When a building is exposed to fire, it is required to remain structurally stable for a period of time. The regulations do however allow some types of localised failures within this time frame. The damage area of these failures must be contained and remain proportional to the initial triggering action and not continue into a widespread collapse, commonly referred to as a progressive collapse. In order to prevent progressive collapses, it is necessary to first identify which types of failures that could result in a progressive collapse. In a recent study (Iqbal N., Ph.D. thesis, Luleå University of Technology, 2016), single-storey steel frame buildings affected by localised fires were analysed. In the study it was identified that an initial failure in the truss’ top chord could potentially result in a progressive collapse. The reason for this is because when the top chord fails, the truss and its roof sheeting deflect and transitions into only handling catenary forces. The catenary forces present in the roof sheeting are then transferred to the adjacent trusses which therefore risks collapsing. The analysis could however not determine the possibility of progressive collapses and how factors such as truss span length affect the possibility of progressive collapses. The purpose of this thesis therefore became to analyse how span length affect the roof sheeting’s catenary forces and try to determine if a failure in the top chord could result in a progressive collapse. To answer this, finite element analyses where conducted on two different truss models with varying span lengths, i.e. 18- and 36-meter. Each model consisted of three trusses along with columns, bracings, and roof sheeting. Additionally, a hand calculation model was adopted to determine the strength of the catenary forces. From the finite element analysis, it could be seen that the adjacent trusses of the 36-meter truss model became grossly deformed. Hence indicating that a longer span length would increase the possibility of a progressive collapse. However, the hand calculation model used to calculate the strength of the catenary forces indicated that catenary forces present in the roof sheeting of the longer truss model, was relatively weak compared to the shorter truss model. The reason for this could not be determined, but some adjustments to the hand calculation model might be necessary to make it compatible with the analysed truss model. Consequently, it was impossible to determine the possibility of a progressive collapse. Additionally, during this work it was identified that other factors, such as truss model, bay length and roof sheeting thickness, could affect the possibility of progressive collapses. Hence, further work is necessary to determine the possibility of a progressive collapse. / När en byggnad utsätts för brandpåverkan ska den förbli strukturellt stabil under en viss tidsperiod. Regelverken tillåter dock att vissa typer av lokala skador inträffar redan under denna tidsperiod. Dessa skador måste begränsas till en viss area och förbli proportionerliga mot den initiala skadan och inte resultera i utbredda kollapser, det vill säga fortskridande ras. För att kunna förhindra fortskridande ras är det nödvändigt att först identifiera vilka typer av skador som skulle kunna resultera i fortskridande ras.  I en relativt ny analys (Iqbal N., Doktorsavhandling, Luleå tekniska universitet, 2016) analyserades den bärande konstruktionen i enplans stålhallar då konstruktionen utsattes för lokala bränder. Där det identifierades att ett brott i balkens överram eventuellt skulle kunna resultera i ett fortskridande ras. Brottet i överramen medförde nämligen att balken och dess takplåt sjönk ihop och övergick till att endast hantera linkrafter. Takplåtens linkrafter fördelades ut till de angränsade balkarna som därmed riskerade att kollapsa. Analysen kunde dock inte verifiera att ett fortskridande ras var möjligt eller avgöra hur faktorer såsom balkspännvidd påverkade sannolikheten för ett fortskridande ras. Syftet med detta arbete blev därför att analysera om balkspännvidd påverkade takplåtens linkrafter samt att försöka avgöra om ett brott i överramen kan resultera i ett fortskridande ras eller inte. För att besvara detta genomfördes finita elementanalyser på en 18- och en 36-meter lång balk. Varje modell bestod av tre balkar med tillhörande pelare och takplåt. För att sedan kunna uppskatta styrkan av linkrafterna i takplåten tillämpades en handberäkningsmodell.  Resultatet från finita elementanalyserna visade att den längre balkmodellen utsattes för högre påkänningar i jämförelse med den kortare balkmodellen. Detta indikerar att en längre spännvidd ökar sannolikheten för fortskridande ras. Handberäkningsmodellen som användes för att beräkna styrkan av linkrafterna gav dock generellt mindre linkrafter för den längre balkmodellen jämfört med den kortare balkmodellen. Anledningen till detta gick inte att fastställa men det skulle kunna vara så att handberäkningsmodellen behöver justeras för att kunna tillämpas på den undersökta balkmodellen. I och med detta var det omöjligt att avgöra sannolikheten för ett fortskridande ras. Under detta arbete identifierades det även att andra faktorer så som balkmodell, centrumavstånd mellan fackverk och plåttakstjocklek skulle kunna påverka linkrafternas styrka. På grund av detta är fortsatt arbete nödvändigt för att kunna avgöra möjligheten och sannolikheten för ett fortskridande ras.

