Browsing Department of Mathematics by Author "Fossum, Kristian"

Now showing items 1-4 of 4

    • Assessment of Sequential and Simultaneous Ensemble-based History Matching Methods for Weakly Non-linear Problems 

      Fossum, Kristian (Doctoral thesis, 2015-02-13)
      The ensemble Kalman filter (EnKF) has, since its introduction in 1994, gained much attention as a tool for sequential data assimilation in many scientific areas. In recent years, the EnKF has been utilized for estimating ...

    • 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 ...

    • Sequential multilevel assimilation of inverted seismic data 

      Nezhadali, Mohammad; Bhakta, Tuhin; Fossum, Kristian; Mannseth, Trond (Journal article; Peer reviewed, 2023)
      We consider estimation of absolute permeability from inverted seismic data. Large amounts of simultaneous data, such as inverted seismic data, enhance the negative effects of Monte Carlo errors in ensemble-based Data ...

    • Value of different data types for estimation of permeability 

      Fossum, Kristian (Master thesis, 2011-06-01)
      The interrelation between sensitivity, non-linearity and scale, associated with the inverse problem of identifying permeability from measurements of fluid flow, is considered. The gouverning equations for fluid flow in a ...