by Yip Chung Sun Danny. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 52-54). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Organization of Thesis --- p.5 / Chapter Chapter 2 --- Background --- p.6 / Chapter 2.1 --- Speech Codec --- p.6 / Chapter 2.2 --- RTP/UDP/IP Header Compression --- p.7 / Chapter 2.2.1 --- Real-Time Transport Protocol --- p.7 / Chapter 2.2.2 --- RTP/UDP/IP Header Compression --- p.8 / Chapter Chapter 3 --- Scenario and Assumptions --- p.10 / Chapter Chapter 4 --- Asynchronous Time Division Multiplexing Scheme --- p.14 / Chapter 4.1 --- Basic Idea --- p.14 / Chapter 4.1.1 --- Bandwidth Efficiency Improvement --- p.16 / Chapter 4.1.2 --- Delay Reduction --- p.18 / Chapter 4.2 --- Header Compression --- p.19 / Chapter 4.2.1 --- Header Compression Process --- p.21 / Chapter 4.2.2 --- Context Mapping Table --- p.23 / Chapter 4.3 --- Protocol --- p.28 / Chapter 4.3.1 --- UNCOMPRESSED_RTP Mini-Header --- p.30 / Chapter 4.3.2 --- SYNCHRONIZATION Mini-header --- p.31 / Chapter 4.3.3 --- COMPRESSED´ؤRTP Mini-header --- p.32 / Chapter 4.4 --- Connection Establishment --- p.33 / Chapter 4.4.1 --- Addressing Phase --- p.34 / Chapter 4.4.2 --- Connection Phase --- p.36 / Chapter 4.5 --- Software Implementation --- p.38 / Chapter Chapter 5 --- Simulation Results --- p.39 / Chapter 5.1 --- Simulation Model --- p.39 / Chapter 5.2 --- Voice Source Model --- p.41 / Chapter 5.3 --- Simulation Results --- p.43 / Chapter 5.3.1 --- Network Utilization and Delay Performance --- p.43 / Chapter 5.3.2 --- Number of Supported Connections --- p.45 / Chapter Chapter 6 --- Conclusion and Future Work --- p.49 / Bibliography --- p.52

Esta pesquisa reflete sobre o ambiente de mobilidade decorrente da popularização das tecnologias móveis, com redes sem fio, no contexto das Novas tecnologias de informação e comunicação (NTICS). O telefone celular, símbolo da mobilidade informacional-virtual na qual estamos inseridos, cria impactos em diferentes práticas sociais, ao trazer a promessa de permanente conexão a outras pessoas e informações, a qualquer momento e em qualquer lugar. As interações entre telefonia celular e mobilidade, consumo e comunicação são o objeto da pesquisa, que tem o objetivo de analisar o processo comunicacional que envolve a produção de sentido por parte das marcas das operadoras de telefonia celular e suas expressões publicitárias, por um lado, e a apropriação dos significados da mobilidade pelo consumidor e presentes visualmente no espaço público, por outro lado. Este processo é cada vez mais dialógico, numa dinâmica negociada entre as instâncias de produção e consumo, configurando um sistema complexo e integrado. Do ponto de vista da comunicação marcária, nosso recorte se concentra na análise das expressividades publicitárias que valorizam os benefícios da mobilidade, a partir de um roteiro analítico que utiliza a semiótica peirceana como fundamento. Em relação ao consumo, realizamos entrevistas em profundidade para investigar os impactos das tecnologias móveis para os indivíduos consumidores em seus processos identitários. Adicionalmente, exploramos a presença visual da mobilidade nos espaços e na cultura urbana, com a realização de trajetos fotoetnográficos. Esta dinâmica comunicacional e de consumo da telefonia móvel foi pesquisada de forma comparativa, avaliando semelhanças e especificidades a partir de contextos socioeconômicos diferentes, que representam igualmente distintos estágios na adoção da tecnologia móvel. Para isso, escolhemos três países (Angola, Brasil e Portugal) que representam estes estágios de adoção, embora partilhem de raízes históricas entrelaçadas, simbolizadas pela língua portuguesa. Pudemos concluir que embora a telefonia móvel traga uma série de significados que pareçam associados intrinsecamente a sua tecnologia, a manipulação ativa de consumidores e marcas criam diferentes relações de sentido de acordo com as características de cada localidade. Além disso, percebemos um processo de evolução nos signos associados à telefonia móvel de acordo com a evolução da popularização dos serviços. Finalmente, propomos a utilização das tríades da semiótica peirceana para propor um modelo de gestão evolutiva de marca, composto por um gradiente sígnico de acordo com o estágio de adoção da telefonia celular, correlacionando-o a cada país pesquisado. Pretendemos organizar os efeitos de uma naturalização da