<p>It is very probable that VoIP will soon replace the ordinary telephone. Beside all advantages of the digital voice-connection it is linked to the danger of spam on the telephone. A lot of approaches have been developed to solve the problem of VoIP spam. Because some of these solutions are based on access to personal information of its users, a broad discussion about the best and most ethical approach has started.</p><p>This thesis analyzes the users’ point of view towards the VoIP spam problem and the extent of users’ willingness to offer private information in order to avoid VoIP spam. It presents results from a qualitative and a quantitative research as well as approaches for a most realistic- and most promising VoIP solution. These new approaches are based on the results of the research.</p><p>The main points of the results showed that users were not willing to offer private information to companies and that they were not willing to pay any amount of money for VoIP spam solutions. Users held governmental organisations and telephone operators responsible for finding a solution against VoIP spam.</p>

It is very probable that VoIP will soon replace the ordinary telephone. Beside all advantages of the digital voice-connection it is linked to the danger of spam on the telephone. A lot of approaches have been developed to solve the problem of VoIP spam. Because some of these solutions are based on access to personal information of its users, a broad discussion about the best and most ethical approach has started. This thesis analyzes the users’ point of view towards the VoIP spam problem and the extent of users’ willingness to offer private information in order to avoid VoIP spam. It presents results from a qualitative and a quantitative research as well as approaches for a most realistic- and most promising VoIP solution. These new approaches are based on the results of the research. The main points of the results showed that users were not willing to offer private information to companies and that they were not willing to pay any amount of money for VoIP spam solutions. Users held governmental organisations and telephone operators responsible for finding a solution against VoIP spam.

Thesis (M. Tech.) - Central University of Technology, Free State, 2008

Thesis (MScEng)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The perceived quality of Voice over Internet Protocol (IP) (VoIP) communication relies on the network which is used to transport voice packets between the end points. Variable network characteristics such as bandwidth, delay and loss are critical for real-time voice traffic and are not always guaranteed by networks. It is important for network service providers to determine the Quality of Service (QoS) it provides to its customers. The solution proposed here is to predict the perceived quality of a VoIP call, in real-time by using network statistics. The main objective of this thesis is to develop a network analysis tool, which gathers meaningful statistics from network traffic. These statistics will then be used for predicting the perceived quality of a VoIP call. This study includes the investigation and deployment of two main components. Firstly, to determine call quality, it is necessary to extract the voice streams from captured network traffic. The extracted sound files can then be analysed by various VoIP quality models to determine the perceived quality of a VoIP call. The second component is the analysis of network characteristics. Loss, delay and jitter are all known to influence perceived call quality. These characteristics are, therefore, determined from the captured network traffic and compared with the call quality. Using the statistics obtained by the repeated comparison of the call quality and network characteristics, a network specific algorithm is generated. This Non-Intrusive Quality Prediction Algorithm (NIQPA) uses basic characteristics such as time of day, delay, loss and jitter to predict the quality of a real-time VoIP call quickly in a non-intrusive way. The realised algorithm for each network will differ, because every network is different. Prediction results can then be used to adapt either the network (more bandwidth, packet prioritising) or the voice stream (error correction, change VoIP codecs) to assure QoS. / AFRIKAANSE OPSOMMING: Die kwaliteit van spraak oor die internet (VoIP) kommunikasie is afhanklik van die netwerk wat gebruik word om spraakpakkies te vervoer tussen die eindpunte. Netwerk eienskappe soos bandwydte, vertraging en verlies is krities vir intydse spraakverkeer en kan nie altyd gewaarborg word deur netwerkverskaffers nie. Dit is belangrik vir die netwerk diensverskaffers om die vereiste gehalte van diens (QoS) te verskaf aan hul kliënte. Die oplossing wat hier voorgestel word is om die kwaliteit van ’n VoIP oproep intyds te voorspel, deur middel van die netwerkstatistieke. Die belangrikste doel van hierdie projek is om ’n netwerk analise-instrument te ontwikkel. Die instrument versamel betekenisvolle statistiek deur van netwerkverkeer gebruik te maak. Hierdie statistiek sal dan gebruik word om te voorspel wat die gehalte van ’n VoIP oproep sal wees vir sekere netwerk toestande. Hierdie studie berus op die ondersoek en implementering van twee belangrike komponente. In die eerste plek, moet oproep kwaliteit bepaal word. Spraakstrome word uit die netwerkverkeer onttrek. Die onttrekte klanklêers kan dan geanaliseer word deur verskeie spraak kwaliteitmodelle om die kwaliteitdegradasie van ’n spesifieke VoIP oproep vas te stel. Die tweede komponent is die analise van netwerkeienskappe. Pakkieverlies, pakkievertraging en bibbereffek is bekend vir hul invloed op VoIP kwaliteit en is waargeneem. Hierdie netwerk eienskappe word dus bepaal uit die netwerkverkeer en daarna vergelyk met die gemete gesprekskwaliteit. Statistiek word verkry deur die herhaalde vergelyking van gesprekkwaliteit en netwerk eienskappe. Uit die statistiek kan ’n algoritme (vir die spesifieke network) gegenereer word om spraakkwaliteit te voorspel. Hierdie Nie-Indringende Kwaliteit Voorspellings-algoritme (NIKVA), gebruik basiese kenmerke, soos die tyd van die dag, pakkie vertraging, pakkie verlies en bibbereffek om die kwaliteit van ’n huidige VoIP oproep te voorspel. Hierdie metode is vinnig, in ’n nie-indringende manier. Die gerealiseerde algoritme vir die verskillende netwerke sal verskil, want elke netwerk is anders. Die voorspelling van spraakgehalte kan dan gebruik word om òf die netwerk aan te pas (meer bandwydte, pakkie prioriteit) òf die spraakstroom aan te pas (foutkorreksie, verander VoIP kodering) om die goeie kwaliteit van ’n VoIP oproep te verseker.

