Publikationer från Uppsala Universitet
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Effective Solving of Arc-Routing Problems by Partially Fixing the Solution
No full textThe arc-routing problem in many real-life applications has a large search space. For that reasonfinding an optimum solution is often not feasible in reasonable time and different types ofapproximations and heuristics are used. One way of approximating the problem is to partially fix the solution, thus reducing the search space. The partial fixing must be done in an intelligent way in order for the approximation to be close to the optimum value of the original problem. In this thesis, an algorithm that given an arc-routing problem partially fixes a solution in an effective way, is constructed. The algorithm is evaluated against a similar algorithm used currently by BM System on two different real-life applications, the capacitated arc-routing problem and the arc-routing problem with schedules. The new algorithm shows substantial improvement in both the quality of the found solution and the solving time, for large instances,while the performance on small instances is on par with the old algorithm
The Impact of Board Gender Diversity on ESG Practices and Company Financial Performance Relationship : Evidence from Nordic Energy Companies.
No full textThis study investigated the influence of board gender diversity (BGD) on the relationship between environmental, social, and governance (ESG) practices and corporate financial performance (CFP) in 26 energy companies listed on stock exchanges in Nordic countries from 2017 to 2022. This study utilises stakeholder theory and diversity, equality, and inclusion (DEI) theory to provide theoretical explanations. Board gender diversity (BGD) is measured by the proportion of female directors to total board members, while CFP is assessed through return on assets (ROA) and Tobin’s Q. ESG performance is evaluated using a one-year lagged combined ESG score and BGD is similarly assessed using a one-year lagged BGD score (from 2016 to 2021). All the quantitative data were obtained from the Refinitiv database hosted by Thomson Reuters. The study employed the two-step generalised method of moments (GMM) regression technique and hierarchical model approach to analyse and interpret the regression models. The findings of this study are mixed. The empirical results indicate that ESG practices positively and significantly impact Tobin's Q (market performance), which aligns with stakeholder theory. Surprisingly, ESG is found to have a significant negative relationship with return on assets (ROA). Furthermore, the study examines the moderating role of board gender diversity (BGD), revealing that the combined interactive effect of BGD and ESG, positively moderates the ESG-ROA relationship, which is consistent with DEI theory. However, the moderating effect of BGD on the ESG-Tobin's Q relationship is found to be insignificant. This study pioneers the examination of board gender diversity's impact on the ESG-CFP relationship within the Nordic energy sector. The insights from this study contribute to the understanding of sustainable business practices in the Nordic energy sector. Further research should explore the underlying mechanisms and implications of corporate decision-makin
Hemflytt - av hela eller led i leverantörskedjan? : En jämförande fallstudie om svenska tillverkningsföretags hemflytt av led i leverantörskedjan under en exogen chock
No full textFör att undersöka hur en hemflytt av led i leverantörskedjan under en exogen chock skiljer sig mellan två svenska tillverkningsföretag har en jämförande fallstudie genomförts. Uppsatsen undersöker två kontrasterande fall, vilka är Kinnarps och Synsam med en kvalitativ innehållsanalys. Det har gjorts eftersom hemflytt blev allt mer populärt under den exogena chocken covid-19-pandemin, däremot förekom hemflytt i olika utsträckning. I vissa fall flyttade företag hem hela sin leverantörskedja och i andra fall flyttade de hem led i leverantörskedjan. Datainsamlingen har gjorts genom en deduktiv ansats, där teorier och tidigare forskning har styrt datainsamlingen. Ansatsen har valts eftersom vi har kodat fenomen i datainsamlingen utifrån teorier om exogen chock, hemflytt, motståndskraft i leverantörskedjan, lokaliseringsfaktorer och ekonomiska drivkrafter för att få en bättre förståelse om fenomenet hemflytt och för att kunna jämföra företagen i deras hemflytt av led i leverantörskedjan
Improved electric load forecasting using quantile long short-term memory network with dual attention mechanism
No full textThe robust and accurate load forecasting is necessary to ensure effective power market operations and optimize load dispatch strategies. Deep learning models have recently gained popularity because of their strong ability to learn data patterns. However, conventional deep-learning models still encounter difficulties in precisely predicting complex load patterns. This paper addresses the difficulties of forecasting intricate load patterns, where conventional deep learning models often fail. Therefore, a novel quantile long short-term memory network with dual attention is proposed for hour-ahead short-term load forecasting. By combining dual attention processes with quantile regression-based long short-term memory networks, the proposed framework effectively captures the temporal dependencies of the complex load pattern. The gates recurrent unit and hybridized methodologies of recurrent neural networks are among the baseline techniques against which the proposed method is thoroughly tested using datasets from Panama City and the Islamabad Electric Supply Company. The proposed quantile long short-term memory network with dual attention mechanism has demonstrated notable performance gains with 2.35% and 5.36% reduction in mean absolute percentage error in comparison to the best-performing models, from the set of baseline models, for the Panama and IESCO datasets, respectively. These results demonstrate the proposed method's effectiveness in providing more improved and accurate forecasts for enhanced grid stability and economic dispatch efficiency
