Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014 / The electric power utilities play a vital role in the generation, transmission and distribution of the electrical power to the end users. The power utilities face two major issues, i.e. i) power grids are expected to operate close to the maximum capacity, and ii) there is a need for accurate and better monitoring and control of the power system network using the modern technology and the available tools. These two issues are interconnected as better monitoring allows for better control of the power system. Development of the new standard-based power system technologies contributed to raising the ideas for building of a Smart grid. The challenges are that this process requires development of new control and operation architectures and methods for data acquisition, data transfer, and control computation. These methods require data for the full dynamic state of the power system in real-time, which leads to the introduction of the synchrophasor-based monitoring and control of the power system. The thesis describes the research work and investigations for integration of the existing new power system technologies to build fully automated systems for real-time solution of power system energy management problems, incorporating data measurement and acquisition, data transfer and distribution through a communication network, and data storage and retrieval in one whole system.

Orientadores: Edson Moschim, Marcelo Francisco Abbade / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T13:37:23Z (GMT). No. of bitstreams: 1 Durand_FabioRenan_D.pdf: 1259125 bytes, checksum: 9e123c3d511429cff5a237aefb19765c (MD5) Previous issue date: 2007 / Resumo: Neste trabalho é realizada a análise da aplicação de códigos ópticos ortgonais (OOC) da tecnologia de multiplexação por divisão de códigos ópticos (OCDM) em redes ópticas híbridas multiplexadas pela divisão de comprimentos de onda e códigos ópticos (WDM)/OCDM e em redes ópticas comutadas por rajadas (OBS). As contribuições da tese consistem da proposta e análise da aplicação da camada de transporte WDM/OCDM em redes OBS roteadas por comprimento de onda (WR-OBS), modelagem matemática de comutadores ópticos (OXC) WDM/OCDM considerando os parâmetros dos códigos OOC, estudo dos efeitos da dispersão por polarização modal (PMD) em redes ópticas WDM/OCDM e, finalmente, a proposta e análise da utilização processamento óptico da sinalização baseada em códigos OOC. Em função dos resultados obtidos se verifica que a aplicação dos códigos ópticos OOC nas redes ópticas de transporte WDM/OCDM, redes de rajadas e redes WR-OBS aumenta o desempenho destas redes por meio da diminuição da probabilidade de perdas de pacotes, latência dos pacotes e aumento da utilização da rede. Palavras-chave: Códigos ópticos ortogonais (OOC), dispersão por polarização modal (PMD), redes ópticas WDM/OCDM, redes ópticas comutadas por rajadas (OBS) / Abstract: This work presents an analysis of optical orthogonal codes (OOC) of optical code division multiplexing (OCDM) in optical networks. These networks uses the hybrid technology of wavelength division multiplexing and optical code division multiplexing (WDM/OCDM) and, optical burst switching networks (OBS). The main contributions are the analyze and propose of WDM/OCDM transport network at wavelength routed OBS networks (WR-OBS), WDM/OCDM optical crossconnects (OXC) modeling considering OOC parameters, study of polarization mode dispersion (PMD) effects in optical WDM/OCDM networks and, finally an OBS architecture with OOC label processing is analyzed. Analytical and simulation results indicate that OOC utilization in WDM/OCDM transport networks, OBS and WR-OBS networks increases the network performance by decrease of packet error rate, latency and network utilization increase. Keywords: Orthogonal optical codes (OOC), polarization mode dispersion (PMD), WDM/OCDM optical networks, optical burst switching (OBS) / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Orientador: Aldario C. Bordonalli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T21:13:22Z (GMT). No. of bitstreams: 1 Carvalho_RaniereNoronhade_M.pdf: 8840404 bytes, checksum: 8fe7c72c315d28741327bdd5e4195146 (MD5) Previous issue date: 2008 / Resumo: Atualmente, têm-se observado tentativas de se transferir o processamento da informação em redes de tráfego de pacotes cada vez mais para o domínio óptico. Isto acarretaria um aumento da quantidade de informações trocadas entre os nós da rede e promoveria a diminuição da latência do fluxo de pacotes. Com este intuito, procurou-se analisar os efeitos da redução do tempo de acionamento de uma chave óptica simples baseada em um amplificador óptico a semicondutor (SOAs) comum e disponível comercialmente no desempenho de um arranjo experimental que simulava uma rede de tráfego de pacotes. Posteriormente, de posse dos resultados obtidos, que assumiram a manutenção da integridade dos bits do pacote dentro de um fator de 10% durante os transientes de chaveamento, a latência da rede foi teoricamente avaliada. Para a melhoria do tempo de chaveamento do SOA, utilizou-se uma técnica de pré-injeção de pulso de corrente de portadores, Como esperado, houve uma redução acentuada dos tempos de acionamento de início e fim do processo de chaveamento óptico em relação ao obtido com pulsos quadrados simples, da ordem de 10 vezes. Verificou-se, também, que, acima de um determinado número de chaveamentos ocorrendo dentro de uma mesma rede óptica de pacotes, a latência da rede poderia ser diminuída de acordo com o tráfego da rede com a aplicação da técnica de redução do tempo de chaveamento do SOA. / Abstract: Currently, more and more attempts are being made to move network processing of information packets to the optical domain. This can potentially lead to an increase of the amount of information that is exchanged among nodes of the network and promote the reduction of latency of packet flow. In this sense, this work examines the effects of reducing the switching time of semiconductor optical amplifier (SOA) based switches in the performance of an experimental arrangement that simulates a network with optieal paeket traffie. By assuming per-bit paeket integrity within a factor of 10% over the switching period of transients, the latency of the network was then theoretically evaluated. j To improve the SOA switching time, a pre-impulse step injected current technique was used to provide excess carriers during transients. As result, a reduction of the order of ten times in the optical switching interval was observed in relation to that provided by ordinary square pulse~. In terms of packet traffic flow, the latency resulting from the improved SOA switching time could considerably be reduced based on the number of switching events occurring within the network. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

