O desenvolvimento e utilização do padrão IEC 61850 alterou a concepção e operação das subestações de energia elétrica. O desempenho e confiabilidade do sistema de proteção depende da rede de comunicação de dados. Esta pesquisa propõe um parâmetro de dimensionamento e comparação de desempenho para o tempo de transferência das mensagens Generic Object Oriented Substation Event (GOOSE) entre Intelligent Electronic Devices (IEDs). Esse parâmetro foi obtido através do levantamento experimental da curva do tempo de transferência das mensagens GOOSE versus a ocupação percentual da largura de banda dos IEDs. Para a realização dos experimentos foram utilizados três IEDs, um switch Ethernet gerenciável, três microcomputadores do tipo PC, um relógio sincronizador Global Positioning System (GPS), cordões de fibra óptica, cabos do tipo par trançado sem blindagem e aplicativos de software. Os resultados mostraram que a partir de um limiar característico, o qual é distinto para cada IED ensaiado, o tempo de transferência excede o limite máximo permitido pelo padrão IEC 61850. A partir da análise destes dados, foi desenvolvido um sistema preditivo de monitoramento de banda para supervisionar a interface de rede dos IEDs. O sistema preditivo apresentou para a medição de banda um erro relativo médio igual a 0,55% em relação ao aplicativo comercial utilizado na comparação, já a predição feita pela rede neural artificial apresentou um erro de estimativa menor do que 3% para 91,30% das amostras utilizadas, além de modelar adequadamente o comportamento da série temporal que representa a ocupação de banda do IED monitorado. / The development and utilization of IEC 61850 standard changed the design and operation of electric power substations. The performance and reliability of the protection system depends on the data communication network. This research proposes a parameter for dimensioning and comparising the transfer time of Generic Object Oriented Substation Event (GOOSE) messages between different Intelligent Electronic Devices (IEDs). This parameter was obtained from experimental data related to the transfer time of GOOSE messages curve versus IEDs bandwidth percentage occupation. In this context, a laboratory structure was set up in order to carry out these experiments. This structure mainly consists of three IEDs, an Ethernet switch, three personal computers, a GPS Clock, fiber optic cables, unshielded twisted pair cables, as well as support software. The results show the existence of a characteristic threshold, different for each IED tested, after which the transfer time exceeded the total transmission time allowed for the IEC 61850 standard. Based on these results, a predictive bandwidth monitoring system was developed to supervise the IEDs bandwidth interface. The bandwidth measurement has a mean relative error of 0.55% regarding to the commercial software used for comparison. Finally, the forecasting made by the artificial neural network has a relative error of 3% for 91,30% of the samples used in test phase. In addition, that it was able to model the behaviour of the time series that represent the bandwidth occupation.

