Les récentes avancées technologiques permettent désormais la fabrication de terminaux mobiles de plus en plus compacts et dotés de plusieurs interfaces réseaux. Le nouveau modèle de consommation de médias se résume par le concept "Anytime, Anywhere, Any Device" et impose donc de nouvelles exigences en termes de déploiement de services ubiquitaires. Cependant la conception et le developpement de réseaux ubiquitaires et convergents de nouvelles générations soulèvent un certain nombre de défis techniques. Les standards actuels ainsi que les solutions commerciales pourraient être affectés par le manque de considération du contexte utilisateur. Le ressenti de l'utilisateur concernant certains services multimédia tels que la VoIP et l'IPTV dépend fortement des capacités du terminal et des conditions du réseau d'accès. Cela incite les réseaux de nouvelles générations à fournir des services ubiquitaires adaptés à l'environnement de l'utilisateur optimisant par la même occasion ses resources. L'IP Multimedia Subsystem (IMS) est une architecture de nouvelle génération qui centralise l'accès aux services et permet la convergence des réseaux fixe/mobile. Néanmoins, l'évolution de l'IMS est nécessaire sur les points suivants :- l'introduction de la sensibilité au contexte utilisateur et de la PQoS (Perceived QoS) : L'architecture IMS ne prend pas en compte l'environnement de l'utilisateur, ses préférences et ne dispose pas d'un méchanisme de gestion de PQOS. Pour s'assurer de la qualité fournit à l'utilisateur final, des informations sur l'environnement de l'utilisateur ainsi que ses préférences doivent transiter en cœur de réseau afin d'y être analysés. Ce traitement aboutit au lancement du service qui sera adapté et optimisé aux conditions observées. De plus pour le service d'IPTV, les caractéristiques spatio-temporelles de la vidéo influent de manière importante sur la PQoS observée côté utilisateur. L'adaptation des services multimédias en fonction de l'évolution du contexte utilisateur et de la nature de la vidéo diffusée assure une qualité d'expérience à l'utilisateur et optimise par la même occasion l'utilisation des ressources en cœur de réseau.- une solution de mobilité efficace pour les services conversationnels tels que la VoIP : Les dernières publications 3GPP fournissent deux solutions de mobilité: le LTE propose MIP comme solution de mobilité alors que l'IMS définit une mobilité basée sur le protocole applicatif SIP. Ces standards définissent le système de signalisation mais ne s'avancent pas sur la gestion du flux média lors du changement d'interface réseau. La deuxième section introduit une étude comparative détaillée des solutions de mobilité dans les NGNs.Notre première contribution est la spécification de l'architecture globale de notre plateforme IMS sensible au contexte utilisateur réalisée au sein du projet Européen ADAMANTIUM. Nous détaillons tout d'abord le serveur MCMS intelligent placé dans la couche application de l'IMS. Cet élément récolte les informations de qualité de services à différents équipements réseaux et prend la décision d'une action sur l'un de ces équipements. Ensuite nous définissons un profil utilisateur permettant de décrire son environnement et de le diffuser en coeur de réseau. Une étude sur la prédiction de satisfaction utilisateur en fonction des paramètres spatio-temporels de la vidéo a été réalisée afin de connaître le débit idéal pour une PQoS désirée.Notre deuxième contribution est l'introduction d'une solution de mobilité adaptée aux services conversationnels (VoIP) tenant compte du contexte utilisateur. Notre solution s'intègre à l'architecture IMS existante de façon transparente et permet de réduire le temps de latence du handover. Notre solution duplique les paquets de VoIP sur les deux interfaces actives pendant le temps de la transition. Parallèlement, un nouvel algorithme de gestion de mémoire tampon améliore la qualité d'expérience pour le service de VoIP. / The latest advances in technology have already defied Moore’s law. Thanks to research and industry, hand-held devices are composed of high processing embedded systems enabling the consumption of high quality services. Furthermore, recent trends in communication drive users to consume media Anytime, Anywhere on Any Device via multiple wired and wireless network interfaces. This creates new demands for ubiquitous and high quality service provision management. However, defining and developing the next generation of ubiquitous and converged networks raise a number of challenges. Currently, telecommunication standards do not consider context-awareness aspects for network management and service provisioning. The experience felt by the end-user consuming for instance Voice over IP (VoIP) or Internet Protocol TeleVision (IPTV) services varies depending mainly on user preferences, device context and network resources. It is commonly held that Next Generation Network (NGN) should deliver personalized and effective ubiquitous services to the end user’s Mobile Node (MN) while optimizing the network resources at the network operator side. IP Multimedia Subsystem (IMS) is a standardized NGN framework that unifies service access and allows fixed/mobile network convergence. Nevertheless IMS technology still suffers from a number of confining factors that are addressed in this thesis; amongst them are two main issues :The lack of context-awareness and Perceived-QoS (PQoS):-The existing IMS infrastructure does not take into account the environment of the user ,his preferences , and does not provide any PQoS aware management mechanism within its service provisioning control system. In order to ensure that the service satisfies the consumer, this information need to be sent to the core network for analysis. In order to maximize the end-user satisfaction while optimizing network resources, the combination of a user-centric network management and adaptive services according to the user’s environment and network conditions are considered. Moreover, video content dynamics are also considered as they significantly impact on the deduced perceptual quality of IPTV services. -The lack of efficient mobility mechanism for conversational services like VoIP :The latest releases of Third Generation Partnership Project (3GPP) provide two types of mobility