Chalmers Open Digital Repository
Not a member yet
26247 research outputs found
Sort by
Utveckling av boggie för en elektrisk snöskoter
No full textThis thesis discusses the development of a boggie for an electric snowmobile for im proved maneuverability. The thesis commences with an introduction which contains background, the purpose and research questions which acts as the main goal of the report. The ultimate objective is to improve the snowmobile’s manueverability compared to its predecessor. The introduction is followed by a chapter of theory. It contains necessary theories and information which will enhance the comprehension throughout the report. The method chapter describes how the work has been carried out. It began with an outlining of the work followed by technical specifications. Thus, product development matrices were made. Otherwise, CAD, force and stress analysis is desribed as well. The result chapter begins with a definitive describtion of the technical specifica tions which the boggie shall fulfill. The result from the matrices is then stated. The winning concept, ”Carvingformad matta” is further described. An additional feature, an adjustable rail is implemented to further improve the maneuverability. The concept is explained further regarding the design in CAD and the force and stress analysis. This is done to show if the boggie is capable of withstanding the assumed load case. The work concluded in a 13.6 % reduction of the required moment needed
to turn in firm snow. However, the work does not succeed in the fulfillment of the remaining research questions
Buckling Screening Analysis of Ship Plate Structures
No full textSufficient strength of the ship’s structure is a significant factor to ensure safe shipping. Thus, it is important to study the failure modes of the structure, such as buckling. However, there are limited methods to perform buckling check efficiently, and it is often still con-ducted manually.
The aim of the study was to create a new buckling check tool, making buckling analysis efficient and saving time for other work. This has solved by implementing a script that cal-culates the buckling of the unstiffened rectangular plate fields of the ship. The script is based on a screening method that is used to find critical plate fields. The criteria for the method are buckling guidelines by DNV.
The functionality of the study method was tested by a case study for a generic global model part. The analysis was performed twice with a coarse mesh by subjecting a global load combination of still water bending moment and ice shear force to the model. The buckling capacity of the plate fields was estimated by examining their transversal and longitudinal compressive and shear stress. The initial model was strengthened according to the initial results, and then the analysis was carried out again.
The main findings of the case study were the effect of the framing system selection and plate field size on buckling capacity. The location of the plate field in the ship was also found to influence the buckling resistance.
The results of the case study were validated using manual calculation and a local model. Manual calculation proved the functionality of the study method and the validity of the results. In turn, the local model analysis ensured the result accuracy with a coarse mesh and the applicability of the study method to different models. The results obtained from the case study are reasonable.
Although the development of the method is still necessary, the study method proves to be an effective and functional approach to buckling check analysis with potential for the future
Adaptive and Generalizable Vision-Language Models
No full textDomain generalization remains a significant challenge for vision-language models, as they are required to perform reliably on previously unseen domains during inference. In this work, we introduce a domain prompt fusion framework aimed at improving the generalization capability of CLIP-based models under domain shift. Our approach integrates three core components: a dual-part soft prompt (comprising domain-agnostic and domain-specific prompts), a domain feature extractor, and a prompt fusion mechanism. The extractor generates domain representations from input images and computes source-domain prototypes, which guide the fusion of prompt-based text features. By weighting and combining domain-aware text features according to their similarity to the input images domain representation, the model achieves improved alignment between visual and textual modalities.
We evaluate the proposed method on two widely-used benchmarks: Office-Home and mini-DomainNet. The results demonstrate consistent performance gains over standard zero-shot CLIP and CoOp. Specifically, our method achieves average accuracies of 84.98% and 85.53% on Office-Home and mini-DomainNet, respectively. Extensive ablation studies and visualizations further validate the effectiveness of our design. While a small performance gap remains compared to the current state-ofthe- art method DDSPL, our analysis identifies key areas for future enhancement, including prompt design refinement, class-dependent fusion strategies, and the use of latent domains in place of manual annotations
Efficient conversion from Dependency Trees to Abstract Syntax Trees in Natural Language Processing
No full textThis thesis is a contribution to the field of rule based Natural Language Processing. Within rule based NLP there are different grammar formalisms, each with their own strengths and weaknesses. This work presents several improvements to a tool for converting between two such grammar formalisms. First we improved the performance significantly. Secondly we improved the debugging facilities of the tool. Thirdly we made it possible to convert between trees that had previously been too structurally different from each other
A room with no view; Sweden’s future housing policies
No full textThis thesis investigates the evolving role of building regulation in defining housing quality
within Swedish policy, with a focus on the ideological and structural
consequences of deregulation. Through a qualitative analysis of historical policy
documents, architectural standards, and empirical data from Gothenburg’s housing
stock, the study traces how regulation has shifted from a welfare-state mechanism for
safeguarding residential quality to a market-oriented tool for enabling cost-efficiency.