An integrative and translational PKPD modelling approach to explore the combined effect of polymyxin B and minocycline against Klebsiella pneumoniae
No full textObjectives: To expand a translational pharmacokinetic-pharmacodynamic (PKPD) modelling approach for assessing the combined effect of polymyxin B and minocycline against Klebsiella pneumoniae. Methods: A PKPD model developed based on in vitro static time-kill experiments of one strain (ARU613) was first translated to characterize that of a more susceptible strain (ARU705), and thereafter to dynamic time-kill experiments (both strains) and to a murine thigh infection model (ARU705 only). The PKPD model was updated stepwise using accumulated data. Predictions of bacterial killing in humans were performed. Results: The same model structure could be used in each translational step, with parameters being re- estimated. Dynamic data were well predicted by static-data-based models. The in vitro/in vivo differences were primarily quantified as a change in polymyxin B effect: a lower killing rate constant in vivo compared with in vitro (concentration of 3 mg/L corresponds to 0.05/h and 57/h, respectively), and a slower adaptive resistance rate (the constant in vivo was 2.5% of that in vitro ). There was no significant difference in polymyxin B-minocycline interaction functions. Predictions based on both in vitro and in vivo parameters indicated that the combination has a greater-than-monotherapy antibacterial effect in humans, forecasting a reduction of approximately 5 and 2 log10 colony-forming units/mL at 24 h, respectively, under combined therapy, while the maximum bacterial load was reached in monotherapy. Conclusions: This study demonstrated the utility of the PKPD modelling approach to understand translation of antibiotic effects across experimental systems, and showed a promising antibacterial effect of polymyxin B and minocycline in combination against K. pneumoniae
'A question of time and work-situation' - a cluster analysis of Swedish midwives' levels of burnout and attitudes towards midwifery continuity of care
No full textBackground: Midwifery continuity of care (MCoC) has been associated with reduced burnout and increased work satisfaction among midwives. Despite these benefits, MCoC is not common in Sweden. Aim: This study aimed to explore midwives' profiles based on burnout levels and attitudes towards midwifery continuity of care, considering various background and work-related factors. Methods: A national cross-sectional digital survey was conducted among midwives in Sweden. The questionnaire covered the Copenhagen Burnout Inventory (CBI), attitudes towards MCoC and background variables. Cluster analysis identified a set of profiles, which were then compared by calculating odds ratios and 95 % confidence intervals for various background and work-related factors. Logistic regression examined the factors most associated with each profile. Findings: A three-cluster solution for the 1,983 midwives surveyed was suggested, labelled as Reserved, Visionary, and Sensitive. Midwives in the Reserved cluster exhibited negative attitudes towards MCoC, through negative scores on both components and negative scores on the CBI. Within the Visionary cluster, midwives showed positive scores on the Relational component of MCoC, but negative scores on the Practical and Organisational component and the CBI. In the Sensitive cluster, midwives exhibited the highest scores on the CBI and negative scores on the Practical and Organisational component of MCoC, with just slightly positive scores on the Relational component. Cluster membership was associated with length of work experience (p<0.001) and work domain (p<0.001). Conclusion: Based on the CBI and attitudes towards MCoC, three distinct clusters of midwives were identified, with different factors contributing to membership in each cluster. Understanding how midwives relate to MCoC can facilitate the implementation of the model, potentially improving midwives' work-related health
Divergence in expression of a singing-related neuroplasticity gene in the brains of 2 Ficedula flycatchers and their hybrids