solutions. Long-Term Evolution (LTE) uses Mobile IP (MIP) and IMS uses Session Initiation Protocol (SIP) mobility. These standards are focusing on signaling but none of them define how the media should be scheduled in multi-homed devices. The second section introduces a detailed study of existing mobility solutions in NGNs. Our first contribution is the specification of the global context-aware IMS architecture proposed within the European project ADAptative Management of mediA distributioN based on saTisfaction orIented User Modeling (ADAMANTIUM). We introduce the innovative Multimedia Content Management System (MCMS) located in the application layer of IMS. This server combines the collected monitoring information from different network equipments with the data of the user profile and takes adaptation actions if necessary. Then, we introduce the User Profile (UP) management within the User Equipment (UE) describing the end-user’s context and facilitating the diffusion of the end-user environment towards the IMS core network. In order to optimize the network usage, a PQoS prediction mechanism gives the optimal video bit-rate according to the video content dynamics. Our second contribution in this thesis is an efficient mobility solution for VoIP service within IMS using and taking advantage of user context. Our solution uses packet duplication on both active interfaces during handover process. In order to leverage this mechanism, a new jitter buffer algorithm is proposed at MN side to improve the user’s quality of experience. Furthermore, our mobility solution integrates easily to the existing IMS platform.

The IP Multimedia Subsystem (IMS) has gone from just a step in the evolution of the GSM cellular architecture control core, to being the de-facto framework for Next Generation Network (NGN) implementations and deployments by operators world-wide, not only cellular mobile communications operators, but also fixed line, cable television, and alternative operators. With this transition from standards documents to the real world, engineers in these new multimedia communications companies need to face the task of making these new networks secure against threats and real attacks that were not a part of the previous generation of networks. We present the IMS and other competing frameworks, we analyze the security issues, we present the topic of Security Patterns, we introduce several new patterns, including the basis for a Generic Network pattern, and we apply these concepts to designing a security architecture for a fictitious 3G operator using IMS for the control core. / by Jose M. Ortiz-Villajos. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Este trabalho visa estudar e implementar a integração entre o domínio de comutação de circuitos e o IP Multimedia Subsystem (IMS) para suportar handovers verticais, ou seja, entre redes de acesso distintas, por exemplo, Global System for Mobile communications (GSM) e WiFi, em especial no Serviço Voice Call Continuity (VCC). Entretanto muito pouco é especificado sobre a integração entre os domínios nas normas das diversas entidades de padronização que tratam sobre o assunto. Assim, apresenta-se uma proposta para essa integração, criando-se uma nova entidade funcional para realizá-la, o Call Data Storage Function (CDSF), que interage com os demais módulos do Serviço VCC e garante que algumas informações que devem ser trocadas entre os módulos não sejam perdidas, devido à conversão de protocolos de sinalização na interface entre tais domínios. O CDSF auxilia também no controle da alocação de endereços de referência utilizados no encaminhamento de chamadas de um domínio para o outro. São definidos os protocolos de acesso ao CDSF, bem como os métodos disponíveis. Em sua concepção, recorre-se a uma modelagem modular, que permite futuras melhorias, apenas por troca de módulos. Como estudos de caso para validar a proposta são apresentados cenários de chamadas que utilizam o Serviço VCC, passando pelo CDSF. Por fim, conclui-se que a integração entre os domínios é viável se a proposta deste trabalho for utilizada. Também se demonstra que a separação dos planos de controle dos planos de dados (de usuário) é uma das contribuições fundamentais da arquitetura NGN para o sucesso de suas implementações, como por exemplo o IMS.Além disso, destacam-se as vantagens que o Serviço VCC pode agregar ao IMS, contribuindo para sua adesão em menor prazo pelas operadoras de telecomunicações, dado que esse serviço contribui para a integração de redes, cada vez mais convergentes, agregando mobilidade e continuidade à sua utilização. / This work intends to study and implement the integration between the circuit switching domain and the IP Multimedia Subsystem (IMS) to support vertical handovers that are between different access networks, such as Global System for Mobile communications (GSM) and WiFi. Therefore the specifications are incomplete about this topic in standards from the entities who works with this subject. Then, is presented a new proposal for this integration: a new functional entity to realize this integration: the Call Data Storage Function (CDSF), which interacts with other modules of VCC Service and guarantees that some information shared between modules are not lost, due to conversion of signalling protocols in the interface between domains. Besides that, CDSF helps in the control of allocation of reference address that are used to route calls from one domain to another. Access protocols to CDSF are defined and CDSF methods are exposed. The CDSF design uses a modular approach, which allows future improvements, just changing modules. As case studies to validate this work proposal, call scenarios are presented that uses the VCC Service, using CDSF. Finally, it is concluded that the integration between domains is viable if this work proposal is used. It is presented, as well, that the separation between control plans and data plans is one of the main contributions of NGN architecture to the success of its implementations, like IMS. Furthermore, it is exposed the advantages that VCC Service can aggregate to IMS, contributing for more rapidly adoption by telecommunications operators, considering that this service helps the networks integration, adding convergence, mobility and continuity.

