The main aim of this project was to find a practical and accurate method to determine the parameters of a transmission line by using current and voltage measurements. The term line parameters refer to the inherent series resistance and inductance that is found on transmission lines. The line parameters were determined by using the voltage and current measurements from either side of the transmission line. An accurate reference signal is needed to precisely compare the measured signals. The timing signals from GPS units were used to reference the measurements. In a field implementation data transfer of the measured signals would be a necessity which can be accomplished by GPRS modems. Three methods are proposed for determining line parameters. These methods were thoroughly tested in the following ways: 1. A model was built in SIMULINK with known elements and values. The three methods were then applied to the model and simulations were run. The results from the simulations are compared to the known values. 2. A system was built in the laboratory with known parameters. The results gathered from testing the system on all three methods are compared to known values. 3. Finally, the methods were applied to field data from recorders of a utility. This was done to see how well the methods would perform on a real system. Accuracy was determined from what the utility accepts as the correct values. Another focus of the project was to determine the surge impedance loading (SIL) curve from measured data. This curve can be used to determine the loadability limit of the transmission line as well as to visually show at what point the line is operating at any given time. The curve is also useful as it provides insight into the additional reactive power needed for a certain active power transfer. The concept of drawing a SIL curve from actual measurements was first tested by means of simulation. The drawing of the proposed curve is also tested on actual measurements from a transmission line. This investigation posed many challenges. These challenges are discussed in detail in the dissertation. Some of these challenges have easily implementable solutions while others still leave room for further research. The results and findings are published in this document. / Dissertation (MEng (Electrical))--University of Pretoria, 2008. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

The objective of the diploma thesis is to design a device for positioning of mobile devices using GPS satellites. When coordinates are acquired they can be sent via the GSM network to a user's cell phone or to an SQL server. A web interface has been designed to access the stored data and to show the current device position and the history. This position datalogging system can be used for monitoring vehicles as well as a security system for cars.

This project deals with the problematics of self-powered universal GSM/GPRS module which is used for sensorical applications. The first part analyzes features of mobile networks and applying energy from the environment. The second section expalins the various parts and characteristic of their associated components together with some fundamental functions of the technology for possible realization of sensoric module. The third part describes plan for system realisation and fourth parth illustrates achiaved results.

The study presented in this thesis is focused on the investigation of wireless application in industrial environment. The objective of this work is to provide an insight on the development of the wireless machine to machine (M2M) application, and a systematic approach for improving the application reliability on radio link level by end users. As a specific case, ABB Robotics’ Remote Service concept is examined to check whether the selection of cellular technology as its wireless access method and the choice of standard radio link components are able to satisfy the application requirement under different circumstances. Several modifications of the radio link components and topologies, e.g. repeater system, combiner, etc, are proposed for the enhancement of radio link reliability. Theoretical evaluations of these options are based on detailed radio link calculation and MATLAB simulation using propagation model dedicated for industrial environment. Furthermore, on site test is carried out to validate the theoretical evaluations. The M2M market investigation is also included in the task, in order to select the most cost-effective components from different suppliers. While walking through the radio link optimization process of the specific case, necessary information and knowledge common to all wireless M2M application are explained. In the end, in addition to a guide line for installation and other supporting documents regarding to the Remote Service, some rules of thumb available for the radio link optimization in all kinds of industrial environments are generalized and presented in the form of a flowchart, which can be beneficial for those support engineers of the application provider, who are not necessarily experts in wireless technology.

La presente tesis consiste en el diseño e implementación de una plataforma que sirva como medio para brindar información a los importadores y exportadores acerca del estado de su mercadería durante el viaje marítimo entre un puerto y otro. El primer presenta una definición del problema que tienen los contenedores durante el proceso de importación, indicando cuales son los principales problemas que ocurren durante las importaciones. Luego se hace el planteamiento de la solución en la cual se describen los alcances y las limitaciones del presente proyecto de tesis. El segundo capítulo presenta el marco teórico necesario para hacer el diseño y la implementación de la plataforma. En este capítulo se ven los conceptos teóricos acerca del funcionamiento del GPS y de los sensores que funcionan en la etapa de adquisición de datos. Luego se presentan los conceptos teóricos como de los sistemas de comunicaciones móviles, de telefonía IP. Se incluye la situación de las plataformas de monitoreo en el mundo y en el Perú El tercer capítulo presenta la arquitectura de solución que se planteó para la implementación de la plataforma. Al principio de este capítulo se hace un descripción de la arquitectura lógica de la plataforma para luego pasar a describir los servidores que se usarán en la plataforma. También se incluye una descripción de las herramientas tecnológicas que se usaron para su implementación como los lenguajes de programación y los AT-Commands. El cuarto capítulo aborda los temas de diseño de la plataforma. En la primera parte se describen los servicios que brindará la plataforma una vez que se implemente, para ello se hace una división modular de la plataforma. Luego de realizar esta división se muestran los diagramas de flujo de cada módulo y se describen los módulos. El quinto capítulo se divide en dos partes, la primera parte aborda los temas de la implementación de la plataforma. En esta parte se hace una descripción de la ii i implementación de la plataforma a nivel modular. En la segunda parte, se describe las pruebas de funcionamiento realizadas a la plataforma. Por último, se presentan las conclusiones y recomendaciones del presente trabajo, además de proponer algunos trabajos futuros que permitan la ampliación de la plataforma no solo a nivel geográfico sino también a nivel modular.

