Department of Mathematics
Recent Submissions
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p-Kernel Stein Variational Gradient Descent for Data Assimilation and History Matching
(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 ... -
Pattern formation in a 2-population homogenized neuronal network model
(Journal article; Peer reviewed, 2021)We study pattern formation in a 2-population homogenized neural field model of the Hopfield type in one spatial dimension with periodic microstructure. The connectivity functions are periodically modulated in both the ... -
Extending Whitney's extension theorem: nonlinear function spaces
(Journal article; Peer reviewed, 2021)We consider a global, nonlinear version of the Whitney extension problem for manifold-valued smooth functions on closed domains , with non-smooth boundary, in possibly non-compact manifolds. Assuming is a submanifold with ... -
Acoustic and Boundary Layer Comparisons Between Navier-Stokes and Svärd's Modified Navier-Stokes Equations
(Master thesis, 2021-12-22) -
A 3-D numerical model of the influence of meanders on groundwater discharge to a gaining stream in an unconfined sandy aquifer
(Journal article, 2017)Groundwater discharge to streams depends on stream morphology and groundwater flow direction, but are not always well understood. Here a 3-D groundwater flow model is employed to investigate the impact of meandering stream ... -
Diagram spaces and multiplicative structures
(Doctoral thesis, 2022-01-14)This thesis explores diagrammatic E_n structures as models for E_n spaces. Paper A: Braided injections and double loop spaces. (Christian Schlichtkrull and Mirjam Solberg.) We consider a framework for representing ... -
Physics Informed Neural Networks for Inverse Advection-Diffusion Problems
(Master thesis, 2021-11-22)In this study, we will address the problem of localising a source of pollutant given a sparse set of noisy data. By sparse we mean spatially separated time-series measurements in space. To this end, we will be adopting a ... -
A nonlinear multi-scale model for blood circulation in a realistic vascular system
(Journal article; Peer reviewed, 2021)In the last decade, numerical models have become an increasingly important tool in biological and medical science. Numerical simulations contribute to a deeper understanding of physiology and are a powerful tool for better ... -
Epistemic uncertainty quantification in deep learning classification by the Delta method
(Journal article; Peer reviewed, 2021)The Delta method is a classical procedure for quantifying epistemic uncertainty in statistical models, but its direct application to deep neural networks is prevented by the large number of parameters . We propose a low ... -
Stochastic Automatic Gradient Tree Boosting
(Master thesis, 2021-11-22) -
Deep learning-based cross-sensor super resolution of satellite images
(Master thesis, 2021-11-22)Subtitle: Multispectral-to-panchromatic single-image super resolution of GeoEye-1 satellite images using an ESRGAN deep learning model trained exclusively on WorldView-2 images. Abstract: Today, easy and abundant access ... -
MPFA methods for Richards' equation
(Master thesis, 2021-11-22) -
The Role of Wettability Alteration in Subsurface CO2 Storage: Modeling and Numerical Analysis
(Doctoral thesis, 2021-12-06)This dissertation is aimed to provide mathematical frameworks to assess the large-scale deployment of CO2 in a subsurface formation, where the formation wettability is assumed to be altering through exposure time to the ... -
Coherence for Monoidal and Symmetric Monoidal Groupoids in Homotopy Type Theory
(Doctoral thesis, 2021-12-03)Homotopy Type Theory (HoTT) is a variant of Martin-Löf Type Theory (MLTT) developed in such a way that types can be interpreted as infinity-groupoids, where the iterated construction of identity types represents the different ... -
A study of the influence of vorticity, capillarity and slope angle on the properties of shoaling and breaking waves
(Doctoral thesis, 2021-10-28)Fluid motion and wave patterns have fascinated humans for centuries if not millennia. Water waves have been studied out of curiosity such as observing the ripples created by a stone dropped in a pond as well as practical ... -
Effective permeability of deformation bands in fault damage zones – Can deformation bands reduce the risk of fault leakage?
(SINTEF Proceedings;7, Chapter, 2021)Faults are major geological structures that can dominate the flow paths in subsurface reservoirs by, e.g., connecting otherwise unconnected layers. In CO2 storage sites where the faults act as the main structural trap, the ... -
Inferring CRCs progression dynamic with HyperTraPS
(Master thesis, 2021-07-07) -
Robust Optimization for Sequential Field Development Planning
(Doctoral thesis, 2021-09-24)To achieve high profitability from an oil field, optimizing the field development strategy (e.g., well type, well placement, drilling schedule) before committing to a decision is critically important. The profitability at ... -
Improving Sequential Decisions – Efficiently Accounting for Future Learning
(Journal article; Peer reviewed, 2021)In sequential field development planning, past decisions not only directly affect the maximum achievable expected NPV but also influence the future information that can be used to reduce geological uncertainty. To act ... -
Brauer Groups of Bielliptic Surfaces and Twisted Derived Equivalences
(Doctoral thesis, 2021-08-30)This thesis focuses on two interrelated projects. The first project concerns the study of bielliptic surfaces, their Brauer groups and the pullback maps from their Brauer groups to those of their canonical covers. We prove ...
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