Approved for public release, distribution is unlimited / Converging voice and data networks has the potential to save money and is the main reason Voice over Internet Protocol (VoIP) is quickly becoming mainstream in corporate America. The potential VoIP offers to more efficiently utilize the limited connectivity available to ships at sea makes it an attractive option for the Navy. This thesis investigates the usefulness of VoIP for the communications needs of a unit level ship. This investigation begins with a review of what VoIP is and then examines the ship to shore connectivity for a typical unit level ship. An OMNeT++ model was developed and used to examine the issues that affect implementing VoIP over this type of link and the results are presented. / Lieutenant Commander, United States Navy

Les services de téléphonie IP automatisent le traitement des stimuli de communication en utilisant des ressources réseaux. Cependant, l'ajout de services rend vulnérable le système de téléphonie car certaines propriétés de fonctionnement des services déployés ne sont pas garanties. Aucune solution de développement de services ne permet de simultanément garantir des propriétés de fonctionnement et d'exploiter des ressources réseaux. Cette thèse propose une approche fondée sur le concept des langages dédiés pour développer des services de communications. Deux nouveaux langages dédiés au domaine des communications ont été développés : SPL et Pantaxou. Le premier sert à router des messages de signalisation tandis que le second, plus généraliste, permet la coordination d'entités communicantes. Dans cette thèse, nous démontrons, grâce à SPL et Pantaxou, que les services de communications peuvent être développés avec un langage de programmation expressif tout en préservant des propriétés critiques du domaine. / IP telephony services use network resources to automate communication stimuli processing. However, deploying services on a telephony system leads to safety issues and programmers need to ensure some safety properties on their services. Several approaches allowing service development have quickly emerged. However, none of them is both expressive and safe. This thesis proposes a new approach that relies on domain-specific languages (DSL) to develop communication services. Two new DSLs have been designed for communication services, namely SPL (Session Processing Language) and Pantaxou. The first one allows to route signaling messages while the second one, more generalist, enables to define coordination logics of communicating entities. In this thesis, we demonstrate thanks to SPL and Pantaxou that communication services could be developed with an expressive programming language that preserves some critical domain properties.

