdf.

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In this thesis, an Experimental Radar System is designed and constructed for use in experimental radar studies such as clutter measurement and target detection, both in the laboratory and outdoor. COTS laboratory equipments are utilized as hardware elements of the radar and MATLAB is used as signal processing and user interface software tool. Vector signal generator (as transmitter), spectrum analyzer with vector signal analysis (as receiver), a high power amplifier, a low noise amplifier, horn antennas and a computer are the hardware units of the system. Various transmit signals are generated and pulse Doppler processing is performed at the receiver side. The system is controlled through the user interface which runs on a PC.

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10

Xie, Jiang (Linda). "Mobility Management in Next Generation All-IP Based Wireless Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5190.

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Next generation wireless systems have an IP-based infrastructure with the support of heterogeneous access technologies. One research challenge for next generation all-IP based wireless systems is to design intelligent mobility management techniques that take advantage of IP-based technologies to achieve global roaming between various access networks. To support global roaming, next generation wireless systems require the integration and interoperation of heterogeneous mobility management techniques. Mobility in a hierarchical structure or multilayered environment should be supported. The objective of this study is to develop new mobility management techniques for global roaming support in next generation all-IP based wireless systems. More specifically, new schemes for location management and paging in Mobile IP for network layer mobility support, and new schemes for location management and handoff management in heterogeneous overlay networks for link layer mobility support are proposed and evaluated. For network layer mobility support, a distributed and dynamic regional location management mechanism for Mobile IP is proposed. Under the proposed scheme, the signaling burden is evenly distributed and the regional network boundary is dynamically adjusted according to the up-to-date mobility and traffic load for each terminal. Next, a user independent paging scheme based on last-known location and mobility rate information for Mobile IP is proposed. The proposed scheme takes the aggregated behavior of all mobile users as the basis for paging. For link layer mobility support, an IP-based system architecture for the integration of heterogeneous mobility management techniques is proposed. Three location management schemes under this IP-based architecture are proposed. All the three schemes support user preference call delivery which is a very important feature of next generation wireless communications. A threshold-based enhancement method is also proposed to further improve the system performance. Finally, a hybrid resource allocation scheme for handoff management in wireless overlay networks is proposed. Under this scheme, the overall system resources can be optimally allocated when mobile users are covered by multiple overlay networks.

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11

Chen, Bosi. "Spectrum Regrowth for OFDM-based LTE and WIMAX Systems." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/601.

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An abstract of the thesis of Bosi Chen for the Master of Science in Electrical and Computer Engineering presented Aug 1st, 2012. Title: Spectrum Regrowth for OFDM-based LTE and WiMAX Systems. In OFDM-based (Orthogonal Frequency Dimension Multiplexing) LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for Microwave Access) Systems, one of the critical components is the RF power amplifier. With current technologies, RF power amplifiers are not perfectly linear. The nonlinearity of an RF power amplifier is one of the main concerns in RF power amplifier design. The nonlinearity control is described by the out-of-band power emission levels, and the nonlinearity of an RF power amplifier is usually described by IP3 (the third-order intercept point). However, there is need of a clear relationship or expression between the out-of-band power emission level and IP3 for LTE and WiMAX Systems, which helps the RF designers to choose components. This thesis presents the analysis of the nonlinear effect of an RF amplifier in LTE and WiMAX Systems, and the derivation of the expressions for the estimated out-of-band emission levels for LTE and WiMAX signals in terms of IP3 and the power level of the signal. The result will be helpful for RF engineers in the design and test of RF power amplifiers in LTE and WiMAX Systems.

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12

Мошинська, Аліна Валентинівна. "Стратегії передачі інформації в мультисервісних телекомунікаційних системах". Doctoral thesis, Київ, 2020. https://ela.kpi.ua/handle/123456789/34482.