Syftet med den här rapporten är att beskriva ett antal olika tillvägagångssätt man kan använda sig av då man har behov av att dela in ett lokalt nätverk i olika segment och med det även kunna reglera trafikflödet mellan segmenten. De lösningar som presenteras i arbetet är inriktade mot mikro- och småföretag.Anledningen till att vi har valt att arbeta med det här området är att vi anser att det är viktigt för organisationer att har en strukturerad och segmenterad design på sitt interna datornätverk.Vi har arbetat genom att i förväg samla in information om olika tekniker som kan tänkas lösa vårt problem, och därefter testat olika scenarion med dessa tekniker. Data har samlats in efter varje genomfört scenario och sammanställts i statistisk form för att kunna avgöra vilken metod som var att föredra.Vi har testat lösningar där man segmenterar nätverket i en lager 2-switch medan man möjliggör och förhindrar trafikflöde mellan segmenten i en router. Även lösningar där man använder en lager 3-switch har testats. På så sätt kan routningen ske direkt i switchen och det blir betydligt mindre belastning i routern. Resultatet visar att då man vill segmentera ett nätverk så är det rekommenderat att man använder sig av VLAN och ACL:er och eventuellt i kombination med en brandvägg.Slutresultatet av rapporten är att en lösning med ”router on a stick” är den billigaste lösningen och troligen den som de flesta mindre företag skulle klara sig med. Vilken lösning man väljer beror dock helt på hur mycket pengar man vill lägga på sitt nätverk samt vad kraven är. / The purpose of this report is to describe a number of approaches that can be used when you are in need of dividing a local area network in a number of segments, and with that also be able to control how data traffic is allowed to traverse between the different segments. The solutions that are presented are focused towards micro and small companies.The reason that we have chosen to work with this matter is that we believe it is important for organizations to have a structured and segmented design of its internal computer network.We have been working by in advance collecting information about various techniques that might solve our problem, and then testing different scenarios using these techniques. Data have been collected after each tested scenario and compiled in statistical form in order to determine which method that was preferable.We have been testing solutions were you segment the network in a layer 2 switch while you allow or deny communication between the segments in a router, and also solutions were you use a layer 3 switch. In that way you can let the routing be performed in the switch, which leads to significantly lower load on the router. The result was that if you are about to segment a local area network it is recommended that you use VLAN and ACL:s, and possibly in combination with a firewall.The final result of this report is that a solution using the “router on a stick”-technique is the cheapest one, and probably the one that most small companies would get along with. However, the solution that you choose depends completely on how much money you want to spend on your network, and also what the needs are.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / The Central Test and Evaluation Investment Program (CTEIP) Integrated Network Enhanced Telemetry (iNET) program is currently testing a wireless local area networking (WLAN) in an L-band telemetry (TM) channel to evaluate the feasibility and capabilities of enhancing traditional TM methods in a seamless wide area network (WAN). Several advantages of networking are real-time command and control of instrumentation formats, quick-look acquisition, data retransmission and recovery (gapless TM) and test point real-time verification. These networking functions, and all others, need to be tested and evaluated. The iNET team is developing a WLAN based on 802.x technologies to test the feasibility of the enhanced telemetry implementation for flight testing.

Approved for public release, distribution is unlimited / Optical fiber has been the preferred cabling technology for certain building and campus network LAN backbones. Until recently, however, the use of fiber as a cabling medium to the desktop has been confined to special environments that require the unique properties of optical fiber such as noise immunity, security, distance, high bandwidth demands (CAD/CAM, video conferencing), and immunity to electrical interference. However, choosing to use optical fiber in a network over other cabling options may present significant advantages in its inherent ability to handle data at higher speeds. Decreasing costs of optical fiber components compared to the increasing electronic costs of carrying Gigabit Ethernet over Cat 5 or Cat 5E UTP copper cabling has also accelerated the migration to optical fiber LAN. The thesis conducts a feasibility study of implementing a Fiber Optic Local Area Network in Software Metrics Laboratory in Ingersoll 158. / Major, Republic of Singapore Air Force

Com o objetivo de auxiliar o projetista na fase de projeto físico, são especificadas duas ferramentas: ferramenta de cabeamento estruturado e ferramenta de seleção de equipamentos. A primeira opera como um sistema de CAD/CAE permitindo que o projetista elabore as plantas civil, de instalação elétrica e da infra-estrutura de comunicação de andares de um prédio ou de um campus e desenvolva o seu projeto de cabeamento estruturado. Para tanto, essa ferramenta verifica as regras de projeto para cada ação executada pelo projetista, implementa tais regras, quando estiver operando em modo automático, e auxilia o projetista na seleção dos componentes de distribuição mais adequados ao projeto. A segunda ferramenta implementa um driver da metodologia proposta. Permite que o projetista especifique as sub-redes do ambiente de redes a ser projetado e o auxilia na seleção da tecnologia e dos equipamentos mais apropriados para cada uma dessas sub-redes. No caso especifico da seleção da tecnologia e equipamentos de rede, essa ferramenta determina o conjunto de tecnologias e equipamentos que podem ser empregados em cada sub-rede, aplicando regras de projeto e utilizando informações sobre tecnologias e equipamentos de rede cadastrados na sua base de dados sobre as características do ambiente de informática considerado e os requisitos de projeto fornecidos pelo próprio projetista. / Today, networks are assuming an increasing importance in all kinds of companies, like bureau of services, bank organizations, shopping stores, educational institutions and hospitals, among others. As a consequence, it\'s becoming more important to offer to these companies high quality network designs, that could warranty the return of the investments made. A high quality design should fulfil the company needs, the addition of new services as the information system evolves and be capable of implementation according to the company budget and time constraints. To achieve this goal it is important to count with a powerful local network design methodology and with designers with strong theoretical and practical knowledge. The designer should apply such methodology and the corresponding designing rules to define the most appropriate network technology and equipments. Inside this context, the purpose of this work is to propose a local network design methodology for environments spanning from a few floors of a building comprising a campus and the supporting software tools for its applications. The proposed methodology consists of various phases: collecting all the information concerning the needs and characteristics of the company\'s present computing environment, their future trends and the development of the physical and logical network design. With exception of the logical networks design, that is out of the scope of this work, this methodology specifies the inputs, the procedure and the expected results for each phase. With the purpose of helping the designer during the physical network design phase two software tools are speciufied: structured cabling tool and equipment selection tool. The first one run like a CAD/CAE the electrical installation and the communication infrastructure for the building and campus and todevelop of the structured cabling solution. In order to accomplish these objectives, this tool verifies the designing rules for each action, implements these rules when operating in the automatic mode, and helps the designer in the selection of the most suited distribution components. The second tool implements a driver of the proposed methodology. It allows the designer to specify the sub-networks (workgroups and backbone networks) and helps with the selection of the most suited technology and network equipments for each sub-network. This tool also chooses the set of technologies and network equipments the could be used in each sub-network. It provides these choices based on the designing rules, on a database of technologies and equipments and on the characteristic of the computing environment and the design requirements provide by the designer. The use of the proposed methodology and its supporting tool\'s warranties the targeted quality and precision for any network design, organize its applications and give the necessary information allowing the designer to specify the desired solution.