Avec la multiplication des antennes radios, due à l’augmentation des abonnés et aux nouveaux services et usages, l’exposition aux ondes électromagnétiques est devenue un sujet interpellant toute une catégorie de personnes, notamment les collectivités locales, les opérateurs, les associations, etc. Dans le domaine de l’exposition des populations aux champs électromagnétiques radiofréquences en milieu urbain, la modélisation numérique a pris depuis quelques années de plus en plus d’importance du fait de la montée en puissance des outils de calcul et de la quantité et qualité des données topographiques disponibles. Elle est utilisée conjointement avec plusieurs types de mesures pour l’analyse et la gestion de risques, comme support d’aide à la décision publique, comme méthode réglementaire et plus largement pour la concertation entre public, industriels, collectivités territoriales, associations, etc. Les résultats de ces méthodes ont donc de plus en plus d’importance. Ce manuscrit permet d'améliorer les connaissances sur la quantification de l'exposition due aux antennes relais en associant mesures et simulations et en prenant en considération la notion de variabilité du champ électrique.Une première partie du travail a permis de déterminer les avantages et les limites des méthodes de calcul, et de même pour les mesures, dans le cadre de l'évaluation de l'exposition à l'échelle urbain. Une seconde partie du travail a consisté à caractériser la variabilité spatiale et temporelle de l'exposition réelle, un point essentiel du fait de la grande variabilité du champ électrique et de la difficulté de trouver un indicateur pertinent pour quantifier l'exposition réelle. / With the increasing number of mobile phone users, new services and mobile applications, the proliferation of radio antennas has raised concerns about human exposure to electromagnetic waves. This is now a challenging topic to many stakeholders such as local authorities, mobile phone operators, citizen and consumer groups, etc. The assessment of human exposure to radiofrequency electromagnetic fields in the urban environment is mainly based on numerical modeling. The improvement of computational tools together with the quantity and quality of available topographic data has strongly promoted this approach. Numerical modeling is now used in combination with several types of measurements to perform risk analysis and management. It is the basis of decision-making tools and local regulations. It is also used during consultations between the public, the industry, local authorities, governments and associations. The results of these methods are therefore increasingly important. This research contributes to gain knowledge about quantifying the human exposure from base stations through the combination of measurements and simulations, while taking into account the concept of variability of the electrical field. A first part of this work establishes the benefits and limitations of computational methods as well as measurements when assessing exposure to electric fields in urban environment. A second part of this work is aimed at characterizing the spatial and temporal variability of the actual exposure, which is a very important requirement because of the high variability of the electrical field and the difficulty of finding a relevant indicator to quantify the real exposure.