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Дисертацію присвячено реалізації нових підходів оцінки ефективності сучасних мультисервісних телекомунікаційних систем. Вперше пропонується об'єднана концепція для відомих і перспективних технологій, пов'язаних з фундаментальним знанням (теорії інформації, теорії завадостійкості, теорії кодування), не втративши при цьому, напрацьованих специфічних особливостей відповідних інженерних методик. Вирішується задача наукового обґрунтування процедур встановлення відповідності між комплексами вимог (Сценаріями) і способами забезпечення своєчасної та достовірної передачі масивів мультисервісної інформації (Стратегіями). В цілому робота присвячена методології формування Телекомунікаційних стратегій Фізичного рівня на основі різноманітних Сценарних концепцій діючих і перспективних мультисервісних телекомунікаційних систем. В роботі пропонується порівняння сучасних мультисервісних телекомунікаційних систем за показником інформаційної ефективності.

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13

de, Paula Andes. "Dynamics of corporate strategy from a value chain perspective : A study of the Swedish telecom and construction industries during the 90’s." Doctoral thesis, Linköping University, Linköping University, Industrial Marketing and Industrial Economics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7252.

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Changes in sectors and industries have brought new challenges to corporations as well as been important driving forces for the dynamics in strategy at the corporate level. With the dramatic developments of the 1990’s in mind, such as multilateral free-trade agreements, liberalization, privatization, sharp industry growth/decline, increased competition and globalization, in particular within the telecom and the construction industry, this study contributes to describing and understanding strategic change at the corporate level as well as changes in the division of work within value chains. Strategy is defined as intentions, decisions and actions that relate to bundling and unbundling at different strategic levels, aiming to establish and reestablish a value chain position. Thus, outsourcing, M&As, modularization and systems development and sales are important strategic components which are examined from a value chain perspective. From a value chain perspective, the purpose of this study is to describe and understand strategic change at the corporate level in the telecom and construction industries during the 1990’s. More specifically this study shall contribute to describing and understanding (i) the dynamics of and between M&As, outsourcing, modularization and systemization, as well as (ii) industrial and financial drivers to strategic change.

The conclusions describe strategic change from a value chain perspective using three descriptive patterns, including an increasing degree of specialization and need for interorganizational coordination across the value chain. In addition, outsourcing and modularization of systems and an increased scope of offering through systemization and BOT-projects, result in the fact that due to M&As the horizontal boundary of the firm sometimes goes beyond the industry scope while the vertical scope is often narrowed through outsourcing. The conclusions also focus on understanding the content of strategic change, that is to say the dynamics of and between mergers and acquisitions, outsourcing, modularization and system sales. These findings are summarized in nine explanatory patterns. These patterns show that the strategic decisions of bundling and unbundling at the corporate and functional level through mergers and acquisitions, outsourcing, systemization and modularization are guided by an industrial as well as a financial logic. By considering the descriptive and explanatory patterns found this study, the conclusions also include what to expect during the next decade with regard to corporate strategy from a value chain perspective in five predictive patterns.

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14

Pangalos, Panagiotis George. "Private telecommunications systems a systems approach /." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA241036.

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Thesis (M.S. in Telecommunications Systems Management)--Naval Postgraduate School, September 1990.
Thesis Advisor(s): Shu, Myung W. ; Gates, William. "September 1990." Description based on title screen as viewed on December 17, 2009. DTIC Identifier(s): Voice Communications, Data Communications, Private Telecommunication Systems, Theses. Author(s) subject terms: Private Telecommunications systems, Computerized Private Branch Exchanges (CPBXs), Request of Proposals (RFP), Life Cycle Costing (LLC). Includes bibliographical references (p. 100-101). Also available in print.

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15

Pointon, Craig T. "Nonlinear dynamics in telecommunication systems." Thesis, Staffordshire University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282553.

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16

Stergiou, Theodore. "Protocol security for third generation telecommunication systems." Thesis, University of Warwick, 2003. http://wrap.warwick.ac.uk/3023/.