tecnologia que impacta gradativamente os significados da mobilidade, e demonstrar que estes são renovados e ressignificados por marcas e consumidores em alta velocidade, de forma semelhante ao que ocorre com o desenvolvimento das próprias tecnologias de informação e comunicação. / This research reflects on mobility environment due to the popularization of mobile technologies (wireless networks) in the context of New Information and Communication Technologies (NICT). The cell phone, symbol of informational-virtual mobility, has created impacts in different social practices, raising promise of permanent connection to other people and information, at anytime and anywhere. The interactions related to mobile telephony and mobility, consumption and communication are the object of this survey, which aims to analyze the communication process involving the production of sense by brands of cell phone operators and their advertising expressions, on the one hand, and the appropriation of meanings by mobility consumers and visually present in public places, on the other hand. This process has been increasingly dialogical, a dynamic negotiation involving the instances of production and consumption, setting up a complex, integrated system. From the point of view of brand communication, this study focuses on analysis of advertising expressiveness that values the benefits of mobility, based on peircean semiotics. In terms of consumption, we investigated the impacts of mobile technologies on consumers, conducting in-depth interviews. In addition, we explored the visual presence of mobility in urban areas, collecting photoetnographic data. This communicational and consumption dynamics of mobile telephony was investigated in a comparative form, assessing similarities and specificities from different socioeconomic contexts, which also represent distinct stages in adoption of mobile technology. For this reason, we chose three Portuguese speaking countries (Angola, Brazil and Portugal) representing these adoption stages, while sharing intertwined historical roots. We can conclude that although the mobile telephony has brought a series of meanings that might seem intrinsically associated to its technology, the active manipulation of consumers and brands may create relations of sense according to characteristics of each locality. Besides that, we noticed a process of evolution in signs related to mobile telephony according to the evolution of popularization of services. Finally, we propose the use of peircean semiotics triads to design a brand evolution model, composed by a signic gradient according to the stage of adoption of mobile telephony, correlating it to each surveyed country. Furthermore, we intend to organize the effects of a naturalization of the services offered by the operators that gradually impact the senses of mobility, and also to demonstrate that these senses are renovated and reinterpreted by brands and consumers at the same speed as it happens in the development of information and communication technologies.

Ho Ho-ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 104-107). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgment --- p.vi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Introduction to PBX based Call Center --- p.1 / Chapter 1.2. --- The Scenarios --- p.2 / Chapter 1.3. --- Thesis Overview --- p.5 / Chapter 2. --- Features of Collaborative Browsing --- p.8 / Chapter 2.1. --- Feature Synchronization vs Bitmap Screen Transfer --- p.8 / Chapter 2.2. --- Basic Collaborative Features of the Collaborative Browser --- p.9 / Chapter 2.2.1. --- Web Page Pushing --- p.10 / Chapter 2.2.2. --- Screen Widget Synchronization --- p.11 / Chapter 2.2.3. --- Tele-pointing and Shared Whiteboard --- p.12 / Chapter 2.3. --- Collaborative Form Manipulation --- p.13 / Chapter 2.3.1. --- Importance of Electronic Form Collaboration --- p.13 / Chapter 2.3.2. --- Basic Support for Form Collaboration ´ؤ´ؤData Synchronization --- p.14 / Chapter 2.3.3. --- Existence of Form Complexity ´ؤForm Data Dependency --- p.75 / Chapter 2.3.4. --- Hinting --- p.17 / Chapter 2.4. --- Collaborative IVR --- p.23 / Chapter 2.4.1. --- Traditional Interactive Voice Response (IVR) Service --- p.23 / Chapter 2.4.2. --- Abstraction ´ؤCorrelating Form Interaction Mechansim with IVR --- p.25 / Chapter 2.4.3 --- Collaborative IVR by Form Interaction Mechanism --- p.27 / Chapter 