Luleå University of Technology Publications
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Zero Latency Per-Task Isolation for the Hippomenes RISCV RealTime Core
No full textMemory safety is a critical concern in embedded systems. Resource constraints and real-time requirements demand efficient and robust solutions. Most systems are usually implemented with a low-level language like C. C, in particular, gives the developer total freedom over the hardware. However, with this freedom comes the responsibility of ensuring memory safety, which can be very difficult in complex systems. Rust partially solves this by ensuring defined behavior and memory safety unless the keyword unsafe is used. Unsafe code is necessary because the Rust compiler denies direct access to the hardware, even when it is essential. Within this unsafe space lies the problem and the focus of this thesis. The primary contribution of this thesis is a hardware-level proof-of-concept: a modified RISC-V RT system with a physical memory protection mechanism featuring per-task configuration. This solution leverages the per-task configuration to achieve zero overhead, requiring only a few lines of assembly for setup. Without setup, each task is restricted to its own stack. However, by writing to the Control and Status Register (CSR), additional allowed memory areas can be defined in a single cycle. Physical memory protection can improve memorysafety in all languages, including (memory) unsafe code in Rust. To ensure a constant configuration, a locking mechanism has been added. This locking mechanism can lock any CSR address in hardware, making it permanent until a system reset. This ensures stack isolation and raises exceptions in cases of buffer overflows or use-after-free errors. These exceptions can simplify error identification and contribute to a more robust system. The current physical memory protection, as proposed, has great potential for security. However, it relies on correct configuration, and this responsibility falls upon the user to set it up correctly. A potential future improvement is to automate this process by generating code during compilation to simplify setup and ensure task isolation
Critical field evaluations of biochar-amended stormwater biofilters for PFAS and other organic micropollutant removals
No full textBiochar is often promoted as an ideal amendment for stormwater biofilters; however, its effectiveness has rarely been tested under field conditions. This study evaluates the impact of biochar addition on the removal of organic micropollutants (OMPs) in field-scale biofilters operating under real-world conditions for the first time. The research comprised four vegetated biofilter facilities (3 − 5 years old), two without and two with 2.1 wt. % (10 vol. %) biochar amendment. Stormwater and filter material samples from various locations after four years of operation were analyzed for a wide range of common and emerging OMPs found in urban runoff. Unlike hydrophobic OMPs (hydrocarbons, polychlorinated biphenyls, and di(2-ethylhexyl) phthalate), the investigated biofilters demonstrated low, or inconsistent, removal of hydrophilic and slow-adsorbing OMPs like bisphenol A, monobutyltin, and per-fluoroalkyl substances (PFASs). Although the physiochemical properties of biochar were well-adapted to pollutant removal, biochar amendment did not significantly improve OMP removal when compared with the status quo. This can be attributed to several field conditions and suboptimal design interfering with the biochar's sorption capacity, namely, the large particle size (D50 ∼4 mm) and low quantity of biochar, high levels of competing agents (i.e., dissolved oxygen carbon (DOC) and cations), co-contaminants in stormwater, limited contact time, biochar pore blockage (e.g., by DOC molecules and sediments/minerals), diminished biochar surface porosity, and sometimes increased removal uncertainty due to low influent concentrations. Our findings demonstrated the complexities associated with applying biochar for stormwater treatment. Further research on biochar-specific biofilter designs is needed to optimize the sorption potential of this material under field conditions.Validerad;2025;Nivå 2;2025-04-04 (u4);Fulltext license: CC BY;This article has previously appeared as a manuscript in a thesis.</p
Both right nearby and far away: Rural Sámi entrepreneurs' engagement with spatial contexts
No full textThis study contributes to the debate on the role of spatial contexts in rural entrepreneurship. Drawing on rural and indigenous entrepreneurship theory, we explore how four Sámi entrepreneurs from Sweden and Norway engage with their spatial contexts. We employ a multiple-case study design, an interpretive philosophy of science, and elements from indigenous research methodologies. Our findings demonstrate that the entrepreneurs engage both within and across their spatial contexts, encompassing environments both nearby and far away. We also identify drivers and practices associated with this entrepreneurial engagement. Based on the findings, we develop The Sámi Entrepreneurial Engagement Framework. The framework serves as an illustration of how a Sámi perspective adds new insight into the field of rural entrepreneurship and offers a comprehensive lens for understanding entrepreneurial engagement with spatial contexts in culturally rich and environmentally sensitive settings.Validerad;2025;Nivå 1;2025-04-15 (u5);Full text license: CC BY 4.0;Funder: Norwegian Regional Research Fund;</p
Objective-and Utility-Based Negotiation for Access Control