As Tecnologias da Informação Móveis e Sem Fio (TIMS) têm sido cada vez mais aplicadas aos processos organizacionais. É importante tentar compreender as formas pelas quais as pessoas e organizações constroem um sentido a respeito dessas tecnologias e como elas as integram em seu trabalho diário. Desta forma, aplicando a Teoria da Hospitalidade proposta por Ciborra (1996, 1999, 2002), este trabalho procura verificar como ocorre o processo de adoção dessas tecnologias no contexto organizacional. A Teoria da Hospitalidade se apresenta como uma alternativa a modelos mais tradicionais para estudo da adoção de TIC (Tecnologias da Informação e Comunicação), considerando elementos sociais, comportamentais e existenciais envolvidos nesse processo, oferecendo uma visão crítica e dialética a respeito dele. Primeiramente, o trabalho explora a literatura existente sobre a natureza e as implicações das TIMS, especialmente para o contexto organizacional. Na seqüência, são analisados os principais modelos teóricos dedicados à compreensão do processo de adoção de TIC, discutindo-se suas principais contribuições e limitações. Com base nisso, a Teoria da Hospitalidade é estudada como um referencial alternativo aos modelos existentes, explorando-se a sua base teórica (filosófica e metodológica) visando a contribuir para o seu detalhamento e compreensão. Na seqüência, essa teoria é aplicada à análise de um caso prático de utilização de TIMS. Para isso, utilizou-se o método do Estudo de Caso único em um banco privado brasileiro. A aplicação pesquisada foi o uso de um telefone inteligente (aparelho que agrega as funcionalidades de um PDA (Personal Digital Assistant – Assistente Digital Pessoal e telefone celular) para o acesso a sistemas de informações organizacionais por Gerentes de Conta e Supervisores Comerciais para o atendimento a clientes empresariais em campo. Os resultados da pesquisa demonstram desafios e dificuldades enfrentadas durante o processo de adoção dessa tecnologia, bem como algumas das principais decorrências (tanto positivas quanto negativas) de sua utilização. Verificou-se que a motivação para adotar a TIMS não se limitou a razões somente econômicas, de redução de custos ou de busca de eficiência, mas também foi fortemente influenciada por questões sociais e teve um foco estratégico, visando ao reforço da imagem da empresa e à melhoria do controle organizacional. O processo de desenvolvimento da solução móvel não seguiu passos lineares e claros, mas ao invés disso foi incremental; os objetivos de uso da nova tecnologia foram sendo descobertos na medida que ela foi aplicada no trabalho do dia-a-dia. Nesse processo, a tecnologia impôs seus padrões, configurações e limitações sobre os usuários, assim como os usuários se engajaram em ações para lidar com isso, procurando descobrir como utilizá-la para os seus próprios propósitos e benefícios. Os usuários interagiram com a tecnologia, avaliando-a e procurando criar sentido em torno dela, à sua própria maneira, uma vez que ela se tratava de um dispositivo de uso pessoal. Emoções e questões existenciais também se fizeram presentes nessa interação e influenciaram a forma pela qual a tecnologia foi aceita. Devido a essa dinâmica e complexa interação houve diferentes níveis de adoção (hospitalidade) e conseqüências inesperadas do uso da tecnologia. A Teoria da Hospitalidade iluminou o estudo da adoção de TIMS na organização pesquisada. Os principais elementos indicados por essa teoria foram encontrados no caso estudado: o processo de adoção de uma nova TIC é um processo incremental e aberto, no qual questões sociais, existenciais e “mundanas" exercem um papel essencial. Com isso, foi possível corroborar as principais proposições da teoria analisada em relação aos demais modelos existentes, bem como identificar algumas de suas limitações. Os resultados apresentados provêm insights sobre o processo de adoção das TIMS que podem ser úteis não só para empresas adotantes, mas também para fornecedores de soluções, assim como para consultores e outros pesquisadores da área de Sistemas de Informação. / The Mobile and Wireless Information Technologies (MWIT) have increasingly been applied to organizational processes. It is important to understand the ways by which both people and organizations make sense of them and integrate these technologies in their daily work. Thus, by applying the Theory of Hospitality proposed by Ciborra (1996, 1999, 2002), this work aims to verify how does the adoption process of these technologies occur in the organizational context. The Theory of Hospitality represents an alternative to traditional models to study ICT (Information and Communication Technology) adoption, considering social, behavioral and existential elements related to this process and offering a critical and dialectical view about it. Firstly, this work explores the literature about the nature and implications of MWIT, especially to the organizational context. After that, main theoretical models about the process of ICT adoption are analyzed, with a discussion about their main contributions and limitations. Based on that, the Theory of Hospitality is studied as an alternative reference to the existing models, through the exploration of its theoretical (philosophical and methodological) basis, attempting to contribute to its depiction and understanding. In the sequence, this theory is applied to the analysis of a case of practical MWIT use. To accomplish this task, a single Case Study method was applied in a private Brazilian bank. The application studied was the use of a smart phone (device which aggregates the functionalities of a PDA - Personal Digital Assistant and a mobile phone) to access organizational information systems by Account Managers and Commercial Supervisors attending corporate clients in field work. The research results show the difficulties and challenges faced during the process of adoption of this technology, as well as some of its main (positive and negative) consequences. It was possible to verify that the motivation to adopt the MWIT has not followed just economic reasons, cost reduction or the search for efficiency, but it was also strongly influenced by social issues with a strategic focus to reinforce the company’s image and to improve organizational control. The process of development of the mobile solution has not followed linear and clear steps, but instead it was an incremental one, the goals of the new technology use were discovered in the extent that the technology was used in everyday work. In this process, the technology has imposed its standards, configurations and limitations over the users as well as the users have engaged in actions to cope with it, trying to find out how to use the technology for their own purposes and benefit. Users have interacted with the technology, evaluated it and attempted to make sense of it in their own way, since it is a personal device. Emotions and existential issues came along in this interaction and have influenced the way technology was accepted. Due to this dynamic and complex interaction there were different levels of adoption (hospitality) and unexpected consequences of technology use. The Theory of hospitality has illuminated the study of MWIT adoption in the organization. The main features of this theory have been found in the case studied: the adoption of a new ICT is an incremental and open process in which social, existential, “mundane" issues play a major role. Considering these results, it was possible to corroborate the main contributions pointed by the analyzed theory, if compared to the others existing models, as well as to identify some of its limitations. The results offer insights about the process of WMIT adoption that can be useful not only to adopting organizations, but also to solution providers, as well as to consultants and other researchers in the Information Systems area.