Com o objetivo de auxiliar o projetista na fase de projeto físico, são especificadas duas ferramentas: ferramenta de cabeamento estruturado e ferramenta de seleção de equipamentos. A primeira opera como um sistema de CAD/CAE permitindo que o projetista elabore as plantas civil, de instalação elétrica e da infra-estrutura de comunicação de andares de um prédio ou de um campus e desenvolva o seu projeto de cabeamento estruturado. Para tanto, essa ferramenta verifica as regras de projeto para cada ação executada pelo projetista, implementa tais regras, quando estiver operando em modo automático, e auxilia o projetista na seleção dos componentes de distribuição mais adequados ao projeto. A segunda ferramenta implementa um driver da metodologia proposta. Permite que o projetista especifique as sub-redes do ambiente de redes a ser projetado e o auxilia na seleção da tecnologia e dos equipamentos mais apropriados para cada uma dessas sub-redes. No caso especifico da seleção da tecnologia e equipamentos de rede, essa ferramenta determina o conjunto de tecnologias e equipamentos que podem ser empregados em cada sub-rede, aplicando regras de projeto e utilizando informações sobre tecnologias e equipamentos de rede cadastrados na sua base de dados sobre as características do ambiente de informática considerado e os requisitos de projeto fornecidos pelo próprio projetista. / Today, networks are assuming an increasing importance in all kinds of companies, like bureau of services, bank organizations, shopping stores, educational institutions and hospitals, among others. As a consequence, it\'s becoming more important to offer to these companies high quality network designs, that could warranty the return of the investments made. A high quality design should fulfil the company needs, the addition of new services as the information system evolves and be capable of implementation according to the company budget and time constraints. To achieve this goal it is important to count with a powerful local network design methodology and with designers with strong theoretical and practical knowledge. The designer should apply such methodology and the corresponding designing rules to define the most appropriate network technology and equipments. Inside this context, the purpose of this work is to propose a local network design methodology for environments spanning from a few floors of a building comprising a campus and the supporting software tools for its applications. The proposed methodology consists of various phases: collecting all the information concerning the needs and characteristics of the company\'s present computing environment, their future trends and the development of the physical and logical network design. With exception of the logical networks design, that is out of the scope of this work, this methodology specifies the inputs, the procedure and the expected results for each phase. With the purpose of helping the designer during the physical network design phase two software tools are speciufied: structured cabling tool and equipment selection tool. The first one run like a CAD/CAE the electrical installation and the communication infrastructure for the building and campus and todevelop of the structured cabling solution. In order to accomplish these objectives, this tool verifies the designing rules for each action, implements these rules when operating in the automatic mode, and helps the designer in the selection of the most suited distribution components. The second tool implements a driver of the proposed methodology. It allows the designer to specify the sub-networks (workgroups and backbone networks) and helps with the selection of the most suited technology and network equipments for each sub-network. This tool also chooses the set of technologies and network equipments the could be used in each sub-network. It provides these choices based on the designing rules, on a database of technologies and equipments and on the characteristic of the computing environment and the design requirements provide by the designer. The use of the proposed methodology and its supporting tool\'s warranties the targeted quality and precision for any network design, organize its applications and give the necessary information allowing the designer to specify the desired solution.

