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  • 1.
    Graham, A.C.
    et al.
    Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United Kingdom.
    Thomas, K.J.
    Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United Kingdom.
    Pepper, M.
    Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United Kingdom.
    Simmons, M.Y.
    Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United Kingdom, School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
    Ritchie, D.A.
    Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE, United Kingdom.
    Berggren, Karl-Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Jaksch, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Debnarova, Andrea
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Yakimenko, I.I.
    0.7 Analogue structures and exchange interactions in quantum wires2004In: Solid State Communications, ISSN 0038-1098, Vol. 131, no 9-10 SPEC. ISS., 591-597 p.Article in journal (Refereed)
    Abstract [en]

    We present experimental studies of crossings of spin-split one-dimensional subbands in ballistic quantum wires in an in-plane magnetic field B ?. At low electron densities, a spontaneous spin-splitting occurs as subbands cross, which gives rise to additional non-quantised conductance structures called 0.7 analogues. We analyse the data within a spin-density-functional model, which includes exchange interactions in a magnetic field. Focussing on the region of the crossings of spin-split subbands, it is found that the energy levels rearrange as they cross due to exchange interactions. © 2004 Elsevier Ltd. All rights reserved.

  • 2.
    Nilsson, Line
    et al.
    Aarhus University, Denmark.
    Palm, Fredrik
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Uppsala University, Sweden.
    Norregaard, Rikke
    Aarhus University, Denmark.
    15-Deoxy-Delta(12,14)-prostaglandin J(2) Exerts Antioxidant Effects While Exacerbating Inflammation in Mice Subjected to Ureteral Obstruction2017In: Mediators of Inflammation, ISSN 0962-9351, E-ISSN 1466-1861, 3924912Article in journal (Refereed)
    Abstract [en]

    Urinary obstruction is associated with inflammation and oxidative stress, leading to renal dysfunction. Previous studies have shown that 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) has both antioxidant and anti-inflammatory effects. Using a unilateral ureteral obstruction (UUO) mouse model, we examined the effects of 15d-PGJ(2) on oxidative stress and inflammation in the kidney. Mice were subjected to UUO for 3 days and treated with 15d-PGJ(2). Protein and RNA expression were examined using immunoblotting and qPCR. 15d-PGJ(2) increased NF-E2-related nuclear factor erythroid-2 (Nrf2) protein expression in response to UUO, and heme oxygenase 1 (HO-1), a downstream target of Nrf2, was induced by 15d-PGJ(2). Additionally, 15d-PGJ(2) prevented protein carbonylation, a UUO-induced oxidative stress marker. Inflammation, measured by nuclear NF-kappa B, F4/80, and MCP-1, was increased in response to UUO and further increased by 15d-PGJ(2). Renal injury was aggravated by 15d-PGJ(2) treatment as measured by kidney injury molecule-1 (KIM-1) and cortical caspase 3 content. No effect of 15d-PGJ(2) was observed on renal function in mice subjected to UUO. This study illustrates differentiated functioning of 15d-PGJ(2) on inflammation and oxidative stress in response to obstructive nephropathy. High concentrations of 15d-PGJ(2) protects against oxidative stress during 3-day UUO in mice; however, it aggravates the associated inflammation.

  • 3.
    Wohlfarth, Ariane
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden.
    Roman, Markus
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden.
    Andersson, Mikael
    Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden.
    Kugelberg, Fredrik C
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden.
    Diao, Xingxing
    Chemistry and Drug Metabolism Section, Clinical Pharmacology & TherapeuticsResearch Branch, Intramural Research Program, National Institute on DrugAbuse, National Institutes of Health, Baltimore, MD, 21224, USA.
    Carlier, Jeremy
    Chemistry and Drug Metabolism Section, Clinical Pharmacology & TherapeuticsResearch Branch, Intramural Research Program, National Institute on DrugAbuse, National Institutes of Health, Baltimore, MD, 21224, USA.
    Eriksson, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Wu, Xiongyu
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Konradsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Josefsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. Department of Forensic Genetics and Forensic Toxicology, National Board ofForensic Medicine, 58758 Linköping, Sweden.
    Huestis, Marilyn A
    School of Medicine, University of Maryland, Baltimore, MD, 21201, USA.
    Kronstrand, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden.
    25C-NBOMe and 25I-NBOMe metabolite studies in human hepatocytes, in vivo mouse and human urine with high-resolution mass spectrometry.2017In: Drug Testing and Analysis, ISSN 1942-7603, E-ISSN 1942-7611, Vol. 9, no 5, 680-698 p.Article in journal (Refereed)
    Abstract [en]

    25C-NBOMe and 25I-NBOMe are potent hallucinogenic drugs that recently emerged as new psychoactive substances. To date, a few metabolism studies were conducted for 25I-NBOMe, whereas 25C-NBOMe metabolism data are scarce. Therefore, we investigated the metabolic profile of these compounds in human hepatocytes, an in vivo mouse model and authentic human urine samples from forensic cases. Cryopreserved human hepatocytes were incubated for 3 h with 10 μM 25C-NBOMe and 25I-NBOMe; samples were analyzed by liquid chromatography high-resolution mass spectrometry (LC-HRMS) on an Accucore C18 column with a Thermo QExactive; data analysis was performed with Compound Discoverer software (Thermo Scientific). Mice were administered 1.0 mg drug/kg body weight intraperitoneally, urine was collected for 24 h and analyzed (with or without hydrolysis) by LC-HRMS on an Acquity HSS T3 column with an Agilent 6550 QTOF; data were analyzed manually and with WebMetabase software (Molecular Discovery). Human urine samples were analyzed similarly. In vitro and in vivo results matched well. 25C-NBOMe and 25I-NBOMe were predominantly metabolized by O-demethylation, followed by O-di-demethylation and hydroxylation. All methoxy groups could be demethylated; hydroxylation preferably occurred at the NBOMe ring. Phase I metabolites were extensively conjugated in human urine with glucuronic acid and sulfate. Based on these data and a comparison with synthesized reference standards for potential metabolites, specific and abundant 25C-NBOMe urine targets are 5'-desmethyl 25C-NBOMe, 25C-NBOMe and 5-hydroxy 25C-NBOMe, and for 25I-NBOMe 2' and 5'-desmethyl 25I-NBOMe and hydroxy 25I-NBOMe. These data will help clinical and forensic laboratories to develop analytical methods and to interpret results. Copyright © 2016 John Wiley & Sons, Ltd.

  • 4.
    Gehlert, Donald R.
    et al.
    Eli Lilly and Company, Indianapolis, IN, USA.
    Cippitelli, Andrea
    National Institute on Alcohol Abuse and Alcoholism, NIH; Bethesda, MD, USA.
    Thorsell, Annika
    National Institute on Alcohol Abuse and Alcoholism, NIH; Bethesda, MD, USA.
    Lê, Anh Dzung
    University of Toronto, Canada.
    Hipskind, Philip A
    Eli Lilly and Company, Indianapolis, IN, USA.
    Hamdouchi, Chafiq
    Eli Lilly and Company, Indianapolis, IN, USA.
    Lu, Jianliang
    Eli Lilly and Company, Indianapolis, IN, USA.
    Hembre, Erik J.
    Eli Lilly and Company, Indianapolis, IN, USA.
    Cramer, Jeffrey
    Eli Lilly and Company, Indianapolis, IN, USA.
    Song, Min
    Eli Lilly and Company, Indianapolis, IN, USA.
    McKinzie, David
    Eli Lilly and Company, Indianapolis, IN, USA.
    Morin, Michelle
    Eli Lilly and Company, Indianapolis, IN, USA.
    Ciccocioppo, Roberto
    University of Camerino, Italy.
    Heilig, Markus
    National Institute on Alcohol Abuse and Alcoholism, NIH; Bethesda, MD, USA.
    3-(4-Chloro-2-morpholin-4-yl-thiazol-5-yl)-8-(1-ethylpropyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine: a novel brain-penetrant, orally available corticotropin-releasing factor receptor 1 antagonist with efficacy in animal models of alcoholism2007In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 27, no 10, 2718-2726 p.Article in journal (Refereed)
    Abstract [en]

