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Automatic Segmentation of the Pectoralis Major Muscle in Magnetic Resonance Imaging Using nnU-Net: Evaluation of Training Mask Modifications and Anatomical Thickness Measurements
(2026) Emteborg Dabrio, David
Computational human body models (HBMs) can improve vehicle safety research by accounting for anatomical variability that is difficult to capture using traditional crash testing methods. Statistical shape models (SSMs) provide a means of representing this variability using medical imaging data, but their development requires accurate and reproducible anatomical segmentations. This thesis investigated the feasibility of automated segmentation of the pectoralis major muscle from magnetic resonance imaging (MRI) data using the nnU-Net framework. To the best of our knowledge, automated segmentation of the pectoralis major muscle from MRI data has not previously been investigated. The applicability of the segmentation methodology to other muscles was not evaluated and therefore remains to be investigated. Eleven manually segmented subjects from the TotalSegmentator MRI dataset were used to train and evaluate three training datasets: the original manually segmented masks (Nominal), masks systematically contracted by one voxel layer (Contracted), and masks systematically expanded by one voxel layer (Expanded). This comparison was performed to investigate how systematic modifications of the training masks affected pectoralis major segmentation performance. In addition, a repeatable landmark-based methodology was developed for measuring pectoralis major muscle thickness from the manually segmented MRI data, providing an initial anatomical baseline for future statistical shape modelling. The results indicate that the use of nnU-Net for automated segmentation of the pectoralis major muscle is feasible; however, due to the limited amount of available data, a highly accurate model could not be trained. The Expanded dataset produced slightly improved average segmentation performance compared with the Nominal dataset, whereas the Contracted dataset resulted in poorer performance. However, the differences between the Nominal and Expanded datasets were small relative to the variation between subjects, indicating that anatomical variability and limited dataset size had a greater influence on segmentation performance than the systematic mask modifications. The proposed pectoralis major segmentation and thickness measurement methodologies provide a foundation for future work on statistical shape models and human body models for vehicle safety applications.
Utveckling av ett Excelbaserat dimensioneringsverktyg för mellanspänningsdrivsystem
(2026) Abbas, Abdullah; Ahmed, Mohammad
Industriella mellanspänningsdrivsystem blir allt mer komplexa, vilket skapar ett behov av tydliga och tillförlitliga metoder för dimensionering i tidiga projektfaser. I många projekt baseras valet av omriktare och tillhörande utrustning, såsom transformatorer, ofta på information från olika tekniska dokument tillsammans med tidigare erfarenhet. Detta kan göra processen tidskrävande och leda till variationer i hur beslut fattas. Detta examensarbete fokuserar på utvecklingen av ett Excel-baserat dimensioneringsverktyg som stödjer val av mellanspänningsomriktare och hjälper till att definiera lämpliga transformatorlösningar. Verktyget är avsett att användas i tidiga projekt- och offertskeden, där beslut ofta behöver fattas inom begränsad tid men ändå baseras på ett tillräckligt tekniskt underlag. Genom att kombinera elektriska beräkningar, produktdata, derating-faktorer och frekvensberoende driftförhållanden samlas dimensioneringsprocessen i ett strukturerat arbetsflöde. En viktig del av arbetet är att transformatorns specifikation inkluderas som en del av valet av omriktare. Utifrån de systemkrav som användaren anger kan verktyget generera ett strukturerat transformer inquiry data sheet och indikera om en standardtransformator är lämplig eller om en kundanpassad transformator krävs. På så sätt kopplas den tekniska dimensioneringen tydligare till praktiska ingenjörsbeslut i projekt- och offertarbete. Microsoft Excel valdes som plattform eftersom det är lättillgängligt, välkänt för många ingenjörer och gör beräkningar och antaganden transparenta. Även om Excel har begränsningar jämfört med mer avancerade simulerings- och designverktyg ger det en praktisk balans mellan funktionalitet och användbarhet i tidiga skeden. Resultatet visar att ett strukturerat dimensioneringsverktyg kan göra urvalsprocessen mer enhetlig och minska beroendet av enskilda personers erfarenhet. Verktyget kan även bidra till snabbare och mer organiserat beslutsfattande i projekt- och offertarbete. Samtidigt bör det ses som ett stöd för preliminära tekniska analyser och inte som en ersättning för detaljerad projektering, slutlig verifiering eller projektspecifik teknisk granskning.