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In this thesis, a novel protocol stack architecture is presented. The Future Core Networks System (FCNS) forms a secure reference model for use in packet-switched structures, with its applicability ranging from computer to telecommunication networks. An insight on currently used network protocol systems is given, analysing standardised sets of communication rules with respect to the security they afford to the messages exchanged. The lack of protection schemes for the internal protocol stack messages and the implementation pitfalls of their security architectures are described, in relation to the effects they have on the communication process. The OSI security model is also considered, with disadvantages identified in the placement of security functionality and its management. The drawbacks depicted for currently used systems form the motivation behind this work. The analysis of the FCNS follows, which is composed of three parts. In the first part, the FCNS communication layers are examined, with respect to the mechanisms used to establish, maintain and tear down a connection between peer entities. In the second part, the security mechanisms of the proposed reference architecture are given, including details on the FCNS keystream generator used for the security of the internal FCNS messages. Finally, the FCNS Error Protocol is depicted, illustrating the modes of operation and advantages it exhibits over currently used systems. The work then moves into presenting details of the software FCNS implementation, followed by the presentation of the results and measurements obtained by the case studies created. Comparisons are given in relation to the TCP/IP suite, to provide the means of identifying the FCNS applicability in various network environments. The work is concluded by presenting the FCNS functionality in delivering information for the UMTS, together with further work that may enhance the flexibility and use of the proposed architecture.

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17

Delivasilis, Dimitrios L. "Data security for third generation telecommunication systems." Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404694.

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18

Yeo, Yong-Kee. "Dynamically Reconfigurable Optical Buffer and Multicast-Enabled Switch Fabric for Optical Packet Switching." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14615.

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Optical packet switching (OPS) is one of the more promising solutions for meeting the diverse needs of broadband networking applications of the future. By virtue of its small data traffic granularity as well as its nanoseconds switching speed, OPS can be used to provide connection-oriented or connectionless services for different groups of users with very different networking requirements. The optical buffer and the switch fabric are two of the most important components in an OPS router. In this research, novel designs for the optical buffer and switch fabric are proposed and experimentally demonstrated. In particular, an optical buffer that is based on a folded-path delay-line tree architecture will be discussed. This buffer is the most compact non-recirculating optical delay line buffer to date, and it uses an array of high-speed ON-OFF optical reflectors to dynamically reconfigure its delay within several nanoseconds. A major part of this research is devoted to the design and performance optimization of these high-speed reflectors. Simulations and measurements are used to compare different reflector designs as well as to determine their optimal operating conditions. Another important component in the OPS router is the switch fabric, and it is used to perform space switching for the optical packets. Optical switch fabrics are used to overcome the limitations imposed by conventional electronic switch fabrics: high power consumption and dependency on the modulation format and bit-rate of the signals. Currently, only those fabrics that are based on the broadcast-and-select architecture can provide truly non-blocking multicast services to all input ports. However, a major drawback of these fabrics is that they are implemented using a large number of optical gates based on semiconductor optical amplifiers (SOA). This results in large component count and high energy consumption. In this research, a new multicast-capable switch fabric which does not require any SOA gates is proposed. This fabric relies on a passive all-optical gate that is based on the Four-wave mixing (FWM) wavelength conversion process in a highly-nonlinear fiber. By using this new switch architecture, a significant reduction in component count can be expected.

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19

Gonzalez, Prieto Alberto. "Adaptive management for networked systems." Licentiate thesis, Stockholm : School of electrical engineering, KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4022.

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20

Kozak, Nadine Irène. "On the last mile the effects of telecommunications regulation and deregulation in the rural western United States and Canada /." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3390098.

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Thesis (Ph. D.)--University of California, San Diego, 2010.
Title from first page of PDF file (viewed Feb. 22, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 421-450).

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21

Archambault, Eric J. A. "Inventors, entrepreneurs and the metamorphosis of telecommunication systems." Thesis, University of Sussex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318614.

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22

Chiurco, Giovanni <1982&gt. "Cooperative and reconfigurable telecommunication systems based on FPGA." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3466/.