Mobile devices have evolved from an accessory to the primary computing device for an increasing portion of the general population. Not only is mobile the primary device, consumers on average have multiple Internet-connected devices. The trend towards mobile has resulted in a shift to “mobile-first” strategies for delivering information and services in business organizations, universities, and government agencies. Though principles for good security design exist, those principles were formulated based upon the traditional workstation configuration instead of the mobile platform. Security design needs to follow the shift to a “mobile-first” emphasis to ensure the usability of the security interface. The mobile platform has constraints on resources that can adversely impact the usability of security. This research sought to identify design principles for usable security for mobile devices that address the constraints of the mobile platform. Security and usability have been seen as mutually exclusive. To accurately identify design principles, the relationship between principles for good security design and usability design must be understood. The constraints for the mobile environment must also be identified, and then evaluated for their impact on the interaction of a consumer with a security interface. To understand how the application of the proposed mobile security design principles is perceived by users, an artifact was built to instantiate the principles. Through a series of guided interactions, the importance of proposed design principles was measured in a simulation, in human-computer interaction, and in user perception. The measures showed a resounding difference between the usability of the same security design delivered on mobile vs. workstation platform. It also reveals that acknowledging the constraints of an environment and compensating for the constraints yields mobile security that is both usable and secure. Finally, the hidden cost of security design choices that distract the user from the surrounding environment were examined from both the security perspective and public safety perspective.

The question of what makes a person, or a society develop has been asked countless of times. There are many factors that can influence this. This research will seek to explore whether culture matters in relation to a person’s personal development. The present study interviewed twelve Afghan immigrants living in Sweden and investigated whether they felt like culture adjustment was necessary in order for them to develop. The study is using an abductive approach as the respondents' answers are analyzed in firsthand while the theoretical framework is used as a guidance throughout the research. Lawrence E. Harrisons theory was conducted as the theoretical framework. Harrison was a professor who believed that culture affects a person's ability to develop (Harrison, 2000, p. 2). This research contributed to the prevailing literature by analyzing this topic from a bottom-up perspective by interviewing the Afghan immigrants and presenting their perspectives. Further research regarding this topic would be appreciated as the research gap still needs research to be filled. The findings of this study suggest that the twelve Afghan immigrants do not feel like a person has to adapt to Swedish culture to develop. By rather mixing different cultures and being openminded they feel has helped them to develop. Further, Harrison is arguably too categorical, hence, it is not feasible to categorize people by culture because development is different from person to person.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13220号 / 論医博第2167号 / 新制||医||1033(附属図書館) / (主査)教授 高橋 淳, 教授 宮本 享, 教授 伊佐 正 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Precast concrete multistory buildings are used in an attempt to optimize the available construction space and reduce costs. However, little is known about predicting their capacity in a brittle response mode due to the sudden loss of a critical element that could induce a Progressive Collapse Scenario. Therefore, the National Institute for Standards and Technology (NIST) developed an explicit approach in the design of precast concrete systems that is intended to mitigate a progressive collapse by enhancing the rotational capacity of joints and the robustness of the structural system. A full-scale experiment was conducted to investigate the structural performance of a prototype design under a column-removal scenario. The test assembly frame, consisting of three columns and two beams, was subjected to a displacement controlled vertical force acting at the center to characterize the failure modes and collapse mechanisms. Brittleailures of critical structural elements were observed and significantly impacted the performance.

The projected and current adoption rates of electric vehicles are increasing. Since electric vehicles require that they be recharged continually over time, the energy needs to support them is immense and growing. Given existing infrastructure is insufficient to supply the projected energy needs, models are necessary to help decision makers plan for how to best expand the power grid to meet this need. A successful power grid expansion is one that enables charging stations to service the electric vehicle community. Thus, plans for power expansion need to be coordinated between the power grid and charging station investors. The infrastructure for the charging stations has to also be resilient and reliable to absorb this increase in load. Charging stations therefore should be included in the plans for post power disruption planning. In this work, two two-stage stochastic programming models are developed that can be used to determine a power grid expansion plan that sup- ports the energy needs, or load, from an uncertain set of electric vehicles geographically dispersed over a region. Another three-stage stochastic programming model is presented, where the decisions are made first to select which charging stations to install and expand uninterruptible power supply units and renewable energy sources. Then, when the disrup- tion occurs in the second-stage, repairs in power system and charging stations take place ahead of the arrival of panicked population to prepare for the expected surge in power de- mand. Finally, as demand is unveiled, managerial and operational decisions at the charging stations are made in the third-stage. To solve the mathematical models, we utilize hybrid approaches which mainly make use of Sample Average Approximation and Progressive Hedging algorithm. To validate the proposed model and gain key insights, we perform computational experiments using realistic data representing the Washington, DC area. Our computational results indicate the robustness of the proposed algorithm while providing a number of managerial insights to the decision makers.