Robust Vehicle Acceleration Control
(2026) Kongstad, Alexander; Karlsson, Fabian
This thesis investigates robust acceleration control for heavy-duty vehicles to improve longitudinal control and driver-assist functions. Despite advances in longitudinal vehicle control, important limitations remain. Existing control strategies may be sensitive to measurement delays, perform poorly for small acceleration errors, and insufficiently reject oscillatory disturbances from driveline windup and tire dynamics. These challenges motivate a model-based control approach that explicitly accounts for the relevant system dynamics to improve tracking performance and disturbance rejection. A third-order state-space driveline model was developed to capture the system’s dominant dynamics, including flexible driveshaft behavior modeled as a springdamper system. The model was tuned and validated against real-world measurements from a battery electric vehicle (BEV), demonstrating close agreement in both speed and acceleration responses across multiple driving scenarios and gear configurations. A Smith predictor was subsequently designed and evaluated to compensate for the system’s inherent dead-time delays. Simulation testing showed that the Smith predictor maintains stability under model and delay mismatches of up to ±50%, while also enabling higher controller gains and faster response times. To further improve performance, the Smith predictor was extended to include measurement updates. An LQG controller with integral action, focusing on robustness properties, was proposed to address driveline oscillation damping and steady-state tracking accuracy. Simulation results show that, given an accurate model, the proposed controller reduces oscillations and improvesmproved steady-state tracking compared to the current controller. Using logged vehicle data, the simulation validated the proposed controllers, showing that model-based control strategies can improve acceleration-tracking performance and robustness compared to the existing controller.
Targeting HER2-positive cell lines by transmembrane peptide based surface-active ionic liquid nanoformulation
(2026) Liu, Siyuan
Human epidermal growth factor receptor 2 (HER2/ErbB2) is a major oncogenic driver in many cancers, and its extracellular or intracellular domains are the main therapeutic targets. In contrast, the transmembrane domain (TMD), which also plays an important role in receptor dimerization and activation, remains comparatively underexplored as a potential therapeutic target. In this study, ErbB2 TMD-derived peptides were investigated as potential competitive inhibitors of receptor dimerization, while a nicotinium-based biamphiphilic surface-active ionic liquid (Nic BAIL) was developed as a vesicular carrier to address the poor aqueous compatibility of highly hydrophobic transmembrane peptides. Three ErbB2-TM peptide variants (v1-v3) were purified and characterized by LC-MS. Nic BAIL was synthesized and characterized by NMR, direct-infusion ESI-MS and differential scanning calorimetry (DSC). The Nic BAIL-v3 nanoformulation was prepared and characterized by dynamic light scattering (DLS) and cryogenic transmission electron microscopy (Cryo-TEM), and its colloidal stability was evaluated under storage and dilution conditions. Planar bilayer electrophysiology was employed to investigate membrane activity, while cellular activity was evaluated in BT-474 and NCI-H23 cells, representing high and low ErbB2 expression, respectively. In addition, live-cell imaging was performed to observe morphological changes after treatment. Nic BAIL formed nanoscale vesicular assemblies, with a predominant nanoscale population maintained following formulation with v3 peptide, although the formulation exhibited time- and concentration-dependent changes in hydrodynamic size and dispersity. Planar bilayer electrophysiology showed that Nic BAIL-v3 increased ionic conductance and decreased electrical resistance across artificial DPhPC bilayers, indicating strongly altered membrane barrier properties. In cell viability assays, free v3 peptide produced similar concentration-dependent effects on BT-474 and NCI-H23 cells, while Nic BAIL-v3 produced an additional significant reduction in BT-474 viability compared to Nic BAIL alone. This enhancement was not observed in NCI-H23 cells. Live-cell imaging further demonstrated sustained cell-associated FAM-v3 fluorescence and progressive morphological deterioration without pronounced acute loss of membrane integrity. In this thesis, Nic BAIL was developed as a self-assembling membrane-active carrier for delivery of highly hydrophobic ErbB2-derived peptides and that Nic BAIL-v3 formulation exhibited a cell-line-dependent biological effect. But the intrinsic inhibitory activity of Nic BAIL complicates interpretation of observed cellular effects. Peptide loading, membrane localization, HER2-specific targeting, and direct interactions between v3 and HER2-TMD remain unconfirmed and require further investigation.
Circular food strategies for the Gothenburg circular economy action plan
(2026) NATH, RAVEENA
Resource efficiency can reduce material demand and support the economy of cities. Circular economy actions can support the reduction of the economic gap between linear metabolism and circular metabolism of a city. Gothenburg aims to improve its food sector by implementing circular action across its food value chain. The thesis analyses the food metabolism of Gothenburg, identify suitable circular strategies relevant to the city based on the circularity pillars and model how the selected strategies affect the metabolism change in the production, consumption, trade and waste stages of the food chain. The results of the three modelled actions shows that import dependency on identified food products could be reduced although in some cases dependency shifted from one product to another. The actions could also support more circular food flows in Gothenburg through increased local production, changes in consumption and redistribution of surplus food. Through action alley farming, oat bread production reduced bread imports by 18 percent resulting in additional wheat imports. Action dietary change reduced modelled school meat demand but also increased imports of identified plant-based products. In centralized retail surplus redistribution, the estimated 6 percent increase in surplus capture rate at redistribution centres directed more food to people, that could potentially reduce the amount sent to waste treatment, while also reducing the import dependency of redistributed food products. The results indicate that the selected actions could contribute to more circular food flow in Gothenburg even though trade dependency is not eliminated. The selected actions show potential to support substitution, extend the use of surplus retail food and improve the resilience of the food system.