3. --- Software Architecture --- p.33 / Chapter 3.1. --- The Three-Tier Architecture --- p.33 / Chapter 3.2. --- The Collaboration Mechanism for Collaborative Browser --- p.37 / Chapter 3.2.1. --- Session Initialization/Termination --- p.37 / Chapter 3.2.2. --- Data Flow of the Basic Collaboration Features --- p.39 / Chapter 3.2.3. --- Control Mechanism --- p.40 / Chapter 3.2.4. --- The Hinting Mechanism for Collaborative Form Manipulation --- p.43 / Chapter 3.3. --- The Collaboration Mechanism for Collaborative IVR --- p.45 / Chapter 4. --- Implementation --- p.51 / Chapter 4.1. --- Shareable Document Object Architecture for Collaboration --- p.51 / Chapter 4.1.1. --- Document Object Architecture --- p.51 / Chapter 4.1.2. --- Generalizing to Shareable Document Object Architecture --- p.53 / Chapter 4.2. --- Whiteboard Mechanism --- p.55 / Chapter 4.3. --- Packet Data Unit for Communication --- p.57 / Chapter 4.4. --- Bridging Different Software Components --- p.60 / Chapter 4.5. --- Hinting Mechanism for Collaborative Form Manipulation --- p.63 / Chapter 4.5.1. --- Relating Form Fields to Table Fields --- p.63 / Chapter 4.5.2. --- Hinting by the Hinting Tables --- p.69 / Chapter 4.6. --- Collaborative IVR --- p.73 / Chapter 4.6.1. --- Using Mediator for Collaborative IVR --- p.73 / Chapter 4.6.2. --- Concept of Telephone Form --- p.74 / Chapter 4.6.3. --- Hinting for Collaborative IVR --- p.78 / Chapter 4.7. --- System Integration --- p.81 / Chapter 5. --- Performance Evaluation and Experiment Results --- p.84 / Chapter 5.1. --- Optimizing the Transmission Methodology --- p.84 / Chapter 5.2. --- Browser Responsiveness Study --- p.86 / Chapter 5.2.1. --- Experiment Details --- p.86 / Chapter 5.2.2. --- The Assumptions --- p.89 / Chapter 5.2.3. --- Experiment Results and Analysis --- p.90 / Chapter 5.3. --- Bandwidth Consumption --- p.94 / Chapter 6. --- Conclusions --- p.97 / Appendix A 一 Government Profit Tax Return Form --- p.101 / Appendix B ´ؤ A Phone Banking IVR Service Tree --- p.103 / Bibliography --- p.104

Universidade Federal do Cearà / Este trabalho apresenta a concepÃÃo, projeto e implementaÃÃo de um conversor CC/CC elevador para interligar um painel fotovoltaico a um banco de ultracapacitores para armazenamento de energia em substituiÃÃo Ãs baterias automotivas convencionais. Na saÃda dos ultracapacitores utiliza-se um conversor CC/CC abaixador, que fornece essa energia a um sistema de telecomunicaÃÃo para suprimento de um transceptor monocanal visando ao atendimento do serviÃo de telefonia rural/Internet em comunidades isoladas da rede pÃblica de energia. O sistema pode suprir o serviÃo de comunicaÃÃo para uma comunidade isolada da rede de energia elÃtrica por atà trÃs horas no perÃodo noturno, quando utilizado um equipamento rÃdio com cabos, conectores e antena para transmissÃo e recepÃÃo de sinal de telefonia com potÃncia de consumo de 13 W e com radiaÃÃo solar mÃdia de 5.500 W/m2/dia. Durante o dia, a energia solar à capturada por um painel fotovoltaico e armazenada em ultracapacitores atravÃs de um conversor boost. Este conversor possibilita a carga dos ultracapacitores no ponto de mÃxima potÃncia (MPP) do painel fotovoltaico. O transceptor à ativado quando se tira o fone do gancho e a alimentaÃÃo do sistema vem do painel via ultracapacitores. Caso haja ligaÃÃes durante o dia, o painel fotovoltaico supre as necessidades do equipamento transceptor. à noite, o painel utilizado nÃo gera energia suficiente para alimentar o sistema de telecomunicaÃÃo. No perÃodo noturno, caso ocorra uma chamada telefÃnica para o sistema proposto, o transceptor serà acionado, o assinante deverà retirar o monofone do gancho do aparelho telefÃnico para realizar o atendimento. Durante essa operaÃÃo o transceptor consome aproximadamente 13 W de potÃncia, que à fornecida pelos ultracapacitores, os quais estÃo interligados atravÃs do conversor buck. O sistema proposto à controlado por um microcontrolador e um circuito de controle, que procura o ponto de mÃxima potÃncia (MPP) do painel fotovoltaico, monitora o nÃvel da tensÃo dos ultracapacitores e determina o tempo de funcionamento do conversor CC/CC, que possibilita o fornecimento de energia para o transceptor pelos ultracapacitores. / This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.This work presents the conception, design and implementation of a DC/DC boost converter to connect a photovoltaic