    We describe a novel corticotropin-releasing factor receptor 1 (CRF1) antagonist with advantageous properties for clinical development, and its in vivo activity in preclinical alcoholism models. 3-(4-Chloro-2-morpholin-4-yl-thiazol-5-yl)-8-(1-ethylpropyl)-2,6-dimethyl-imidazo[1,2-b]pyridazine (MTIP) inhibited 125I-sauvagine binding to rat pituitary membranes and cloned human CRF1 with subnanomolar affinities, with no detectable activity at the CRF2 receptor or other common drug targets. After oral administration to rats, MTIP inhibited 125I-sauvagine binding to rat cerebellar membranes ex vivo with an ED50 of approximately 1.3 mg/kg and an oral bioavailability of 91.1%. Compared with R121919 (2,5-dimethyl-3-(6-dimethyl-4-methylpyridin-3-yl)-7-dipropylamino-pyrazolo[1,5-a]pyrimidine) and CP154526 (N-butyl-N-ethyl-4,9-dimethyl-7-(2,4,6-trimethylphenyl)-3,5,7-triazabicyclo[4.3.0]nona-2,4,8,10-tetraen-2-amine), MTIP had a markedly reduced volume of distribution and clearance. Neither open-field activity nor baseline exploration of an elevated plus-maze was affected by MTIP (1-10 mg/kg). In contrast, MTIP dose-dependently reversed anxiogenic effects of withdrawal from a 3 g/kg alcohol dose. Similarly, MTIP blocked excessive alcohol self-administration in Wistar rats with a history of dependence, and in a genetic model of high alcohol preference, the msP rat, at doses that had no effect in nondependent Wistar rats. Also, MTIP blocked reinstatement of stress-induced alcohol seeking both in postdependent and in genetically selected msP animals, again at doses that were ineffective in nondependent Wistar rats. Based on these findings, MTIP is a promising candidate for treatment of alcohol dependence.

  • 5.
    Eriksson, Henrik
    et al.
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Magnusson, Henrik
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    Pop, Adrian Dan Iosif
    Linköping University, Department of Computer and Information Science, PELAB - Programming Environment Laboratory. Linköping University, The Institute of Technology.
    3D Animation and Programmable 2D Graphics for Visualization of Simulations in OpenModelica2008In: Proceedings from the 49th Scandinavian Conference on Simulation and Modeling, 2008, www.scansims.org: Scandinavian Simulation Society , 2008, 10- p.Conference paper (Refereed)
    Abstract [en]

    This paper describes recent work on visualization of simulation results from simulating Modelica models in Open-Modelica. A new 3D graphics package with interactive animation and a new flexible programmable 2D graphicshave been added to OpenModelica. The 2D graphics package provides very flexible usage, either directly from asimulation, from the electronic book client OMNotebook, or programmable graphics, called directly from aModelica model.

  • 6.
    Josefsson, Mattias
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    3D camera with built-in velocity measurement2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In today's industry 3D cameras are often used to inspect products. The camera produces both a 3D model and an intensity image by capturing a series of profiles of the object using laser triangulation. In many of these setups a physical encoder is attached to, for example, the conveyor belt that the product is travelling on. The encoder is used to get an accurate reading of the speed that the product has when it passes through the laser. Without this, the output image from the camera can be distorted due to a variation in velocity.

    In this master thesis a method for integrating the functionality of this physical encoder into the software of the camera is proposed. The object is scanned together with a pattern, with the help of this pattern the object can be restored to its original proportions.

  • 7.
    Ji, W
    et al.
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Lofgren, PM
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Gu, CY
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    3-D computational modeling of SiC epitaxial growth in a hot wall reactor2000In: Materials Science Forum, ISSN 0255-5476, Vol. 338-3, 149-152 p.Article in journal (Refereed)
    Abstract [en]

    A three-dimensional computational model for chemical vapor deposition (CVD) of silicon carbide (SiC) in a hot wall reactor is developed, where the susceptor is tapered with a rectangular cross-section. The present work focuses on the advection-diffusion-reaction process in the susceptor. The precursors are propane and silane, and the carrier gas is hydrogen with mass fraction higher than 98%. Computed growth rates under different system pressures and precursor concentrations are compared with the experimental data measured on samples grown in the Linkoping CVD reactor. The gas composition distribution and the growth rate profile are shown. Dependence of the growth rate on precursor concentrations is investigated.

  • 8.
    Grönwall, Christina
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    3D Content-Based Model Matching using Geometric Features2006Report (Other academic)
    Abstract [en]

    We present an approach that utilizes efficient geometric feature extraction and a matching method that takes articulation into account. It is primarily applicable for man-made objects. First the object is analyzed to extract geometric features, dimensions and rotation are estimated and typical parts, so-called functional parts, are identified. Examples of functional parts are a box's lid, a building's chimney, or a battle tank's barrel. We assume a model library with full annotation. The geometric features are matched with the model descriptors, to gain fast and early rejection of non-relevant models. After this pruning the objectis matched with relevant, usually few, library models. We propose a sequential matching, where the number of functional parts increases in each iteration. The division into parts increases the possibility for correct matching result when several similar models are available. The approach is exemplifi…ed with an vehicle recognition application, where some vehicles have functional parts.

  • 9.
    Rodríguez-Vila, Borja
    et al.
    Bioengineering and Telemedicine Group, Universidad Politécnica de Madrid Spain.
    Pettersson, Johanna
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Institute of Technology.
    García-Vicente, Feliciano
    Medical Physics, Radiotherapy Department, University Hospital La Princesa Spain.
    Gómez, Enrique J.
    Bioengineering and Telemedicine Group, Universidad Politécnica de Madrid Spain.
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    3D deformable registration for monitoring radiotherapy treatment in prostate cancer2007In: Image Analysis: 15th Scandinavian Conference, SCIA 2007, Aalborg, Denmark, June 10-14, 2007, Berlin/Heidelberg, Germany: Springer Berlin/Heidelberg, 2007, 750-759 p.Conference paper (Refereed)
    Abstract [en]

    Two deformable registration methods, the Demons and the Morphon algorithms, have been used for registration of CT datasets to evaluate their usability in radiotherapy planning for prostate cancer. These methods were chosen because they can perform deformable registration in a fully automated way. The experiments show that for intrapatient registration both of the methods give useful results, although some differences exist in the way they deform the template. The Morphon method has, however, some advantageous compared to the Demons method. It is invariant to the image intensity and it does not distort the deformed data. The conclusion is therefore to recommend the Morphon method as a registration tool for this application. A more flexible regularization model is needed, though, in order to be able to catch the full range of deformations required to match the datasets.

  • 10. Imura, M
    et al.
    Kuroda, T
    Oshiro, O
    Chihara, K
    Brandberg, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    3-D flow visualization for construction of the model of the blood flow in the heart2000In: Japanese Journal of Applied Physics, ISSN 0021-4922, Vol. 39, no 5 B, 3246-3251 p.Article in journal (Refereed)
    Abstract [en]

    The authors have been developing a model of blood flow in the heart. The flow model of the heart enables us to estimate the entire blood flow of the heart from a couple of 2-D color Doppler images. Therefore, the load on patients is expected to be reduced. To develop the model of the heart, precise observation and an understanding of the blood flow are indispensable, because the flow is strongly related to the diagnosis of heart diseases. The visualization method must have the following features: (1) 3-D (2) objectivity (3) interactivity and (4) multi-aspect. The authors have developed visualization methods to meet the above-mentioned requirements and evaluated the proposed methods with the in-vitro flow data set. The results clearly reveal that the proposed system enables the researchers of the modeling group to obtain the state of entire flow, such as the occurrence of turbulence.

