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Although project work has received considerable attention in Swedish educational research, it has rarely been investigated within a specific school subject. Drawing on video recordings from two upper-secondary schools in Sweden and grounded in ethnomethodological conversation analysis, this compilation dissertation explores how project work is interactionally accomplished in English as a foreign language (EFL) classrooms. Across the constituent studies, I examine students’ task discussions, teacher–student desk interactions, and follow-up discussions after students’ project presentations, describing how these events are interactionally organized and what they reveal about the situated accomplishment of project work in EFL classrooms.

The first study explores how students perform a film-based group discussion task designed to engage them with the project theme. The analysis shows how students, in the course of reconstructing scenes from the film, engage in corrections and word searches. In doing so, they create learning opportunities that involve both linguistic forms and content-related words and expressions that are consequential for their understanding of the film and their engagement with the project theme. Both the second study and the third examine how instructional support is given and received during teacher–student desk encounters. The second study focuses on student-initiated interactions and investigates how shared understanding of task instructions and procedures is established. As the analysis shows, students use so-prefaced formulations to display their understanding of the teacher’s prior responses, which the teacher then either confirms or disconfirms. In this way, establishing shared understanding becomes a joint, collaborative process between the teacher and the students. The third study zooms in on how teachers respond to different types of student questions that emerge throughout the different stages of project work. Analyzing the response formats, the study shows that teachers design their responses in different ways, depending on students’ needs and the pedagogical contingencies of the moment. Centered on follow-up discussions after students’ project presentations, the fourth study investigates how students hold one another accountable for their project outputs. The findings show that students mobilize question–answer sequences in which the presented work is explained and justified in relation to the task expectations. 

Taken together, these studies illuminate the interactional ecology of EFL project work by showing how participants create learning opportunities, manage contingent instructional support, and organize accountability for both the process and the product. With this dissertation, I argue that project work is not a fixed educational approach, but a situated classroom practice that is socially and locally accomplished.

Integrating bioenergy with carbon capture and storage (BECCS) into biomass-fired combined heat and power (CHP) plants offers crucial potential for achieving negative emissions. To respond to fluctuating heat demand and volatile electricity markets, CHP plants must operate dynamically, and this results in largely fluctuating operation of CO₂ capture. This dissertation aims to improve the dynamic operation of CO₂ capture in biomass-fired CHP plants to boost negative emissions through dynamic modelling, advanced control and potential assessment under different operating modes.

To provide systematic guidance for selecting appropriate modelling approaches, both first principles and machine learning (ML) approaches are established and compared. Systematic comparison is first conducted across three first-principles models (ideal static models, dynamic models with control, and dynamic models without control) under three varying operating parameters (flue gas flow rate, CO₂ concentration, and available heat). Three ML models (Informer, long short-term memory, and back-propagation neural network) are further compared across four applications (system identification, monitoring, optimisation, and performance estimation). Results show that no single model consistently outperforms the others across all cases. While Informer achieves the highest accuracy in most applications and for most target variables, model selection should be tailored to the specific application. Model predictive control (MPC) is then developed and evaluated for managing operational variability of CHP plants. MPC demonstrates superior controller performance over conventional proportional integral (PI) control, achieving a 47–62% reduction in settling time and recovery time, and a 66–74% reduction in integrated absolute errors for CO₂ capture rate.

With modelling foundations, negative emission potential is evaluated at both plant and national scales under two operating modes (OMs), both of which prioritise heat supply. OM1 maximises CO₂ capture by sacrificing electricity output while maintaining heat supply, achieving 8.7 MtCO₂/yr nationwide negative emissions at a levelized cost of CO₂ avoided of 36.9 $/tCO₂. OM2 maximises CO₂ capture while maintaining both heat and electricity supply, yielding 4.3 MtCO₂/yr positive emissions at 52.0 $/tCO₂ (but still reducing emissions by 6.3 MtCO₂/yr compared with the reference plant without CO₂ capture). The biogenic fraction of fuel emerges as the critical parameter, requiring minimum fractions of 32.8% and 84.3% for the two OMs to meet Sweden’s 3 MtCO₂/yr target.

The contributions of this work include: (i) systematic guidance for dynamic model selection tailored to different CO₂ capture applications, (ii) quantitative evidence of MPC’s superiority over PI control under realistic CHP dynamic scenarios, and (iii) a national-scale BECCS potential and cost assessment for Sweden under maintained heat supply constraints. Results demonstrate that Sweden’s BECCS climate targets (3–10 MtCO₂/yr by 2045) are technically achievable, as OM1 alone can deliver 8.7 MtCO₂/yr negative emissions. The choice between operating modes represents a fundamental trade-off between maximising carbon removal and maintaining electricity supply. These results offer quantitative guidance for policymakers weighing carbon removal ambitions against energy system constraints.

The evolution of telecommunications networks continues without interruption, transforming society and redefining many of the services we've become familiar with, often improving the quality of life. Connectivity, mobility, and the network's ability to support new services have changed the way we perform daily activities: reading a newspaper, managing a bank account, playing games, or communicating. And technologies like IoT, artificial intelligence, virtualization, and the widespread availability of data are paving the way for services that are even difficult to imagine today.

As services become increasingly central and critical, their availability over time cannot be compromised without a significant impact. Disruption can cause a severe setback for those who rely on those services. Network resilience becomes a key requirement for next-generation mobile networks. But what does it mean to have a resilient network? What makes a system resilient, and how can we improve it? Our research starts with these key questions. While using the classic definition of resilience (the ability of a system to respond rapidly to internal or external stresses that compromise performance), we argue that improving it requires identifying the system functions that contribute to resilience and quantifying their contributions.There is also a connection to reliability. Reliability describes a system's ability to maintain expected performance over time under normal conditions. In contrast, resilience is the ability to withstand abnormal conditions and restore proper operation. Both involve managing faults. Increasing service availability means reducing the probability of faults and the time and costs to resolve them.

