In this thesis I address challenges related to the design, development anddeployment of web and mobile technologies used to support CollaborativeSeamless Learning (CSL) activities practiced across a variety of learningcontexts. The scientific publications at the core of this thesis offer adescription of the research I have performed over the last five years, andcomprise studies involving several hundred users.My research efforts included the elicitations of the requirements for and thedesign of a number of web and mobile tools to support collaborative seamlesslearning activities. A web-based environment called CeLS was developed tosupport the orchestration of CSL activities. It was then expanded to integratemobile solutions, aimed to extend the ability of CeLS to support educationalinteractions performed inside as well as outside physical classroom. Thesemobile solutions were designed to implement learning activities that supportdata collection, personal response systems and interaction with mobile videos.The main aim of the research was to investigate how best to design tools andsystems to support students during the enactment of collaborative seamlesslearning activities, and to provide teachers with artifacts to design and assessthose. Special emphasis has been given to the exploration of approaches thatenhance the flow, reusability and sharing of learner-generated content acrossdifferent learning activities. Several studies were conducted in order to validateand assess these ideas and concepts. Various data collection methods wereused to gather data from different stakeholders during the deployment of thedifferent CSL activities. The outcomes were processed and analyzed resultingin a set of recommendations concerning the design, development anddeployment of web and mobile applications to support collaborative seamlesslearning. A software architecture including various web and mobile integratedcomponents used to support innovative CSL activities is also proposed.

1x Evolution-Data Optimized Revision A (1xEV-DO Rev. A) is a cellular communications standard that introduces key enhancements to the high data rate packet switched 1xEV-DO Release 0 standard. The enhancements are driven by the increasing demand on some applications that are delay sensitive and require symmetric data rates on the uplink and the downlink. Some examples of such applications being video telephony and voice over internet protocol (VoIP). The handoff operation is critical for delay sensitive applications because the mobile station (MS) is not supposed to lose service for long periods of time. Therefore seamless server selection is used in Rev. A systems. This research analyzes the performance of this handoff technique. A theoretical approach is presented to calculate the slot error probability (SEP). The approach enables evaluating the effects of filtering, hysteresis as well as the system introduced delay to handoff execution. Unlike previous works, the model presented in this thesis considers multiple base stations (BS) and accounts for correlation of shadow fading affecting different signal powers received from different BSs. The theoretical results are then verified over ranges of parameters of practical interest using simulations, which are also used to evaluate the packet error rate (PER) and the number of handoffs per second. Results show that the SEP gives a good indication about the PER. Results also show that when considering practical handoff delays, moderately large filter constants are more efficient than smaller ones.

In mobile IP, a triangular routing problem usually leads to additional delays and non-seamless handoff, which causes the loss of a large amount of in-fly packets. In this thesis we propose an adaptive route optimization scheme that considers the seamless handoff and mobility rate. The proposed scheme adopts the mobile routing table scheme and includes an efficient cost function. The cost function is a trade-off between network bandwidth utilized by the routing path, signaling messages and processing loads of agents. The primary idea is to adaptively determine when to perform route optimization. The effect of the mobility rate and the cell sojourn time of a mobile node are studied. Both new call and handoff call are considered in the cost calculation. Simulation result shows that the proposed scheme can effectively reduce the total cost composed of link and signaling costs.

