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Electrification of Braking Systems on an Electric Regional Aircraft
No full textThe aviation industry is moving toward "more-electric" aircrafts to improve efficiency, reduce complexity, and lower overall system weight. Companies like Heart Aerospace are leading this transition by developing regional hybrid-electric aircraft, where traditionally hydraulic or mechanical systems are being replaced by electrically actuated alternatives to enhance sustainability and adaptivity to new power trains.
This thesis investigates the feasibility of replacing conventional centralized hydraulic braking systems with electrically actuated, brake-by-wire systems in regional turboprop aircrafts. Electrically actuated brakes offer the potential for weight reduction, improved modularity, and simplified system integration. A structured design approach was applied using the Double Diamond framework to generate, evaluate, and refine multiple braking system architectures in line with stringent aerospace requirements.
The most promising concepts were sized based on performance requirements, and their behavior was modeled and simulated under various runway conditions, including integration with anti-skid braking functionality. Additionally, an economic and energy impact assessment was conducted for implementing an electric taxiing motor, considering energy savings, motor and propeller efficiency, and taxi duration.
Results suggest that a federated electro-hydraulic system could provide the required braking performance while maintaining redundancy and enabling future integration of advanced controllers. The findings support the potential for transitioning to more-electric braking solutions in future regional aircrafts
Biophilic design in residential architecture; an exploration of indoor outdoor interfaces
No full textAutonomous Excavation Using Reinforcement Learning with Proximal Policy Optimization
No full textThis thesis presents a reinforcement learning based approach for grading, applied in
the Volvo excavator EC550E. The work was based around a simulation model of the
excavator which facilitated easy training of the algorithm. A hydraulic controller was
trained using proximal policy optimization. Together with the hydraulic controller,
a PID was implemented as a positional controller for a complete system capable of
performing grading tasks.
Training was conducted by testing different reward functions and parameter choices
to improve policy performance. The results showcases hyperparameter evaluation,
velocity tracking accuracy for the hydraulic controller as well as grading accuracy
of the complete system. The implemented solution had an accuracy of ± 4 cm during
grading. However, the hydraulic controller was not able to consistently follow
the target velocities in the cylinders, particularly for the bucket. In future works
the hydraulic controller needs to be retrained for better precision before being deployed
in a real machine. This thesis shows the potential and possibility of replacing
traditional control policies with an machine-learning driven approach
A Health Technology Assessment of the Strokefinder MD100 For Early Detection of Stroke and Traumatic Brain Injury in the Western Cape Healthcare System, South Africa
No full textStroke is the second leading cause of death worldwide, with particularly high prevalence in low- and middle-income countries (LMIC) such as South Africa. Traumatic Brain Injury (TBI) accounts for approximately six million deaths annually and is commonly caused by trauma, an especially significant issue in South Africa (SA), where rates of interpersonal violence and traffic accidents are notably high. The South African healthcare system consists of a private and a public sector. The private sector are profit-driven hospital groups, while the public sector is governmentfunded. The public system operates on a referral-based model, which is not wellsuited to managing time-sensitive medical conditions such as stroke and TBI. This report presents a Health Technology Assessment (HTA) of the Strokefinder MD100 device developed by the Swedish company Medfield Diagnostics AB, within the context of the healthcare system in the Western Cape, South Africa. The HTA is based on an extensive literature review combined with semi-structured qualitative interviews conducted with relevant stakeholders. The findings support the final recommendations for optimal implementation sites of the MD100 with the main purpose of minimising time-to-treatment and thereby improve patient outcomes. With the identified healthcare needs in the Western Cape, the most appropriate implementation sites are identified to be in pre-hospital units, within both private
and public healthcare sectors, or in level 1 hospital facilities lacking CT imaging capabilities within the public healthcare sector
Organising for Circularity in Construction - A Study of the Implementation of Reuse in Swedish Redevelopment Projects
No full textThe construction industry is a significant contributor to both greenhouse
gas emissions and waste, and it is facing increasing pressure to reduce its
climate impact. As a result, interest in the circular economy (CE) within
the construction sector is growing. However, the transition towards
circular practices remains in its early stages, and new workflows have not
yet been fully established. This thesis investigates how circular practices
– particularly the reuse of building products and components – can be
effectively integrated into building transformation and redevelopment
projects. The study explores organisational approaches to reuse, aiming to
identify success factors and provide practical examples of methods and
solutions, with a focus on contract types, procurement strategies,
adaptations to the design and construction process, and the management
of reuse-related challenges. The research was conducted as a multiple
case study with an abductive approach, combining a theoretical
framework with empirical data from 11 semi-structured interviews across
three case projects. The findings show that both partnering agreements
with design-build contractors and divided contract structures with
traditional construction contracts can support reuse, though roles and
responsibilities differ. Traditional contracts require clearly defined reuse
requirements, while design-build contracts rely more on contractor
incentives. Reuse also introduces new activities – such as inventory,
disassembly, and quality control – that increase coordination needs and
challenge traditional workflows. Moreover, the study identifies three
main types of barriers to reuse: cultural, regulatory, and financial.