No full textAccess control in modern digital ecosystems is challenging due to dynamic resources and diverse stakeholders. Traditional mechanisms struggle to adapt, causing inefficiencies and inequities. We propose a novel algorithm that automates access control policy negotiation via objective optimization and utility-based methods. It enables stakeholders to jointly select policies aligned with their preferences, provided a suitable policy exists. Suggested criteria guide the evaluation of predefined policies, and a mathematical formulation quantifies stakeholder preferences with utility functions, using optimization to achieve consensus. The algorithm’s multilinear scalability is demonstrated through time and space complexity analysis. An evaluation tool supports practical testing, and the approach enhances efficiency and trust by ensuring equitable data access within digital ecosystems.Funder: Skellefteå Municipality; Digitala Stambanan IndTech;ISBN for host publication: 978-989-758-735-1;Full text license: CC BY-NC-ND</p
Elderly people’s experience of digital healthcare services
No full textBakgrund: Äldre personer är en sårbar grupp i samhället som riskerar att hamna i digitaltutanförskap. För att inkludera de äldre i samhällets utveckling inom digitalisering måste behoven identifieras och tillgodoses utifrån allas perspektiv. För att tillgodose detta bör bra alternativ med anpassningar göras utifrån äldres erfarenheter och deras förmågor för att skapa jämlik vård. Syfte: Att beskriva äldre personers upplevelse av digitala vårdtjänster. Metod: Litteraturstudie som inkluderade 10 artiklar som analyserades med kvalitativ manifest innehållsanalys med induktiv ansats. Resultat: Analysen resulterade i sex kategorier som beskriver personers upplevelse av digitala vårdtjänster; att digitalt handhavande kan vara en utmaning, att känna rädsla och osäkerhet att använda digitala vårdtjänster, att känna behov av ökad kunskap och utbildning, att digital vård ger ökad tillgänglighet samt sparar tid och pengar, att digitala vårdtjänster bidrar till ökad självständighet, att visuell kontakt och kommunikation har betydelse. Slutsats: Äldre personers behov av stöd och deras brist på kunskap inom vårdens digitalisering behöver synliggöras. Detta genom att lyssna till äldres behov av anpassningar och inkludera de äldre i utvecklingen av digitala vårdtjänster. Därigenom förbättra användningen av digitala vårdtjänster genom att stödja äldre personer till mer aktiv användning av vårdtjänster i vårdprocessen. Eftersom digitala vårdtjänster utvecklas och förändras behövs fortlöpande forskning inom området för att få ytterligare förståelse för äldre personers upplevelser.
Assessing Sustainability of Regional Climate and Energy Targets at Local Level for Supporting Municipalities in Navigating the Green Transition
No full textThe European Union has implemented targets to address climate change, air pollution and increase the share of renewable energy. Local governments play a significant role in executing actions to contribute to these targets while meeting local sustainability targets. This research aims to guide the local governance by assessing the impact of implementing key energy targets from the European Union at the local level from a sustainability perspective using indicators based on sustainable development goals. An energy system optimization model is used to assess the case study of Gällivare, a municipality in Northern Sweden. The results show that localized climate and air quality targets effectively support the integration of renewable energy, improvements in energy efficiency, and reductions in final energy consumption. Air quality targets correspond carbon reduction targets and subsequently leading to the net zero emission. However, while air pollution targets help achieve 100% carbon dioxide reduction by 2050, achieving 100% reduction in air pollution requires specific air pollution targets.Godkänd;2025;Nivå 0;2025-06-19 (u2);Full text license: CC BY</p
Associations between objective measures of performance-related characteristics and perceived stress in young cross-country skiers during pre-season training
No full textMonitoring performance-related characteristics of athletes can reveal changes that facilitate training adaptations. Here, we examine the relationships between submaximal running, maximal jump performance (CMJ), concentrations of blood lactate, sleep duration (SD) and latency (SL), and perceived stress (PSS) in junior cross-country skiers during pre-season training. These parameters were monitored in 15 male and 14 females (17 ± 1 years) for the 12-weeks prior to the competition season, and the data was analysed using linear and mixed-effect models. An increase in SD exerted a decrease in both PSS (B = -2.79, p ≤ 0.01) and blood lactate concentrations during submaximal running (B = -0.623, p ≤ 0.05). In addition, there was a negative relationship between SL and CMJ (B = -0.09, p = 0.08). Compared to males, females exhibited higher PSS scores and little or no change in performance-related tests. A significant interaction between time and sex was present in CMJ with males displaying an effect of time on CMJ performance. For all athletes, lower PSS appeared to be associated with longer overnight sleep. Since the females experienced higher levels of stress, monitoring of their PSS might be beneficial. These findings have implications for the preparation of young athletes’ competition season.Validerad;2025;Nivå 2;2025-04-22 (u5);Funder: The Amer Cultural Foundation, Finland;Full text license: CC BY</p
Patients’ experiences of racism in healthcare
