Publikationer från Uppsala Universitet
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Towards Real-World Control With Reinforcement Learning
No full textReinforcement learning (RL) has achieved remarkable success in simulated environments and games,yet its deployment in real-world applications remains challenging due to at least three critical issues:poor sample efficiency, inadequate uncertainty handling, and safety concerns.While RL algorithms can learn complex policies through trial and error,they often require thousands or millions of interactions and struggle with the constraints of physical systems, where data collection is expensive and unsafe exploration is prohibitive. This dissertation addresses these challenges by developing methods that bridge RL with classical control theory, uncertainty quantification, and generative modeling. Our research is focused on three complementary approaches: integration of control knowledge into RL frameworks, modeling of both aleatoric and epistemic uncertainty, and development of computationally efficient expressive policy representations using diffusion models. For control integration, we introduce controller-guided exploration techniques, structured neural network architectures inspired by observer-controller principles, and residual learning approaches that leverage simple controllers.For uncertainty quantification, we develop ensemble-based methods that address epistemic uncertainty in model parameters and aleatoric uncertainty in environment dynamics, enabling risk-sensitive optimization and conservative value estimation in regions with limited data coverage. For policy representation, we leverage diffusion models with novel entropy regularization schemes and consistency models for real-time inference. Empirical evaluations on both simulated benchmarks and physical control systems demonstrate substantial improvements in sample efficiency, robustness, and computational performance. Our control-guided approaches reduce training time from hours to minutes on water tank level control tasks while significantly improving disturbance rejection capabilities. The uncertainty-aware methods balance performance with safety constraints, addressing distribution shift challenges in offline RL settings. Additionally, our consistency model approach enables real-time policy deployment with inference speeds up to 60 Hz while maintaining competitive performance. This work represents a step toward practical RL by combining the theoretical guarantees of control theory, the uncertainty awareness, and the expressiveness of generative models. As I realized through my research journey, integrating domain knowledge with learning is far more powerful than either approach alone, and awareness of uncertainty is crucial for building reliable decision-making systems. These approaches enable more reliable and efficient learning in complex real-world settings, potentially expanding the application of RL to safety-critical domains including industrial control systems, autonomous vehicles, and robotics
Corrosion resistance of additively manufactured Ti-6Al-4V titanium
No full textTitanium alloy Ti-6Al-4V (Ti64) offers excellent properties for biopharmaceutical applications but remains less studied compared to stainless steel 316L (SS316L). This thesis characterized the corrosion resistance of additively manufactured Ti64 produced by Laser Powder Bed Fusion (LPBF) and Electron Beam Melting (EBM), using L-PBF SS316L as reference. Samples were manufactured in different orientations (0°, 45°, 90°) and L-PBF Ti64 underwent heat treatments including stress relief (595°C/1h), solution treatment (900°C/1h), and aging (500°C/4h). Immersion tests were conducted in 1M NaCl and 1M NaOH solutions for 24 hours and 21 days at 37°C. Characterization included microstructural analysis (SEM), porosity measurements, mechanical testing (tensile, impact, microhardness), surface profilometry, and weight difference. All samples showed high density (>99.92%). L-PBF Ti64 exhibited α' martensitic microstructure transforming to lamellar α+β after heat treatment, while as-printed EBM Ti64 displayed coarse lamellar α+β structure. In NaCl, all materials developed pitting corrosion. In NaOH, stress-relieved L-PBF Ti64 formed a protective oxide layer (~200 nm), while EBM Ti64 showed localized oxidation at defects. SS316L exhibited smaller but higher amount of pitting. Microhardness decreased from ~375 HV (stress-relieved) to ~355 HV (heat-treated) for L-PBF Ti64 but did not change after immersion. Impact testing revealed Ti64's brittleness (7-13 J) versus SS316L (153-243 J). Galvanic corrosion occurred between stainless steel washers and Ti64 plates. L-PBF Ti64 demonstrated superior corrosion resistance in NaOH through uniform oxide formation. The finer microstructure of L-PBF provided better passivation than EBM. Despite excellent corrosion resistance, Ti64's lower impact toughness may limit certain applications. Heat treatment is essential for optimizing both mechanical properties and corrosion resistance of LPBF Ti64 for biopharmaceutical use.