panel to a bank of ultracapacitors for energy storage to replace the conventional automotive batteries. In the output of ultracapacitors a DC/DC step-down converter is used. This converter provides power to a telecommunication system for the supply of a single channel transceiver with the purpose of providing the services of rural telephony and Internet in isolated communities from the public energy grid. The system can provide the communication service to a isolated community from the power grid for up to three hours at night when used with radio equipment with cables, connectors and antenna for transmitting and receiving phone signal with consumption power of 13 W and with solar radiation rate of 5.500 W/m2/day. During the day solar energy is captured by a photovoltaic panel and stored in ultracapacitors through a boost converter. This converter enables ultracapacitors to charge at the maximum power point (MPP) of the photovoltaic panel. The transceiver is activated when the phone is taken off the hook and the system power comes from the panel via ultracapacitors. If there are calls during the day, the photovoltaic panel meets the needs of the transceiver. At night, the panel used does not generate enough energy to power the telecommunication system. At night, if there is a phone call to the proposed system, the transceiver will be triggered, and the subscriber should take the handset off the hook to answer an incoming call. During this operation, the transceiver consumes approximately 13 W of power, which is provided by ultracapacitors that are interconnected through the buck converter. The proposed system is controlled by a microcontroller and a control circuit which tracks the maximum power point (MPP) of the photovoltaic panel, monitors the voltage level of ultracapacitors and determines the operating time of the DC/DC converter which enables the provision of power to the transceiver by the ultracapacitors.

Novas demandas por serviços de valor agregado têm surgido constantemente em sistemas de telefonia celular. Somente o tráfego de voz não tem sido mais suficiente para suprir as necessidades dos usuários, que hoje clamam também por serviços de dados que sejam rápidos, eficientes, baratos, com mobilidade e que atendam às mais diversas aplicações, como correio eletrônico, vídeo-conferência ou acesso à Internet. Este trabalho apresenta um método de determinação das taxas mínimas necessárias nos canais de tráfego para atender a essas aplicações. Utilizando-se da tecnologia CDMA2000, será feita uma análise do impacto na interface aérea da alocação dos canais de tráfego determinados. A mesma análise será feita nos casos em que se determinem taxas mínimas e/ou máximas alocadas para cada usuário, comparando-se também tempo necessário para a transmissão dos dados, eficiência na célula (taxa útil / taxa total transmitida), etc. As conclusões deste trabalho podem indicar estratégias para se atender aos usuários de serviços de dados em redes de telefonia móvel sob diferentes aspectos, como melhor relação custo-benefício, nichos específicos (concentrar-se em serviços que demandem maiores ou menores taxas de transmissão, por exemplo) ou até mesmo prever a quantidade de recursos de rede necessária para atender a uma determinada base de usuários. / Mobile telephony systems have been constantly asked for new demands of value added services. Voice traffic only is not enough anymore to support the new needs of mobile users because nowadays they ask for fast, cost-efficient, cheap and mobile services to support electronic mail, videoconference or Internet access. This work presents a method of how to determine minimum rates on traffic channels to support these services. Considering CDMA2000 technology, an impact analysis will be made in the air interface for these specific traffic channels. Same analysis will be made when minimum or maximum rates are reserved for each user, also comparing the time needed for data transmission, efficiency of the cell (useful rate / maximum rate) and others. The conclusions of this work may allow strategies to support data users in mobile telephony networks in such different ways, as better cost-effective solution, specific segment of the market (i.e., to concentrate in services with higher or lower transmission rates) or even to foresee the amount of resources needed in a network to support a forecasted number of users.