Cultural barriers can be mitigated by fostering shared commitment and
individual engagement. Regulatory barriers remain resource-intensive to
navigate, suggesting a need for simplified regulations and clearer
standards. Financial barriers, often tied to added labour costs, may be
reduced through more efficient reuse processes. Ultimately, the findings
of this thesis provide guidance on how reuse can be organised in practice,
supporting stakeholders involved in future transformation and
redevelopment projects in planning and organising for reuse
Software-Defined Radio Testbed for 6G Research
No full textAs the demand on speed, coverage and bandwidth continues to increase for wireless
communications, the sixth generation of mobile networks builds on and extends
existing technologies. There is a testbed at Chalmers University of Technology focusing
on the promising technology of distributed multiple input multiple output
(D-MIMO). This project aims at assisting the D-MIMO testbed by constructing a
flexible user equipment based on a software defined radio. Specifically, this is done
by configuring the USRP B205mini-i, a universal software radio peripheral (USRP)
from Ettus Research, in MATLAB to fully utilize its capabilities in signal processing
and wireless communication. Trough simulations in MATLAB and physical testing
of both wired and wireless transmissions, several key aspects are evaluated: the maximum
bandwidth and its limitations on data rate, the relationship between signal
duration and the on-board memory of the USRP, and the possibility of synchronizing
multiple USRPs. Results show a maximum bandwidth of 41.24 MHz and a
symbol rate of 10.31 Msym/s. Moreover, the result does not show a strict limitation
on the signal duration as the USRP seems to stream data directly to and from
the host computer. Synchronization is possible between two USRPs with a precision
of a few microseconds at best. The USRP B205mini-i proves to be a flexible
and cost-effective candidate for UE in the D-MIMO testbed. However, performance
enhancements, such as lower-level configuration via FPGA programming, may be
necessary depending on future system requirements
Analysis of Electric Conductivity Variance in the Insulation of HVDC Cables
No full textPower cables with insulation based on cross-linked polyethylene (XLPE) are used
in high voltage direct current (HVDC) onshore and offshore power grids to transmit
large amounts of electric energy over long distances. One of the important aspects
to be considered when designing the insulation system of such cables is the
variation of the electric conductivity of the insulation material in radial direction
between the energized conductor and grounded screen. Since the conductivity
of XLPE is dependent on electric field strength and temperature, predicting its
actual changes in the cable is challenging and typically is done based on some
empirical formulas. These, however, do not take into account the effect of the
diffusion of impurities and byproducts introduced into the material during the
manufacturing process on conductivity variations.