Este trabalho visa estudar e implementar a integração entre o domínio de comutação de circuitos e o IP Multimedia Subsystem (IMS) para suportar handovers verticais, ou seja, entre redes de acesso distintas, por exemplo, Global System for Mobile communications (GSM) e WiFi, em especial no Serviço Voice Call Continuity (VCC). Entretanto muito pouco é especificado sobre a integração entre os domínios nas normas das diversas entidades de padronização que tratam sobre o assunto. Assim, apresenta-se uma proposta para essa integração, criando-se uma nova entidade funcional para realizá-la, o Call Data Storage Function (CDSF), que interage com os demais módulos do Serviço VCC e garante que algumas informações que devem ser trocadas entre os módulos não sejam perdidas, devido à conversão de protocolos de sinalização na interface entre tais domínios. O CDSF auxilia também no controle da alocação de endereços de referência utilizados no encaminhamento de chamadas de um domínio para o outro. São definidos os protocolos de acesso ao CDSF, bem como os métodos disponíveis. Em sua concepção, recorre-se a uma modelagem modular, que permite futuras melhorias, apenas por troca de módulos. Como estudos de caso para validar a proposta são apresentados cenários de chamadas que utilizam o Serviço VCC, passando pelo CDSF. Por fim, conclui-se que a integração entre os domínios é viável se a proposta deste trabalho for utilizada. Também se demonstra que a separação dos planos de controle dos planos de dados (de usuário) é uma das contribuições fundamentais da arquitetura NGN para o sucesso de suas implementações, como por exemplo o IMS.Além disso, destacam-se as vantagens que o Serviço VCC pode agregar ao IMS, contribuindo para sua adesão em menor prazo pelas operadoras de telecomunicações, dado que esse serviço contribui para a integração de redes, cada vez mais convergentes, agregando mobilidade e continuidade à sua utilização. / This work intends to study and implement the integration between the circuit switching domain and the IP Multimedia Subsystem (IMS) to support vertical handovers that are between different access networks, such as Global System for Mobile communications (GSM) and WiFi. Therefore the specifications are incomplete about this topic in standards from the entities who works with this subject. Then, is presented a new proposal for this integration: a new functional entity to realize this integration: the Call Data Storage Function (CDSF), which interacts with other modules of VCC Service and guarantees that some information shared between modules are not lost, due to conversion of signalling protocols in the interface between domains. Besides that, CDSF helps in the control of allocation of reference address that are used to route calls from one domain to another. Access protocols to CDSF are defined and CDSF methods are exposed. The CDSF design uses a modular approach, which allows future improvements, just changing modules. As case studies to validate this work proposal, call scenarios are presented that uses the VCC Service, using CDSF. Finally, it is concluded that the integration between domains is viable if this work proposal is used. It is presented, as well, that the separation between control plans and data plans is one of the main contributions of NGN architecture to the success of its implementations, like IMS. Furthermore, it is exposed the advantages that VCC Service can aggregate to IMS, contributing for more rapidly adoption by telecommunications operators, considering that this service helps the networks integration, adding convergence, mobility and continuity.

