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Today hundreds of millions of users are interconnected by communication channels allowing them to communicate and to share information. These users and the devices that interconnect them are what constitute the Internet. The Internet is a network of networks with a myriad of computer devices, including smartphones, game consoles (handheld/stationary), IP televisions, tablet computers, laptop computers, desktop computers, palmtop computers, etc. This network of computers flourishes because of careful planning and maintenance by Internet Service Providers (ISPs), backbone network operators, and others. An additional factor that enables the Internet to operate is the four logical layers of abstraction in the TCP/IP protocol stack. One of these layers is the layer responsible for the transfer of datagrams/packets from one host to another. This layer is known as the Internet Protocol (IP) layer. However, as originally conceived a 32 bit address was thought to be more than enough. The space of IP addresses was distributed among different regions rather disproportionately, driven largely by the numbers of addresses that were requested (ordered in time). Today after a series of inventions in the field (such as the world wide web) and a rapid growth in the number of devices that wish to connect to the Internet the available unassigned address space has largely been depleted. Regions with large populations, but with few assigned blocks of IP addresses have begun to exhaust all their assigned addresses, while other regions face the same fate in a few months. The need for a larger address space was predicted years ago and the next generation addressing scheme was devised as part of the development of Internet Protocol Version 6 (IPv6). Countries such as China and India had few IPv4 addresses and they have been forced to transition to IPv6 rather quickly. Today a significant number of the users in these countries are unable to communicate over IPv4 networks. The purpose of this thesis project is to discuss the transition to IPv6 and the transition to this new addressing scheme. IPv6 provides a much larger address space, along with a number of additional improvements in comparison to the previous version of IP (i.e., IPv4). Despite the advantages of adopting IPv6, the incentive to transition is low amongst well established businesses, especially those in regions that received a considerable number of IPv4 addresses initially. Instead different techniques have been employed in these places to mitigate the problem of IPv4 address exhaustion. It is also probable that this reluctance is a way to keep competing businesses out of the market for a while longer. This thesis aims to facilitate the transition from IPv4 to IPv6. / Miljontals användare är idag sammankopplade genom kommunikationskanaler som tillåter utbyte av information. Datornätet Internet utgörs av dessa användare och de enheter som sammanbinder dem. Internet är ett nätverk av nätverk med en myriad av olika datorutrustning såsom; spelkonsoler, smartphones, bärbara datorer, stationära datorer, handdatorer, även IPTV, kylskåp, tvättmaskiner, osv. Detta nätverk blomstrar på grund av noggrann planering och underhåll av internetleverantörer, nätoperatörer och andra. En ytterligare faktor som gör det möjligt för Internet att fungera är de fyra logiska skikt av abstaktion i TCP/IP-protokollstacken, en standard för datakommunikation. Ett av dessa skikt ansvarar för överföring av datapaket från en ändpunkt till en annan. Detta skikt är kallad Internet Protocol(IP) layer. Ursprungligen ansågs en 32-bitars adress vara mer än tillräcklig. Dessa IP-adresser delades ut till olika regioner rätt så oproportionerligt till stor del beroende på antalet adresser en region begärt. Idag efter en rad uppfinningar inom området(såsom webben/world wide web) och en snabb tillväxt i antal enheter som önskar ansluta sig till Internet är det tillgängliga adressutrymmet i stort sett slut. Regioner med stor befolkning men med få tilldelade block av IP-addresser har börjat göra slut på sina tilldelade adresser medan andra regioner står inför samma öde inom några månader. Behovet av ett större adressrymd sågs flera år sedan och nästa generations addresseringsschema utformades som en del av utveckligen, Internet Protocol version 6(IPv6). Länder som Kina och Indien hade ett fåtal IPv4-adresser och de har varit tvungna att övergå till IPv6 ganska snabbt. Idag kan inte ett stort antal användare i dessa länder kommunicera över IPv4-nätverk. Syftet med detta examensarbete är att diskutera övergången till IPv6 samt övergången till detta nya adresseringsschema. IPv6 ger en mycket större adressrymd samt en rad ytterligare förbättringar i jämförelse med den tidigare versionen av IP(dvs IPv4). Trots fördelarna med att övergå till IPv6 är viljan låg bland väletablerade företag, särskilt i regioner som mottagit ett stort antal IPv4-adresser från början. Dessa regioner tillämpar istället olika tekniker för att bromsa utmattningen av IPv4-adresser. Det är också troligt att denna motvija är ett sätt att hålla konkurrerande företag från marknaden ett tag till. Detta examensarbete syftar till att underlätta övergången från IPv4 till IPv6.

