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- Correa, Maicon Ribeiro, et al.
(författare)
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A transient thermoelastic mathematical model for topology optimization of support structures in additive manufacturing
- 2024
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Ingår i: Structural and multidisciplinary optimization (Print). - : SPRINGER. - 1615-147X .- 1615-1488. ; 67:3
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a Topology Optimization (TO) methodology for determining the optimal distribution of support structures in the powder bed fusion Additive Manufacturing (AM) fabrication technology. The support structures enhance thermal dissipation, reducing distortion on overhang surfaces during the build process and improving printability. A novel transient thermoelastic layer-by-layer model simulates the AM process, evaluating temperature and displacement in partially built structures with supports. We propose two new objective functions related to part distortion, perform their adjoint sensitivity analysis, and present a comprehensive set of numerical experiments with different geometries and levels of overhang complexity. The numerical results show non-standard optimal support structures obtained using the proposed TO-AM methodology for different model parameters, including support volume, thermal anisotropy, time discretization method, and building times for each layer.
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- Gleeson, Daniel, 1988, et al.
(författare)
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Generating Optimized Trajectories for Robotic Spray Painting
- 2022
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Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 19:3, s. 1380-1391
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Tidskriftsartikel (refereegranskat)abstract
- In the manufacturing industry, spray painting is often an important part of the manufacturing process. Especially in the automotive industry, the perceived quality of the final product is closely linked to the exactness and smoothness of the painting process. For complex products or low batch size production, manual spray painting is often used. But in large scale production with a high degree of automation, the painting is usually performed by industrial robots. There is a need to improve and simplify the generation of robot trajectories used in industrial paint booths. A novel method for spray paint optimization is presented, which can be used to smooth out a generated initial trajectory and minimize paint thickness deviations from a target thickness. The smoothed out trajectory is found by solving, using an interior point solver, a continuous non-linear optimization problem. A two-dimensional reference function of the applied paint thickness is selected by fitting a spline function to experimental data. This applicator footprint profile is then projected to the geometry and used as a paint deposition model. After generating an initial trajectory, the position and duration of each trajectory segment are used as optimization variables. The primary goal of the optimization is to obtain a paint applicator trajectory, which would closely match a target paint thickness when executed. The algorithm has been shown to produce satisfactory results on both a simple 2-dimensional test example, and a non-trivial industrial case of painting a tractor fender. The resulting trajectory is also proven feasible to be executed by an industrial robot.
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- Gleeson, Daniel, 1988, et al.
(författare)
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Robot spray painting trajectory optimization
- 2020
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Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. ; 2020-August, s. 1135-1140
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Konferensbidrag (refereegranskat)abstract
- In the manufacturing industry, spray painting is often an important part of the process. Especially in the automotive industry, the perceived quality of the final product is closely linked to the exactness and smoothness of the painting process. For complex products or low batch size production, manual spray painting is often used. But in large scale production with a high degree of automation, the painting is normally performed by industrial robots. There is a need to improve and simplify the generation of robot trajectories used in industrial paint booths. A method for spray paint optimization is presented, which can be used to smooth out an initial trajectory and minimize paint thickness deviations from a target thickness. By fitting a spline function to experimental data, an applicator footprint profile is determined, which is a two-dimensional reference function of the applied paint thickness. This footprint profile is then projected to the geometry and used as a deposition model at each point along the trajectory. The positions and durations of all trajectory segments are used as optimization variables. They are modified with the primary goal to obtain a paint applicator trajectory, which will closely match a target paint thickness when executed. The algorithm is shown to produce satisfactory results on both a simple 2-dimensional test example, and a nontrivial industrial case of painting a tractor render. The final trajectory shows an overall thickness close to the target thickness, and the resulting trajectory is feasible to execute directly on an industrial robot.
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- Gustafsson, Christian Jamtheim, et al.
(författare)
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Development and evaluation of a deep learning based artificial intelligence for automatic identification of gold fiducial markers in an MRI-only prostate radiotherapy workflow
- 2020
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 65:22
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Tidskriftsartikel (refereegranskat)abstract
- Identification of prostate gold fiducial markers in magnetic resonance imaging (MRI) images is challenging when CT images are not available, due to misclassifications from intra-prostatic calcifications. It is also a time consuming task and automated identification methods have been suggested as an improvement for both objectives. Multi-echo gradient echo (MEGRE) images have been utilized for manual fiducial identification with 100% detection accuracy. The aim is therefore to develop an automatic deep learning based method for fiducial identification in MRI images intended for MRI-only prostate radiotherapy. MEGRE images from 326 prostate cancer patients with fiducials were acquired on a 3T MRI, post-processed with N4 bias correction, and the fiducial center of mass (CoM) was identified. A 9 mm radius sphere was created around the CoM as ground truth. A deep learning HighRes3DNet model for semantic segmentation was trained using image augmentation. The model was applied to 39 MRI-only patients and 3D probability maps for fiducial location and segmentation were produced and spatially smoothed. In each of the three largest probability peaks, a 9 mm radius sphere was defined. Detection sensitivity and geometric accuracy was assessed. To raise awareness of potential false findings a 'BeAware' score was developed, calculated from the total number and quality of the probability peaks. All datasets, annotations and source code used were made publicly available. The detection sensitivity for all fiducials were 97.4%. Thirty-six out of thirty-nine patients had all fiducial markers correctly identified. All three failed patients generated a user notification using the BeAware score. The mean absolute difference between the detected fiducial and ground truth CoM was 0.7 ± 0.9 [0 3.1] mm. A deep learning method for automatic fiducial identification in MRI images was developed and evaluated with state-of-the-art results. The BeAware score has the potential to notify the user regarding patients where the proposed method is uncertain.