  • 11.
    Engelson, Vadim
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    3D graphics and Modelica: an integrated approach2000In: Linköping Electronic Articles in Computer and Information Science, ISSN 1401-9841, Vol. 5, no 9Article in journal (Refereed)
    Abstract [en]

    The Modelica standard library and available Modelica tools contain some facilities for specification of 3D geometry and 3D graphics. Geometry and graphics is associated with physical objects included in simulated Modelica models. However, important graphics properties are missing from this model. In particular, physical objects cannot change their shape (geometry) and rendering features (graphics) dynamically. The physics of simulation, is often not affected by geometry of physical objects. For instance, a body is often approximated by its center of mass under certain conditions. Either simple predefined shapes or specifications of geometry via external files are used. The last facility leads to separation between the model and the corresponding graphics and geometry. Our proposal is to integrate 3D geometric and graphical features with Modelica models of physical objects. The 3D graphics information is specified explicitly via annotations containing certain graphics primitives or using instances from a specially designed geometry class library. The motivation, syntax and implementation outline for this approach are discussed in this report.

  • 12.
    Lundqvist, Tobias
    Linköping University, Department of Electrical Engineering, Computer Vision.
    3D mapping with iPhone2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today, 3D models of cities are created from aerial images using a camera rig. Images, together with sensor data from the flights, are stored for further processing when building 3D models. However, there is a market demand for a more mobile solution of satisfactory quality. If the camera position can be calculated for each image, there is an existing algorithm available for the creation of 3D models.

    This master thesis project aims to investigate whether the iPhone 4 offers good enough image and sensor data quality from which 3D models can be created. Calculations on movements and rotations from sensor data forms the foundation of the image processing, and should refine the camera position estimations.

    The 3D models are built only from image processing since sensor data cannot be used due to poor data accuracy. Because of that, the scaling of the 3D models are unknown and a measurement is needed on the real objects to make scaling possible. Compared to a test algorithm that calculates 3D models from only images, already available at the SBD’s system, the quality of the 3D model in this master thesis project is almost the same or, in some respects, even better when compared with the human eye.

  • 13.
    Wikström, Jonas
    Linköping University, Department of Management and Engineering, Machine Design.
    3D Model of Fuel Tank for System Simulation: A methodology for combining CAD models with simulation tools2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Engineering aircraft systems is a complex task. Therefore models and computer simulations are needed to test functions and behaviors of non existing systems, reduce testing time and cost, reduce the risk involved and to detect problems early which reduce the amount of implementation errors. At the section Vehicle Simulation and Thermal Analysis at Saab Aeronautics in Linköping every basic aircraft system is designed and simulated, for example the fuel system. Currently 2-dimensional rectangular blocks are used in the simulation model to represent the fuel tanks. However, this is too simplistic to allow a more detailed analysis. The model needs to be extended with a more complex description of the tank geometry in order to get a more accurate model.

    This report explains the different steps in the developed methodology for combining 3-dimensional geometry models of any fuel tank created in CATIA with dynamic simulation of the fuel system in Dymola. The new 3-dimensional representation of the tank in Dymola should be able to calculate fuel surface location during simulation of a maneuvering aircraft. 

    The first step of the methodology is to create a solid model of the fuel contents in the tank. Then the area of validity for the model has to be specified, in this step all possible orientations of the fuel acceleration vector within the area of validity is generated. All these orientations are used in the automated volume analysis in CATIA. For each orientation CATIA splits the fuel body in a specified number of volumes and records the volume, the location of the fuel surface and the location of the center of gravity. This recorded data is then approximated with the use of radial basis functions implemented in MATLAB. In MATLAB a surrogate model is created which are then implemented in Dymola. In this way any fuel surface location and center of gravity can be calculated in an efficient way based on the orientation of the fuel acceleration vector and the amount of fuel.

    The new 3-dimensional tank model is simulated in Dymola and the results are compared with measures from the model in CATIA and with the results from the simulation of the old 2-dimensional tank model. The results shows that the 3-dimensional tank gives a better approximation of reality and that there is a big improvement compared with the 2-dimensional tank model. The downside is that it takes approximately 24 hours to develop this model.

  • 14.
    Schlaug, Frida
    Linköping University, Department of Electrical Engineering, Information Coding.
    3D Modeling in Augmented Reality2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project aims to make 3D modeling easy through the use of augmented reality. Black and white markers are used to augment the virtual objects. Detection of these is done with help from ARToolKit, developed at University of Washington.

    The model is represented by voxels, and visualised through the marching cubes algorithm. Two physical tools are available to edit the model; one for adding and one for removing volume. Thus the application is similar to sculpting or drawing in 3D.

    Thee resulting application is both easy to use and cheap in that it does not require expensive equipment.

     

  • 15.
    Dahlin, Johan
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    3D Modeling of Indoor Environments2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the aid of modern sensors it is possible to create models of buildings. These sensorstypically generate 3D point clouds and in order to increase interpretability and usability,these point clouds are often translated into 3D models.In this thesis a way of translating a 3D point cloud into a 3D model is presented. The basicfunctionality is implemented using Matlab. The geometric model consists of floors, wallsand ceilings. In addition, doors and windows are automatically identified and integrated intothe model. The resulting model also has an explicit representation of the topology betweenentities of the model. The topology is represented as a graph, and to do this GraphML isused. The graph is opened in a graph editing program called yEd.The result is a 3D model that can be plotted in Matlab and a graph describing the connectivitybetween entities. The GraphML file is automatically generated in Matlab. An interfacebetween Matlab and yEd allows the user to choose which rooms should be plotted.

  • 16.
    Johansson, Erik
    Linköping University, Department of Electrical Engineering.
    3D Reconstruction of Human Faces from Reflectance Fields2004Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    Human viewers are extremely sensitive to the appearanceof peoples faces, which makes the rendering of realistic human faces a challenging problem. Techniques for doing this have continuously been invented and evolved since more than thirty years.

    This thesis makes use of recent methods within the area of image based rendering, namely the acquisition of reflectance fields from human faces. The reflectance fields are used to synthesize and realistically render models of human faces.

    A shape from shading technique, assuming that human skin adheres to the Phong model, has been used to estimate surface normals. Belief propagation in graphs has then been used to enforce integrability before reconstructing the surfaces. Finally, the additivity of light has been used to realistically render the models.

    The resulting models closely resemble the subjects from which they were created, and can realistically be rendered from novel directions in any illumination environment.

  • 17.
    Lofgren, PM
    et al.
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Hallin, Christer
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Gu, CY
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    Ji, W
    ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, Faxen Lab, SE-10044 Stockholm, Sweden Linkoping Univ, IFM, SE-58183 Linkoping, Sweden.
    3-d thermal and flow modeling of hot wall epitaxial chemical vapor deposition reactors, heated by induction2000In: Materials Science Forum, ISSN 0255-5476, Vol. 338-3, 153-156 p.Article in journal (Refereed)
    Abstract [en]

    A three dimensional computational model for temperature and flow predictions in hot wall chemical vapor deposition (CVD) reactors, heated by induction, is presented. It includes heating by a Radio Frequency (RF) coil, flow and heat transfer. Thermal radiation is modeled by a modified Monte Carlo method. Model predictions are compared to full scale experiments at Linkoping CVD reactor for epitaxial growth of silicon carbide (SIC). Both streamwise and spanwise temperature gradients are well predicted, with the temperature maximum location shifted slightly upstream compared to the measured. Additionally, the model succeeds in predicting a recirculation zone just downstream of the susceptor. It is demonstrated how thermal gradients can be greatly reduced by simple geometrical changes.

  • 18.
    Chau, Chieu Vinh
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    3D-modeling of Norrköping2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The interest for a detailed and high solution city model has been large within the project” Optical signature analysis” at the department for Sensor Technology in FOI, Linköping. Thus, a textured 3D-model over Norrköping is needed, which later can be imported into simulation software to study optical signature in urban environment.

    The aim with this thesis work is to be able to use the result as a multi-used 3D-model within applications of the Swedish defence force for future usage. It is important to have a realistic representation of the environment so that the exercises can be planned and analyzed at the current position.