LEDs are being developed as the next generation lighting source due to their high efficiency and long life time, with a potential to save $15 billion per year in energy cost by 2020. State of the art LEDs are capable of emitting light at ~115 lm/W and have lifetime over 50,000 hours. It has already surpassed the efficiency of incandescent light sources, and is even comparable to that of fluorescent lamps. Since the total luminous flux generated by a single LED is considerably lower than other light sources, to be competitive the total light output must be increased with higher forward currents and packages of multiple LEDs. However, both of these solutions would increase the junction temperature, which degrades the performance of the LED--as the operating temperature goes up, the light intensity decreases, the lifetime is reduced, and the light color changes. The word "junction" refers to the p-n junction within the LED-chips. Critical to the temperature rise in high powered LED sources is the very large heat flux at the die level (100-500 W/cm2) which must be addressed in order to lower the operating temperature in the die. It is possible to address the spreading requirements of high powered LED die through the use of power electronic substrates for efficient heat dissipation, especially when the die are directly mounted to the power substrate in a chipon- board (COB) architecture. COB is a very attractive technology for packaging power LEDs which can lead improved price competiveness, package integration and thermal performance. In our work high power LED-chips (>1W/die) implementing COB architectures were designed and studied. Substrates for these packaging configurations include two types of power electronic substrates; insulated-metal-substrates (IMS) and direct-bonded-copper (DBC). To lower the operating temperature both the thermal impedance of the dielectric layer and the heat spreading in the copper circuit layers must be studied. In the analysis of our architectures, several lead free solders and thermal interface materials were considered. We start with the analysis of single-chip LED package and extend the result to the multi-chip arrays. The thermal resistance of the system is only a function of geometry and thermal conductivity if temperature-independent properties are used. Thus through finite element analysis (ANSYS) the effect of geometry and thermal conductivity on the thermal resistance was investigated. The drawback of finite element analysis is that many simulations must be conducted whenever the geometry or the thermal conductivity is changed. To bypass same of the computational load, a thermal resistance network was developed. We developed analytical expressions of the thermal resistance, especially focusing on the heat spreading effect at the substrate level. Finally, multi-chip LED arrays were analyzed through finite element analysis and an analytical analysis; where die-spacing is another important factor to determine the junction temperature. With this thermal analysis, critical design considerations were investigated in order to minimize device temperatures and thereby maximizing light output while also maximizing device reliability.

本研究旨在探討固網及行動電話業的雙網整合(Fixed-Mobile Convergence，簡稱FMC)，造就此一趨勢的市場背景及促成技術，影響此趨勢未來發展走向的因素，電信業界的實施方式，與手機製造業的機會。 為何要討論固網及行動電話的整合? 因為它是近兩、三年來全世界電信業界最重要的發展趨勢，是電信業與網際網路的碰撞及交融，電信業界的典範轉移，也是固網業與行動電話業的大競合。它會影響電信業版圖勢力的重整，電訊網路的變革，手機功能的調整，服務提供的方式，是整個「未來世代網路」(NGN: Next Generation Network)的核心議題。 什麼是固網及行動電話的整合? 簡單說來，是指在同一支手機或PDA上，既可接打一般行動電話，又可打網路電話(Mobile Voice over IP)。換言之，雙網整合的行動電話同時具備GSM與Wi-Fi兩種網路之接取能力，在Wi-Fi範圍內時打網路電話，不在時就仍用GSM打電話，由於網路電話通常免費或價錢很低，如此既得到良好通話品質，又享受最低通話費用。要做出這種產品與服務，除了需要手機製造端的技術整合外，電信業者也需整合其通訊網路技術，並更新服務模式，牽涉層面十分廣泛。 本研究發現，促成雙網整合的市場因素包括: (1) 有線電話逐漸被行動電話取代，固網業者為奪回市場佔有率，遂以雙網整合模式推出新的服務模式 (2) 行動電話電信業者希望降低客戶轉換率 (3) 電信業者增加收入的壓力 (4) 消費者簡化通訊方式的需求 而雙網整合的促成技術包括: (1) 「網路電話」(VoIP)技術的發展 (2) 無線寬頻技術的發展，固接式寬頻連線的普及 (3) 整合式手持通訊裝置的製造技術日益成熟，市場接受度高 如何實施雙網整合，固網電信業與行動電話電信業各有不同打算。純粹的固網電信業多選擇成為「虛擬行動電話業者」(Mobile Virtual Network Operator)，或與行動電話電信業策略聯盟，以取得後者在行動電話網路的接取能力。同時，它們以具備Wi-Fi接取點功能的「家用閘道」(Residential Gateway)，與Cellular/Wi-Fi雙網手機，提供家庭用戶雙網整合的服務。在未來電信網路設備的選擇上，多傾向採用符合IMS (IP Multimedia Subsystem)標準的產品。 行動電話電信業者則多選擇UMA (Unlicensed Mobile Access)技術，在其基地台建設中，加入UMA網路控制器，並提供UMA雙網整合手機與服務給用戶。目前有多家行動電話電信業者在測試此技術與服務模式。如果採用UMA技術，未來如何與IMS技術接軌，會是行動電話電信業者需要考量的議題。 未來會影響雙網整合發展的因素則為: (1) 標準的採用: 雙網整合相關的標準包括SIP (Session Initiation Protocal)，UMA與IMS等。SIP與UMA目前已有產品問市，IMS則有待未來。 (2) 電信業者的經營模式是否成功，即推出的雙網整合服務的產品與價位，是否足以吸引消費者換機，與學習新的使用模式 (3) Wi-Fi/Cellular雙網手機有耗電量，通話品質，使用方法友善程度等問題，這些是消費者能否接受的關鍵因素 (4) 企業界整合語音通訊與資料通訊的意願及速度，並將辦公室交換機昇級至IP PBX的決心。企業界將會是雙網整合技術最早的採用者，其使用經驗將對一般消費者有很大影響力。 雙網整合的真正主角，是具備雙網整合能力的智慧型手機。手機製造業者在此趨勢中的市場機會包括:UMA雙網手機，SIP Wi-Fi單網手機，SIP Wi-Fi/Cellular雙網手機等。但要製造這些手機，需解決許多技術問題，包括:數位語音壓縮/解壓縮方法，回音消除處理，Wi-Fi耗電問題，Wi-Fi通訊之安全保護機制，使用者介面整合，互通性測試等等。再加上雙網整合的遊戲規則是由電信業者制定，如何使手機與電信業者的服務模式搭配完美，是一大挑戰。 雙網整合目前仍在發展階段，相關的標準、技術、產品、與服務皆未臻成熟，非常值得持續的研究與觀察。 / “Fixed-mobile convergence” (FMC) is the theme of study in this research. This research attempts to find out: 1) the “Pull” forces coming from the market demand for FMC solutions; 2) the “Push” forces of the enabling technologies that make FMC possible; 3) the factors that will impact FMC’s future; 4) how the carriers are deploying FMC; and, 5) FMC-related opportunities for the mobile phone manufacturers. FMC is about the convergence of telecommunication world and the Internet world. It is the former’s endeavor to benefit from Internet’s low cost, and richness in online services. It stems from the business battle for market share between the fixed network operators and the mobile operators, and it will affect the future power span of these operators. FMC trend includes the following aspects: terminal devices, services, business models, and network technologies. It is so crucial in forming the telecommunication industry’s future, which makes it the core subject of Next Generation Network implementation. FMC is the enablement of mobile phones to use fixed network technologies, such as Wi-Fi network, corporate LANs, IP PBXs, and so on. A Wi-Fi/Cellular dual-mode mobile phone has telephony capability on both Wi-Fi network via mobile VoIP (Voice over IP) technology, and on cellular (such as GSM) network. When the end user is within the Wi-Fi hot spot coverage, the voice communication will be on top of IP. When the user is out of Wi-Fi coverage, then the phone calls are running on cellular network. For the consumers, this technology promises “any time, any where” ubiquitous connectivity and mobility, while at the lowest possible price, since VoIP is normally free or has very low cost. To deploy such products & services, the operators have both technical & business issues to deal with. Based on the findings of this research, the market demand which accelerates converging mobile & fixed network include:  Fixed-mobile substitution (FMS), which means people are using mobile phones more often than fixed-line phones. In many Western European countries, about one third of the household do not install fixed phone lines any more. They only use mobile phones as communication vehicle. Under such circumstances, fixed-line operators are forced to fight back for their market share. FMC is one of such strategies for launching new products and services to win back the end customers.  Mobile operators need to lower the subscriber churn rate, for which they are losing customers. In the United States and some areas in Europe, mobile phone coverage in residential area is unsatisfactory, due to the high cost of building up cellular infrastructure to cover vast space. This is the main reason for the subscribers to switch operators, for the mobile operators, FMC seems a logical solution. Since household penetration rate of high-speed broadband access is high in US, Europe, and many Asian countries, with a Wi-Fi access point and Wi-Fi/cellular dual mode phone, even when the cellular signal strength is weak at home, the user is still able to make phone calls using Mobile VoIP technology on Wi-Fi. This is the origin of UMA (Unlicensed Mobile Access) technology and standard, which mobile operators are pursuing.  All network operators are under constant pressure for growing their revenue, since voice service has quickly become a commodity when flat-rate tariff model is getting prevalent. With FMC solution, mobile operators could earn back the users who are attracted away by the low cost of Internet telephony. For fixed-line operators, FMC is a mechanism for providing packaged deal of broadband access and dual-mode mobile phones. More over, they could provide “quadruple play” services to support IP TV, Video on Demand, and other Internet services to increase their revenue.  “Less is more” mentality of the consumers. Most consumers or working people nowadays have at least three telephone numbers: home phone, office phone, and mobile phone. Each one of them has its own phone bill, voice mail box, and phone book. Some people even have e-mail account, instant message account, and Internet telephony account (such as Skype screen name). The mobility or interchange between these mechanisms of communication, and to manage them is becoming complex. The consumers are asking the mobile operators to integrate their services and phone bills, which again, pulls the operator to FMC solutions. The following are the enabling technologies that facilitate the development of FMC. Without these technologies, FMC can not take root in the telecommunication industry, and generate commercial products in the future.  VoIP (Voice over IP). VoIP service, products, and PC-based software clients have flourished in the past several years along with the exponential growth of the Internet. With the success of Vonage (pure-play VoIP service provider) and Skype (peer-to-peer internet telephony network based on PC), internet telephony has entered the main stream. Network operators that seek to lower the operation cost are turning to this technology as well. Mobile VoIP over EVDO, HSDPA, Wi-Fi, & WiMAX are getting a lot of attention recently since it can help to reduce the tariff, thus attract more users. For Mobile VoIP technologies to secure its market foothold, many issues need to be tackled, such as AEC, voice codec (compression & decompression), jitter buffer handling, SIP (Session Initiation Protocol) stack and RTP (Real-time Protocal) stack handling, power consumption, telephony UI integration, and so on.  