Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Oct. 7, 2008; title from PDF t.p. Includes bibliographical references (p. 80-81).

Bibliography: leaves 128-135. Investigates the behaviour of TCP bulk file transfer application sessions in a broadband access environment. Introduces some concepts for evaluating network behaviour: a path instability parameter for analyzing different TCP connections; a minimum RTT delay and a minimum typical path for estimating path characteristics between a client and application servers.

Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The aim of this thesis is to investigate the implementation of a high-speed serial bus based on the IEEE Std 1394-1995 specification for use in a microsatellite. Earth observation microsatellites carry imagers (or cameras) that take photographs of the earth. Each photograph generates a large volume of digital data that has to be transferred to either a storage device, a RF transmission unit or a video processing device. Traditionally, the connection between such systems were dedicated serial bus systems that were custom designed for just that purpose. This thesis will investigate the the implementation of a generic alternative to such a custom serial bus. The IEEE 1394 serial bus will allow many devices and subsystems to be connected to the serial bus and will allow these different subsystems to exchange data between each other. As an example implementation, a real-time video link between two points using the IEEE 1394 serial bus will be developed. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om ondersoek in te stel na die bou van 'n hoëspoed seriebus vir gebruik in 'n mikrosatelliet gebaseer is op die IEEE Std 1394-1995 spesifikasie. Aardobservasie-mikrosatelliete bevat kameras wat fotos van die aarde neem. Elke foto genereer groot volumes digitale data wat na óf 'n massastoor, óf 'n RF-sender, óf 'n video-verwerkingseenheid gestuur word. Tradisioneel is elkeen van hierdie verbindings met 'n toegewyde seriebus gedoen wat spesiaal vir daardie doel gemaak is. Hierdie tesis het dit ten doelom ondersoek in te stel na 'n generiese alternatief vir hierdie toegewyde seriële busse. Die IEEE 1394 seriebus sal toelaat dat verskeie eenhede en substelsels aan mekaar gekoppel kan word en dat hulle data tussen mekaar kan uitruil. Ter demonstrasie sal 'n intydse videoskakel ontwerp word wat die IEEE 1394 seriebus gebruik om data tussen twee punte oor te dra.

The Session Initiation Protocol (SIP) has in recent years become a popular protocol for the exchange of text, voice and video over IP networks. This thesis proposes the use of a class of structured peer to peer protocols - commonly known as Distributed Hash Tables (DHTs) - to provide a SIP overlay with services such as end-point location management and message relay, in the absence of traditional, centralised resources such as SIP proxies and registrars. A peer-to-peer layer named OverCord, which allows the interaction with any specific DHT protocol via the use of appropriate plug-ins, was designed, implemented and tested. This layer was then incorporated into a SIP user agent distributed by NIST (National Institute of Standards and Technology, USA). The modified user agent is capable of reliably establishing text, audio and video communication with similarly modified agents (peers) as well as conventional, centralized SIP overlays.

Orientador: Rubén Augusto Romero Lázaro / Resumo: Tradicionalmente, o problema de Planejamento da Expansão de Sistemas de Transmissão (PEST) é solucionado considerando apenas um único cenário de geração, embora sistemas elétricos reais operem em diferentes cenários de geração. Nessa pesquisa são propostos modelos matemáticos para resolver o problema de PEST, considerando múltiplos cenários de geração de forma que o plano de expansão obtido permita uma operação adequada do sistema. No modelo proposto, o custo de investimento é maior em relação aos planos de expansão encontrados pelo planejamento tradicional, que considera apenas um cenário de geração. Para reduzir o correspondente custo de investimento são apresentadas estratégias eficientes para encontrar planos de expansão para o problema de PEST considerando múltiplos cenários. As estratégias utilizadas foram: permitir pequenos cortes de carga; permitir o deslocamento do nível de geração em uma pequena faixa de geração mínima e máxima em relação à geração ideal e permitir pequenas sobrecargas nas linhas de transmissão. Adicionalmente, uma combinação entre essas estratégias é apresentada e o problema PEST também foi resolvido para o planejamento multiestágio, considerando múltiplos cenários de geração. O método proposto foi implementado com o uso da linguagem de modelagem algébrica AMPL e resolvido com o uso do solver comercial CPLEX. Os resultados encontrados correspondem à propostas de solução que são válidas para diferentes cenários de geração e apresentam diferentes alt... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Traditionally, the Transmission Network Expansion Problem is solved considering only a single generation scenario. However, a real power system operates in different generation scenarios. This work presents the disjunctive linear model for the Transmission Network Expansion Problem considering multiple generation scenarios to provide a single expansion plan, which must operate in a appropriate way in each one of the different scenarios. The investment cost of the proposed model is greater in relation to the traditional expansion plans, that consider single generation scenario. In order to reduce the investment costs, efficient strategies are presented to find the expansion plans for multiples scenarios. Therefore those strategies are: allow small load cuts; allow generation level displacement in a narrow generation range in relation to the ideal one; and allow small overload in the transmission lines. Moreover, a combination between those strategies is shown and the Transmission Network Expansion Problem was also solved for multistage planning for multiple generation scenarios. The proposed method was implemented using A Mathematical Programming Language (AMPL) and the commercial solver CPLEX. The results were of optimal quality, considering the characteristics of the used solver, and they were compared with methods found in the specialized literature. / Doutor