Neste trabalho, uma versão de RBM (Restricted Boltzmann Machine) tendo uma camada de classificação é adaptada a fim de permitir o seu uso com dados definidos num domínio contínuo. Essa adaptação dá origem a uma variante do modelo para o qual são desenvolvidas as regras de atualização de parâmetros dos treinamentos discriminativo, generativo e híbrido. A aplicação da variante como classificador no problema de VAD (Voice Activity Detection) é então investigada. Por meio de simulações envolvendo o corpus NOIZEUS e empregando como entradas do classificador tanto MFCCs (Mel-Frequency Cepstral Coefficients) quanto FBEs (Filter-Bank Energies), são obtidos resultados comparáveis aos de detectores considerados como estado da arte, com um menor custo computacional. A variante de RBM é comparada também com as SVMs (Support Vector Machines) lineares e com núcleo gaussiano. Com treinamento discriminativo, a RBM fornece desempenhos intermediários entre as duas versões de SVM, porém um custo computacional que é consideravelmente inferior aos de ambas. Adicionalmente, um conjunto de medidas do áudio que tiveram seu uso em VAD proposto recentemente são avaliadas com o emprego da RBM com treinamento discriminativo. Embora os resultados não sejam conclusivos, os desempenhos conseguidos indicam que essas medidas não são vantajosas quando comparadas com os tradicionais MFCCs. / In this work, a type of Restricted Boltzmann Machine (RBM) having a classification layer is adapted to allow its use with data defined in a continuous domain. Such adaptation gives rise to a variant of the model for which the parameter update rules are developed for the discriminative, generative and hybrid types of training. The application of the variant as a classifier to the Voice Activity Detection (VAD) problem is then investigated. By means of simulations involving the corpus NOIZEUS and employing Mel-Frequency Cepstral Coefficients (MFCCs) or Filter-Bank Energies (FBEs) as classifier inputs, results comparable to those of state-of-the-art detectors are achieved with a lower computational cost. The RBM variant is also compared to the linear and Gaussian kernel Support Vector Machines (SVMs). With the discriminative training, the RBM provides intermediate performances between the two SVM types, but a computational cost that is considerably lower than theirs. Additionally, a set of measures from the audio whose application in VAD has been recently proposed are evaluated by employing the RBM with discriminative training. Although the results are not conclusive, the performances obtained indicate that the measures are not advantageous when compared to the traditional MFCCs.

Made available in DSpace on 2016-04-28T20:19:12Z (GMT). No. of bitstreams: 1 2006-Helio Fernandez Figueira Filho.pdf: 1336727 bytes, checksum: 07d2e7bb6b7ffbda72fcc7a373a13c14 (MD5) Previous issue date: 2006-08-24 / This dissertation deals with the dynamic environment regarding the Brazilian residential telephone service established since its privatization, in 1997. The territorial division made by players with distinct strategies, all followed by a strict federal law, and the existence of a regulation organ for telecom services (ANATEL) contributed for the continuous expansion suffered by the sector between 1997 and 2003. At the same time, the mobile telephone industry revealed its competitive side, willing to increase its participation in this newborn market share. Considering this context, we search and present the theoretical and practical concepts for companies that offer residential telephone services so they can use them to create marketing strategies in order to defend themselves from the mobile telephone service threat and assure its sustentability as well. By using marketing concepts, wich allows the correct interaction between companies and the market, we add the possibility of using a statistic tool, specifically the linear regression type, that can point out the influence degree on different customers by the current and future demand for residential phone services. This right perception, even before the strategy itself, is fundamental condition for the future decision making regarding this sector of services. By analyzing the telephone market, a line is drawn between the present time, solid but with no further growth perspectives, and the future, that hides threats and opportunities in several segments, obliging companies to constantly study the customer s behave, each day more demanding, but still undefined. The segmentation concept, acquired by the analysis of the variables available that presented influence in the volume of residential phones in use, demonstrates the importance of the social classes and customer companies in the agreement and demand of the services offered. From this facts, the work has its closure by concluding that, if