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- Landström, Fredrik J., 1966-, et al.
(författare)
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Successful electrochemotherapy treatment of a large bleeding lymph node melanoma metastasis
- 2022
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Ingår i: Melanoma Management. - : Future Medicine LTD. - 2045-0885 .- 2045-0893. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Despite the progress in immunotherapy and targeted therapy for patients with cutaneous malignant melanoma not all patients with loco-regional recurrences will respond to treatment. Electrochemotherapy is a relatively new treatment modality where the efficacy of a chemotherapeutic drug is enhanced by an electrical field. Here we report a case of a 68-year-old woman with a large therapy resistant inguinal lymph node melanoma metastasis complicated by bleeding that was successfully treated with electrochemotherapy.
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- Malmstroem, Nina, et al.
(författare)
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Living with a parent with ALS-adolescents' need for professional support from the adolescents' and the parents' perspectives
- 2023
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Ingår i: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. - : Taylor & Francis. - 2167-8421 .- 2167-9223. ; 24:7-8, s. 727-735
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Tidskriftsartikel (refereegranskat)abstract
- AimThe aim of the study was to qualitatively investigate the adolescents' need for professional support when a parent has amyotrophic lateral sclerosis (ALS) - from the adolescents' and the parents' perspectives.MethodsA total of 37 individual semi-structured single interviews with 18 families were conducted, including 11 adolescents aged 8-25 and 26 parents, 13 with ALS and 13 co-parents. Data was analysed using qualitative content analysis.ResultsBoth adolescents and parents described the adolescents as needing professional support but found it difficult to articulate this need. However, the results indicate that the adolescents needed help in bringing manageability into their lives due to the uncertainty of living with the illness in the family. It was therefore essential to ensure that the adolescents were not forgotten in the disease context and that their needs for being involved as well as for obtaining information and understanding, was addressed. The importance of offering the adolescents support early was emphasized, but also of actively helping the families to master challenges in their everyday life. Support adapted to each family's unique situation and preferences was desired, as the adolescents' need for support seemed to be individual, disease-dependent and varied during different phases.ConclusionGiven the adolescents' need for information and understanding, healthcare professionals must actively work to reach the adolescents as early as possible. It is crucial to ensure that the adolescents are given the opportunity to be involved based on their own conditions, as well as to support the families to strengthen their communication.
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- Malmström, Nina, et al.
(författare)
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Adolescents' challenging and grief-filled transitions when living with a parent with ALS : a qualitative interpretive study
- 2024
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Ingår i: Social Science and Medicine. - : Elsevier. - 0277-9536 .- 1873-5347. ; 354
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The study aimed to explore the meaning for adolescents of living with a parent with amyotrophic lateral sclerosis (ALS).Methods: The design is qualitative. Interviews were conducted between December 2020 and April 2022 with 11 adolescents (8-25 y), living in households with a parent with ALS in Sweden. The analysis was phenomenologically hermeneutical.Results: The adolescents were in a difficult and exposed situation, especially if the parent had a severe disability and assistant care providers were in the home. Witnessing the gradual loss of the parent in an indefinite battle against time, while still needing them, elicited grief-filled and hard-to-manage emotions. Everyday life was turned upside down, resulting in greater responsibility for the adolescents, not only in helping with household chores and assisting the ill parent, but also in emotionally protecting both parents. It forced the adolescents to mature faster and put their own life on hold, triggering experiences of being limited. This, together with changing family roles yet being more attached to home, reinforced the imbalance in the adolescents' lives. The interpreted whole of the adolescents' narratives revealed that living with a parent with ALS meant a challenging and grieving transition during an already transition-filled adolescence, which left the adolescents struggling to keep a foothold on a life torn apart.Conclusion: The unbalanced life situation may hinder the adolescents' identity formation and emancipation, which are developmentally important for managing a healthy and independent adulthood. The results emphasize the importance of early targeted support to reach this vulnerable group in order to secure their health.
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