The transmission of realtime audio data across digital networks is subject to strict quality of service requirements. These networks need to be able to guarantee network resources (e.g., bandwidth), ensure timely and deterministic data delivery, and provide time synchronisation mechanisms to ensure successful transmission of this data. Two open standards-based networking technologies, namely IEEE 1394 and the recently standardised Ethernet AVB, provide distinct methods for achieving these goals. Audio devices that are compatible with IEEE 1394 networks exist, and audio devices that are compatible with Ethernet AVB networks are starting to come onto the market. There is a need for mechanisms to provide compatibility between the audio devices that reside on these disparate networks such that existing IEEE 1394 audio devices are able to communicate with Ethernet AVB audio devices, and vice versa. The audio devices that reside on these networks may be remotely controlled by a diverse set of incompatible command and control protocols. It is desirable to have a common network-neutral method of control over the various parameters of the devices that reside on these networks. As part of this study, two Ethernet AVB systems were developed. One system acts as an Ethernet AVB audio endpoint device and another system acts as an audio gateway between IEEE 1394 and Ethernet AVB networks. These systems, along with existing IEEE 1394 audio devices, were used to demonstrate the ability to transfer audio data between the networking technologies. Each of the devices is remotely controllable via a network neutral command and control protocol, XFN. The IEEE 1394 and Ethernet AVB devices are used to demonstrate the use of the XFN protocol to allow for network neutral connection management to take place between IEEE 1394 and Ethernet AVB networks. User control over these diverse devices is achieved via the use of a graphical patchbay application, which aims to provide a consistent user interface to a diverse range of devices.

Notorious for its high poverty levels and low socio-economic status, the Navajo Nation’s socio-economic well-being is hindered greatly in part by the lack of an adequate potable water infrastructure which has resulted in health disparities and has attributed to stunted economic growth within the Nation. Large candidate regional water transmission pipelines projects aimed to meet these needs have been identified. With capital costs exceeding their fiscal capability, decision-makers must choose projects that generate the most bang for the buck. To address these challenges, three (3) interconnected planning tools have been developed: (1) a water pipe installation construction cost estimation model (WaterCOSTE) to improve the accuracy of capital cost estimates; (2) a hydraulic optimization model (WaterTRANS) that improves design efficiency for branched water transmission systems; and (3) a decision support system (DSS) that allows candidate water transmission projects to be ranked while considering economic development, health improvement and environmental protection objectives. Estimates derived from WaterCOSTE are used as input into WaterTRANS to find least-cost system designs. The system costs along with other project data are then input into the DSS to determine project rankings. To demonstrate how the DSS can be used and applied, two candidate projects on the Navajo Nation are evaluated. The tools developed will enable decision-makers to improve planning processes and make wiser investment decisions that will lead to expanding the water infrastructure coverage and living conditions on the Navajo Nation.

Approved for public release, distribution is unlimited / In this thesis, the scalability issues of Simple Network Management Protocol (SNMP) in optical network management are explored. It is important to understand the effect of varying the number of nodes, the request inter-arrival times and the polling interval on the performance of SNMP and number of nodes that can be effectively managed. The current study explored the effect of varying these parameters in a controlled test environment using the OPNET simulation package. In addition, traffic analysis was performed on measured SNMP traffic and statistics were developed from the traffic analysis. With this understanding of SNMP traffic, an SNMPv1 model was defined and integrated into an OPNET network model to study the performance of SNMP. The simulation results obtained were useful in providing needed insight into the allowable number of nodes an optical network management system can effectively manage. / Civilian, Singapore Ministry of Defense

Approved for public release, distribution is unlimited / This thesis studies and discusses the development of the API, called the persistency API, for supporting the persistent data sessions. Without persistent session support, network applications often need to be restarted from the beginning when intermittent physical connection loss happens. Application programmers can use the persistency API to achieve the service continuity. The persistency API provides the interface that allows a program to continue retrieve data from the point the connection is lost after the physical connection is restored. The focus of this thesis is to develop a generalized persistency API that supports various types of applications. This thesis studies the persistent session support for two types of transport protocols, TCP and UDP, which are used by major network applications. An application that performs text file and video file transfer is implemented to demonstrate the persistent data transfer sessions for TCP and UDP, respectively. The study shows that the proposed APIs can support the data transfer continuity in the reconnection process. / Captain, Royal Thai Army

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