there is any group of consumers that demonstrates its force by the numbers of telephone lines in use, there is another one that is more vulnerable to the cancellation of the existing lines. / Esta disserta??o apresenta a forte din?mica apresentada pelo setor de telefonia fixa no mercado brasileiro a partir de sua privatiza??o, em 1997. A divis?o do territ?rio brasileiro entre empresas com estrat?gias distintas e tendo como ponto comum uma forte legisla??o federal, acompanhada de um ?rg?o regulador (ANATEL), fomentou este crescimento at? 2003. No mesmo per?odo a telefonia m?vel mostrou-se competitiva e capaz de disputar este mercado ainda em forma??o. Partindo deste contexto, s?o pesquisados e apresentados os subs?dios te?ricos necess?rios ?s empresas concession?rias de telefonia fixa para que, atrav?s do entendimento do cen?rio atual, possam ser criadas estrat?gias que garantam sua sustentabilidade frente ? amea?a da telefonia m?vel. Aos conceitos de marketing, que possibilitam o correto encadeamento de etapas de an?lise da intera??o empresa/mercado, soma-se a possibilidade de uso de ferramenta estat?stica, mais exatamente a regress?o linear, capaz de utilizar segmentos de mercado na pondera??o da influ?ncia de grupos distintos de consumidores na demanda atual e futura de acessos fixos. Esta percep??o correta, antes mesmo da defini??o da estrat?gia, ? condi??o sine qua non para a tomada de decis?o sobre o futuro deste setor da economia. Faz-se assim uma caminhada entre o presente, que se mostra forte por?m sem grandes perspectivas de crescimento, e o futuro, que esconde amea?as e oportunidades em diferentes segmentos, exigindo das organiza??es modelos distintos de acompanhamento de um mercado consumidor heterog?neo e exigente, por?m ainda n?o definido. A segmenta??o, obtida pela an?lise das vari?veis dispon?veis que apresentaram influ?ncia no volume de acessos fixos em uso, demonstra a import?ncia das classes sociais e das empresas consumidoras no entendimento e na demanda dos servi?os oferecidos. A partir desta constata??o, o trabalho se conclui com a avalia??o de que, se existe um grupo de consumidores que demonstra sua for?a pela quantidade de linhas em uso, existe outro que se apresenta mais vulner?vel ao cancelamento das linhas existentes.

[pt] A competição no setor de telefonia celular tem apresentado forte acirramento nos últimos anos, levando a uma tendência de queda no faturamento médio por usuário nas empresas. Os serviços de valor adicionado vêm cumprindo importante papel no esforço de aumento do faturamento das empresas com seus clientes. A mídia tem sido adotada por executivos do setor como instrumento de marketing para promover o uso de alguns serviços e, conseqüentemente, melhorar o faturamento médio por usuário. Neste contexto, o presente estudo tenta avaliar a relevância da mídia para o desempenho dos serviços de valor adicionado. Para tal, foram realizadas análises estatísticas no esforço de identificar a correlação entre volume de mídia e o tráfego de um determinado serviço de valor adicionado. Recorre-se a uma revisão bibliográfica de disciplinas de marketing de serviços, mídia e estatística aplicada. Também é conduzido um estudo de caso do serviço visando um melhor entendimento do contexto de negócios em que o mesmo está inserido, pois entende-se como fundamental para uma resposta mais consistente ao problema da pesquisa. Os resultados apontam para a relevância da mídia e também para outros aspectos importantes para o desempenho do serviço, tais como as características de uso do produto e o modelo comercial adotado entre os provedores do serviço e a empresa de mídia. / [en] The competition in the telephony sector has become harder in the last years, leading to a decrease in the average revenue per user of the companies. The value added services have been developing an important role in the effort of revenue increase by the companies with its users. Media has been adopted as a marketing tool by its executives to promote the usage of some services and, consequently, improve the average revenue per user. In this scenario, this study evaluates the media relevance to the performance of value added services. To conclude that, some statistical analysis were conducted in the effort to identify correlation between media volume and traffic of some value added services. A bibliographic revision was made in disciplines of marketing services, media and applied statistics. A case study was conducted aiming a better understanding of the service´s business context, as it is fundamental to a more consistent answer of the research problem. The results present the relevance of media and other aspects that are also important to the service performance, such as the products use characteristics and the business model adopted among the service providers and the media company.