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This work has been realized by the author in his PhD course in Electronics, Computer Science and Telecommunication at the University of Bologna, Faculty of Engineering, Italy. The subject of this thesis regards important channel estimation aspects in wideband wireless communication systems, such as echo cancellation in digital video broadcasting systems and pilot aided channel estimation through an innovative pilot design in Multi-Cell Multi-User MIMO-OFDM network. All the documentation here reported is a summary of years of work, under the supervision of Prof. Oreste Andrisano, coordinator of Wireless Communication Laboratory - WiLab, in Bologna. All the instrumentation that has been used for the characterization of the telecommunication systems belongs to CNR (National Research Council), CNIT (Italian Inter-University Center), and DEIS (Dept. of Electronics, Computer Science, and Systems). From November 2009 to May 2010, the author spent his time abroad, working in collaboration with DOCOMO - Communications Laboratories Europe GmbH (DOCOMO Euro-Labs) in Munich, Germany, in the Wireless Technologies Research Group. Some important scientific papers, submitted and/or published on IEEE journals and conferences have been produced by the author.

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23

Petropoulos, Periklis. "Novel techniques and materials for optical telecommunication systems." Thesis, University of Southampton, 2000. https://eprints.soton.ac.uk/15506/.

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This thesis describes work on a variety of novel fibre-based, all-optical approaches to the implementation of several key telecommunications operations. It can be divided into two distinct parts. The first part relates to the generation and coherent manipulation of short pulses in all-fibre systems. The development of an actively and harmonically mode-locked polarisation-maintaining erbium fibre ring laser operating at a repetition rate of 10GHz is first presented. Long-term stable operation is ensured by the use of an optical phase lock loop to maintain resonant operating conditions. The ring laser incorporated a long length of dispersion-shifted fibre that enhanced soliton compression of the generated pulses, and a filter to allow for tuneable operation within the erbium gain bandwidth. The output was in the form of 2 - 4ps nearly transform-limited solitons, the width of which depended on pump power. A series of characterisation measurements on this laser is presented. These include autocorrelation and optical spectrum measurements of the pulses, frequency resolved optical gating (FROG) characterisation, an interpulse noise measurement, jitter measurements using the RF spectrum of the pulses, and bit error-rate measurements. A technique that uses superstructured fibre Bragg gratings for passively manipulating short pulses in a coherent manner is presented. The technique relies on filtering in both amplitude and phase the (broad) spectrum of the input pulses, thereby producing pulses of a desired spectral, and hence temporal response. The pulses generated from the erbium fibre ring laser were used in a series of experiments that demonstrated this technique. A basic pulse encoding and decoding scheme, pulse shaping of soliton pulses into square pulses, and repetition rate multiplication from 10 to 40GHz are presented. The second part of the thesis concerns a detailed characterisation of the recently discovered optical nonlinearities associated with the reflectivity of a gallium:glass interface. It is demonstrated that such mirrors can be formed at the tip of a cleaved fibre. The reflectivity of these mirrors is shown to change at the erbium wavelengths by 30% under suitable temperature and optical excitation. An assessment of the dependence of the magnitude, dynamics and optical phase response of the nonlinearity on temperature and pump power is carried out. The reproducibility of the nonlinear effect was also examined. Gallium mirrors were then used to passively Q-switch a variety of fibre lasers. Due to their broadband nature, Q-switching of lasers of significantly different lasing wavelengths was achieved (1064 and 1550nm). Pulse energies up to 10 µJ were obtained. This performance is directly comparable to that achieved using state-of-the-art (wavelength-selective) saturable absorbers.

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24

Shi, Ming Hao. "Research and realization on virtual roaming based 3D scene construction of ancient architectures." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691584.

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25

Barghouthi, Ramzi. "Sequence acquisition for DS/CDMA communication systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15435.