This study explores the application of wireless local area network (WLAN) in retailing industy for enhancing experiential marketing. As competition in the retailing industry increases, added with new entrants competing for old customers, department stores nowadays must consider new ways of attracting customers. Against that backdrop , experiential marketing becomes increasing important. Taking Kaohsiung¡¦s six department stores as cases for study, the author conducted a two-wave survey to examine whether and to what extent visitors of deparment stores appreciate the introduction and possible deployment of wireless local area networks as a means for enhancing experiential marketing. Using analytic hierarchy process (AHP) as a research method, this study sorts out not only the key success factors of introducing wireless Internet in the context of department stores but also the priority setting of those key success factors, which includes seventeen elements falling into five categories. Broadly put, marketing and promotion stands out as the first priority setting, followed by business model and infrastructure. The finding of such priority setting has deep implications for experiential marketing which also falls into five modules of analysis: sense, feel, think, act and relate. It shows that visitors are more satisfied with the aspects of sense and feel, whereas the other three leave rooms for improvement. By introducing and deploying information and communications technologies, such as WLAN, that weakness of experiential marketing can be improved.

Through technological innovation and various stages of standardisation, wireless Internet has developed into a powerful business tool. Nowadays, business becomes not only e-business but also mobile business, or m-business, where business is done via mobile devices. This is especially true in industries where the provision of real-time and location-based information is important. Cultural tourism is one evident example of such industry. And museum might be the best testing ground for the effective use of wireless Internet in cultural tourism. Taking Taiwan¡¦s five national museums as cases, this study explores the current wireless deployment and the applications with it. It specifically examines whether and to what extent museum visitors would appreciate such deployment. After a thorough literature review, the author sorts out seven dimensions (comprising 40 elements) for the first wave of survey. Using fuzzy analytic hierarchy process (FAHP), the author further finds out the priority setting of those key success factors. The priority settings fall into three groups according to their significance. Connectivity and content design are perceived as the most important. The second group inlcudes, information content, marketing and promotion, and user¡¦s experience. The least urgent dimensions for wireless Internet development are applications and business model. This study should contribute to the understanding of applying new information and communications technologies (ICTs) in museum exhibitions. It suggests that museums should consider enhancing experiential marketing by thoughtful introduction of ICTs, notably wireless Internet application such as WLAN. This study is also characterised by using FAHP for sorting out the priority settings in the minds of museum visitors and related experts.

The Metro Ethernet network (MEN) expands the advantages of Ethernet to cover areas wider than LAN. MENs running Ethernet Services as specified by the Metro Ethernet Forum (MEF) are known as Carrier Ethernet Networks (CENs). CENs can cover not only metro areas, but it can expand to cover global areas by connecting multiple MENs. Next-generation CENs are expected to support 100 GbE. With arising technologies for Ultra Long-haul (ULH) networks the bandwidth bottleneck of CENs is shifting to other areas like the transport layer protocol (such as the Transport Control Protocol or TCP) and the chip-to-chip channel capacity found at the network edge, which in general has an electrical backplane. Traditional TCP is well known to have difficulties reaching the full available bandwidth, due to its inefficient AIMD mechanisms under a high-delay-bandwidth-product environment. At the network edge, network equipment with electrical backplanes poses many problems including inductive-capacitive effects that limit its bandwidth. These are the two main issues addressed in this work. To resolve the transport layer issue, this work proposes a transport protocol that fully utilizes the available bandwidth while preserving TCP-friendliness and providing QoS support that is compatible with Ethernet Services. It can guarantee throughputs above the Committed Information Rate (CIR), which is specified in the Service Level Agreement (SLA). To resolve the physical layer limitations, a novel optical coupling technique is examined to encourage the use of optical backplanes for network-edge and core technology. The proposed technique consists of aligning the normal of the laser emission plane, waveguide plane and the normal of the photodetector active region plane with the purpose of reducing optical power loss caused by common methods of light manipulation. By addressing the shortcomings of both Traditional TCP and electrical backplane technology the overall throughput can be significantly increased.

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