The IP Multimedia Subsystem (IMS) is the technology that will merge the Internet (packet switching) with the cellular world (circuit switching). It will make Internet technologies, such as the web, email, instant messaging, presence, and videoconferencing available nearly everywhere. Presence is one of the basic services that is likely to become omnipresent in IMS. It is the service that allows a user to be informed about the reachability, availability, and willingness of communication of another user. Push to talk over Cellular (PoC) is another service in IMS that is intended to provide rapid communications for business and consumer customers of mobile networks. In order to become a truly successful mass-market service for the consumer segment, the only realistic alternative is a standardized Push-to-talk solution providing full interoperability between terminals and operators. Instant Messaging (IM) is the service that allows an IMS user to send some content to another user in near real-time. This service works under IETF’s Message Session Relay protocol (MSRP) to overcome the congestion control problem. We believe the efficiency of these services along with the mobility management in IMS session establishment has not been sufficiently investigated.In this research work, we identify the key issues to improve the existing protocols in IMS for better system behaviour. The work is centred on the three services of IMS: (1) Presence Service, (2) Push-to-Talk over cellular and, (3) Instant Messaging and over the issue of (4) IMS session set up. The existing session establishment scenario of IP Multimedia Subsystem (IMS) suffers from triangular routing for a certain period of time when an end IMS user or terminal is mobile. In this thesis, the performance of three possible session establishment scenarios in a mobile environment is compared by using an analytical model. The model is developed based on the expressions of cost functions, which represents system delay and overhead involved in sessions’ establishment. The other problem areas in optimizing presence service, dimensioning a PoC service and analysing service rates of IM relay extensions in IMS are identified. A presence server becomes overloaded when massive number of IMS terminals joins a network to request presence facility. Performance models are developed in this research to mitigate such load during heavy traffic for the presence service. Queuing analyses for different cases are provided while instant messaging chunks go through two consecutive relay nodes. The specific factors such as blocking probability, stability conditions, optimized subscription lifetime etc. in IMS environment parameters have been investigated. We have also elaborated models to dimension a PoC service for service providers with regards to controlling PoC session access, optimal PoC session timer, path optimization and number of allowable simultaneous PoC sessions for given network grade of service.In a nutshell, the contribution of this dissertation are: (a) a proposed robust scheduler to improve performance of the IMS presence service, (b) several derived models to dimension IMS Push-to-talk over cellular service, (c) a new mechanism to reduce cost for the IMS session set ups in mobile environment and (d) evaluation of message blocking and stability in IMS Instant Messaging (IM) service by applying queuing theories. All of these analyses have resulted in recommendations for the performance enhancements with optimal resource utilization in IMS framework.

<p>In today's world, more and more phone calls are made over IP. This results in an increasing demand for scalable IP telephony equipment.</p><p>Ingate Systems AB produces firewalls specialized in handling IP telephony. They have an inherent limit in the number of concurrent phone calls that they can handle. This can be a bottleneck at high loads. There is a load balancing solution available in the platform, but it has a number of drawbacks, such as media latency and client capability requirements, limiting its usage.</p><p>Many companies provide load balancing solutions for SIP. However, it appears few handle all the problematic scenarios that the Ingate firewall does. This master's thesis aims to add load balancing functionality to the Ingate firewall, so that it can handle all types of clients.</p><p>By splitting the firewall into two completely separate layers - a SIP layer and a firewall layer - the concept of a virtual machine emerges. A machine is no longer restricted to its physical SIP and firewall layers. Instead, virtual machines are used to process calls. They still have SIP and firewall layers, but the layers can reside on different physical machines.</p><p>This thesis demonstrates the operation of an innovative load balancing implementation. The implementation was evaluated, and using four machines the test setup performed 50% better than the original Ingate platform, while still retaining all functionality -- something that was not possible with the original platform. This surpassed both the company's and my own expectations.</p>