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<p>In this thesis we study a wireless mesh network (WMN), where a number of access points (APs) form a wireless infrastructure and provide communications to the mobile stations (MSs). Different APs share the same frequency channel. We study how to provide fair throughput for the MSs while efficiently utilizing the channel resources through effective handoff management and channel timeline allocations.</p> <p>In the first part of the thesis, we assume that the channel time allocations at the AP level are given, and jointly consider the handoff management of the MSs and the channel time allocations at the MS level. An optimization problem is formulated based on long-term proportional fairness (PF) and solved. A heuristic distributed scheme is then proposed, which can be easily implemented in a practical WMN.</p> <p>In the second part, we jointly study the channel time allocations at the AP level and the MS level together with the MS handoff management. An optimization problem is first formulated and solved as a benchmark. Two distributed schemes are proposed by decoupling the handoff management and time allocations. The HO-CA scheme performs heuristic handoff decisions for the MSs and then optimizes the channel time allocations. The CA-HO scheme allocates the channel time to individual APs based on the neighboring relationship of the APs, and then makes handoff.</p> <p>Numerical results indicate that our proposed distributed schemes can achieve close-to-optimum fairness, improve the network utilization and balance the traffic load under uneven MSs geographical distributions.</p> / Master of Applied Science (MASc)

Bakgrund: Ett av de mest kritiska momenten inom vården, där risken för hotadpatientsäkerhet är som störst, är vid överrapportering av kritiskt sjuka patienter. SBAR är enstandardiserad överrapporteringsmodell som rekommenderas att användas inom all hälso- ochsjukvård och anses stärka patientsäkerheten. Aktuell forskningen går dock isär om SBAR ären bra överrapporteringsmodell. Den fungerar bra vid övningar men sämre i praktiken. Akutatidskritiska situationer anses ha en tydlig påverkan på användandet av SBAR. Komplexiteten idessa situationer anses inte tillräckligt utforskad och det behövs mer forskning om vad sompåverkar ambulanssjuksköterskors användande av SBAR. Syfte: Syftet är att beskriva vad som påverkar användandet av SBAR vid överrapportering avkritiskt sjuka patienter till vårdpersonal på akutrummet. Metod: Kvalitativ deltagande observationsstudie med efterföljande intervju med induktivansats. 20 stycken observationer utfördes på ett akutrum med intervjuer som utfördes direktefteråt. Den insamlade datan analyserades manifest med Graneheim och Lundmans (2004)kvalitativa innehållsanalys. Resultat: I intervjuernas resultat framkom två kategorier: Inre och Yttre faktorer och iobservationernas resultat framkom en kategori: Yttre faktorer. Inre faktorer beskriverambulanspersonalens egna påverkan på SBAR där förberedelser och justeringar av SBARhade störst påverkan. Yttre faktorer beskriver hur vårdpersonalens mottagande av rapport påakutrummet och arbetsmiljön påverkade ambulanspersonalens användande av SBAR. Slutsats: Resultatet visar på inre och yttre faktorer som både underlättar och försvårarambulanspersonalens överrapporteringar. Denna förståelse kan leda till förbättrat användandeav SBAR och därför en ökad patientsäkerhet. / Bakground: A critical moment where the risk to patient safety is high is during handover ofcritically ill patients. SBAR is recommended for use across all healthcare settings and isbelieved to increase patient safety. However, current research diverges on whether SBAR is agood model. It performs well in exercises but not as good in practice. Acute time-criticalsituations are considered to influence the use of SBAR. The complexity of these situations isdeemed insufficiently explored and further research about factors influencing ambulancenurses use of SBAR is needed. Aim: The aim of this study is to describe the factors influencing the use of SBAR duringhandover of critically ill patients to healthcare personnel in the emergency room. Method: Qualitative participatory observational study followed by interviews using aninductive approach. Twenty observations were conducted in an emergency room followed byinterviews. The collected data was analyzed manifest and by using Graneheim and Lundmans(2004) qualitative content analysis method. Results: The interviews revealed two categories: Internal factors and external factors. Theobservations revealed one category: External factors. Internal factors describes theambulance personnel´s own influence on SBAR, where preparations and adjustments toSBAR had the greatest impact. External factors describes how the reception of the patienthandover and the work environment affected the ambulance personnel´s use of SBAR. Conclusion: The result indicates that internal and external factors both facilitates and hinderambulance personnel´s handovers. This understanding can lead to improved use of SBAR andthus increase patient safety.