In the thesis, the electric conductivity of XLPE was measured using material samples
taken from continuous peelings of the insulation of a real cable. This allowed
for examining its field and temperature dependencies at different distances from
the conductor, i.e. at different contents of byproducts. The experimentally obtained
material properties were further utilized as input for a computer model,
which was developed to analyze the dynamics of space charge accumulation and
corresponding electric field in the cable. The results outlined in the thesis are
essential for improving the design rules for HVDC cables to ensure their reliable
and safe operation
Development of a Lightweight Fixed-Wing Drone for Early Situational Awareness in Critical Applications
No full textThis thesis explores the development of a lightweight, sub-250 g fixed-wing drone intended
for early situational awareness in emergency response scenarios. Conducted
in collaboration with Remote.aero and the Swedish Sea Rescue Society, the work
focuses on concept development, aerodynamic optimization, prototyping and validation
through flight testing. An extensive benchmarking study identified key design
parameters and trade-offs for tailless UAVs. Utilizing XFLR5 aerodynamic simulations,
the study optimized critical design variables, notably aspect ratio, taper ratio
and wing span, to maximize the L/D ratio within the intended flight envelope. Two
prototypes were constructed using 3D printing, confirming theoretical predictions
and demonstrating competitive performance during flight tests. The final prototype
achieved a stall speed below 8 m/s, a maximum estimated endurance of approximately
43 minutes at loiter speed of 10 m/s, and a maximum estimated range of
55 km at a cruise speed of 25 m/s. The maximum L/D ratio was 16, at a loiter
speed of 11 m/s. Its low intrinsic ground risk classification (iGRC 1) under current
regulations simplifies deployment in both urban and rural settings, allowing it to
compete with heavier systems while offering critical regulatory advantages. However,
flight testing revealed that the reduced mass of the drone makes it sensitive to
wind gusts, limiting reliable flight at wind speeds exceeding approximately 10 m/s
unless additional airspeed margins are maintained. Ultimately, the design met all
other requirements and could carry out a typical mission profile with ease, fulfilling
the purpose of the projec
PPP solutions for prefabricated modular housing in post conflict Syria
No full textSyria’s prolonged conflict has left over one-third of its housing stock damaged or destroyed and
displaced more than 13 million people. Traditional reconstruction methods are too slow, costly, and
institutionally demanding for Syria’s current fragile context. This thesis explores the potential of
combining Public-Private Partnerships (PPPs) with modular prefabricated housing as a feasible
solution for large-scale, affordable housing delivery in post-conflict Syria.
The study employs a qualitative methodology based on a systematic literature review and six semi structured
interviews with stakeholders from development institutions, the private sector, academic
researcher, NGOs and International banking institutions. It identifies a key research gap in
integrating PPP financing with modular construction technologies in fragile states.
Findings show that modular housing offers significant benefits, including speed, cost-efficiency,
reduced labor needs, and quality control. However, its application in Syria faces multiple barriers,
high capital costs, cultural resistance, legal ambiguity, and weak institutional capacity. The research
shows that context-adapted PPP frameworks, utilizing tools such as Islamic finance instruments
(e.g., Ijara, Istisna), minimum revenue guarantees, and lifecycle-based blended financing, can help
mitigate these risks.
The thesis proposes a pilot PPP model to be implemented on secure, state-owned land in relatively
stable areas like Aleppo or Homs countryside. The model emphasizes phased implementation, local
authority engagement, and transparent governanc
Defining attractive cities with focus on social sustainability and aesthetics; examination of the redevelopment of Selma Lagerlöfs torg
No full textCreating attractive cities is a complex process, where the urban environments play a
central role in shaping the everyday experiences of their inhabitants. The surroundings
affect people's social interactions, economic opportunities and overall quality of life.
The aim of this study is to define what the concept of attractiveness in urban spaces is,
with focus on aesthetics and social sustainability. This is examined through a literature
study of urban theories and policy documents, particularly policies of the New
European Bauhaus (NEB), Gestaltad Livsmiljö (GL), and the Architectural Policy of
Gothenburg (AP), and the urban theory Life between buildings by Jan Gehl.
Attractiveness is further studied through a case study at Selma Lagerlöfs torg in
Gothenburg. This case study compares perceptions from both a project management
perspective and from a residential perspective after the redevelopment. This was done
through an interview study with 10 main contributors to the project, and site visits with
a survey study, which was answered by 59 residents in the area.
The results of this study show that an attractive city is not solely characterized by visual
qualities, but also by its capacity to promote social sustainability, inclusiveness, and
aesthetics. To plan an attractive city the process of urban development must be an
iterative, inclusive, human centred and context aware process, creating inclusivity with
the contemporary and future locals in the area.
Selma Lagerlöfs torg was overall a successful project, appreciated both by main
contributors and by locals in the area. However, none of the policy frameworks were
consciously used when planning the redevelopment, only the theories by Gehl were
partly considered. This concludes, that while policy and theory provide valuable
guidance true attractiveness ultimately depends on how spaces are perceived, used, and
lived in by diverse groups over time