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26

McCormack, Andrew. "A business continuity solution for telecommunications billing systems." [Denver, Colo.] : Regis University, 2008. http://165.236.235.140/lib/AMcCormack2008.pdf.

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27

Bergman, Svante. "Bit loading and precoding for MIMO communication systems." Doctoral thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10622.

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28

Johansson, Björn. "Distributed resource allocation in networked systems using decomposition techniques." Licentiate thesis, KTH, School of Electrical Engineering (EES), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4096.

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The Internet and power distribution grids are examples of ubiquitous systems that are composed of subsystems that cooperate using a communication network. We loosely define such systems as networked systems. These systems are usually designed by using trial and error. With this thesis, we aim to fill some of the many gaps in the diverse theory of networked systems. Therefore, we cast resource allocation in networked systems as optimization problems, and we investigate a versatile class of optimization problems. We then use decomposition methods to devise decentralized algorithms that solve these optimization problems.

The thesis consists of four main contributions: First, we review decomposition methods that can be used to devise decentralized algorithms for solving the posed optimization problems. Second, we consider cross-layer optimization of communication networks. Network performance can be increased if the traditionally separated network layers are jointly optimized. We investigate the interplay between the data sending rates and the allocation of resources for the communication links. The communication networks we consider have links where the data transferring capacity can be controlled. Decomposition methods are applied to the design of fully distributed protocols for two wireless network technologies: networks with orthogonal channels and network-wide resource constraints, as well as wireless networks using spatial-reuse time division multiple access. Third, we consider the problem of designing a distributed control strategy such that a linear combination of the states of a number of vehicles coincide at a given time. The vehicles are described by linear difference equations and are subject to convex input constraints. It is demonstrated how primal decomposition techniques and incremental subgradient methods allow us to find a solution in which each vehicle performs individual planning of its trajectory and exchanges critical information with neighbors only. We explore various communication, computation, and control structures. Fourth, we investigate the resource allocation problem for large-scale server clusters with quality-of-service objectives, in which key functions are decentralized. Specifically, the problem of selecting which services the servers should provide is posed as a discrete utility maximization problem. We develop an efficient centralized algorithm that solves this problem, and we propose three suboptimal schemes that operate with local information.

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29

Bria, Aurelian. "Hybrid cellular-broadcasting infrastructure systems : radio resource management issues." Licentiate thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3922.

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30

Aladeloba, Abisayo Olufemi. "Optically amplified free-space optical communication systems." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13304/.

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This thesis investigates terrestrial atmospheric FSO communication systems operating under the influence of turbulence-induced scintillation, beam spreading, optical interchannel crosstalk, amplified spontaneous emission noise and pointing errors. On-off keying-non–return-to-zero (OOK-NRZ) and digital pulse position (DPPM) are the modulation schemes used for the calculations. The possibility of using sophisticated performance evaluation techniques such as moment generating function (MGF)-based Chernoff bound (CB), modified Chernoff bound (MCB) and saddlepoint approximation (SPA) for terrestrial DPPM and OOK-NRZ–based FSO communication systems employing optical amplification are investigated and compared with the conventional Gaussian approximation (GA) method. Relative to the other techniques, the MCB can be considered a safe estimation method for practical systems since it provides an upper bound upon the BER. The turbulent optically preamplified DPPM FSO receiver employing integration over a time slot and comparing the results to choose the largest slot, is seen to give better advantage (about 7 - 9 dB) compared to an equivalent employing OOK-NRZ signalling. The atmospheric turbulence-induced spreading of the beam, ASE noise, and pointing error are seen to combine in a problematic way resulting in high BERs, depending on the size of the receiver and the beam’s jitter standard deviation. Using FSO communication for the distribution links of a passive optical network-like wavelength division multiplexing access network is investigated in the presence of atmospheric turbulence, ASE noise and interchannel crosstalk. The results show that, for clear atmosphere, FSO distribution link length up to 2000 m can be reliably used (depending on turbulence strength) to achieve human eye safety and high capacity access networks. Also, error floors occur due to turbulence accentuated crosstalk effect for the cases of (i) signal turbulent, but crosstalk not and (ii) crosstalk turbulent, but signal not.