Mobile wireless environments present new challenges to the design and validation of system supports for facilitating development of mobile applications. This dissertation concerns two major system-support mechanisms in mobile wireless networks, namely, location management and service management. We address this research issue by considering three topics: location management, service management, and integrated location and service management. A location management scheme must effectively and efficiently handle both user location-update and location-search operations. We first quantitatively analyze a class of location management algorithms and identify conditions under which one algorithm may perform better than others. From insight gained from the quantitative analysis, we design and analyze a hybrid replication with forwarding algorithm that outperforms individual algorithms and show that such a hybrid algorithm can be uniformly applied to mobile users with distinct call and mobility characteristics to simplify the system design without sacrificing performance. For service management, we explore the notion of location-aware personal proxies that cooperate with the underlying location management system with the goal to minimize the network communication cost caused by service management operations. We show that for cellular wireless networks that provide packet services, when given a set of model parameters characterizing the network and workload conditions, there exists an optimal proxy service area size such that the overall network communication cost for service operations is minimized. These proxy-based mobile service management schemes are shown to outperform non-proxy-based schemes over a wide range of identified conditions. We investigate a class of integrated location and service management schemes by which service proxies are tightly integrated with location databases to further reduce the overall network signaling and communication cost. We show analytically and by simulation that when given a user's mobility and service characteristics, there exists an optimal integrated location and service management scheme that would minimize the overall network communication cost for servicing location and service operations. We demonstrate that the best integrated location and service scheme identified always performs better than the best decoupled scheme that considers location and service managements separately. / Ph. D.

Introduktion: Informationsöverföring inom sjukvården är ett kritiskt moment där viktig information kan försvinna eller missuppfattas. Ett sådant moment är sjuksköterskornas skiftöverlämning som kan genomföras på olika sätt. Att skiftöverlämningen sker på patientsal beskrivs av sjuksköterskor som både mer effektiv, korrekt och inbjudande för patienten. Syfte: Syftet var att beskriva patienters upplevelser av sjuksköterskans överrapportering på patientsal inom slutenvården.  Metod: Beskrivande design med allmän litteraturstudie som datainsamlingsmetod. Fem kvalitativa artiklar och sex mixed-method artiklar användes som grund för arbetet. Resultat: Resultatet visade att patienter genom överrapportering på patientsal kände sig mer involverade och delaktiga i sin vård. De upplevde även att överrapportering på patientsal bidrog till en tryggare sjukhusvistelse då sjuksköterskan introducerades tidigt under sitt skift men också möjligheten att verifiera den information som förs vidare. En stor del av patienterna ansåg inte att det var något problem att information delades så att andra kunde höra, det innebar inte att alla ämnen passade att pratas om på patientsalen då patienter såg vissa ämnen som mer inskränkande på deras integritet. Patienterna beskrev även sjuksköterskans förhållningssätt som en viktig del i hur patienters deltagande påverkas. Slutsats: Slutsatsen dras att överrapportering på patientsal bidrar till ökad delaktighet för patienten men att strukturen av överrapportering på patientsal bör utformas vidare för att säkerställa att sekretessen inte bryts samt att patienten blir involverad på ett lämpligt sätt. / Introduction: Information transfer in healthcare is a critical moment where important information can be lost or misunderstood. One such element is the nurses' shift handover, which can be carried out in different ways. That the shift handover takes place at the patient's bedside is described by nurses as both more efficient, correct and inviting. Aim: The aim of this study was to describe patients experiences with nursing bedside handover. Method: Descriptive design with general literature study as data collection method. Five qualitative articles and six mixed-method articles were used as a basis for the work.  Results: The results showed that through nursing bedside handoff, patients felt more involved in their care. Patients also felt that bedside handoff contributed to a safer hospital stay as the nurse was introduced early during the shift and with the opportunity to verify the information being passed on. Many patients did not consider it a problem that information was shared in a way that other patients could hear, but it did not mean that all topics were suitable to discuss at the bedside as patients saw certain topics as more intrusive of their privacy. The patients also described the nurse's approach as an important part of how patients' participation was affected. Conclusion: The conclusion is drawn that nursing bedside handoff contributes to increased participation for the patient, but that the structure of bedside handoff should be developed further to ensure that confidentiality is not breached and that the patient becomes involved in an appropriate way.