El presente proyecto de tesis consiste en la implementación un aplicativo para teléfonos móviles que pueda listar las rutas de transporte público urbano de la ciudad de Lima Metropolitana tomando como datos de entrada la información de la ubicación del usuario. Para ello la tesis se ha dividido en cinco capítulos que abarcan los aspectos teóricos y prácticos de la implementación del sistema el cual está compuesto por un servidor de aplicaciones, un servidor de base de datos y la aplicación móvil. El primer capítulo se enfoca en el estudio de las tecnologías relacionadas al desarrollo de las aplicaciones móviles en general, asimismo se detallan las características de las herramientas disponibles para el desarrollo del proyecto. El segundo capítulo busca presentar el análisis de la solución realizado a partir de los conceptos y herramientas presentadas en el capítulo anterior, además de ello se explica las características de la propuesta de solución. El tercer capítulo describe el diseño de la solución el cual incluye la información de la arquitectura del sistema, el flujo de datos, la descripción de la base de datos a utilizar y finalmente las interfaces de la aplicación. El cuarto capítulo, por su parte, explica la implementación realizada para ello se detalla tanto la estructura de la aplicación como las configuraciones realizadas en el sistema. El quinto capítulo expone las pruebas del prototipo, las herramientas utilizadas y los resultados obtenidos durante ese proceso. Por último, se presentan las conclusiones y recomendaciones del trabajo, además de proponer algunos trabajos futuros que permitan la integración de este sistema con nuevas herramientas de telecomunicaciones que complementen el trabajo presentado y le añadan nuevas características de acuerdo a los nuevos requerimientos de los usuarios.

No / For decades, the development of the Internet was driven by the purpose of providing applications to non-mobile users. No specific Quality of Service (QoS) requirement is necessary, other than ensuring reliability in the end-to-end data transfers. As such, best effort service model was deemed more than appropriate to satisfy the users' needs. Nevertheless, the scenario has changed in the last few years. A new population of nomadic users, who requires access to Internet services regardless of their location and mode of transportation is growing, while new typologies of Internet applications are being continuously developed, in which best effort service level may no longer be adequate. The SUITED project has been devised to address the emerging issues generated by this new and challenging scenario. SUITED aims at contributing towards the design and deployment of the Global Mobile Broadband System (GMBS), a unique satellite/terrestrial infrastructure, which will ensure that nomadic users have access to Internet services with a negotiated QoS. An overview of the main results achieved in the SUITED project is provided in this article. Some of the most innovative solutions developed by the SUITED team for the joint management of global mobility and end-to-end QoS support are presented. The SUITED demonstrator platform, which was developed to validate the system specifications, is also described. Finally, the results of the experimental measurement campaigns carried out with this platform are reported.

This master thesis deals with a data remote transmission by means of SMS and GPRS technology. The overview of current solutions is presented and then a remote temperature measurement and a data transmission employing a communication module GSM/GPRS TM1 through GSM network using GPRS technology is described. As a response to an impulse, the communication module sends SMS. The technical solution is described in details including HW and SW design of the data transfer and processing equipment using a ATmega 162 microprocessor. This equipment communicates with a server (PC), which displays the measured temperature. A prototype which was used for a validation of the design is also described.