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31

Sun, Yuhao. "Power optimised narrowband power-line communication systems." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648110.

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32

Gürbüz, Özgür. "Power control based QoS provisioning for wireless multimedia networks." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14888.

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33

Bowman, W. Stevenson. "Communication module for the micro-based small purchase contracting program." Thesis, Monterey, Calif. : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA250092.

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Thesis (M.S. in Information Systems)--Naval Postgraduate School, March 1992.
Thesis Advisors: Matsushima, Rodney ; Sengupta, Kishore. "March, 1992." Description based on title screen as viewed on March 4, 2009. Includes bibliographical references (p. 270-271). Also available in print.

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34

Balasubramaniyan, Vijay A. "Effective identities for trusted interactions in converged telecommunication systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44920.

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Telecommunication systems have evolved significantly and the recent convergence of telephony allows users to communicate through landlines, mobile phones and Voice over IP (VoIP) phones. Unfortunately this convergence has resulted in easy manipulation of caller identity, resulting in both VoIP spam and Caller ID spoofing. In this dissertation, we introduce the notion of effective identity which is a combination of mechanisms to (1) establish identity of the caller that is harder to manipulate, and (2) provide additional information about the caller. We first use effective identities to address the VoIP spam problem by proposing CallRank, a novel mechanism built around call duration and social network linkages to differentiate between a legitimate user and a spammer. To ensure that this mechanism is privacy preserving, we create a token framework that allows a user to prove the existence of a social network path between him and the user he is trying to initiate contact with, without actually revealing the path. We then look at the broader issue of determining identity across the entire telecommunication landscape to address Caller ID spoofing. Towards this, we develop PinDr0p, a technique to determine the provenance of a call - the source and the path taken by a call. In the absence of any verifiable metadata, provenance offers a means of uniquely identifying a call source. Finally, we use anomalies in timbre to develop London Calling, a mechanism to identify geography of a caller. Together, the contributions made in this dissertation create effective identities that can help address the new threats in a converged telecommunication infrastructure.

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35

Tanir, Oryal. "Specification driven architectural modelling environment for telecommunication systems synthesis." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28537.

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Design automation has steadily contributed to improvements witnessed in the system design process. Initial applications were to address low level design concerns such as transistor layout and simulation; however the focus of tools has slowly been progressing up the design abstraction scale. The current state-of-the-art provides modelling capabilities at different levels of abstraction, but solutions for synthesis issues at the register-transfer and lower levels are the norm. The proliferation of design description languages at different abstraction levels has prompted the need for standardization (VHDL and Open-Verilog) to promote design migration and re-use.
While design automation has helped in reducing design time-lines and design churn, a major source of design difficulties is just recently being addressed and promise to be the next wave in design automation applicability. The problems arise within the architectural (or system) level of abstraction very early in the design cycle. The recent research in this field attempts to bridge the design process gap between specification and design, and provides a platform for experimenting with hardware and software trade-offs.
This dissertation studies the requirements for an environment for architectural design. In particular, an environment specific to the telecommunications domain is proposed in order to limit the potentially large design exploration space. An intermediate design language is also introduced to accommodate both high level modelling and synthesis driven by the user and environment. Finally a Design Analysis and Synthesis Environment (DASE) is described to facilitate the architectural level activities. The environment, a proof of concept, provides generic modal library, simulation, synthesis and Petri-net analysis support. Realistic design examples are explored, to illustrate architectural design activities with the environment.

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36

Hess, Rolando. "Ultrafast all-optical time demultiplexer for optical telecommunication systems /." Zürich, 1998. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=12525.

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37

Fischer, Stefan. "Versatile all-optical interferometric switch for optical telecommunication systems /." Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13836.

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38

Marburger, André [Verfasser]. "Reverse Engineering of Complex Legacy Telecommunication Systems / André Marburger." Aachen : Shaker, 2005. http://d-nb.info/1186580232/34.