Please read the abstract in the section 00front of this document / Dissertation (MSc (Computer Science))--University of Pretoria, 2006. / Computer Science / unrestricted

Digital audio networks allow multiple channels of audio to be streamed between devices. This eliminates the need for many different cables to route audio between devices. An added advantage of digital audio networks is the ability to configure and control the networked devices from a common control point. Common control of networked devices enables a sound engineer to establish and destroy audio stream connections between networked devices that are distances apart. On a digital audio network, an audio transport technology enables the exchange of data streams. Typically, an audio transport technology is capable of transporting both control messages and audio data streams. There exist a number of audio transport technologies. Some of these technologies implement data transport by exchanging OSI/ISO layer 2 data frames, while others transport data within OSI/ISO layer 3 packets. There are some approaches to achieving interoperability between devices that utilize different audio transport technologies. A digital audio device typically implements an audio control protocol, which enables it process configuration and control messages from a remote controller. An audio control protocol also defines the structure of the messages that are exchanged between compliant devices. There are currently a wide range of audio control protocols. Some audio control protocols utilize layer 3 audio transport technology, while others utilize layer 2 audio transport technology. An audio device can only communicate with other devices that implement the same control protocol, irrespective of a common transport technology that connects the devices. The existence of different audio control protocols among devices on a network results in a situation where the devices are unable to communicate with each other. Furthermore, a single control application is unable to establish or destroy audio stream connections between the networked devices, since they implement different control protocols. When an audio engineer is designing an audio network installation, this interoperability challenge restricts the choice of devices that can be included. Even when audio transport interoperability has been achieved, common control of the devices remains a challenge. This research investigates protocol command translation as a means to enable interoperability between networked audio devices that implement different audio control protocols. It proposes the use of a command translator that is capable of receiving messages conforming to one protocol from any of the networked devices, translating the received message to conform to a different control protocol, then transmitting the translated message to the intended target which understands the translated protocol message. In so doing, the command translator enables common control of the networked devices, since a control application is able to configure and control devices that conform to different protocols by utilizing the command translator to perform appropriate protocol translation.