    For the final result to be as good as possible, the thesis work has been concentrated and limited into a smaller area, i.e. the quarter of Svärdet at Nya torget. Thereafter the thesis work has been divided into different stages: photographing, laser measurement, photomontage, modeling and texturing.

    One of the most important and extensive stages is to make the high solution and detailed texture pictures with photomontage. These pictures are first created with photographing and then be performed into panorama pictures. Further, the thesis work has been performed with suitable software, such as 3ds Max and Photoshop CS.

    The finished 3D-model will be supplied as a 3ds-file and max-file, where the textured pictures from the model have been moved into a folder to facilitate future works, for example in classification of texture-pictures.

  • 19.
    Andersson, Tim
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lind, Kristoffer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    3D-visualization of residential buildings in Manstorp2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In real estate ads in both newspapers and on the Internet, there are more and more computer modeled houses for sale. We believe that this is one of the biggest markets for visualization today. When time and technology are ready, we expect that visualization will be used a lot more to create projects where people can “trust” in what is being visualized. For our final thesis we wanted to work with

    Visualization, our concentration within the Construction Engineering program at Linköping University. We managed to do this with the construction company Peab in Linköping, who wanted to make their marketing of their project Manstorp in Linghem more efficient. The pictures that the hired architect firm used to visualize the property with were not sufficient enough, according to Peab, in giving the true picture of the area. The goal for our thesis was to create more realistic and living images, and thereby help Peab sell all of the real estates before completing the constructions.

    We were continuously given material from Peab and the architect firm White in order to visualize a realistic set of pictures for potential clients. One of computer visualizations biggest advantages is that it is easy to modify the models according to changes in the material given. Compared to classic design methods such as hand-drawn sketches, physical models and computer manipulated pictures it was easy for us to change features such as color, displacement and size. We wanted to show how the cooperation between people who visualizes, construction companies and architects could work, where problems could evolve and which solutions and methods are to be preferred.

    The goal was to create a model of the exterior and interior of the individual buildings in their final environment and display this with pictures on Peab’s and the real estate agent’s website. We achieved this goal and the result can be seen at:

    http://www.peab.se/Bostader_lokaler/Bostader/ostergotland/Linkoping/Manstorp

  • 20.
    Evaldsson, Chamilly
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Rydén, Ingvar
    Division of Clinical Chemistry, Kalmar County Hospital, Kalmar, Sweden.
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Uppugunduri, Srinivas
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    4-Thiouridine induces dose-dependent reduction of oedema, leucocyte influx and tumour necrosis factor in lung inflammation2009In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 155, no 2, 330-338 p.Article in journal (Refereed)
    Abstract [en]

    Recent reports demonstrate a role for nucleotides as inflammatory modulators. Uridine, for example, reduces oedema formation and leucocyte infiltration in a Sephadex-induced lung inflammation model. Tumour necrosis factor (TNF) concentration was also reduced. Previous in vivo observations indicated that 4-thiouridine might have similar effects on leucocyte infiltration and TNF release. The aim of this study was thus to investigate the effects of 4-thiouridine in greater detail. We used a Sephadex-induced acute lung inflammation model in Sprague-Dawley rats. The dextran beads were instilled intratracheally into the lungs, which were excised and examined after 24 h. Sephadex alone led to massive oedema formation and infiltration of macrophages, neutrophils and eosinophils. Microgranulomas with giant cell formations were clearly visible around the partially degraded beads. A significant increase in bronchoalveolar lavage fluid (BALF) content of TNF and leukotrienes was also seen. 4-Thiouridine co-administration affected all variables investigated in this model, i.e. oedema, microscopic and macroscopic appearance of lung tissue, total leucocyte and differential leucocyte counts in BALF, TNF and leukotrienes C-4 (LTC4), LTD4 and LTE4 in BALF, indicating a reproducible anti-inflammatory effect. In conclusion, we have demonstrated that 4-thiouridine has anti-inflammatory effects similar to those of uridine. To our knowledge, this is the first demonstration of pharmacological 4-thiouridine effects in vivo. The results suggest nucleoside/nucleotide involvement in inflammatory processes, warranting further studies on nucleoside analogues as attractive new alternatives in the treatment of inflammatory diseases.

  • 21.
    Andersson, Gerhard
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Hesser, Hugo
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Hummerdal, Daniel
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Bergman Nordgren, Lise
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Carlbring, Per
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Faculty of Arts and Sciences. Department of Psychology , Umeå University, Umeå, Sweden.
    A 3.5-year follow-up of Internet-delivered cognitive behavior therapy for major depression2013In: Journal of Mental Health, ISSN 0963-8237, E-ISSN 1360-0567, Vol. 22, no 2, 155-164 p.Article in journal (Refereed)
    Abstract [en]

    BackgroundInternet-delivered cognitive behavior therapy (ICBT) for major depression has been tested in several trials, but only with follow-ups up to 1.5 years.

    AimThe aim of this study was to evaluate the outcome of ICBT 3.5 years after treatment completion.Methods

    A total of 88 people with major depression were randomized to either guided self-help or e-mail therapy in the original trial. One-third was initially on a waiting-list. Treatment was provided for eight weeks and in this report long-term follow-up data were collected. Also included were data from post-treatment and six-month follow-up. A total of 58% (51/88) completed the 3.5-year follow-up. Analyses were performed using a random effects repeated measures piecewise growth model to estimate trajectory shape over time and account for missing data.

    ResultsResults showed continued lowered scores on the Beck Depression Inventory (BDI). No differences were found between the treatment conditions. A large proportion of participants (55%) had sought and received additional treatments in the follow-up period. A majority (56.9%) of participants had a BDI score lower than 10 at the 3.5-year follow-up.

    ConclusionsPeople with mild to moderate major depression may benefit from ICBT 3.5-years after treatment completion.

  • 22.
    Braian, Clara
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Svensson, Mattias
    Karolinska Institute, Sweden.
    Brighenti, Susanna
    Karolinska Institute, Sweden.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Parasa, Venkata R.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Institute, Sweden.
    A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection2015In: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, no 104, 1-9 p., e53084Article in journal (Refereed)
    Abstract [en]

    Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.

  • 23.
    Stefanescu, I.
    et al.
    Technical University of Munich, Germany .
    Abdullahi, Y.
    Technical University of Munich, Germany .
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Defendi, I.
    Technical University of Munich, Germany .
    Hall-Wilton, R.
    European Spallat Source ESS AB, Sweden .
    Hoglund, C.
    European Spallat Source ESS AB, Sweden .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Zee, M.
    Technische Universität München, D-85748 Garching, Germany.
    Zeitelhack, K.
    Technical University of Munich, Germany .
    A B-10-based neutron detector with stacked MultiWire Proportional Counters and macrostructured cathodes2013In: Journal of Instrumentation, ISSN 1748-0221, Vol. 8, no P12003Article in journal (Refereed)
    Abstract [en]

    We present the results of the measurements of the detection efficiency for a 4.7 angstrom neutron beam incident upon a detector incorporating a stack of up to five MultiWire Proportional Counters (MWPC) with Boron-coated cathodes. The cathodes were made of Aluminum and had a surface exhibiting millimeter-deep V-shaped grooves of 45 degrees, upon which the thin Boron film was deposited by DC magnetron sputtering. The incident neutrons interacting with the converter layer deposited on the sidewalls of the grooves have a higher capture probability, owing to the larger effective absorption film thickness. This leads to a higher overall detection efficiency for the grooved cathode when compared to a cathode with a flat surface. Both the experimental results and the predictions of the GEANT4 model suggests that a 5-counter detector stack with coated grooved cathodes has the same efficiency as a 7-counter stack with flat cathodes. The reduction in the number of counters in the stack without altering the detection efficiency will prove highly beneficial for large-area position-sensitive detectors for neutron scattering applications, for which the cost-effective manufacturing of the detector and associated readout electronics is an important objective. The proposed detector concept could be a technological option for one of the new chopper spectrometers and other instruments planned to be built at the future European Spallation Source in Sweden. These results with macrostructured cathodes generally apply not just to MWPCs but to other gaseous detectors as well.

