IEEE 802.11-based wireless local area networks (WLANs) have been set up in many public places in last few years. It provides convenient network connectivity to mobile nodes (MNs) and allows users moving from one wireless network to another. With mobility protocol support, such as Mobile IPv6 (MIPv6), people can roam across wireless IP subnets without loss of network-layer connectivity. However, the handover latency may make users feel uncomfortable in MIPv6. To support seamless handover, an enhanced MIPv6 scheme, Fast Handovers for Mobile IPv6 (FMIPv6)[13], was been proposed. In order to further reduce the handover latency, integrating the lower layer procedure with the upper layer procedure is necessary. Unfortunately, when integrating the IEEE 802.11-based standard with FMIPv6, FMIPv6 always fails to perform predictive handover procedure. This may make the handover procedure result in reactive handover. It is because of the protocol nature of IEEE 802.11 and the weak relation between IEEE 802.11 and FMIPv6. Furthermore, a MN can¡¦t receive packets destined to it when it sends the Fast Binding Update (FBU) to the original access router (OAR). This would cause unnecessary packet loss and make the redictive handover have more packet loss then reactive. Those issues will cause quality of services degradation and make real-time applications unreachable. In this dissertation, a low-latency MIPv6 handover scheme will be proposed. It is a FMIPv6-based scheme which is assisted by an active-scan link layer scheme. It has the advantage of FMIPv6 and can reduce unnecessary packet loss when the handover occurs. Also, with the assistance of the active scheme, it can avoid the longest phase that IEEE 802.11 will enter, and can lower the handover latency.

The standard of Wireless Metropolis Area Network, IEEE 802.16e, has mechanisms beyond the static standard, IEEE 802.16d, to cope with mobile nodes. One of the mechanisms is the handover procedure. Mobile node scanning of neighbor BSs in the IEEE 802.16e handover procedure has a procedure: Association. Association is an initial ranging procedure. The transmission is discontinued when a mobile node is scanning of neighbor BSs. Because initial ranging procedure is defined from the static standard, the delay time of association becomes a bottleneck of handover. One of the researches, NFHO (Network-assisted Fast Handover), proposes a method -¡¨Fast Association¡¨ to shorten the scanning time. In the method, the serving BS coordinates neighbor stations the exactly synchronization time for mobile node transmission of the initial ranging code. Another method of NFHO is to add an equipment, CSSC (Convergence Sublayer Switch Center). CSSC stores and broadcasts the data packets which are discontinued between handover. The metric proposed in this thesis called RAPHO (Rapid Association and Prediction-assisted Handover) which can shorten much scanning discontinued time. In one part of RAPHO, the serving BS takes the role of the mobile node to send the initial ranging code; in another part, the serving BS predicts the possible target BSs list. Because the mobile node doesn¡¦t participate in association and the number of scanning neighbor BSs is decreased, the improving scanning delay time of RAPHO is better than that of NFHO. According to the result of simulation, the total delay time (the scanning time plus the handover time) of RAPHO is better than that of NFHO.

A major consideration for mobile WiMAX is seamless handoff. The British English term for transferring a cellular call is handover whereas the Americans prefer to call it handoff. Cellular-based standards have the advantage of many years experience in handover for voice calls, while for broadband mobility in itself is no mean feat, and handover is still a challenge. Mobile IP, with "slow" handover, will be fine for web-browsing but not good enough for decent voice quality. Many services require the appearance of seamless connections (VoIP, VPNs, etc). Much of the complexity (and latency) in the cellular network is from maintaining these connections across cell boundaries. Handovers in wireless technologies have always been a challenging topic of discussion. According to the mobility framework of IEEE 802.16e, a Mobile Station (MSS) should scan the neighbouring Base Stations (BSs) for selecting the best BS for a potential handover. However, the standard does not specify the number of BSs to be scanned leaving room for unnecessary scanning. Moreover, prolonged scanning also interrupts data transmissions thus degrading the QoS of an ongoing connection. Reducing unnecessary scanning is an important issue. This thesis proposes a scheme to reduce the number of BSs to scan, thus improving the overall handover performance. Simulation results show that the proposed hybrid predictive BS selection scheme for potential scanning activities is more effective than the conventional IEEE 802.16e handover scheme in terms of handover delay and resource wastage. Before the actual handover process, there is scope of reducing the total number of iterations of message exchanges occurring between the mobile MSS, the SBS and the neighbouring BSs which are potential targets for handover. Simulations prove that it takes upto 700 ms to decide the target BS before initiating the handover process with it. There are multiple message exchanges to choose a set of potential target BSs from all the neighbouring BSs. A few more messages flow between the MSS, SBS and potential target BSs to choose the best candidate BS for handover. The many stages and messages waste time and could be reduced. This thesis discusses some ways to reduce them and backs it up with simulation results.