Processuell legitimitet i granskning av utländska direktinvesteringar : Investerares processuella garantier i Sveriges granskningsregim för utländska direktinvesteringar enligt EU-rätten och internationell investeringsrätt
No full textThis thesis evaluates the procedural safeguards available to foreign investors within Sweden’s recently established foreign direct investment (FDI) screening regime, specifically assessing its alignment with procedural standards required by EU law and international investment law. By examining the Regulation (EU) 2019/452 and the Swedish Act on the Screening of Foreign Direct Investments (2023:560), the thesis identifies fundamental procedural shortcomings, particularly regarding impartiality, independence, and effective judicial remedies. The thesis finds that Sweden’s current appellate framework, which delegates certain screening decisions directly to the Swedish Government, does not fully comply with the fundamental procedural guarantees mandated by Article 6(1) ECHR, Article 19(1) TEU and Article 47 CFR. Furthermore, by exploring the supplementary protections available under international investment law, the thesis highlights how procedural deficiencies within Sweden’s domestic screening system may constitute breaches of international obligations. Employing the case example of the Chinese investor, Shanghai Putailai New Energy Technology Co., Ltd (PTL), the analysis demonstrates the practical relevance and important role international investment law plays in safeguarding investors' procedural rights when national frameworks fail to fully uphold EU standards.Denna examensuppsats utvärderar de processuella skyddsåtgärder som står till buds för utländska investerare inom ramen för Sveriges nyligen etablerade granskningsregim för utländska direktinvesteringar (UDI), med särskilt fokus på dess förenlighet med de processuella standarder som följer av unionsrätten och internationell investeringsrätt. Genom en granskning av Europaparlamentets och rådets förordning (EU) 2019/452 samt lagen (2023:560) om granskning av utländska direktinvesteringar, identifierar uppsatsen grundläggande processuella brister, särskilt vad gäller opartiskhet, oberoende och tillgång till ett effektivt domstolsprövning. Uppsatsen konstaterar att det nuvarande svenska överklagandeförfarandet, vilket innebär att vissa granskningsbeslut delegeras direkt till regeringen, inte uppfyller de grundläggande processuella garantier som föreskrivs i artikel 6.1 i Europakonventionen, artikel 19.1 i EU-fördraget samt artikel 47 i Europeiska unionens stadga om de grundläggande rättigheterna. Vidare framhåller uppsatsen, genom att undersöka de kompletterande skydd som erbjuds inom ramen för internationell investeringsrätt, hur brister i det svenska granskningssystemet kan innebära överträdelser av internationella åtaganden. Med stöd av det kinesiska investeringsfallet Shanghai Putailai New Energy Technology Co., Ltd (PTL), belyses den internationella investeringsrättens praktiska relevans och centrala roll i att upprätthålla investerares processuella rättigheter i de fall där nationella system inte till fullo säkerställer efterlevnaden av unionsrättsliga normer
The Court of Arbitration for Sport and EU Law: An Independent Tribunal or a Challenge to EU Legal Autonomy?
No full textÅldern på den månvulkanism som registrerats i klaster från månbrecciameteoriten
No full textUnderstanding the duration and diversity of lunar volcanism requires access to samples that record both early and late-stage magmatic activity. This study investigates the lunar polymict breccia meteorite NWA 12384, which provides a unique record of lithological diversity across the Moon’s crust. Fourteen lithic clasts were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), revealing a petrographic continuum from mafic cumulates to evolved basalts and felsic clasts. These lithologies reflect distinct magmatic sources and crystallization conditions, preserved within a breccia matrix that has been reshaped by impacts and regolith processes. One representative basaltic clast was selected for in situ Pb-Pb isotopic dating using Secondary Ion Mass Spectrometry (SIMS) on phosphate and feldspar grains. The isotopic data yield a 204Pb/206Pb vs. 207Pb/206Pb isochron age of 3219 ± 13 Ma, placing its crystallization firmly within the Late Imbrian epoch. This age is consistent with a growing number of meteorite-based studies suggesting that volcanic activity on the Moon continued well after the primary phase of mare basalt emplacement recorded by Apollo samples. These findings support models of prolonged, spatially heterogeneous thermal evolution, potentially sustained by localized concentrations of radiogenic elements. They also reinforce the scientific value of lunar meteorites as records of magmatic and surface processes from across the Moon, offering critical constraints that mission-returned samples alone cannot provide
Atypical development of sequential manual motor planning and visuomotor integration in children with autism at early school-age : A longitudinal kinematic study