  • 24.
    Mahmoud, Nawrous Ibrahim
    Linköping University, Department of Electrical Engineering.
    A Backstepping Design of a Control System for a Magnetic Levitation System2003Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    The subject of this thesis is the design of a control law for a magnetic levitation system, which in this case is the system 33-210. The method used is backstepping technique and specifically adaptive observer backstepping due to parameter uncertainties and lack of access to all the states of the system. The second state of the system, the speed of the steel ball, was estimated by a reduced order observer. The model used gave us the opportunity to estimate a parameter which in the literature is denoted virtual control coefficient. Backstepping method gives us a rather straight forward way to design the controlling unit for a system with these properties. Stabilization of the closed-loop system is achieved by incorporating a Lypapunov function, which were chose a quadratic one in this thesis. If thederivative of this function is rendered negative definite by the control law, then we achieve stability. The results of the design were evaluated in simulations and real-time measurements by testing the tracking performance of the system. The simulation results were very promising and the validations in real-time were satisfying. Note that this has been done in previous studies; the new aspect here is the limitation of the voltage input. The real-time results showed that the parameter estimation converges only locally.

  • 25.
    Lindström, Tom
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    Grear, Daniel A.
    Colorado State University, USA .
    Buhnerkempe, Michael
    Colorado State University, USA .
    Webb, Colleen T.
    Colorado State University, USA .
    Miller, Ryan S.
    US Anim and Plant Health Inspect Serv, CO USA .
    Portacci, Katie
    US Anim and Plant Health Inspect Serv, CO USA .
    Wennergren, Uno
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, The Institute of Technology.
    A Bayesian Approach for Modeling Cattle Movements in the United States: Scaling up a Partially Observed Network2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 1Article in journal (Refereed)
    Abstract [en]

    Networks are rarely completely observed and prediction of unobserved edges is an important problem, especially in disease spread modeling where networks are used to represent the pattern of contacts. We focus on a partially observed cattle movement network in the U.S. and present a method for scaling up to a full network based on Bayesian inference, with the aim of informing epidemic disease spread models in the United States. The observed network is a 10% state stratified sample of Interstate Certificates of Veterinary Inspection that are required for interstate movement; describing approximately 20,000 movements from 47 of the contiguous states, with origins and destinations aggregated at the county level. We address how to scale up the 10% sample and predict unobserved intrastate movements based on observed movement distances. Edge prediction based on a distance kernel is not straightforward because the probability of movement does not always decline monotonically with distance due to underlying industry infrastructure. Hence, we propose a spatially explicit model where the probability of movement depends on distance, number of premises per county and historical imports of animals. Our model performs well in recapturing overall metrics of the observed network at the node level (U.S. counties), including degree centrality and betweenness; and performs better compared to randomized networks. Kernel generated movement networks also recapture observed global network metrics, including network size, transitivity, reciprocity, and assortativity better than randomized networks. In addition, predicted movements are similar to observed when aggregated at the state level (a broader geographic level relevant for policy) and are concentrated around states where key infrastructures, such as feedlots, are common. We conclude that the method generally performs well in predicting both coarse geographical patterns and network structure and is a promising method to generate full networks that incorporate the uncertainty of sampled and unobserved contacts.

  • 26.
    Wrangsjö, Andreas
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    A Bayesian approach to image restoration2004In: Biomedical Imaging: Nano to Macro, 2004. IEEE International Symposium on, IEEE , 2004, 764-767 vol. 1 p.Conference paper (Refereed)
    Abstract [en]

    A method for reducing additive noise in images by explicit analysis of local image statistics is introduced and compared to other noise reduction methods. The proposed method, which makes use of an a priori noise model, has been evaluated on artificial and real (MRI) image data.

  • 27.
    Özkan, Emre
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lundquist, Christian
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Bayesian Approach to Jointly Estimate Tire Radii and Vehicle Trajectory2011In: Proceedings of the International IEEE Conference on Intelligent Transportation Systems, Washington DC, USA: IEEE conference proceedings, 2011, 1-6 p.Conference paper (Refereed)
    Abstract [en]

    High-precision estimation of vehicle tire radii is considered, based on measurements on individual wheel speeds and absolute position from a global navigation satellite system (GNSS). The wheel speed measurements are subject to noise with time-varying covariance that depends mainly on the road surface. The novelty lies in a Bayesian approach to estimate online the time-varying radii and noise parameters using a marginalized particle filter, where no model approximations are needed such as in previously proposed algorithms based on the extended Kalman filter. Field tests show that the absolute radius can be estimated with millimeter accuracy, while the relative wheel radius on one axle is estimated with submillimeter accuracy.

  • 28.
    Lindström, Tom
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering. Colorado State University, CO 80523 USA; US National Institute Heatlh, MD USA; University of Exeter, England.
    Tildesley, Michael
    US National Institute Heatlh, MD USA; University of Nottingham, England.
    Webb, Colleen
    Colorado State University, CO 80523 USA; US National Institute Heatlh, MD USA.
    A Bayesian Ensemble Approach for Epidemiological Projections2015In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 11, no 4, e1004187- p.Article in journal (Refereed)
    Abstract [en]

    Mathematical models are powerful tools for epidemiology and can be used to compare control actions. However, different models and model parameterizations may provide different prediction of outcomes. In other fields of research, ensemble modeling has been used to combine multiple projections. We explore the possibility of applying such methods to epidemiology by adapting Bayesian techniques developed for climate forecasting. We exemplify the implementation with single model ensembles based on different parameterizations of the Warwick model run for the 2001 United Kingdom foot and mouth disease outbreak and compare the efficacy of different control actions. This allows us to investigate the effect that discrepancy among projections based on different modeling assumptions has on the ensemble prediction. A sensitivity analysis showed that the choice of prior can have a pronounced effect on the posterior estimates of quantities of interest, in particular for ensembles with large discrepancy among projections. However, by using a hierarchical extension of the method we show that prior sensitivity can be circumvented. We further extend the method to include a priori beliefs about different modeling assumptions and demonstrate that the effect of this can have different consequences depending on the discrepancy among projections. We propose that the method is a promising analytical tool for ensemble modeling of disease outbreaks.

  • 29.
    Eklund, Anders
    et al.
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Science & Engineering. Linköping University, Faculty of Arts and Sciences.
    Lindqvist, Martin A
    Department of Biostatistics, Johns Hopkins University, Baltimore, USA.
    Villani, Mattias
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    A Bayesian Heteroscedastic GLM with Application to fMRI Data with Motion Spikes2017In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 155, 354-369 p.Article in journal (Refereed)
    Abstract [en]

    We propose a voxel-wise general linear model with autoregressive noise and heteroscedastic noise innovations (GLMH) for analyzing functional magnetic resonance imaging (fMRI) data. The model is analyzed from a Bayesian perspective and has the benefit of automatically down-weighting time points close to motion spikes in a data-driven manner. We develop a highly efficient Markov Chain Monte Carlo (MCMC) algorithm that allows for Bayesian variable selection among the regressors to model both the mean (i.e., the design matrix) and variance. This makes it possible to include a broad range of explanatory variables in both the mean and variance (e.g., time trends, activation stimuli, head motion parameters and their temporal derivatives), and to compute the posterior probability of inclusion from the MCMC output. Variable selection is also applied to the lags in the autoregressive noise process, making it possible to infer the lag order from the data simultaneously with all other model parameters. We use both simulated data and real fMRI data from OpenfMRI to illustrate the importance of proper modeling of heteroscedasticity in fMRI data analysis. Our results show that the GLMH tends to detect more brain activity, compared to its homoscedastic counterpart, by allowing the variance to change over time depending on the degree of head motion.