Enabling vehicles to preempt the normal operation of traffic signals has the potential to improve the safety and efficiency of both the requesting vehicle and all of the other vehicles. Little is known about which strategy is the most effective to exit from preemption control and transition back to the traffic signals normal timing plan. Common among these traffic signal transition strategies is the method of either increasing or decreasing the cycle length of the signal timing plan, as the process followed to return to the coordination point of the effected signal timing plan, to coordinate its operation with adjacent traffic signals. This research evaluates commonly available transition strategies: best way, long, short, and hold strategies. The major contribution of this research is enhancing the methodology to evaluate the impacts of using these alternative transition strategies. Part of this methodology consists of the "software-in-the-loop" simulation tool which replicates the stochastic characteristics of traffic flow under different traffic volume levels. This tool combines the software from a traffic signal controller (Gardner NextPhase Suitcase Tester, version 1.4B) with a microscopic traffic simulation model (CORSIM, TSIS 5.2 beta version). The research concludes that a statistically significant interaction exists between traffic volume levels and traffic signal transition strategies. This interaction eliminates the ability to determine the isolated effects of either the transition strategies on average travel delay and average travel time, or the effects of changes in traffic volume levels on average travel delay and average travel time. Conclusions, however, could be drawn on the performance of different transition strategies for specific traffic volume levels. As a result, selecting the most effective transition strategy needs to be based on the traffic volume levels and conditions specific to each traffic signal or series of coordinated traffic signals. The research also concludes that for the base traffic volume and a 40% increase in traffic volume, the most effective transition strategies are the best way, long or hold alternatives. The best way was the most effective transition strategy for a 20% increase in traffic volume. The least effective strategy is the short transition strategy for both the base and 40% increase in traffic volume, and the long and short for a 20% increase in traffic volume. Further research needs to be conducted to assess the performance of different transition strategies in returning to coordinated operation under higher levels of traffic volume (e.g., approaching or exceeding congested flow regime), with varying cycle lengths, with different signal timing plans, and when different roadway geometric configurations (e.g., turn lanes, length of turn lanes, number of lanes, spacing between intersections) are present. / Ph. D.

abstract: Research shows that many water governance regimes are failing to guide social-ecological systems away from points, beyond which, damage to social and environmental well-being will be difficult to correct. This problem is apparent in regions that face water conflicts and climate threats. There remains a need to clarify what is it about governance that people need to change in water conflict prone regions, how to collectively go about doing that, and how research can actively support this. To address these needs, here I present a collaborative research project from the dry tropics of Guanacaste Province, Costa Rica. The project addressed the overarching questions: How can water be governed sustainably in water-contested and climate-threatened regions? And, how can people transition current water governance regimes toward more sustainable ones? In pursuit of these questions, a series of individual studies were performed with many partners and collaborators. These studies included: a participatory analysis and sustainability assessment of current water governance regimes; a case analysis and comparison of water conflicts; constructing alternative governance scenarios; and, developing governance transition strategies. Results highlight the need for water governance that addresses asymmetrical knowledge gaps especially concerning groundwater resources, reconciles disenfranchised groups, and supports local leaders. Yet, actions taken based on these initial results, despite some success influencing policy, found substantial challenges confronting them. In-depth conflict investigations, for example, found that deeply rooted issues such friction between opposing local-based and national institutions were key conflict drivers in the region. To begin addressing these issues, researchers and stakeholders then constructed a set of governing alternatives and devised governance transition strategies that could actively support people to achieve more sustainable alternatives and avoid less sustainable ones. These efforts yielded insight into the collective actions needed to implement more sustainable water governance regimes, including ways to overcoming barriers that drive harmful water conflicts. Actions based on these initial strategies yielded further opportunities, challenges, and lessons. Overall, the project addresses the research and policy gap between identifying what is sustainable water governance and understanding the strategies needed to implement it successfully in regions that experience water conflict and climate impacts. / Dissertation/Thesis / Ph.D. Sustainability 2014