Estudos têm sido realizados sobre artigos têxteis de diferentes fibras quanto ao desempenho em relação ao conforto e à funcionalidade. Porém, são raros os que tratam das malhas sintéticas com elastano, utilizando-se da tecnologia denominada seamless com uma proposta de vestuário exterior para gestantes. O objetivo deste trabalho foi desenvolver um protótipo de roupa para gestantes, fabricado a partir de fibras sintéticas de poliamida e poliéster (convencional e microfibra), utilizando a tecnologia seamless, que atendesse às necessidades de conforto e bem-estar deste grupo especial de usuárias. A metodologia utilizada para o desenvolvimento do protótipo foi o Design Thinking, que partiu da busca de conhecimento sobre as necessidades destas usuárias e da obtenção de depoimentos de trinta gestantes. Com o material coletado, identificou-se uma centralidade na necessidade de vestimentas que privilegiassem o conforto das mamas. Em seguida, foi desenvolvido um protótipo de blusa, com malha sintética contendo elastano, utilizando-se da tecnologia denominada seamless e com uma proposta de vestuário exterior para gestantes que dispensasse o uso de sutiã. Para verificar a validade da pesquisa um protótipo foi confeccionado e posteriormente foram fabricadas trinta e duas amostras com as matérias-primas selecionadas. Com os protótipos fabricados, foram realizados os seguintes ensaios físicos: densidade linear (ASTM D3776-96), determinação da espessura (ASTM D 1777 06), tendência à formação de snagging (JIS L 1058), determinação do alongamento e da elasticidade (JIS L 1018 02), gestão da umidade (AATCC Test Method 195 01) e determinação da absorção por capilaridade (JIS 1907 02). Também foi feito um teste de usabilidade com um grupo menor de gestantes, avaliando-se a funcionalidade, o conforto, a adequação das cores e o desejo de compra das peças. A partir da análise dos resultados dos ensaios físicos e do teste de experimentação das amostras, foi possível avaliar a eficiência dos produtos desenvolvidos e a possibilidade de um aprimoramento da solução encontrada. O protótipo se mostrou bem avaliado, sobretudo, no quesito sustentação das mamas. Entre as sugestões de adequações destacaram-se adequação do manequim ao tamanho P e a oferta de cores mais escuras que não evidenciem os mamilos, mais protusos na gestação, além da não retenção de umidade, uma vez que gestantes têm maior produção de suor. A tecnologia seamless agradou as gestantes, por dispensar costuras, causadoras de desconforto e alergias. A presente investigação apresenta o potencial de inspirar o prosseguimento de mais estudos integrando tecnologia têxtil, produção de moda e saúde / There have been a number of studies of textiles made up of different yarns regarding comfort and functionality. However, few have dealt with synthetic fabrics combined with spandex, using seamless technologies to provide outer garments for pregnant women. In order to assess the properties of items of clothing manufactured from different syntetic yarns, the experimental procedure was based on Design Thinking. During the first stage of the investigation, a semi structured interview was conducted with a group of thirty pregnant women. With the collected material, the need of clothes that favor comfort in the breast region was identified as a common issue. A prototype of a blouse with synthetic (polyamide and polyester) knitted fabric containing elastane was developed using the so-called seamless technology. The product was proposed as an outdoor garment for pregnant women, that could also dispense bra use. The prototype was then created and in order to check for validity, thirty-two samples were manufactured from the selected raw materials. The next stage dealt with following physical tests of the manufactured items of clothing: assessment of linear density (ASTM D 3776-96), thickness determination (ASTM D 1777 06), tendency to the formation of snagging (JIS L 1058), stretching determination (JIS L 1018-02), management of liquid moisture (AATCC test Method 195-01) and absorption for capillarity (JIS 1907 02). After that, a smaller group of pregnant women undertook a usability test in order to assess functionality, comfort, color suitability and purchase desirability of the garment. The prototype was well evaluated, above all, in the matter of breast support. Among suggestions highlighted for adjustments are the suitability of size S and the availability of darker colors so that nipples would not show. Seamless technoloty pleased the pregnant women in this study due to dispensing seams that often cause discomfort and allergies. The present research presents the potential to inspire the continuation of further studies integrating textile technoloty, fashion production and health

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / FLL’s are extensively used for fast carrier synchronization. A common approach to meet the wide acquisition range and sufficiently small tracking error requirements is to adopt the wide or narrow band FLL loop in the acquisition and tracking modes and direct switching the loop. The paper analyze the influence of direct switching on performance, including the narrow band loop convergence, transition time etc. and propose applying the Kalman filtering theory to realize the seamless switching (SS) with time-varying loop gains between the two different loop tracking state. The SS control gains for the high dynamic digital spread spectrum receiver is derived. Simulation results for the SS compared to the direct switching demonstrate the improved performance.

Due to terminal mobility and change of service area, efficient IP mobility support is an important aspect in UMTS networks in order to provide mobile users negligible packet loss rate and low handover latency, and thus some level of guaranteed quality-ofservice (QoS) to support real-time applications. 3G/UMTS has been specified and implemented as an end-to-end mobile communications system. The underlying WCDMA access systems manage radio access handover (layer 1) and provide linklayer mobility (layer 2) in terms of connection setup and resource management. For the UMTS nodes to have seamless connectivity with the Internet, the UMTS core networks need to be able to support continuous and no network service session handover (layer 3 and above). A long IP handover latency results in high packet loss rate and severely degrades its end-to-end transport level performance. Network-layer handover latency has therefore been regarded as one of the fundamental limitations in IP-based UMTS networks. Therefore, it is crucial to provide efficient network-layer mobility management in UMTS/WCDMA networks for seamless end-to-end TCP connection with the global Internet. Mobility of UMTS nodes necessitates extra functionalities such as user location tracking, address registration and handover related mechanisms. The challenge to provide seamless mobility in UMTS requires localised location management and efficient IP handover management. Mobile IPv6 protocol offers a better mobility support as the extended IPv6 features with mobility mechanism are integrated to the mobile nodes. To mitigate the effect of lengthy IP handover latency, two well-known handover reducing mechanisms based on Mobile IPv6 support have been proposed in the literature. They are designed with hierarchical network management and address pre-configuration mechanism. Hierarchical management aims to reduce the network registration time, and fast-handover attempts to minimise the address resolution delay. S-MIP (Seamless Mobile IP) integrates the key benefits of the above IP mobility mechanisms coupled with local retransmission scheme to achieve packet lossless and extremely low handover latency, operating in WLAN environments. In this thesis, we explore the possible Mobile IP solutions and various IP handover optimisation schemes in IPv6 to provide seamless mobility in UMTS with the global Internet. It aims at developing an optimised handover scheme that encompasses the packet lossless and extremely low handover latency scheme in S-MIP, and applying it into the UMTS/WCDMA packet data domain. Therefore, the hybrid UMTS-SMIP architecture is able to meet the requirements of delay sensitive real-time applications requiring strict delay bound, packet lossless and low handover latency performance for end-to-end TCP connection during a UMTS IP-based handover. The overall seamless handover architecture in UMTS facilitates integrated, scalable and flexible global IP handover solution enabling new services, assuring service quality and meeting the user???s expectations in future all-IP UMTS deployment. The viability of the seamless mobility scheme in UMTS is reflected through and validated in our design model, network protocol implementation, and service architecture. We illustrate the performance gained in QoS parameters, as a result of converged UMTS-SMIP framework compared to other Mobile IPv6 variants. The simulation results show such a viable and promising seamless handover scheme in UMTS on IP handover latency reduction on its end-to-end TCP connection.