    The full text will be freely available from 2018-05-01 10:46
  • 30. Rantanen, VV
    et al.
    Gyllenberg, M
    Koski, Timo
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Mathematical Statistics .
    Johnson, MS
    A Bayesian molecular interaction library2003In: Journal of Computer-Aided Molecular Design, ISSN 0920-654X, Vol. 17, no 7, 435-461 p.Article in journal (Refereed)
    Abstract [en]

    We describe a library of molecular fragments designed to model and predict non-bonded interactions between atoms. We apply the Bayesian approach, whereby prior knowledge and uncertainty of the mathematical model are incorporated into the estimated model and its parameters. The molecular interaction data are strengthened by narrowing the atom classification to 14 atom types, focusing on independent molecular contacts that lie within a short cutoff distance, and symmetrizing the interaction data for the molecular fragments. Furthermore, the location of atoms in contact with a molecular fragment are modeled by Gaussian mixture densities whose maximum a posteriori estimates are obtained by applying a version of the expectation-maximization algorithm that incorporates hyperparameters for the components of the Gaussian mixtures. A routine is introduced providing the hyperparameters and the initial values of the parameters of the Gaussian mixture densities. A model selection criterion, based on the concept of a 'minimum message length' is used to automatically select the optimal complexity of a mixture model and the most suitable orientation of a reference frame for a fragment in a coordinate system. The type of atom interacting with a molecular fragment is predicted by values of the posterior probability function and the accuracy of these predictions is evaluated by comparing the predicted atom type with the actual atom type seen in crystal structures. The fact that an atom will simultaneously interact with several molecular fragments forming a cohesive network of interactions is exploited by introducing two strategies that combine the predictions of atom types given by multiple fragments. The accuracy of these combined predictions is compared with those based on an individual fragment. Exhaustive validation analyses and qualitative examples ( e. g., the ligand-binding domain of glutamate receptors) demonstrate that these improvements lead to effective modeling and prediction of molecular interactions.

  • 31.
    Danner, Torrin
    Linköping University, Department of Computer and Information Science, Statistics.
    A Bayesian Multilevel Model for Time Series Applied to Learning in Experimental Auctions2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Establishing what variables affect learning rates in experimental auctions can be valuable in determining how competitive bidders in auctions learn. This study aims to be a foray into this field. The differences, both absolute and actual, between participant bids and optimal bids are evaluated in terms of the effects from a variety of variables such as age, sex, etc. An optimal bid in the context of an auction is the best bid a participant can place to win the auction without paying more than the value of the item, thus maximizing their revenues. This study focuses on how two opponent types, humans and computers, affect the rate at which participants learn to optimize their winnings.

    A Bayesian multilevel model for time series is used to model the learning rate of actual bids from participants in an experimental auction study. The variables examined at the first level were auction type, signal, round, interaction effects between auction type and signal and interaction effects between auction type and round. At a 90% credibility interval, the true value of the mean for the intercept and all slopes falls within an interval that also includes 0. Therefore, none of the variables are deemed to be likely to influence the model.

    The variables on the second level were age, IQ, sex and answers from a short quiz about how participants felt when the y won or lost auctions. The posterior distributions of the second level variables also found to be unlikely to influence the model at a 90% credibility interval.

    This study shows that more research is required to be able to determine what variables affect the learning rate in competitive bidding auction studies

  • 32.
    Corander, Jukka
    et al.
    Department of Mathematics, Åbo Akademi University, Åbo, Finland.
    Ekdahl, Magnus
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    Koski, Timo
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, The Institute of Technology.
    A bayesian random fragment insertion model for de novo detection of DNA regulatory binding regions2007Manuscript (preprint) (Other academic)
    Abstract [en]

    Identification of regulatory binding motifs within DNA sequences is a commonly occurring problem in computationnl bioinformatics. A wide variety of statistical approaches have been proposed in the literature to either scan for previously known motif types or to attempt de novo identification of a fixed number (typically one) of putative motifs. Most approaches assume the existence of reliable biodatabasc information to build probabilistic a priori description of the motif classes. No method has been previously proposed for finding the number of putative de novo motif types and their positions within a set of DNA sequences. As the number of sequenced genomes from a wide variety of organisms is constantly increasing, there is a clear need for such methods. Here we introduce a Bayesian unsupervised approach for this purpose by using recent advances in the theory of predictive classification and Markov chain Monte Carlo computation. Our modelling framework enables formal statistical inference in a large-scale sequence screening and we illustrate it by a set of examples.

  • 33.
    Lindblad, Ulrik
    et al.
    Linköping University, Department of Electrical Engineering.
    Thalin, Patrik
    Linköping University, Department of Electrical Engineering.
    A Behavioral Model of a DSP Processor with Scalable Structure2002Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    In mobile digital devices, low power consumption is an important matter to reduce the need for a heavy and big battery. One way of reducing the power consumption is to construct the hardware so that the performance is optimal for the application. The demand of performance is dependent of the tasks that the device will be performing. This is where scalable structure of the hardware is an idea to solve the problem.

    This master thesis serve as a starting point for developing a digital signal processor with scalable structure. The digital signal processor is a common and important part of digital processing. Scalable struture is in this case adding and removing parts of the memory and/or the instruction set, and to make the data wordlength variable. The development is simplified by modeling it on an existing processor. The result of this master thesis is an instruction simulator written in C language. The simulator will be a model for development of the hardware.

  • 34.
    Moberg, Stig
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Öhr, Jonas
    ABB AB, Crane Systems, Sweden.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Benchmark Problem for Robust Control of a Multivariable Nonlinear Flexible Manipulator2008Report (Other academic)
    Abstract [en]

    A benchmark problem for robust feedback control of a manipulator is presented. The system to be controlled is an uncertain nonlinear two link manipulator with elastic gear transmissions. The gear transmission is described by nonlinear friction and elasticity. The system is uncertain according to a parametric uncertainty description and due to uncertain disturbances affecting both the motors and the tool. The system should be controlled by a discrete-time controller that optimizes performance for given robustness requirements. The control problem concerns only disturbance rejection. The proposed model is validated by experiments on a real industrial manipulator.

  • 35.
    Moberg, Stig
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Öhr, Jonas
    ABB AB, Crane Systems, Sweden.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Benchmark Problem for Robust Control of a Multivariable Nonlinear Flexible Manipulator2008In: Proceedings of the 17th IFAC World Congress, 2008, 1206-1211 p.Conference paper (Refereed)
    Abstract [en]

    A benchmark problem for robust feedback control of a manipulator is presented. The system to be controlled is an uncertain nonlinear two link manipulator with elastic gear transmissions. The gear transmission is described by nonlinear friction and elasticity. The system is uncertain according to a parametric uncertainty description and due to uncertain disturbances affecting both the motors and the tool. The system should be controlled by a discrete-time controller that optimizes performance for given robustness requirements. The control problem concerns only disturbance rejection. The proposed model is validated by experiments on a real industrial manipulator.

  • 36.
    Moberg, Stig
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Öhr, Jonas
    ABB AB, Sweden.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Benchmark Problem for Robust Feedback Control of a Flexible Manipulator2009In: IEEE Transactions on Control Systems Technology, ISSN 1063-6536, E-ISSN 1558-0865, Vol. 17, no 6, 1398-1405 p.Article in journal (Refereed)
    Abstract [en]

    A benchmark problem for robust feedback control of a flexible manipulator is presented. The system to be controlled is a four-mass system subject to input saturation, nonlinear gear elasticity, model uncertainties, and load disturbances affecting both the motor and the arm. The system should be controlled by a discrete-time controller that optimizes performance for given robustness requirements. Four suggested solutions are presented, and even though the solutions are based on different design methods, they give comparable results.

  • 37.
    Moberg, Stig
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Öhr, Jonas
    ABB AB, Sweden.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Benchmark Problem for Robust Feedback Control of a Flexible ManipulatorA benchmark problem for robust feedback control of a flexible manipulator2007Report (Other (popular science, discussion, etc.))
    Abstract [en]

    A benchmark problem for robust feedback control of a flexible manipulator is presented. The system to be controlled is a four-mass system subject to input saturation, nonlinear gear elasticity, model uncertainties, and load disturbances affecting both the motor and the arm. The system should be controlled by a discrete-time controller that optimizes performance for given robustness requirements. Four suggested solutions are presented, and even though the solutions are based on different design methods, they give comparable results.