Väl genomförda övergångsstrategier kan bidra till ett bättre utfall i vuxen ålder för elever med Austismspektrumdiagnos (ASD). Med övergångsstrategier menas i denna studie insatser som genomförs för att underlätta övergången för en elev med ASD från gymnasieskolan vidare till eftergymnasiala verksamheter. Syftet med studien var att identifiera övergångsstrategier i vetenskapliga artiklar. Syftet var även att undersöka vilka uppfattningar gymnasiepersonal med erfarenhet av övergångar för elever med ASD har om dessa övergångsstrategier. För att identifiera övergångsstrategier genomfördes en litteraturöversikt i vilken 22 artiklar inkluderades. Två synteser av innehållet i artiklarna gjordes, dels grupperades innehållet kring vilka uttryck övergångsstrategier kan ta sig, dels försågs varje identifierad grupp med strategier med ett namn och en definition. Detta resulterade i att nio distinkta övergångsstrategier definierades. Data samlades in från gymnasiepersonal genom semistrukturerade intervjuer. Fynden i litteraturstudien låg till grund för utformningen av intervjuguiden. Fem informanter med erfarenhet av arbete med elever med ASD rekryterades genom ett strategiskt urval från fyra olika skolor. Fenomenografisk metod användes vid dataanalysen. Den teoretiska utgångspunkten var Bronfenbrenners ekologiska modell samt Rimm-Kaufman och Piantas ekologiska och dynamiska modell för övergångar. Analysen resulterade i ett utfallsrum för varje forskningsfråga. Utfallsrummet avseende informanternas uppfattningar av övergångsstrategier utgjordes av tre beskrivningskategorier. Dels aktiv och generell medverkan, dels behovsanpassa övergångsstrategierna, dels andra aktörer bör vara drivande. I studien undersöktes också vad som framträder i informanternas beskrivningar av sina erfarenheter kring övergångsstrategier. Tre beskrivningskategorierna framträdde, nämligen inget aktivt arbete med de beskrivna övergångsstrategierna, ad hoc-lösningar samt systematiskt arbete. Vilka möjligheter och hinder personalen såg för ett genomförande var också en frågeställning. Utfallsrummet avseende möjligheter utgjordes av två beskrivningskategorier: gynnsam organisation samt nätverk familj-skola-andra aktörer. Även två beskrivningskategorier avseende hinder framträdde: Bristande förståelse för ASD och/eller stöd kring ASD på olika nivåer samt fokus på övergångar saknas på organisations- och systemnivå. När det inbördes förhållandet mellan utfallsrummen analyserades identifierades olika former av stöd och incitament som faktorer med generellt inflytande. / Well conducted transition strategies can lead to better outcomes in adulthood for students with autism spectrum disorders (ASD). In this study, transition strategies are defined as interventions that are carried out in order to facilitate transition from upper secondary school to post school settings. The purpose of the study was to identify transition strategies in scientific articles The purpose was also to investigate what perceptions upper secondary school staff with experience of transition of students with ASD have about those transition strategies. In order to identify transition strategies, a literature study was carried out in which 22 articles were included. Two synthetises of the content in the studies were carried out. Firstly, the content was grouped under what expressions the transition strategies can take. Secondly, each identified group of strategies was given a name and a definition. As a result, nine different transition strategies were identified. Data was collected from upper secondary school staff by semi structured interviews. The findings in the literature study were used for the design of the interview guide. Five informants with experience of working with pupils with ASD were recruited by strategic sample from four different schools. The phenomenographic method was used to analyse data from the interviews. Both Bronfenbrenner’s ecological model and Rimm-Kaufman and Pianta’s ecological and dynamic model for transitions were used as a theoretical framework. The analysis resulted in one outcome space for each of the research questions. The outcome space concerning the informant’s perceptions about transition strategies resulted in three descriptive categories: active and general participation, adapt the strategies to the needs and other adequate providers should be the driving force. The study also investigated what appears in the informants’ descriptions of their experiences of transition strategies. Three different description categories were identified. No active work with transition strategies was practically implemented, ad hoc solutions and systematic implementation. Another point of research was what staff identified as possibilities and obstacles for implementation. Two descriptive categories concerning the informants’ perceptions of possibilities were identified: favourable organisation and an established network consisting of family, school and other adequate providers. Two descriptive categories concerning obstacles appeared as discouraging: comprehension for ASD and/or support for ASD on different levels was inadequate and lack of focus on transition on an organisational and systemic level. When the internal relationships between the outcome spaces were analysed, different forms of support and incentives were identified as factors with general influence.