Due to terminal mobility and change of service area, efficient IP mobility support is an important aspect in UMTS networks in order to provide mobile users negligible packet loss rate and low handover latency, and thus some level of guaranteed quality-ofservice (QoS) to support real-time applications. 3G/UMTS has been specified and implemented as an end-to-end mobile communications system. The underlying WCDMA access systems manage radio access handover (layer 1) and provide linklayer mobility (layer 2) in terms of connection setup and resource management. For the UMTS nodes to have seamless connectivity with the Internet, the UMTS core networks need to be able to support continuous and no network service session handover (layer 3 and above). A long IP handover latency results in high packet loss rate and severely degrades its end-to-end transport level performance. Network-layer handover latency has therefore been regarded as one of the fundamental limitations in IP-based UMTS networks. Therefore, it is crucial to provide efficient network-layer mobility management in UMTS/WCDMA networks for seamless end-to-end TCP connection with the global Internet. Mobility of UMTS nodes necessitates extra functionalities such as user location tracking, address registration and handover related mechanisms. The challenge to provide seamless mobility in UMTS requires localised location management and efficient IP handover management. Mobile IPv6 protocol offers a better mobility support as the extended IPv6 features with mobility mechanism are integrated to the mobile nodes. To mitigate the effect of lengthy IP handover latency, two well-known handover reducing mechanisms based on Mobile IPv6 support have been proposed in the literature. They are designed with hierarchical network management and address pre-configuration mechanism. Hierarchical management aims to reduce the network registration time, and fast-handover attempts to minimise the address resolution delay. S-MIP (Seamless Mobile IP) integrates the key benefits of the above IP mobility mechanisms coupled with local retransmission scheme to achieve packet lossless and extremely low handover latency, operating in WLAN environments. In this thesis, we explore the possible Mobile IP solutions and various IP handover optimisation schemes in IPv6 to provide seamless mobility in UMTS with the global Internet. It aims at developing an optimised handover scheme that encompasses the packet lossless and extremely low handover latency scheme in S-MIP, and applying it into the UMTS/WCDMA packet data domain. Therefore, the hybrid UMTS-SMIP architecture is able to meet the requirements of delay sensitive real-time applications requiring strict delay bound, packet lossless and low handover latency performance for end-to-end TCP connection during a UMTS IP-based handover. The overall seamless handover architecture in UMTS facilitates integrated, scalable and flexible global IP handover solution enabling new services, assuring service quality and meeting the user???s expectations in future all-IP UMTS deployment. The viability of the seamless mobility scheme in UMTS is reflected through and validated in our design model, network protocol implementation, and service architecture. We illustrate the performance gained in QoS parameters, as a result of converged UMTS-SMIP framework compared to other Mobile IPv6 variants. The simulation results show such a viable and promising seamless handover scheme in UMTS on IP handover latency reduction on its end-to-end TCP connection.