Au cours des dernières décennies, nous avons été témoins d'une évolution considérable dans l'informatique mobile, réseau sans fil et des appareils portatifs. Dans les réseaux de communication à venir, les utilisateurs devraient être encore plus mobiles exigeant une connectivité omniprésente à différentes applications qui seront de préférence au courant de leur contexte. Certes, les informations de localisation dans le cadre de leur contexte est d'une importance primordiale à la fois la demande et les perspectives du réseau. Depuis l'application ou de point de vue utilisateur, la fourniture de services peut mettre à jour si l'adaptation au contexte de l'utilisateur est activée. Du point de vue du réseau, des fonctionnalités telles que le routage, la gestion de transfert, l'allocation des ressources et d'autres peuvent également bénéficier si l'emplacement de l'utilisateur peuvent être suivis ou même prédit. Dans ce contexte, nous nous concentrons notre attention sur la localisation à l'intérieur et de la prévision transfert qui sont des composants indispensables à la réussite ultime de l'ère de la communication omniprésente envisagé. Alors que les systèmes de positionnement en plein air ont déjà prouvé leur potentiel dans un large éventail d'applications commerciales, le chemin vers un système de localisation à l'intérieur de succès est reconnu pour être beaucoup plus difficile, principalement en raison des caractéristiques difficiles à l'intérieur et l'exigence d'une plus grande précision. De même, la gestion de transfert dans le futur des réseaux hétérogènes sans fil est beaucoup plus difficile que dans les réseaux traditionnels homogènes. Régimes de procédure de transfert doit être sans faille pour la réunion strictes de qualité de service (QoS) des applications futures et fonctionnel malgré la diversité des caractéristiques de fonctionnement des différentes technologies. En outre, les décisions transfert devraient être suffisamment souples pour tenir compte des préférences utilisateur d'un large éventail de critères proposés par toutes les technologies. L'objectif principal de cette thèse est de mettre au point précis, l'heure et l'emplacement de puissance et de systèmes efficaces de gestion de transfert afin de mieux satisfaire applications sensibles au contexte et mobiles. Pour obtenir une localisation à l'intérieur, le potentiel de réseau local sans fil (WLAN) et Radio Frequency Identification (RFID) que l'emplacement autonome technologies de détection sont d'abord étudiés par des essais plusieurs algorithmes et paramètres dans un banc d'essai expérimental réel ou par de nombreuses simulations, alors que leurs lacunes sont également été identifiés. Leur intégration dans une architecture commune est alors proposée afin de combiner leurs principaux avantages et surmonter leurs limitations. La supériorité des performances du système de synergie sur le stand alone homologues est validée par une analyse approfondie. En ce qui concerne la tâche de gestion transfert, nous repérer que la sensibilité au contexte peut aussi améliorer la fonctionnalité du réseau. En conséquence, deux de tels systèmes qui utilisent l'information obtenue à partir des systèmes de localisation sont proposées. Le premier schéma repose sur un déploiement tag RFID, comme notre architecture de positionnement RFID, et en suivant la scène WLAN analyse du concept de positionnement, prédit l'emplacement réseau de la prochaine couche, c'est à dire le prochain point de fixation sur le réseau. Le second régime repose sur une approche intégrée RFID et sans fil de capteur / actionneur Network (WSAN) de déploiement pour la localisation des utilisateurs physiques et par la suite pour prédire la prochaine leur point de transfert à deux couches de liaison et le réseau. Etre indépendant de la technologie d'accès sans fil principe sous-jacent, les deux régimes peuvent être facilement mises en œuvre dans des réseaux hétérogènes [...] / Over the last few decades, we have been witnessing a tremendous evolution in mobile computing, wireless networking and hand-held devices. In the future communication networks, users are anticipated to become even more mobile demanding for ubiquitous connectivity to different applications which will be preferably aware of their context. Admittedly, location information as part of their context is of paramount importance from both application and network perspectives. From application or user point of view, service provision can upgrade if adaptation to the user's context is enabled. From network point of view, functionalities such as routing, handoff management, resource allocation and others can also benefit if user's location can be tracked or even predicted. Within this context, we focus our attention on indoor localization and handoff prediction which are indispensable components towards the ultimate success of the envisioned pervasive communication era. While outdoor positioning systems have already proven their potential in a wide range of commercial applications, the path