No full textSpecies-specific sexual traits facilitate species-assortative mating by reducing mating across species and reducing hybrid sexual attractiveness. For learned sexual traits, such as song in oscine birds, species distinctiveness can be eroded when species co-occur. Transcriptional regulatory divergence in brain regions involved in sensory learning is hypothesized to maintain species distinctiveness, but relatively few studies have compared gene expression in relevant brain regions between closely related species. Species differences in song are an important premating reproductive barrier between the collared (Ficedula albicollis) and pied flycatcher (F. hypoleuca). Here, we compare brain gene expression in adult males from each species and their naturally occurring F1 hybrids. We report overall conserved expression across species in a portion of the brain containing regions and nuclei known to be involved in song responses and learning. Further, among those genes that were differentially expressed between species, we find largely intermediate expression in hybrids. A single gene, SYT4 (synaptotagmin 4), known to be singing-associated, both was differentially expressed and has a putative upstream transcriptional regulatory factor containing fixed differences between the 2 species. Although a finer-scale investigation limited to song-specific regions may reveal further species differences, our findings provide insight into regulatory divergence in the brain between closely related species
Broadband seismic data acquisition and processing of iron oxide deposits in Blötberget, Sweden
No full textIn June 2022, an innovative seismic survey was conducted in Bl & ouml;tberget, central Sweden, to evaluate the effectiveness of employing both a broadband seismic source and broadband receivers for mineral exploration in a challenging hardrock setting. The Bl & ouml;tberget mine hosts high-quality iron oxides, predominantly magnetite and hematite, sometimes enriched with apatite. These deposits comprise 10-50 m thick sheet-like horizons with a moderate eastward dip (similar to45 degrees) along an NNE-trending zone. The survey employed a combination of co-located micro-electromechanical sensors, three-component recorders, surface and borehole distributed acoustic sensing, along with a 77-kN broadband seismic vibrator operating with 2-200 Hz linear sweeps. A tailored processing workflow was applied to preserve the broadband nature of the recorded data, and a one-dimensional velocity model was derived from the borehole distributed acoustic sensing data for migration and time-to-depth conversion purposes. Compared to the previous seismic surveys, the resulting seismic cross section reveals several well-defined reflections with improved resolution. Notably, a reflection intersecting the main deposits at a depth of approximately 1200 m exhibits a distinct polarity reversal relative to the reflection from the mineralization, providing further evidence for its interpretation as originating from a fault zone. Shallow reflections align with geological boundaries and partially coincide with weak magnetic anomalies. Additional reflections were revealed underneath the known mineralization on both sides of the fault zone and may suggest the presence of potential additional resources. The delineation of these reflections and the fault zone is critical for future mine planning and development in the region. This case study underscores the potential of broadband data in achieving high-resolution subsurface imaging in hardrock environment and its pivotal role in mineral resource assessment processes
Implementation of Secure Pairing using a Shared Secret Source for OpenMote devices
No full textThis thesis explores the potential of using Received Signal Strength Indicators (RSSIs) as a Shared Secret Source for generating secret keys between two small IoT (Internet of Things) devices, notably for wearables and implantable medical devices. The main goal is to create an efficient algorithm, decreasing the computational cost required for key generation without compromising security. The algorithm consists of three main parts: preparing the data, quantizing the data into bits for key generation, and reconciling errors. The results suggest a promising potential for the use of RSSI as a shared source for secret key generation, with efficiency at a peak bit generation rate of 1.27 valid key bits per RSSI value for 64-bit keys with 8-bin quantization while blocking 97.6% of intrusion attempts. Future work for improving the results further includes exploring a narrower requirement for what values are to be used at the quantization stage as well as implementing a more sophisticated error reconciliation algorithm
School staff's perceptions of implementing the Inclusive Behavioral Support in Schools framework in Swedish schools
No full textThe Determinants of Implementation Behavior Questionnaire for school settings (DIBQ-S) was administered to examine questionnaire internal structure evidence and ascertain 127 Swedish school staff's perceived barriers to and facilitators of implementing the Inclusive Behavioral Support in Schools program. Using confirmatory factor analysis, we tested a 3-factor model (capability, opportunity, motivation) corresponding to the Theoretical Domain Framework and the COM-B system. Measurement of motivation was suboptimal, but a 2-factor model exclusively retaining capability and opportunity had fair fit. The questionnaire showed overall fair internal structure evidence. Facilitators related primarily to motivation, whereas potential barriers related to capability, opportunity, and motivation. Teachers working in early school years perceived higher opportunity and capability than teachers working in later school years. School staff in the implementation team perceived higher opportunity than other school staff. The DIBQ-S could support school implementations by ensuring that the process feels coherent, manageable, and meaningful for frontline implementers