High density of wireless broadband network such as Wi-Fi and WiMAX, and wide spread availability of wired broadband access such as xDSL and FTTH in school campus, office buildings, hot spots, transportation hubs, and homes, lay the foundation of FMC. Without such infrastructure, FMC can not thrive. With the combination of both wireless and wired broadband accessibility, Wi-Fi/cellular dual mode phone becomes practical and useful to the general public.  Converged handheld devices with multiple functionalities like push e-mail, PIM (Personal Information Management), Camera, SMS/MMS, internet browsing, phone book, Calendar, and so on, are getting very popular among business professionals in the last two, three years. With the advent of 3G network, data transmission need for email and SMS, more than voice, has increased peoples’ appetite for more powerful devices. Smartphones or PDA Phones that use open operating system such as Windows Mobile, Linux, or Symbian, have become powerful productivity and connectivity tools that cater to consumers’ needs, and have gained great success. The market demand helped to increase the sales volume, and drive down the unit price, which in turns stimulate more buyers. Bluetooth and Wi-Fi capabilities are newly added functions that further facilitates mobile VoIP in an economical way. Once the phone makers have taken care of issues like AEC (Acoustic Echo Cancellation), voice codec (compression/decompression), power consumption, integrated user interface for telephony, CPU loading, GSM/Wi-Fi handover, and so on, the Wi-Fi/Cellular dual-mode phone are taking the center stage of FMC. The factors that will impact the future direction of FMC:  Uncertainty of the FMC-related standards, especially for UMA (Unlicensed Mobile Access). UMA was adopted as FMC solution mostly by the mobile operators, however, it was considered as an intermediate solution toward IMS (IP Multimedia Subsystem), which so far was mainly adopted by fixed-line operators. UMA-compliant products are yet to be launched and proved by the market in the later half of year 2006, its fate uncertain at this moment. SIP (Session Initiation Protocol) is now de facto standard for VoIP, yet its implementation has many variations depending on the vendor. As for IMS (IP Multimedia Subsystem), its standardization process is still undergoing, VCC (Voice Call Continuity) specification is not final yet, the commercialization of IMS could take another two to four years. With all these standards evolving, both consumers and businesses could hesitate in their purchase decisions, and this may impose negative effect on FMC.  Business model of the operators. How they are going to launch FMC service, at what price, with which handheld device, will affect the end customers’ willingness to purchase. They need to provide good incentives for the end users to switch to the new dual-mode phone, and the UI needs to be intuitive enough to shorten the learning curve, and at attractive price.  As described above, the quality of the handset itself plays a critical role on the future of FMC, and its user friendliness and benefits will define the development of FMC.  How fast the enterprises will upgrade their PBX and networking facilities to integrate outbound data and voice communication. VoIP, IP PBX/Centrex, office software, and phone vendors are working together now to provide the enterprises “premised-based” FMC solutions. These solutions promise the executives more efficient administration of the phone bills, better productivity of the employees, and better customer relationship, and so on. Enterprises are the early adopters and test beds for FMC. If they find it useful, it will be helpful for the sales and distribution to the home and personal market. FMC deployment strategy varies from one operator to the other. Pure-play wired operators tend to become MVNO (Mobile Virtual Network Operator), or at least to have alliance with the mobile operators, so that they could get access to the mobile network infrastructure. Since wireline operators in most cases are also suppliers of broadband service to the home, they will take advantage of this infrastructure, and provide residential gateway (e.g. Wi-Fi access point) and Cellular/Wi-Fi dual-mode mobile phone as the FMC solution for the home market. In preparing for future, they tend to select IMS-compliant network equipments. Mobile Operators prefer UMA technology as FMC solution. It is comparatively simple in deployment in the network. Quite a few mobile operators are now in trial run of UMA. In the future, how to migrate UMA to IMS will be a challenge for those who adopt the former. For the mobile phone makers, FMC trend indicates the market opportunity of: UMA dual-mode phone, SIP Wi-Fi single-mode phone, and SIP Wi-Fi/Cellular dual-mode phone. Yet, unlike general purpose consumer market, these FMC phones need to be tied hand-in-hand with the operators for better integration of services and tariff plans. If these solutions are targeted at the enterprises, the phone makers need to work with IP PBX vendors as well. How to work with these parties, and come out good, integrated phones, is a great challenge. Fixed-mobile convergence is still evolving in the telecommunication world, with many vendors and parties involved, and each has its unique way of FMC implementation and business model. How it will turn out takes continuous research and observation. Due to its scale and influence for the future, the effort will definitely be worthwhile.