行動上網之概念已提出多年，然受制於硬體規格限制與資訊實用面廣度、深度不足，因此市場未如預期般快速成長。如今受惠於系統業者廣佈GPRS系統，功能性手機普及化，以及內容提供者積極參與，行動數據服務始展露一絲曙光。和信電訊公司看好市場前景，藉與NTT DoCoMo合資關係引進行動上網服務典範─i-mode。本研究之主要目的旨在檢視目前台灣i-mode服務之品質，經結合理論探討與實務分析，具體提出發展行動數據服務之改善要素。 本研究彌補國內相關研究在深度上之不足，採質性研究法，以NTT DoCoMo發展i-mode服務為模式，就技術、內容、策略和使用之關鍵面向，深入訪談系統業者、內容提供者和使用者後，交叉分析以找出三者認知上之落差，進而推論改善行動數據服務品質之關鍵要素，並提出建議解決方案。 本研究結果發現：系統業者之改善要素包括價格、手機選擇、連線品質、行銷、後端管理及利潤分享；內容提供者之改善要素包括價格、實用性、介面、品牌及獲利模式。本研究最大貢獻亦在於提供相關業者諸多建言及產業發展方針，整體而論：第一，系統業者應致力於提升行動上網平台之可用性；第二，內容提供者宜鎖定目標客群主動創造需求；第三，系統業者和內容提供者應從商業合作關係提升為策略聯盟關係。在延伸討論部份，本研究認為：第一，應建立以內容聚集為中心之商務模式架構；第二，推動XHTML做為改善非人性化介面和網路封閉性之解決方案；第三，將行動數據服務從以個人為單位提升到社會關係的層次；第四，開發企業用途之應用，將服務拓展至企業市場。 / The concept of mobile internet has been introduced many years ago; however, due to the limits of hardware standards and the inadequacies of breadth and depth of information practicability, the market didn’t rise and flourish as expectations. Now because of the benefits of distributions of GPRS network system, popularization of feature cellular phones, and active participation of content providers, the mobile data services start to grow. With faith in good prospects of the market, the KGT company introduced i-mode, the paradigm of mobile internet services, from NTT DoCoMo through their partnership. The main purposes of this research are to view the quality of recent i-mode service in Taiwan, and to concretely propose key improving factors of developing mobile data services through integration of theory reviews and practice analyses. For retrieving the lacks of depth in former domestic researches, this research uses the i-mode service as an example and adopts qualitative research methods by deeply interviewing with the operator, the content providers, as well as the users on critical aspects of the technology, the content, the strategy, and the usage. Then, after cross-analyzing to find gaps of the cognition among the three roles, this research infers the key factors to improve the quality of mobile data services and proposes the corresponding solutions. The major findings of this research are as follows. The improving factors of operators includes the price, the phones selectivity, the connection quality, the marketing, and the profits share. Those of content providers includes the price, the practicability, the interface, the brand, and the profit-earning model. This thesis also contributes many suggestions and guidelines of industry development for relevant players. First, operators should strive for enhancing the usability of mobile internet platforms. Second, content providers ought to aim at target customers and actively create demands. Third, the relationship of operators and content providers must be promoted from business cooperation to strategic alliance. In the section of extended discussions, this research presents several recommendations. First, a framework of content aggregation-centered business models should be established. Second, XHTML should be drived as a solution to improve recent unfriendly interfaces and network closure. Third, mobile data services based on individuals should be raised to a high level based on social relationships. Fourth, services should be expanded to cooperate market by developing applications for enterprise purposes.

費率組合在電信業市場上行之有年，但長久以來，電信業一直以傳統的語音服務計費模式套用在所有的服務上，其中通話費的部分則是以通話時間作為計費的基礎，甚至連架構在語音服務上的數據傳輸也是如此。新引進的整合封包無線電服務(General Packet Radio Service, GPRS)在技術本質上與語音服務有很大的差異，因此計費方式也必須作一番變革，以傳輸量作為計費的基礎是較佳的選擇。 　由於GPRS屬於寬頻數據網路，再加上無線電資源的有限性，在傳輸品質上的要求也較高，GPRS在設計時就已經規劃了支援「服務品質(Quality of Service，QoS)」。因此，品質因素也應被列入計費的要項之一。 　本文嘗試提出一個GPRS的計費架構，並找出所有的計費因子，使未來經營GPRS的電信業者的行銷人員及計費系統設計人員有一個依循的準則。而在實例中也的確發現本文所提出的GPRS計費架構，可以應用在現實的計費系統上，提供各式各樣的費率組合。 / Pricing Package was used in telecommunications industry for many years. However, the operators always use the conventional voice service packages to cover the data services. The charge for every call is duration based but it cannot be applied for new introduced technology, e.g. GPRS. The technology of GPRS is quite different with the voice services; the charging model will be different as well. A volume-based charging model is an ideal way. 　GPRS is a broadband mobile data service. According to the limitation of wireless resources, the demand of quality of service is high. GPRS was designed to support QoS (Quality of Service) which can be considered as a charging factor. 　This material tried to propose a GPRS charging architecture and find out all of the charging factors. The marketing people and charging system designers of GPRS operators can create their own pricing packages based on this GPRS charging architecture. In the case study, we found that this GPRS charging architecture can be applied to the real world charging systems and provide kinds of pricing packages.