The objective of this research is to investigate and develop an efficient and seamless data transport protocol for a heterogeneous wireless mobile network. In next-generation network, most of heterogeneous wireless mobile networks will be combined and complementarily constitute a hierarchical network. To integrate different networks, many challenging issues should be solved. In this thesis, an efficient and seamless data transport mechanisms are explored. We investigate the problems that the current transport control protocol (TCP) will experience within the heterogeneous mobile network. In a heterogeneous network, a mobile host experiences drastic changes in network condition during a session. Traditional TCP struggles with abrupt network changes by intersystem handoff and cannot work efficiently in this environment. We propose a TCP scheme to be tailored to the heterogeneous mobile network to support seamless data transport. In the proposed scheme, a TCP is informed the impending handoff events and works differently based on a handoff type. Simulation results present the proposed algorithm improves throughput, stabilizes data transmission rapidly, and provides a seamless data transfer. We also propose an adaptive resource management scheme within a 3G cellular network based on a users priority level to reduce the call dropping and blocking rates. In a heterogeneous network, a network that provides smaller bandwidth may struggle with handed-off calls being served with a higher bandwidth. Therefore, a resource management algorithm should be defined so that an ongoing call is not dropped by a handoff and provides seamless data transfer. We propose an adaptive resource management scheme based on downgrading the quality of some existing services in a 3G cellular network. We analyze the system capacity, call blocking rate and call dropping rate of the proposed algorithm, and simulate the performance variation of the downgraded traffic. The results show that the proposed scheme increases system capacity, and decreases the call dropping rate at the cost of small delay of the downgraded data traffic.

A growing number of IEEE 802.11-based wireless LANs have been set up in many public places in the recent years. These wireless LANs provide convenient network connectivity to users. Although mobile nodes allowed roaming across wireless LANs, handoff latency becomes an obstacle when mobile nodes migrate between different IP networks. Advanced, the link-layer handoff process disrupts the association when a mobile node moves from one access point to another. Even without discussing the latency of Mobility Protocols, this link-layer handoff latency already made many real time applications can not meet their requirements. In this dissertation, it is proposed three schemes to solve the problems occurred in the different network layers. These schemes not only reduce the latency of whole handoff procedure but also have no violation to the existing specifications in the IEEE 802.11 standard and compatible with existing devices. L2-Optimize and AIL used to minimize the duration of link-layer handoff. With LASP, Mobility handoff can be reduced to an acceptable situation. Therefore, even real time applications can meet their requirements when users are roaming across wireless LANs.

Due to terminal mobility and change of service area, efficient IP mobility support is an important aspect in UMTS networks in order to provide mobile users negligible packet loss rate and low handover latency, and thus some level of guaranteed quality-ofservice (QoS) to support real-time applications. 3G/UMTS has been specified and implemented as an end-to-end mobile communications system. The underlying WCDMA access systems manage radio access handover (layer 1) and provide linklayer mobility (layer 2) in terms of connection setup and resource management. For the UMTS nodes to have seamless connectivity with the Internet, the UMTS core networks need to be able to support continuous and no network service session handover (layer 3 and above). A long IP handover latency results in high packet loss rate and severely degrades its end-to-end transport level performance. Network-layer handover latency has therefore been regarded as one of the fundamental limitations in IP-based UMTS networks. Therefore, it is crucial to provide efficient network-layer mobility management in UMTS/WCDMA networks for seamless end-to-end TCP connection with the global Internet. Mobility of UMTS nodes necessitates extra functionalities such as user location tracking, address registration and handover related mechanisms. The challenge to provide seamless mobility in UMTS requires localised location management and efficient IP handover management. Mobile IPv6 protocol offers a better mobility support as the extended IPv6 features with mobility mechanism are integrated to the mobile nodes. To mitigate the effect of lengthy IP handover latency, two well-known handover reducing mechanisms based on Mobile IPv6 support have been proposed in the literature. They are designed with hierarchical network management and address pre-configuration mechanism. Hierarchical management aims to reduce the network registration time, and fast-handover attempts to minimise the address resolution delay. S-MIP (Seamless Mobile IP) integrates the key benefits of the above IP mobility mechanisms coupled with local retransmission scheme to achieve packet lossless and extremely low handover latency, operating in WLAN environments. In this thesis, we explore the possible Mobile IP solutions and various IP handover optimisation schemes in IPv6 to provide seamless mobility in UMTS with the global Internet. It aims at developing an optimised handover scheme that encompasses the packet lossless and extremely low handover latency scheme in S-MIP, and applying it into the UMTS/WCDMA packet data domain. Therefore, the hybrid UMTS-SMIP architecture is able to meet the requirements of delay sensitive real-time applications requiring strict delay bound, packet lossless and low handover latency performance for end-to-end TCP connection during a UMTS IP-based handover. The overall seamless handover architecture in UMTS facilitates integrated, scalable and flexible global IP handover solution enabling new services, assuring service quality and meeting the user???s expectations in future all-IP UMTS deployment. The viability of the seamless mobility scheme in UMTS is reflected through and validated in our design model, network protocol implementation, and service architecture. We illustrate the performance gained in QoS parameters, as a result of converged UMTS-SMIP framework compared to other Mobile IPv6 variants. The simulation results show such a viable and promising seamless handover scheme in UMTS on IP handover latency reduction on its end-to-end TCP connection.