No full textSensorimotor difficulties are common in children with autism spectrum disorder, and it has been suggested that motor planning problems underlie their atypical movements. At early school-age, motor planning development typically involves changes in visuomotor integration, a function known to be affected in autism spectrum disorder. However, there is a lack of detailed characterization of typical motor planning development during this stage, and how motor planning develops in children with autism spectrum disorder is largely unknown. This longitudinal kinematic study examined goal-directed sequential manual movements in children with autism spectrum disorder and in typically developing children across ages 7, 8, and 9 years. We manipulated goal-difficulty and availability of initial visual information to investigate visuomotor integration and chaining of subparts during movement performance. The results revealed emerging group differences at older age, suggesting atypical motor planning development in children with autism spectrum disorder. Notably, unlike the typically developing group, availability of initial visual information did not facilitate motor planning for the autism spectrum disorder group. The results show that motor planning differences in autism spectrum disorder appear related to atypical visuomotor integration and global processing of sensorimotor information. The findings also emphasize the importance of considering developmental aspects in research and practice related to motor problems in children with autism spectrum disorder
Exploring the use of Generative AI Chatbots in Eliciting Software Sustainability Requirements
No full textThe integration of sustainability into software development is increasingly recognized as essential. However, defining, eliciting, and evaluating sustainable software requirements remains a complex challenge. This thesis investigates whether generative AI chatbots can support the elicitation of sustainable requirements and how their outputs compare to those generated through traditional human-led methods. The study was conducted in two parts. In Part One, four generative AI chatbots (ChatGPT, Claude, Grok, and DeepSeek) were prompted to generate sustainable requirements for a bio-feedback-based mental health app, both before and after providing formal definitions of sustainability dimensions. Their outputs were thematically analysed and evaluated for dimension alignment and requirement quality. In Part Two, a controlled experiment compared two groups of human participants—one using generative AI assistance and one using traditional elicitation techniques—on the same task. The results show that generative AI chatbots can generate sustainability-aligned requirements across all three dimensions, often without formal definitions. Thematic diversity was high in multifaceted aspects of sustainability, but the requirements frequently lacked specificity, clarity, or feasibility. Evaluation against ISO/IEC/IEEE 29148:2018 criteria revealed that most chatbot- and participant-generated requirements lacked implementation readiness. However, generative AI-assisted participants reported higher confidence and fewer difficulties, despite their requirements often being of lower quality, a pattern consistent with the Dunning–Kruger effect, where lower performance is accompanied by greater self-reported confidence. Traditional participants, while more cautious, produced some stronger and more contextually grounded ideas. These findings suggest that generative AI can assist in the ideation phase of sustainable requirements elicitation but should be used as a complement and not a replacement for human judgment. Future research should explore hybrid elicitation workflows and the cognitive impacts of generative AI assistance in early design
Noncollinear Edge Magnetism in Nanoribbons of Fe3GeTe2 and Fe3GaTe2
No full textFe3GeTe2 and Fe3GaTe2 are ferromagnetic conducting materials of van der Waals type with unique magnetic properties that are highly promising for the development of new spintronic, orbitronic, and magnonic devices. Even in the form of two-dimensional-like ultrathin films, they exhibit a relatively high Curie temperature, magnetic anisotropy perpendicular to the atomic planes, and multiple types of Hall effects. We explore nanoribbons made from single layers of these materials and show that they display noncollinear magnetic ordering at their edges. This magnetic inhomogeneity allows angular momentum currents to generate magnetic torques at the sample edges, regardless of their polarization direction, significantly enhancing the effectiveness of magnetization manipulation in these systems. We also demonstrate that it is possible to rapidly reverse the magnetization direction of these nanostructures by means of spin–orbit and spin-transfer torques with rather low current densities, making them quite propitious for nonvolatile magnetic memory units
A one health approach to prioritizing emerging zoonotic diseases (EZDs) in northern Vietnam
No full textBackground Vietnam, with its significant agricultural sector, large livestock population, rich biodiversity and close human-animal interactions, is highly vulnerable to zoonotic disease transmission. To better address this threat, representatives from the human, animal, and environmental health sectors in Vietnam worked together at two one health zoonotic disease prioritization (OHZDP) workshops to develop a list of priority zoonotic diseases for multisectoral one health collaboration in Hoa Binh and Lao Cai provinces in April 2024. Methods We modified the OHZDP process, developed by the U.S. Centers for Disease Control and Prevention (CDC), and utilized it to prioritize zoonotic diseases in Vietnam. This involved conducting defining prioritization criteria, developing specific questions with assigned weights for each criterion, and organizing two workshops with stakeholders. Result There were 25 participants in Hoa Binh's workshop (7 females and 18 males), and 27 participants in Lao Cai's workshop (9 females and 18 males). Following a discussion of tool outputs among experts, four zoonotic diseases were prioritized in Lao Cai province: Rabies, avian influenza, Streptococcus suis, and leptospirosis. In Hoa Binh province, three diseases were identified as priorities: Rabies, avian influenza, and Streptococcus suis. Conclusion Rabies, avian influenza and Streptococcus suis were the three most prioritized diseases across the two provinces. This list can serve as a foundation for strengthening one health collaboration for disease prevention and control in these targeted provinces