In this sense, if resilience is the system's ability to respond to an internal or external event that compromises its performance, then fault management (the process of detecting, isolating, and correcting faults) is the system function through which we address faults and seek to resolve them.Our research, as presented in this thesis, produced several key outcomes. We defined a resilience model for mobile network nodes, explored the concept of failure, and developed a flexible method for calculating failure probability. We investigated its probability and the costs to mitigate its impact. Based on these results, we proposed a framework for fault management and identified an optimal hardware design to improve reliability and resilience. Maintaining a holistic approach was necessary to develop a fault management model for all system levels—hardware, firmware, and software. Each layer works autonomously when possible or with others to achieve fault management's essential goal: recovery from a faulty condition. This leads to board-level design requirements for high-quality service and experience.

Decarbonisation of the energy sector is now an urgent worldwide challenge. Among the different transportation industries, aviation is one of the most difficult in which to achieve this. Towards that goal, this thesis establishes a map for the design and environmental potential of novel hybrid-electric and hydrogen-powered regional aircraft. It does so, by revealing and connecting the multi-disciplinary interactions between propulsion and aircraft systems. It advances the evaluation of novel electrified powertrains from simplistic representations to comprehensive models, capable of credible and consistent conclusions.

The deployed platform for investigations consists of detailed models for turbomachinery components, electrical power system, aircraft/mission and environmental performance. It is capable of the integrated propulsion-aircraft design, considering cross-system top-level requirements and connections. This is complemented by the framework's ability to separate conceptual design stages and quantify their individual impacts.

The system-level impact of critical component interactions is investigated to enhance the conceptual design process' fidelity. By highlighting trade-offs in the sizing and performance of the electrified powertrain, a design and operation balance for favorable environmental performance is established. This reveals and fortifies the understanding of connections between system design choices and optimal power management guidelines. Electrification enables several operational and propulsive synergies, which are conceptualized within the thesis. Their contribution and effects are assessed and quantified. Major gravimetric, volumetric and operational limitations in the design of alternative-energy aircraft are also identified and their impact is quantified. 

The holistic knowledge of opportunities and challenges in hybrid-electric aircraft design crafts a pathway for conscious and effective conceptual design. It reveals the viability of small electrified and H₂-fired regional aircraft and sets a roadmap of necessary component-level advancements that could facilitate their integration in civil aviation.

Globally, society is undergoing a demographic shift characterised by an ageing population and increased life expectancy, posing challenges to the healthcare system that may be addressed through health promotion interventions supporting beneficial health behaviours. The transition from working life to retirement could be a potential window for such interventions. Sedentary behaviour, common among older adults, is associated with adverse health outcomes. Although eHealth interventions incorporating self‑management strategies may support reductions in sedentary time, there is a lack of research targeting reduced sedentary time during the transition to retirement. Involving end users in the development of eHealth interventions through participatory design may help ensure alignment with users’ needs. The overall aim was to contribute to health promotion by generating new knowledge on how sedentary time can be reduced, and how adherence to reduced sedentary time can be promoted, through an eHealth intervention including self-management strategies, in older adults transitioning from working life to retirement. A further aim was to develop and test such an intervention.

The thesis comprises four studies following a participatory design approach. In the initial needs‑assessment phase, focus groups with older adults transitioning to retirement explored perceptions of self‑management strategies for reducing sedentary time (Study I). In the idea generation phase, workshops were conducted to explore desired features of an eHealth intervention including self‑management for reducing sedentary time and promoting adherence to the reduced sedentary time among the target group and to develop a digital prototype of such an intervention (Study II). In the testing and retesting phase, the feasibility and usability of the developed eHealth intervention were examined through a mixed-methods evaluation study which applied an ABA single-case experimental design (Study III). In the evaluation phase the effect of the eHealth intervention on daily sedentary time, assessed using an accelerometer, was examined through a randomised controlled trial (RCT) (Study IV).  

The findings highlight the importance of supporting autonomy in eHealth interventions for reducing sedentary time through adaptable self‑management strategies and user‑directed intervention use (Studies I–II). Reducing sedentary time required support for making changes in everyday life. Self‑management strategies addressing both affective and cognitive determinants – especially identifying joyful activities – were identified as central in reducing sedentary time and supporting adherence (Studies I–II). The GAUdiS (an acronym for the Swedish equivalent of Joyful Activities Facilitate Reduced Sedentary Time) eHealth intervention was developed, comprising features for identifying joyful activities and supporting goalsetting and planning based on mental contrasting with implementation intentions, which can be understood based on the Integrated Behavior Change model (Study II). Although GAUdiS was developed together with older adults transitioning to retirement as active participants, it demonstrated only modest feasibility and usability, possibly partly due to the demands associated with a standalone eHealth design (Study III). The final RCT showed no reduction in sedentary time with GAUdiS among older adults transitioning to retirement; these findings should be interpreted in light of the small sample size (Study IV).

In conclusion, the findings suggest that employing autonomy‑supportive approaches, as well as targeting both affective and cognitive determinants, are considered central to reducing sedentary time in the transition to retirement. However, for an eHealth intervention to be effective in reducing sedentary time in the transition for retirement, additional components beyond those offered by the current standalone version of GAUdiS may be needed. Given that the studies included in the thesis involved a limited number of participants, further research including larger groups is needed in order to examine how sedentary time can be reduced during the transition to retirement. While this thesis focused on total sedentary time, future research might explore whether GAUdiS could be effective when targeting only those sedentary behaviours that individuals perceive as unwanted or unhealthy, in alignment with health promotion values.