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39

Borg, Andreas. "Processes and Models for Capacity Requirements in Telecommunication Systems." Doctoral thesis, Linköping : Department of Computer and Information Science, Linköpings universitet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16932.

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40

Barannik, Vlad, Y. Babenko, S. Shulgin, and M. Parkhomenko. "Video encoding to increase video availability in telecommunication systems." Thesis, Taras Shevchenko National University of Kyiv, 2020. https://openarchive.nure.ua/handle/document/16582.

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Article shows presence of the imbalance caused by insufficient level of productivity of modern and perspective information communication technologies concerning information intensity of bit streams. It is described how imbalance level reducing can be formed as a result of increasing of information processing technologies efficiency and that JPEG platform is the basic concept for construction of technologies of compression representation. Therefore it is proposed to provide further development of video processing methods using individual components of the JPEG platform for improving the integrity of information in terms of ensuring the required level of its availability.:

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41

Khanna, Yogesh. "Requirements analysis of federal governments international telecommunications services." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-02022010-020111/.

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42

Cheema, Kanwarpreet Singh. "Synthesis of serial communications controller using higher abstraction level derivation (HALD) model /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16309.pdf.

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43

Chien, Tien-chen. "Technical competency needs assessment for the graduates of telecommunication systems at UW-Stout." Online version, 1999. http://www.uwstout.edu/lib/thesis/1999/1999chien.pdf.

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44

Svedman, Patrick. "Cross-layer Aspects in OFMDA Systems : Feedback, Scheduling and Beamforming." Doctoral thesis, KTH, Signalbehandling, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4429.

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This thesis mainly studies the downlink of a wireless multiuser system, where the transmitter has limited knowledge about the communication channels of the users. Key techniques to improve the performance of such systems are, for instance, multiple antennas, multiuser diversity and orthogonal frequency-division multiple access (OFDMA). Common for these techniques is that, to exploit them fully, a cross-layer approach has to be adopted. This means that the scheduling and the signal designs are done jointly and based on parameters from several communication layers. Multiuser diversity can be used to significantly increase system throughput in wireless communication systems. The idea is to schedule users when they experience good channel conditions and let them wait when the channels are weak. In this thesis, several aspects of OFDMA systems that exploit multiuser diversity are investigated. An adaptive reduced feedback scheme for OFDMA is proposed. It significantly reduces the total feedback overhead while maintaining a multiuser diversity gain. The scheme uses clusters of sub-carriers as feedback units and feeds back information about the fading peaks only. It adapts to the number of users so that less feedback per user is required if there are many users in the system. With such a selective feedback scheme, there is a risk that the scheduler has no instantaneous channel quality information for some parts of the spectrum. Better uses for these sub-carriers are investigated. In addition, an alternative based on the the channel quality feedback of some uniformly spaced sub-carriers is proposed. The scheduler estimates the channel quality on the other sub-carriers. Channel-aware scheduling is necessary in order to exploit multiuser diversity. A modified proportional fair (PF) scheduler is proposed. It incorporates individual target bit-rates and delays and a tunable fairness level. An opportunistic beamforming scheme for clustered OFDMA is presented and evaluated. A key aspect of the opportunistic beamforming scheme is that it induces artificial frequency selectivity for users with relatively flat channels. Several aspects of the proposed system are evaluated by means of simulations. In the simulations, the clustered beamforming with the modified PF scheduler performs better than three comparison systems. The modified PF scheduler manages to divide the resources according to the user targets, while at the same time exploiting the multiuser diversity as well as the standard PF algorithm. In many scenarios, the largest gains from having multiple antennas at the basei station come from space-division multiple access (SDMA). In the downlink, this means that data is transmitted to several users simultaneously by using several beams. Opportunistic space-division OFDMA is proposed and evaluated. An enhancement that exploits temporal channel correlation is able to boost the throughput significantly. SDMA based on subspace packings is proposed and evaluated. A set of beamforming matrices (a subspace packing) is made a priori available at the base-station and at all users. In each block, one of the matrices is used for multi-beam transmission. The users pick and feed back the index of one preferred column (beam) from one of the matrices, and the corresponding SINR, which includes all potential inter-beam interference. This enables scheduling of spatially compatible users and accurate rate adaptation, with relatively little feedback. Three different subspace packings are considered and evaluated with simulations. For the i.i.d. Rayleigh fading channel, Grassmannian subspace packings were the best choice. Moreover, a method to further reduce the feedback for large packings is proposed and evaluated. It is based on the arrangement of beams in a graph and the feedback of a neighbor index. Numerical results show that the feedback can be significantly reduced with only small performance losses, even for relatively fast fading channels.
QC 20100819