This thesis deals with the analysis of a Wired High Speed Serial Data Link (PAM2) which is commonly used throughout the data-communications and tele-communications industry. The goal of this study is to build a scalable simulation tool using Matlab that ultimately uses Receiver Bit Error Ratio (BER) as the metric for data link health. This study is also designed to aid in link specification development. The Matlab and theoretical development is broken up into three sections being Transmitter (TX), Channel (Hs) and Receiver (RX). Realistic noise impairments can be added to each section along the signal path creating signal stresses commonly seen in data center applications. The TX function is designed to create random and periodic timing jitter, voltage noise and deterministic pre-distortion filtering effects. For the channel response s-parameters are used as the model result for many commonly seen channel loss and reflection scenarios. The RX model uses signal to noise ratio and vertical eye margin to determine the equalized link BER. The study results show many tradeoffs between noises, RX Equalizer, RX gain and RX BER. The simulation results also reveal that there is no closed form solution for converging the modern closed-eye PAM2 detector.

In the past it has been convenient to adopt existing long haul network (LHN) protocols for use in local area networks (LANs). However, due to the different operating parameters that exist between these two types of networks, it is not possible for a LHN protocol to fully exploit the characteristics of a LAN. Thus, the need arises for a protocol designed specifically for use in a LAN environment. LNTP is one such transport level protocol. It was designed for exclusive use in LANs, and thus does not incorporate those features which are not relevant to a LAN environment. The result of this is a simpler and more efficient protocol. As well, LNTP employs a novel deferred flow control strategy which minimizes the time that a transmitting process will be blocked. This thesis examines the implementation of LNTP in the 4.2 BSD UNIX operating system. Various measurements are taken, and LNTP's performance is compared to that of TCP/IP, a LHN protocol which is often used in LAN environments. Several formulas are developed to determine the optimum values for various LNTP parameters, and these theoretical results are compared to the experimentally observed values. We conclude that LNTP does indeed outperform TCP/IP. However, due to the overhead of the non-LNTP specific protocol layers, this improvement is not as great as it might be. Nonetheless, LNTP proves itself to be a viable replacement for TCP/IP. / Science, Faculty of / Computer Science, Department of / Graduate

Priority schemes employing the inherent properties of carrier-sense multiple-access (CSMA) schemes are investigated and then applied to the integrated transmission of voice and data. A priority scheme composed of 1-persistent and non-persistent CSMA protocols is proposed. The throughput and delay characteristics of this protocol are evaluated by mathematical analysis and simulation, respectively. The approach of throughput analysis is further extended to another more general case, p-persistent CSMA with two persistency factors, the throughput performance of which had not been analyzed before. Simulations are carried out to study the delay characteristics of this protocol. After careful consideration of the features of the priority schemes studied, two protocols are proposed for integrated voice and data transmission. While their ultimate purpose is for integrated services, they have different application. One of them is applied to local area network; the other is suitable for packet radio network. The distinctive features of the former are simplicity and flexibility. The latter is different from other studies in that collision detection is not required, and that it has small mean and variance of voice packet delay. Performance characteristics of both of these protocols are examined by simulations under various system parameter values. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Bibliography: pages 233-235. / The CCITT X.400 Message Handling System resides in the Application Layer of the seven-layer Reference Model for Open Systems Interconnection. It bypasses the services of the Presentation Layer completely to interact directly with the Session Layer. The objectives of this thesis are to show how the general Session Layer may be tailored to be minimally conformant to the requirements of X. 400; to produce a formal specification of this session layer; and to show how this session layer may be implemented on a real system. The session services required by X. 400 are those of the Halfduplex, Minor Synchronization, Exceptions and Activity Management functional units of the CCITT X.215 Session Service Definition. These services, and particularly their use by X.400, are described in detail. State tables describing these services are derived from the general session service state tables. Those elements of the CCITT X. 225 Session Protocol Specification which are required to provide only those services required by X. 400 are described in detail. State tables describing this session protocol are derived from the general session protocol state tables. A formal specification of the session layer for X.400 is presented using the Formal Description Technique Estelle. This specification includes a complete session entity, which characterizes the entire session layer for X.400. A session entity for supporting X.400 is partially implemented and interfaced to an existing X.400 product on a real system. Only the Session Connection Establishment Phase of the session protocol is implemented to illustrate the technique whereby the entire session protocol may be implemented. This implementation uses the C programming language in the UNIX operating system environment.

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