  • 38.
    Bergkvist, Liza
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Sandin, Linnea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Kågedal, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    A beta PP processing results in greater toxicity per amount of A beta(1-42) than individually expressed and secreted A beta(1-42) in Drosophila melanogaster2016In: BIOLOGY OPEN, ISSN 2046-6390, Vol. 5, no 8, 1030-1039 p.Article in journal (Refereed)
    Abstract [en]

    The aggregation of the amyloid-beta (A beta) peptide into fibrillar deposits has long been considered the key neuropathological hallmark of Alzheimers disease (AD). A beta peptides are generated from proteolytic processing of the transmembrane A beta precursor protein (A beta PP) via sequential proteolysis through the beta-secretase activity of beta-site A beta PP-cleaving enzyme (BACE1) and by the intramembranous enzyme gamma-secretase. For over a decade, Drosophila melanogaster has been used as a model organism to study AD, and two different approaches have been developed to investigate the toxicity caused by AD-associated gene products in vivo. In one model, the A beta peptide is directly over-expressed fused to a signal peptide, allowing secretion of the peptide into the extracellular space. In the other model, human A beta PP is co-expressed with human BACE1, resulting in production of the A beta peptide through the processing of A beta PP by BACE1 and by endogenous fly gamma-secretase. Here, we performed a parallel study of flies that expressed the A beta(1-42) peptide alone or that co-expressed A beta PP and BACE1. Toxic effects (assessed by eye phenotype, longevity and locomotor assays) and levels of the A beta(1-42), A beta(1-40) and A beta(1-38) peptides were examined. Our data reveal that the toxic effect per amount of detected A beta(1-42) peptide was higher in the flies co-expressing A beta PP and BACE1 than in the A beta(1-42)-expressing flies, and that the co-existence of A beta(1-42) and A beta(1-40) in the flies co-expressing A beta PP and BACE1 could be of significant importance to the neurotoxic effect detected in these flies. Thus, the toxicity detected in these two fly models seems to have different modes of action and is highly dependent on how and where the peptide is generated rather than on the actual level of the A beta(1-42) peptide in the flies. This is important knowledge that needs to be taken into consideration when using Drosophila models to investigate disease mechanisms or therapeutic strategies in AD research.

  • 39.
    Saifullah, Mohammad
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Balkenius, Christian
    Lund University Cognitive Science, Sweden.
    Jönsson, Arne
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    A biologically based model for recognition of 2-D occluded patterns2014In: Cognitive Processing, ISSN 1612-4782, Vol. 15, no 1, 13-28 p.Article in journal (Refereed)
    Abstract [en]

    In this work, we present a biologically inspired model for recognition of occluded patterns. The general architecture of the model is based on the two visual information processing pathways of the human visual system, i.e. the ventral and the dorsal pathways. The proposed hierarchically structured model consists of three parallel processing channels. The main channel learns invariant representations of the input patterns and is responsible for pattern recognition task. But, it is limited to process one pattern at a time. The direct channel represents the biologically based direct connection from the lower to the higher processing level in the human visual cortex. It computes rapid top-down pattern-specific cues to modulate processing in the other two channels. The spatial channel mimics the dorsal pathway of the visual cortex. It generates a combined saliency map of the input patterns and, later, segments the part of the map representing the occluded pattern. This segmentation process is based on our hypothesis that the dorsal pathway, in addition to encoding spatial properties, encodes the shape representations of the patterns as well. The lateral interaction between the main and the spatial channels at appropriate processing levels and top-down, pattern-specific modulation of the these two channels by the direct channel strengthen the locations and features representing the occluded pattern. Consequently, occluded patterns become focus of attention in the ventral channel and also the pattern selected for further processing along this channel for final recognition.

  • 40.
    Saifullah, Mohammad
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    A Biologically Inspired Model for Occluded Patterns2011In: Neural Information Processing: proceedings of the 18th International Conference on Neural Information Processing, ICONIP 2011,  Shanghai, China, November 2011., 2011, 88-96 p.Conference paper (Refereed)
    Abstract [en]

    In this paper a biologically-inspired model for partly occluded patterns is proposed. The model is based on the hypothesis that in human visual system occluding patterns play a key role in recognition as well as in reconstructing internal representation for a pattern’s occluding parts. The proposed model is realized with a bidirectional hierarchical neural network. In this network top-down cues, generated by direct connections from the lower to higher levels of hierarchy, interact with the bottom-up information, generated from the un-occluded parts, to recognize occluded patterns. Moreover, positional cues of the occluded as well as occluding patterns, that are computed separately but in the same network, modulate the top-down and bottom-up processing to reconstruct the occluded patterns. Simulation results support the presented hypothesis as well as effectiveness of the model in providing a solution to recognition of occluded patterns. The behavior of the model is in accordance to the known human behavior on the occluded patterns.

  • 41.
    Saifullah, Mohammad
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    A Biologically-Inspired Approach for Object Search2013In: Proceedings of the World Congress on Engineering 2013 WCE 2013, July 3-5, 2013, London, U.K. Vol. III, Newswood and International Association of Engineers , 2013, 792-797 p.Conference paper (Refereed)
    Abstract [en]

    In this paper a biologically-inspired approach for object search is introduced. This approach is based on the visual information processing in the human brain and more specifically along the two visual processing pathways of the visual cortex. According to this approach different processes, with similar representational structure, work in parallel toward their local tasks, while at the same time, their mutual interaction leads to achievement of larger global goals. The model based on this approach provides a platform where bottom-up and top-down cues are computed and integrated in small incremental steps and lead to emergence of attention that selects an appropriate object. The two important principles of visual information processing, i.e., constraint satisfaction and inhibition play the key role in this model. The model is implemented with an interactive neural network. Simulation results demonstrate the practicality as well as the strength of this approach for object search tasks.

  • 42.
    Saifullah, Mohammad
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    A Biologically-Inspired Model for Recognition of Overlapped Patterns2011In: Proceedings International ICST Conference on Bio-Inspired Models of Network, Information and Computing Systems, 2011Conference paper (Refereed)
    Abstract [en]

    In this paper a biologically-inspired model for recognition of overlapped patterns is proposed. Information processing in the two visual information processing pathways, i.e., the dorsal and the ventral pathway, is modeled as a solution to the problem. We hypothesize that dorsal pathway, in addition to encoding the spatial information, learns the shape representation of the patterns and, later uses this knowledge as a top-down guidance signal to segment the bottom-up, image-based saliency map. This process of segmentation in the dorsal pathway is implemented as an interactive process, where interaction between bottom-up image information and top-down shape cues lead to incremental development of a segmented saliency map for one of the overlapped object at a time. This segmented map encodes spatial as well as shape information of the respective pattern in the input. The interaction of the dorsal channel with the ventral channel leads to modulation and selective processing of the respective pattern in the ventral pathway for final recognition. Simulation results support the presented hypothesis as well as effectiveness of the model in providing a solution to the recognition of overlapped patterns. The behavior of the model is in accordance to the known human behavior on the occluded patterns.