A agricultura de precisão (AP) é um das grandes responsáveis pela inserção de tecnologias cada vez mais avançadas dentro dos sistemas de produção agrícola. Um equipamento que já faz parte da AP é o computador de mão (Personal Digital Assistant, PDA). Porém com a evolução crescente dos dispositivos móveis tais como smartphones e tablets, os PDAs têm se tornado uma alternativa mais obsoleta do ponto de vista tecnológico. São várias as características que tornam smartphones e tablets dispositivos móveis mais atraentes tecnologicamente. A comunicação direta destes com sistemas de posicionamento via satélite foi o primeiro passo para torna-los válidos para o uso em AP. Além disso, dentre as tecnologias de computação, a computação móvel é a que tem mais aceitação pelos usuários do meio agrícola devido à gradativa inserção mercadológica que os telefones celulares exerceram durante os anos passados em todo o mundo. Com a ideia de criar uma nova ferramenta para a AP baseando-se no reconhecimento de voz para substituir e/ou minimizar o uso das telas sensíveis ao toque e planilhas no campo foi escolhido o sistema operacional Android para o desenvolvimento desse aplicativo. O projeto se baseou inicialmente em revisão bibliográfica de estudos de aplicativos móveis desenvolvidos para a AP e por acompanhamento em campo de procedimentos de coleta de dados. O aplicativo resultante desse desenvolvimento se baseou em três partes: configurações, coleta de dados por voz e mapas. Na parte de configurações é permitido ao usuário configurar opções como: variáveis de coleta, uso do GPS (Global Positioning System), uso do reconhecimento de voz, pasta de armazenamento e informações cadastrais. Na coleta de dados por voz o usuário tem um formulário com as variáveis configuradas, que é preenchido por reconhecimento de voz, automaticamente. Os mapas utilizados para auxiliar o usuário a se orientar pelo campo são criados a partir do sistema Google Maps®. É possível também habilitar um assistente de voz que fala ao usuário, por sintetização de voz, o nome da variável que está coletando e confirma para ele o valor que foi reconhecido a partir de sua voz. Um arquivo \'txt\' é criado a partir das informações do formulário contendo também as coordenadas geográficas de cada ponto de coleta, obtidas pelo sistema integrado de GPS do dispositivo, e esse arquivo pode ser utilizado para a entrada de dados em sistemas de informação geográfica (SIG) para a criação de mapas posteriormente. / Precision agriculture (PA) is one of the major responsible for the insertion of increasingly advanced technologies within agricultural production systems. Equipment that is already part of precision agriculture is the handheld computer (PDA). But with the growing trend of mobile devices such as smartphones and tablets, PDAs have become a more obsolete option in the technological context. There are several characteristics that make these devices technologically more attractive. Direct communication of such devices with satellite positioning systems was the first step to make them applicable for use in PA. Moreover, among the computing technologies, mobile computing has more acceptance by users of agricultural marketing due to the gradual insertion that mobile phones have had over the past years worldwide. With the idea of creating a new tool for PA based on the speech recognition to replace and/or minimize the use of touchscreen and worksheets in the field, Android was chosen as the operating system for the development of this application. The design was based initially on studies of mobile applications developed for PA through published articles or through monitoring procedures in field data collection. The application resulting from this development is based on three parts: settings, speech data collection and maps. Part of settings allows the user to set some options for operation of the application as: variables to collect, use of GPS, use of speech recognition, file storage folder to \'txt\' file and registration information, etc. In the data collection the user configures the variables he wants to collect and the application creates a form that is filled through speech recognition automatically. The map is used to help the user navigate the route through the use of Google Maps® base. It is possible to enable a voice assistant that tells him, by voice synthesizer, the name of the variable he is collecting and confirms to him the value that has been recognized by his voice. A \'txt\' file is created containing data along with geographic coordinates obtained from the onboard GPS of the device and it can be used for creating maps in geographic information systems (GIS).

O projeto VoIPFix surgiu da necessidade de uma ferramenta que complementasse as demais existentes no ramo de análise de redes de computadores para telefonia IP. Ele foi construído para ser uma ferramenta de gerenciamento eficiente e exclusiva para VoIP, com funcionalidades necessárias para dar suporte ao profissional de rede de computadores e telefonia IP a observar e diagnosticar problemas de VoIP. / The VoIPFix project arose from the need for a tool to complement similar tools in the analysis of computer networks for IP telephony. It was built to be an efficient and unique management tool for VoIP, with advanced features required to support the computer network and IP telephony professionals to observe and diagnose problems related to VoIP.