Browsing Bergen Open Research Archive by Author "Stordal, Andreas Størksen"

Now showing items 1-9 of 9

    • Bridging the ensemble Kalman filter and particle filters: the adaptive Gaussian mixture filter 

      Stordal, Andreas Størksen; Karlsen, Hans A.; Nævdal, Geir; Skaug, Hans J.; Vallès, Brice (Peer reviewed; Journal article, 2010)
      The nonlinear filtering problem occurs in many scientific areas. Sequential Monte Carlo solutions with the correct asymptotic behavior such as particle filters exist, but they are computationally too expensive when working ...

    • Marginalized iterative ensemble smoothers for data assimilation 

      Stordal, Andreas Størksen; Lorentzen, Rolf Johan; Fossum, Kristian (Journal article; Peer reviewed, 2023)
      Data assimilation is an important tool in many geophysical applications. One of many key elements of data assimilation algorithms is the measurement error that determines the weighting of the data in the cost function to ...

    • An organ deformation model using Bayesian inference to combine population and patient-specific data 

      Rørtveit, Øyvind Lunde; Hysing, Liv Bolstad; Stordal, Andreas Størksen; Pilskog, Sara Margareta Cecilia (Journal article; Peer reviewed, 2023)
      Objective. Organ deformation models have the potential to improve delivery and reduce toxicity of radiotherapy, but existing data-driven motion models are based on either patient-specific or population data. We propose to ...

    • p-Kernel Stein Variational Gradient Descent for Data Assimilation and History Matching 

      Stordal, Andreas Størksen; Moraes, Rafael J.; Raanes, Patrick N.; Evensen, Geir (Journal article; Peer reviewed, 2021)
      A Bayesian method of inference known as “Stein variational gradient descent” was recently implemented for data assimilation problems, under the heading of “mapping particle filter”. In this manuscript, the algorithm is ...

    • Reducing systematic errors due to deformation of organs at risk in radiotherapy 

      Rørtveit, Øyvind Lunde; Hysing, Liv Bolstad; Stordal, Andreas Størksen; Pilskog, Sara Margareta Cecilia (Journal article; Peer reviewed, 2021)
      Purpose In radiotherapy (RT), the planning CT (pCT) is commonly used to plan the full RT-course. Due to organ deformation and motion, the organ shapes seen at the pCT will not be identical to their shapes during RT. Any ...

    • Sequential Data Assimilation in High Dimensional Nonlinear Systems 

      Stordal, Andreas Størksen (Doctoral thesis, 2011-10-21)
      Since its introduction in 1994, the ensemble Kalman filter (EnKF) has gained a lot of attention as a tool for sequential data assimilation in many scientific areas. Due to its computationally fast and easy to implement ...

    • Sequential Monte Carlo Methods for Bayesian Filtering 

      Stordal, Andreas Størksen (Master thesis, 2008)

    • Short-term Music Therapy for Families With Preterm Infants: A Randomized Trial 

      Gaden, Tora Söderström; Ghetti, Claire; Kvestad, Ingrid; Bieleninik, Lucja; Stordal, Andreas Størksen; Assmus, Jörg; Shmuel, Arnon; Elefant, Cochavit; Epstein, Shulamit; Ettenberger, Mark; Lichtensztejn, Marcela; Lindvall, Merethe Wolf; Mangersnes, Julie; Janner, Catharina; Vederhus, Bente Johanne; Gold, Christian (Journal article; Peer reviewed, 2022)
      OBJECTIVES To evaluate short-term effects of music therapy (MT) for premature infants and their caregivers on mother-infant bonding, parental anxiety, and maternal depression. METHODS Parallel, pragmatic, randomized ...

    • Treatment fidelity in a pragmatic clinical trial of music therapy for premature infants and their parents: the LongSTEP study 

      Gaden, Tora Söderström; Gold, Christian; Assmus, Jörg; Kvestad, Ingrid; Stordal, Andreas Størksen; Bieleninik, Lucja; Ghetti, Claire (Journal article; Peer reviewed, 2023-03-03)
      Background: Treatment fidelity (TF) refers to methodological strategies used to monitor and enhance the reliability and validity of interventions. We evaluated TF in a pragmatic RCT of music therapy (MT) for premature ...