The goal of this thesis is to provide enhanced mechanisms to deploy competitive services in a rapid and cost-effective manner. To achieve this goal, we first propose an automatic service composition model relying on an IMS/Web converged environment. This service composition model is intended to be one in which even non-professional users can easily reuse existing services to create new services. To further improve the automatic service composition feature, three strategies including passive update, active update and hybrid update are proposed and analyzed. We then propose a centralized service exposure framework for a variey of services, including Telecom / Web / Device / user-generated services. This framework aims at enhancing the user-centric and convergence features, and providing the unified access to diverse services.Subsequently, two P2P based service information sharing models are designed to complement the centralized service exposure model : i) A hierarchical P2P based model, which reuses Chord for guaranteeing the service discovery efficiency, meanwhile adopts the concept of abstract service publication and discovery for enabling the ambiguous services searching. ii) A triplex P2P overlay based model, which mainly targets the devices offered services. In this model, we use the gateways to delegate the devices residing in them for the global service exposure, and use a triplex overlay based architecture, which includes an underlying unstructured P2P layer, a Semantic Overlay Network (SON) based overlay and a service dependency overlay, for the service information sharing and discovery

The use of objective tests in Technology Enhanced Learning (TEL) is based on the application of computers to support automatic assessment. Current research in this domain is mainly focused on the design of new question-items, being IMS Question and Test Interoperability (QTI) the recognized de-facto standard. This thesis claims that the domain can be extended with the design of advanced test-scenarios that integrate new interactive contexts for the visualization of question-items and tests, and that consider different types of devices and technologies that enable diverse activity settings. In this context, the dissertation proposes to term the domain as Computing-Based Testing (CBT) instead of Computer- Based Testing because it captures better the new technological support possibilities for testing. Advanced CBT scenarios can increase teachers’ choices in the design of more appropriate tests for their subject areas, enabling the assessment of higher-order skills. With the aim of modelling an advanced CBT domain that extends the current possibilities of QTI and related work, this thesis provides a set of contributions around three objectives. The first objective deals with proposing a Conceptual Model for the CBT domain considering three main dimensions: the Question-item, the Test and the Activity. To tackle this objective, the thesis presents, on the one hand, a framework to assist in the categorization and design of advanced CBT scenarios and, on the other hand, two models that suggest elements for technologically representing the Test and Question-item dimensions. The models are platform-independent models (PIM) that extend QTI in order to support advanced CBT. Besides, the use of patterns is proposed to complement the modelling of the domain. The second objective seeks to show the relevance, value and applicability of the CBT Conceptual Model through exemplary challenging scenarios and case studies in authentic settings. To this end, the dissertation evaluates the design and implementation of a set of CBT systems and experiments. All the experiments use the proposed CBT Conceptual Model for designing an advanced CBT scenario. For each case the CBT-PIMs serve as the basis for developing a particular CBT-PSM and system. The evaluation results show that the implementations foster educational benefits, enable the assessment of higher-order skills and enhance the students’ motivation. Finally, the third objective is devoted to propose extension paths for QTI. The collection of models proposed in the thesis suggests different extension directions for QTI so as to enable the implementation of advanced questions, tests and activities. The proposed systems and scenarios also represent reference implementation and good practices of the proposed extension paths. / El uso de test de corrección automática, en el Aprendizaje Apoyado por Tecnologías de la Información y las Comunicaciones, se basa en el uso de ordenadores. Las propuestas actuales se centran en el diseño de nuevas preguntas, siendo IMS Question and Test Interoperability (QTI) el estándar de-facto. La tesis propone que este dominio puede ser extendido con el diseño de escenarios de test avanzados que integren nuevos contextos de interacción para la visualización de preguntas y tests, y que consideren la aplicación de diversos dispositivos tecnológicos para permitir diversos tipos de actividades. En este contexto se propone usar el término inglés Computing-Based Testing (CBT) para