towards a successful indoor location system is recognized to be much more difficult, mainly due to the harsh indoor characteristics and requirement for higher accuracy. Similarly, handoff management in the future heterogeneous wireless networks is much more challenging than in traditional homogeneous networks. Handoff schemes must be seamless for meeting strict Quality of Service (QoS) requirements of the future applications and functional despite the diversity of operation features of the different technologies. In addition, handoff decisions should be flexible enough to accommodate user preferences from a wide range of criteria offered by all technologies. The main objective of this thesis is to devise accurate, time and power efficient location and handoff management systems in order to satisfy better context-aware and mobile applications. For indoor localization, the potential of Wireless Local Area Network (WLAN) and Radio Frequency Identification (RFID) technologies as standalone location sensing technologies are first studied by testing several algorithms and metrics in a real experimental testbed or by extensive simulations, while their shortcomings are also identified. Their integration in a common architecture is then proposed in order to combine their key benefits and overcome their limitations. The performance superiority of the synergetic system over the stand alone counterparts is validated via extensive analysis. Regarding the handoff management task, we pinpoint that context awareness can also enhance the network functionality. Consequently, two such schemes which utilize information obtained from localization systems are proposed. The first scheme relies on a RFID tag deployment, alike our RFID positioning architecture, and by following the WLAN scene analysis positioning concept, predicts the next network layer location, i.e. the next point of attachment to the network. The second scheme relies on an integrated RFID and Wireless Sensor/Actuator Network (WSAN) deployment for tracking the users' physical location and subsequently for predicting next their handoff point at both link and network layers. Being independent of the underlying principle wireless access technology, both schemes can be easily implemented in heterogeneous networks. Performance evaluation results demonstrate the advantages of the proposed schemes over the standard protocols regarding prediction accuracy, time latency and energy savings

Over recent years, wireless communication systems have been experiencing a dramatic and continuous growth in the number of subscribers, thus placing extra demands on system capacity. At the same time, keeping Quality of Service (QoS) at an acceptable level is a critical concern and a challenge to the wireless network designer. In this sense, performance analysis must be the first step in designing or improving a network. Thus, powerful mathematical tools for analysing most of the performance metrics in the network are required. A good modelling and analysis of the wireless cellular networks will lead to a high level of QoS. In this thesis, different analytical models of various handoff schemes and resource re-allocation in homogeneous and heterogeneous wireless cellular networks are developed and investigated. The sustained increase in users and the request for advanced services are some of the key motivations for considering the designing of Hierarchical Cellular Networks (HCN). In this type of system, calls can be blocked in a microcell flow over to an overlay macrocell. Microcells in the HCN can be replaced by WLANs as this can provide high bandwidth and its users have limited mobility features. Efficient sharing of resources between wireless cellular networks and WLANs will improve the capacity as well as QoS metrics. This thesis first presents an analytical model for priority handoff mechanisms, where new calls and handoff calls are captured by two different traffic arrival processes, respectively. Using this analytical model, the optimised number of channels assigned to II handover calls, with the aim of minimising the drop probability under given network scenarios, has been investigated. Also, an analytical model of a network containing two cells has been developed to measure the different performance parameters for each of the cells in the network, as well as altogether as one network system. Secondly, a new solution is proposed to manage the bandwidth and re-allocate it in a proper way to maintain the QoS for all types of calls. Thirdly, performance models for microcells and macrocells in hierarchical cellular networks have been developed by using a combination of different handoff schemes. Finally, the microcell in HCN is replaced by WLANs and a prioritised vertical handoff scheme in an integrated UMTS/WLAN network has been developed. Simulation experiments have been conducted to validate the accuracy of these analytical models. The models have then been used to investigate the performance of the networks under different scenarios.