No full textRasism är ett socialt system som bygger på diskriminering och orättvisor. Denna ideologi existerar även inom hälso- och sjukvården, trots att det finns lagar som betonar vikten av jämlikhet både i samhället och inom vården. Därför behöver problemet belysas för att skydda individen och motverka rasism inom vårdsektorn. Syfte: Syftet med studien var att beskriva patienters upplevelser av rasism i vården. Metod: För att besvara syftet genomfördes en litteraturöversikt baserad på tio vetenskapliga artiklar med kvalitativ ansats. Artiklarna hämtades från databaserna PubMed och CINAHL. Resultat: Resultatet baserades på tio kvalitativa studier och resulterade i fem slutkategorier: att känna sig misstrodd, att känna misstro mot vårdpersonal, att känna sig bortprioriterad, att känna sig dåligt bemött samt att känna sig mindre värd. Diskussion och slutsats: Patienter upplever diskriminering när de blir respektlöst bemötta. De känner sig bortprioriterade när vårdpersonal inte lyssnar eller tar deras upplevelser på allvar. Att bli validerad och tagen på allvar utgör grunden för personcentrerad omvårdnad. För att motverka eller minska rasism i vården bör sjuksköterskan fördjupa sin kunskap om personcentrerad vård och utveckla kulturell kompetens
Decoration of Two-Dimensional Cus Nanoflakes on Graphitic Carbon Foam Derived from Waste Plastic for Interfacial Solar Desalination
No full textInterfacial solar desalination using plasmonic metal semiconductors is a valuable process for freshwater production. However, the design of a sustainable and efficient photothermal evaporator is still challenging. In the present research, polyethylene terephthalate waste bottles were upcycled into carbon foam (CF) and further functionalized with CuS nanoflakes as a photothermal layer. Analytical characterizations (X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy, and scanning transmission electron microscopy–high-angle annular dark field) demonstrated the successful decoration of two-dimensional Covellite CuS nanoflakes on graphitic CF having microporous channels. UV/vis spectroscopy measurements show enhanced optical absorption with CuS/CF of up to 95% compared to bare CF (72%). The photothermal desalination experiment displayed an improved evaporation rate of 1.90 kg m−2 h−1 for the CuS–CF compared to 1.58 kg m−2 h−1 for the bare CF and CuS 1.41 kg m−2 h1, reveling the excellent water evaporation efficiency of 91%. The obtained results suggested that the design of CuS-functionalized CF derived from waste plastic for solar desalination is a useful strategy to produce fresh water from the upcycling of waste materials and a good example of circular economy through the development of engineered composite systems.Validerad;2025;Nivå 2;2025-04-09 (u2);Full text license: CC BY 4.0;Funder: MCIN/AEI; European Union NextGeneration EU/PRTR (TED2021-130756B-C31); Marie Skłodowska-Curie Individual Fellowship (GA101027930); Progetti di Ricerca Scientifica di Rilevante InteresseNazionale (2022FNL89Y);</p
Strukturanalys av träbyggnad utsatt för brand baserat på SS-EN 1995-1-2
No full textDenna studie undersöker hur det förkolnade tvärsnittet i sjukhusbyggnad, med en KL-trästomme,påverkas av ett 60 minuters brandförlopp, baserat på SS-EN 1995-1-2. Det förkolnade tvärsnittet behöver trots förkolningen motstå belastning av egenvikt, snö och vind för att inte kollapsa. Målet med projektet är att genom finita elementmetoden bestämma vilken tjocklek på det förkolnade tvärsnittet som krävs för att motstå belastning av egenvikt, snö och vind efter ett 60 minuters brandförlopp. Dessutom undersöks åtgärder som kan bidra till ett högre brandmotstånd samt för- och nackdelar med en trästomme i förhållande till en betongstomme. Studiens resultat angav att standarddimensioner utifrån Svenskt trä (2017) inte kan motstå belastningarna efter ett 60 minuters brandförlopp. Däremot motstår konstruktionen belastning, om KL-träskivornas tjocklek ökas med cirka 20-30 mm. För att uppnå ett högre brandmotstånd kan både passiva och aktiva brandskydd användas, vilket bidrar till att konstruktionen motstår brand under en längre tid, utan att förlora sina egenskaper. Den främsta anledningen till att trä efterfrågas i konstruktioner framför betong är att trä har ett betydligt lägre koldioxidutsläpp, medan betong vid mindre tvärsnitt kan motstå högre laster. Denna studie bidrar med ett underlag och kunskaper för framtida forskning vid användning av KL-trästommar i bärande konstruktioner. This study investigates how the charred cross-section in a hospital building with a CLT (Cross-Laminated Timber) frame is affected by a 60-minute fire scenario, based on SS-EN 1995-1-2. Despite the charring, the cross-section needs to withstand loads from self-weight, snow, and wind to prevent collapse. The goal of the project is to determine, using the finite element method, the required thickness of the charred cross-section to withstand loads from self-weight, snow, and wind after a 60-minute fire scenario. Additionally the study investigates factors that can contribute to higher fire resistance and the advantages and disadvantages of a timber frame compared to a concrete frame. The results indicated that standard dimensions according to Svenskt Trä (2017) cannot withstand the loads after a 60-minute fire scenario. To resist the loads from self-weight, snow and wind, the thickness of the CLT panels need to be increased by approximately 20-30 mm. To achieve higher fire resistance, both passive and active fire protection factors can be used, which help the structure withstand fire for a longer period without losing its properties. Timber is preferred over concrete in constructions because the timber has significantly lower carbon dioxide emissions, while concrete can withstand higher loads with smaller cross-sections. This study provides a basis and knowledge for future research on the use of CLT frames in load-bearing constructions.