Drawing on socio-technical systems theory and the social shaping of technology,
the research identifies how contemporary rhetoric around innovation and flexibility
conceals a systematic erosion of spatial and qualitative standards in housing. Findings
reveal that deregulation has contributed to fragmented governance, reduced
accountability, and a housing market increasingly unable to meet the needs of its residents.
By exploring the gap between policy discourse and lived outcomes, this thesis
challenges prevailing narratives of progress and argues that meaningful innovation
requires a redefinition—not a desertion—of housing quality
Measurements of heat current and its fluctuations in superconducting quantum systems
No full textAs the quantum systems we can control and manipulate increase in size, understanding
heat dynamics becomes increasingly important. In this master’s project,
we study the heat currents flowing between two out-of-equilibrium reservoirs across
a superconducting quantum circuit composed of two mutually coupled, flux-tunable
qubits. Electrical noise applied to the flux line of a qubit induces incoherent coupling
between the modes in the single excitation manifold. Each mode is coupled
to a thermal bath, realized with microwave waveguides. By coherently driving one
of the modes to its first excited state, a heat current is induced. We measure heat
currents on the scale of a few attoWatts, along with the fluctuations in said current.
The results are compared to simulations that use full counting statistics to
compute the currents and fluctuations of the process. These findings pave the way
for demonstrating advantages of quantum systems over classical ones in quantum
thermodynamics
Effektivisering av stämpningsprocessen i byggproduktion - En kvalitativ studie av ergonomi, arbetsflöde och hållbarhet vid JM
No full textI takt med ökad komplexitet i byggproduktion har behovet av effektiva, ergonomiska
och hållbara arbetsmetoder blivit allt mer centralt. Ett ofta förbisett men
fysiskt krävande moment i denna process är stämpning, särskilt rivningen av tillfälliga
stämpmaterial vid bjälklagsgjutning. Denna studie har genomförts i samarbete
med JM Bostad Riks och syftar till att analysera och effektivisera stämpningsprocessens
rivningsmoment ur ett ergonomiskt, logistiskt och ekonomiskt perspektiv.
Genom semistrukturerade intervjuer, observationer och litteraturstudier har nuläget
kartlagts, med fokus på arbetsmiljö, arbetsflöde och hållbarhetsaspekter. Resultatet
visar att rivningsmomentet ofta saknar tydlig planering, ansvarsfördelning och
tillgång till hjälpmedel, vilket skapar risk för belastningsskador, ineffektiva arbetsflöden
och ökade kostnader. Samtidigt framkommer att kunskapen kring mer effektiva
arbetssätt ofta är tyst och inte överförs inom organisationen.
Utifrån teorier om Lean production, ergonomi och hållbar utveckling identifieras
flera förbättringsförslag: införande av standardiserade rutiner, arbetsrotation, förbättrade
hjälpmedel och tydligare planering. Studien visar att även till synes små
och rutinmässiga moment kan ha stor påverkan på produktionsflöde och arbetsmiljö,
och att organisatoriska förbättringar kan generera både sociala och ekonomiska vinster.
På så vis kan en mer hållbar och motståndskraftig byggproduktion möjliggöras,
där människans förutsättningar står i centrum
Lásságámmi - main model
No full textLásságámmi was designed by the self-taught architect Eino Jokinen together with Valkeapää himself. According to the architect, the buildings design was the result of a close friendship and over a year long process. The house was intended to look like a large turf hut, and the name therefore literally translates to “the sloping rock turf hut”. Long before the construction started, Nils-Aslak Valkeapää spent a lot of time on the plot while working with the text for his book “Girddán Seivvodan” (I Fly, I Soar). In this way, the plot became his ruoktu (home) long before the building was completed, which in a way reflects his definition of space and the scope of home. The concept of ruotku is central to his art, and there are often clear parallels between the building's structure and composition of rooms, to the creative processes behind his texts. Since his passing in 2001, artists and researchers, chosen by a council, can live and work with their art of research in his house