referirse al dominio, en vez de usar el término Computer-Based Testing, enfatizando el papel de la tecnología para la evaluación basada en test. Los escenarios CBT avanzados pueden aumentar la posibilidad de que los profesores puedan diseñar test más adecuados para sus asignaturas, permitiendo la evaluación de habilidades de alto nivel. Con el reto principal de modelar el dominio del CBT extendiendo las posibilidades actuales de QTI y las aproximaciones actuales, esta tesis proporciona un conjunto de contribuciones relacionadas con tres objetivos. El primer objetivo de la tesis es proponer un Modelo Conceptual definiendo y relacionando tres dimensiones: Pregunta, Test y Actividad. Por una parte, se propone un marco como guía en la categorización y diseño de escenarios CBT. Además, se proponen dos modelos que indican los elementos para la representación tecnológica de preguntas y test. Estos modelos son independientes de plataforma (PIM) que extienden QTI formulando los elementos que permiten implementar escenarios CBT avanzados. Además, se propone el uso de patrones como complemento en el modelado del dominio. El segundo objetivo trata de mostrar la relevancia y aplicabilidad de las contribuciones a través de escenarios y casos de estudio representativos en contextos reales. Para ello, se evalúa el diseño e implementación de un conjunto de experimentos y sistemas. En todos los experimentos se utiliza el Modelo Conceptual para diseñar escenarios CBT avanzados. Para cada caso los CBT-PIMs sirven como base para desarrollar modelos específicos de plataforma (CBT-PSMs) y sistemas asociados. La evaluación muestra que las implementaciones resultantes tienen beneficios educativos positivos, permitiendo la evaluación de habilidades de alto nivel y mejorando la motivación de los estudiantes. Finalmente, el tercer objetivo se centra en proponer vías de extensión para QTI. La colección de modelos propuestos sugiere diferentes direcciones de extensión de QTI para la implementación de preguntas, tests y actividades avanzados. Los escenarios y sistemas llevados a cabo representan implementaciones de referencia y buenas prácticas para las vías de extensión propuestas.

Cryptosporidium is a protozoan parasite infecting the intestines of its hosts, leading to acute diarrheal disease. Out of 26 recognized species, 14 are known to infect humans. Of most importance, from a human perspective are Cryptosporidium parvum and Cryptosporidium hominis, of which the former is known to have zoonotic potential. Globally, cryptosporidiosis affect people with lowered immune status particularly hard; among children under five it is the most important parasitic cause of gastroenteritis. In the region of KwaZulu-Natal, on the east coast of South Africa, Cryptosporidium is considered endemic. Drinking water is frequently collected from river systems and as Cryptosporidium spp. can be transmitted via contaminated water, this may be one source of infection. Research on the species distribution is important for outbreak investigations and prevention efforts. In water and wastewater such speciation is commonly performed using immunomagnetic separation, an antibody dependent method. There is however a suspicion that these antibodies have less affinity to some species and hence contorts the detected species distribution. An alternative approach is therefore of interest.   In the present study, Cryptosporidium diversity in wastewater collected from four different wastewater treatment plants in KwaZulu-Natal, is evaluated with an optimized antibody-free workflow and a single cell platform. It was shown that the workflow is suitable for complex samples, such as wastewater. Furthermore, diversity was assessed with amplicon sequencing, revealing four different species and genotypes. Further modifications of the methods used could benefit the field of Cryptosporidium research, along with improving global health and preventing disease outbreaks.

The theoretical part of dissertation is devoted to familiarization with the process of assembly and soldering of PCBs. There are described the selected types of lead-free solder paste, the various procedures of flux deposition, where the greater part is focuses to the printing through template. Also, I analyze the different procedures shouldering and soldering. I focused mainly on the mechanical mounting of SMD components soldering with help convection reflow and soldering in the vapor. In the practical part is described the design of the test PCB, methodology of assembly PCB and soldering various technologies with predefined settings. The analysis of the results is done by a non-destructive x-ray method and destructive micro-cut method. The x-ray method detects the position and size of the voids in the solder. This information is used for faster processing of micro-cut. The micro-cut method is included in the analysis for a more detailed examination of the solder joint. At the end of the thesis, there is a summary of the recommendation that the setting of the manufacturing process increases the quality of the brazed joint.