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45

Fu, Jing. "Design and evaluation of network processor systems and forwarding applications." Licentiate thesis, KTH, School of Electrical Engineering (EES), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4248.

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During recent years, both the Internet traffic and packet transmission rates have been growing rapidly, and new Internet services such as VPNs, QoS and IPTV have emerged. To meet increasing line speed requirements and to support current and future Internet services, improvements and changes are needed in current routers both with respect to hardware architectures and forwarding applications. High speed routers are nowadays mainly based on application specific integrated circuits (ASICs), which are custom made and not flexible enough to support diverse services. Generalpurpose processors offer flexibility, but have difficulties to in handling high data rates. A number of software IP-address lookup algorithms have therefore been developed to enable fast packet processing in general-purpose processors. Network processors have recently emerged to provide the performance of ASICs combined with the programmability of general-purpose processors.

This thesis provides an evaluation of router design including both hardware architectures and software applications. The first part of the thesis contains an evaluation of various network processor system designs. We introduce a model for network processor systems which is used as a basis for a simulation tool. Thereafter, we study two ways to organize processing elements (PEs) inside a network processor to achieve parallelism: a pipelined and a pooled organization. The impact of using multiple threads inside a single PE is also studied. In addition, we study the queueing behavior and packet delays in such systems. The results show that parallelism is crucial to achieving high performance,but both the pipelined and the pooled processing-element topologies achieve comparable performances. The detailed queueing behavior and packet delay results have been used to dimension queues, which can be used as guidelines for designing memory subsystems and queueing disciplines.

The second part of the thesis contains a performance evaluation of an IP-address lookup algorithm, the LC-trie. The study considers trie search depth, prefix vector access behavior, cache behavior, and packet lookup service time. For the packet lookup service time, the evaluation contains both experimental results and results obtained from a model. The results show that the LC-trie is an efficient route lookup algorithm for general-purpose processors, capable of performing 20 million packet lookups per second on a Pentium 4, 2.8 GHz computer, which corresponds to a 40 Gb/s link for average sized packets. Furthermore, the results show the importance of choosing packet traces when evaluating IP-address lookup algorithms: real-world and synthetically generated traces may have very different behaviors.

The results presented in the thesis are obtained through studies of both hardware architectures and software applications. They could be used to guide the design of next-generation routers.

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46

Hammarwall, David. "Resource Allocation in Multi-Antenna Communication Systems with Limited Feedback." Doctoral thesis, Stockholm : Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4487.

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47

Lau, Siu Lik. "Reliability of optical crossconnect systems /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20LAUS.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 73-76). Also available in electronic version. Access restricted to campus users.

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48

Yunus, Muhammad Naim. "Blocking in teletraffic systems under nonstationary arrival and service conditions /." Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phy95.pdf.

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49

Wuhib, Fetahi Zebenigus. "Real-Time Monitoring of Global Variables in Large-Scale Dynamic Systems." Licentiate thesis, Stockholm : Kommunikationsnät, Communication Networks, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4646.

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50

Antonopoulos, Andreas. "Planning telecommunication transport networks : metrication, analysis and design." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287551.

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