Background Handover occurs as a daily task for health care professionals in all levels of care. Handover between ambulance crew and emergency department staff stands for the first exchange of information about a patient’s condition. Different factors may impact the handover communication and make it vulnerable. Aim The aim is to highlight factors of importance at handover between the ambulance and emergency room. Method A literature review of thirteen studies with qualitative and quantitative research approach. The purpose of this literature review was to provide an overview of the area. Results Experiences for health care professionals is that communication is important for patient handover between ambulance and emergency department. This information, as well as how information is structured and communicated, is an important part of the handover process. Knowledge, skills, responsibility and professionalism is conducive for making professional judgments. Health care workers pressured work environment, and lack of organizational structure are factors that can compromise patient safety. Conclusion Lack of good work environment, structure and common language has a negative impact on communication. Good attitudes as active listening and interest among staff increases prerequisites for good cooperation in handover

Handover from one healthcare professional is an essential component of patient care. This can be a challenge in community care where staff provide interventions in the patient’s home and do not have the benefit of face-to-face interactions with colleagues. The purpose of this quantitative study was to explore the perceptions of nurses working in community care about handover and their views on using an electronic handover tool as opposed to their current email system. The goal of the study, to assess whether nurses would have a greater understanding of their patients’ needs through standardized reporting as opposed to emailed narratives of time and tasks was studied. Nurses completed a pre, post likert-type survey, and reviewed an electronic handover tool. Both surveys were analyzed by nursing professional designation and age to explore whether either factor influenced opinions. Nurses reported that handover was important and they supported a standardized communication tool as opposed to relying on an email system without structure. / Graduate / 0569 / nmichaudhamilton@gmail.com

Handover from one healthcare professional is an essential component of patient care. This can be a challenge in community care where staff provide interventions in the patient’s home and do not have the benefit of face-to-face interactions with colleagues. The purpose of this quantitative study was to explore the perceptions of nurses working in community care about handover and their views on using an electronic handover tool as opposed to their current email system. The goal of the study, to assess whether nurses would have a greater understanding of their patients’ needs through standardized reporting as opposed to emailed narratives of time and tasks was studied. Nurses completed a pre, post likert-type survey, and reviewed an electronic handover tool. Both surveys were analyzed by nursing professional designation and age to explore whether either factor influenced opinions. Nurses reported that handover was important and they supported a standardized communication tool as opposed to relying on an email system without structure. / Graduate / 0569 / nmichaudhamilton@gmail.com

Techn. Hochsch., Diss., 2006--Aachen.

Techn. University, Diss., 2003--Berlin.

Techn. University, Diss., 2004--Berlin.

Made available in DSpace on 2014-06-12T15:58:06Z (GMT). No. of bitstreams: 2 arquivo3254_1.pdf: 2461964 bytes, checksum: ee6651fba198053b9390d4e1c2f5c45d (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Espera-se que a Internet do Futuro permitirá aos usuários grandes taxas de transferência de dados, mobilidade e heterogeneidade de conexão transparente e ubíqua. Para que isto seja possível, devem existir mecanismos que permitam a manutenção da conectividade dos Terminais Móveis (TM), mesmo quando estiverem se deslocando entre diversas tecnologias sem fio (e.g., IEEE 802.11, IEEE 802.16 e redes celulares 3G) e utilizando aplicações baseadas no protocolo IP (Internet Protocol). Porém, um problema existente neste contexto é o atraso gerado no momento em que usuário necessita realizar a mudança entre pontos de acoplamento heterogêneos (e.g., entre uma estação base (BS) IEEE 802.16 e um ponto de acesso (AP) IEEE 802.11). Esta troca, decorrente da mobilidade nesse cenário, é denominada de handover vertical e pode gerar degradação na qualidade de serviço (QoS) das aplicações e qualidade de experiência (QoE) percebida pelo usuário. Este trabalho apresenta uma técnica de predição de caminhos para Terminais Móveis que utiliza informações baseadas em coordenadas geográficas para modelar os caminhos do usuário. Com isto é possível descrever um modelo de movimentação independente de qualquer tecnologia. Dessa forma, diferente dos métodos tradicionais, esta técnica pode ser aplicada a ambientes baseados em redes heterogêneas sem fio. As simulações realizadas com redes de Petri e com o Network Simulator, bem como as análises estatísticas descritas, demonstram que é possível diminuir o atraso gerado no processo de handover através da antecipação de informações em até 500ms. Assim como, as avaliações em termos de métricas de QoE demonstraram que para aplicações de vídeo é possível manter a qualidade durante o handover, evitando assim, a aparição de borrões no vídeo que ocorrem devido a interrupção do fluxo de dados resultante do atraso no decorrer do handover