  • 43.
    Holmberg, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Mechanics. Linköping University, The Institute of Technology.
    Wagenius, P.
    Mid Sweden University.
    A biomechanical model of a double‐poling skier2003In: In International Society of Biomechanics XIXth Congress on The human body in motion, CD Rom Abstracts and Proceedings, Milburn, P. (Ed.), University of Otago, Dunedin, New Zealand, 6‐11 July, 2003Conference paper (Other academic)
  • 44.
    Kiflemariam, Jordanos
    Linköping University, Department of Science and Technology.
    A Biomimetic Manganese Model for Artificial Photosynthesis: Q-band Electron Paramagnetic Resonance Study of a Novel Mn2(II,III) Complex2005Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    In natural oxygen-producing photosynthesis solar energy is stored as chemical energy, in carbohydrates, fats and amino acids, using water as electron source. The large transmembrane protein complex, PSII, is the key enzyme in the light-driven reactions. Water oxidation is accomplished by a triad in PSII in which the Mn-cluster plays an important role. In the artificial photosynthetic system, nature’s photosynthesis will be mimicked such that hydrogen, a sustainable energy source, can be produced from solar energy and water alone. Since water oxidiation requires the catalytic activity of a Mn-cluster in photosynthesis, different artificially constructed manganese complexes are investigated.

    The dinuclear ([Mn2(II,III)L(µ-OAc)2]ClO4), where L is the X-anion of 2-(N,N-Bis(2-methylpyridyl)aminomethyl)-6-(N-(3,5-ditert-butylbenzyl-2-hydroxy)-N-(pyridylmethyl)aminomethyl)-4-methylphenol, an unsymmetric ligand with two coordinating phenolate groups, has been studied. The two Mn-ions are linked via a mono-µ-oxo bridge and two acetate ligands. Q-band Electron Paramagnetic Resonance was conducted on the Unsymmetric Mn2(II,III) Complex. Aquired results show that the complex has a 2600 Gauss broad signal (11 400-14 000 Gauss) with 14-17 lines at g~2 and hyperfines of 120 Gauss. This is consistent with previous X-band studies. Q-band spectra of the Unsymmetric Mn(II,III) display increased hyperfine resolution compared to Qband spectra of the symmetric complex, Mn2(bpmp)(µ-OAC)2. This is noticeable since Unsymmetric Mn2(II,III) and Mn2 (bpmp)(µ-OAC)2 partly overlap in low-frequency experiments (X-band EPR).

    Further investigations are yet to be expected. Nevertheless, the conducted thesis study provides important knowledge in the futuristic goal of building an artificial super-complex.

  • 45. Macoveanu, Julian
    et al.
    Klingberg, T.
    Tegnér, Jesper
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Computational Biology .
    A biophysical model of multiple-item working memory: A computational and neuroimaging study2006In: Neuroscience, ISSN 0306-4522, Vol. 141, no 3, 1611-1618 p.Article in journal (Refereed)
    Abstract [en]

    Biophysically based computational models have successfully accounted for the persistent neural activity underlying the maintenance of single items of information in working memory. The aim of the present study was to extend previous models in order to retain multiple items, in agreement with the observed human storage capacity. This was done by implementing cellular mechanisms known to occur during the childhood development of working memory, such as an increased synaptic strength and improved contrast and specificity of the neural response. Our computational study shows that these mechanisms are sufficient to create a neural network which can store information about multiple items through sustained neural activity. Furthermore, by using functional magnetic resonance imaging, we found that the information-activity curve predicted by the model corresponds to that in the human posterior parietal cortex during performance of working memory tasks, which is consistent with previous studies of brain activity related to working memory capacity in humans. © 2006 IBRO.

  • 46.
    Agnafors, Sara
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Svedin, Carl Göran
    Linköping University, Department of Clinical and Experimental Medicine, Barnafrid. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Child and Adolescent Psychiatry in Linköping.
    Oreland, Lars
    Uppsala University, Sweden.
    Bladh, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Comasco, Erika
    Uppsala University, Sweden.
    Sydsjö, Gunilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    A Biopsychosocial Approach to Risk and Resilience on Behavior in Children Followed from Birth to Age 122017In: Child Psychiatry and Human Development, ISSN 0009-398X, E-ISSN 1573-3327, Vol. 48, no 4, 584-596 p.Article in journal (Refereed)
    Abstract [en]

    An increasing prevalence of mental health problems calls for more knowledge into factors associated with resilience. The present study used multiple statistical methodologies to examine a biopsychosocial model of risk and resilience on preadolescence behavior. Data from 889 children and mothers from a birth cohort were used. An adversity score was created by combining maternal symptoms of depression, psychosocial risk and childrens experiences of life events. The proposed resilience factors investigated were candidate genetic polymorphisms, child temperament, social functioning, and maternal sense of coherence. The l/ l genotype of the serotonin transporter linked polymorphic region was associated with lower internalizing scores, but not mainly related to the level of adversity. An easy temperament was associated with resilience for children exposed to high adversity. Social functioning was found to be promotive independent of the risk level. The results support a multiple-level model of resilience indicating effects, though small, of both biological and psychosocial factors.

  • 47.
    Agnafors, Sara
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Svedin, Carl Göran
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Child and Adolescent Psychiatry in Linköping.
    Oreland, Lars
    Department of Neuroscience, Uppsala University, Uppsala, Sweden.
    Bladh, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Comasco, Erika
    Department of Neuroscience, Uppsala University, Uppsala, Sweden.
    Sydsjö, Gunilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    A biopsychosocial approach to risk and resilience on behavior in children followed from birth to age twelve2016Manuscript (preprint) (Other academic)
    Abstract [en]

    An increasing prevalence of mental health problems calls for more knowledge into factors associated with resilience in the context of child behavior. Biological factors are seldom considered in psychosocial models of resilience. The present study used multiple statistical methodologies to examine a biopsychosocial model of risk and resilience on behavior at preadolescence. Data from 889 children and their mothers were used. A cumulative adversity score was created by combining maternal symptoms of depression, psychosocial risk and children’s experiences of life events. The proposed resilience factors investigated were candidate genetic polymorphisms, child temperament and social functioning, and maternal sense of coherence. Results show that the l/l genotype of the serotonin transporter linked polymorphic region (5-HTTLPR) was associated with lower internalizing scores, especially for children exposed to low adversity. An easy temperament was associated with resilient outcomes for children exposed to high adversity. Child social functioning was found to be more of a general resource variable buffering risk in both high and low adversity groups. The results support a multiple level model of resilience indicating effects, though small, of both biological and psychosocial factors. The present findings call for both preventive actions and further studies on biopsychosocial models in resilience research.

  • 48.
    Granström, Kjell
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Stiwne, Dan
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Clinical and Social Psychology.
    A bipolar model of groupthink - An expansion of Janis' concept1998In: Small group research : an international journal of theory, investigation, and application, Vol. 29, 32-56 p.Article in journal (Refereed)
  • 49.
    Granström, Kjell
    et al.
    Linköping University, Department of Behavioural Sciences and Learning.
    Stiwne, Dan
    Linköping University, Department of Behavioural Sciences and Learning.
    A bipolar model on groupthink : An expansion of Janis' concept groupthink.1994Report (Other academic)
  • 50.
    Elfving, Tommy
    et al.
    Linköping University, Department of Mathematics, Scientific Computing. Linköping University, The Institute of Technology.
    Skoglund, Ingegerd
    Linköping University, Department of Mathematics, Scientific Computing. Linköping University, The Institute of Technology.
    A block-preconditioner for a special regularized least-squares problem2007In: Linear Algebra with Applications, ISSN 1070-5325, Vol. 14, no 6, 469-484 p.Article in journal (Refereed)
    Abstract [en]

    We consider a linear system of the form A1x1 + A2x2 + =b1. The vector consists of independent and identically distributed random variables all with mean zero. The unknowns are split into two groups x1 and x2. It is assumed that AA1 has full rank and is easy to invert. In this model, usually there are more unknowns than observations and the resulting linear system is most often consistent having an infinite number of solutions. Hence, some constraint on the parameter vector x is needed. One possibility is to avoid rapid variation in, e.g. the parameters x2. This can be accomplished by regularizing using a matrix A3, which is a discretization of some norm (e.g. a Sobolev space norm). We formulate the problem as a partially regularized least-squares problem and use the conjugate gradient method for its solution. Using the special structure of the problem we suggest and analyse block-preconditioners of Schur compliment type. We demonstrate their effectiveness in some numerical tests. The test examples are taken from an application in modelling of substance transport in rivers.

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