Department of Mathematics
Recent Submissions
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Robust solvers for fully coupled transport and flow in saturated/unsaturated porous media
(Doctoral thesis, 2021-03-29)Numerical simulations and laboratory studies are our main tools to comprehend better processes happening in the subsurface. The phenomena are modeled thanks to systems of partial differential equations (PDEs), which are ... -
Iterative schemes for surfactant transport in porous media
(Journal article; Peer reviewed, 2020)In this work, we consider the transport of a surfactant in variably saturated porous media. The water flow is modelled by the Richards equations and it is fully coupled with the transport equation for the surfactant. Three ... -
Sparse-Data Based 3D Surface Reconstruction for Cartoon and Map
(Conference object, 2018)A model combining the first-order and the second-order variational regularizations for the purpose of 3D surface reconstruction based on 2D sparse data is proposed. The model includes a hybrid fidelity constraint which ... -
Associations between the number of children, age at childbirths and prevalence of chronic low back pain: the Nord-Trøndelag Health Study
(Journal article; Peer reviewed, 2020)Background Associations between childbirths and subsequent risk of low back pain (LBP) have not been clarified. Changes in sex hormone levels or lumbar posture during pregnancy may have an impact on LBP later in life. The ... -
Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in the flowing and no-flowing microchannels
(Journal article; Peer reviewed, 2019)Biofilm accumulation in porous media can cause pore plugging and change many of the physical properties of porous media. Engineering bioplugging may have significant applications for many industrial processes, while improved ... -
TV-Stokes And Its Variants For Image Processing
(Doctoral thesis, 2021-03-30)The total variational minimization with a Stokes constraint, also known as the TV-Stokes model, has been considered as one of the most successful models in image processing, especially in image restoration and sparse-data-based ... -
A singularity removal method for coupled 1D–3D flow models
(Journal article; Peer reviewed, 2019)In reservoir simulations, the radius of a well is inevitably going to be small compared to the horizontal length scale of the reservoir. For this reason, wells are typically modelled as lower-dimensional sources. In this ... -
Modelling and simulation of thermo-hydro-mechanical processes in fractured porous media
(Doctoral thesis, 2021-02-26)Understanding and predicting processes in fractured porous media is of wide interest, with applications such as geothermal energy extraction, water management and storage of CO$_2$ and energy. Characterisation and monitoring ... -
The Effect of Environmental Stressors on Tinnitus: A Prospective Longitudinal Study on the Impact of the COVID-19 Pandemic
(Journal article; Peer reviewed, 2020-08)Tinnitus, the perception of sound in the absence of a corresponding sound, and the distress caused by it, is rarely a static phenomenon. It rather fluctuates over time depending on endogenous and exogenous factors. The ... -
Impact of drone route geometry on information collection in wireless sensor networks
(Journal article; Peer reviewed, 2020-09)The recent technological evolution of drones along with the constantly growing maturity of its commercialization, has led to the emergence of novel drone-based applications within the field of wireless sensor networks for ... -
Sexual dimorphism in the familial aggregation of tinnitus
(Journal article; Peer reviewed, 2020-11)Twin and adoption studies point towards a genetic contribution to tinnitus; however, how the genetic risk applies to different forms of tinnitus is poorly understood. Here, we perform a familial aggregation study and ... -
Association between Hyperacusis and Tinnitus
(Journal article; Peer reviewed, 2020-07)Many individuals with tinnitus report experiencing hyperacusis (enhanced sensitivity to sounds). However, estimates of the association between hyperacusis and tinnitus is lacking. Here, we investigate this relationship in ... -
Relationship between headaches and tinnitus in a Swedish study
(Journal article; Peer reviewed, 2020-05)The heterogeneity of tinnitus is likely accounting for the lack of effective treatment approaches. Headaches have been related to tinnitus, yet little is known on how headaches impact tinnitus. We use cross-sectional data ... -
Iterative solvers for Biot model under small and large deformation
(Journal article; Peer reviewed, 2020-07-18)We consider L-scheme and Newton-based solvers for Biot model under large deformation. The mechanical deformation follows the Saint Venant-Kirchoff constitutive law. Furthermore, the fluid compressibility is assumed to be ... -
Functional analysis and exterior calculus on mixed-dimensional geometries
(Journal article; Peer reviewed, 2020-07-12)We are interested in differential forms on mixed-dimensional geometries, in the sense of a domain containing sets of d-dimensional manifolds, structured hierarchically so that each d-dimensional manifold is contained in ... -
4D seismic history matching: Assessing the use of a dictionary learning based sparse representation method
(Journal article; Peer reviewed, 2020-12)It is possible to improve oil-reservoir simulation models by conditioning them on 4D seismic data. Computational issues may arise related to both storage and CPU time due to the size of the 4D seismic dataset. An approach ... -
Dynamic modelling of biochemical reaction networks and sampling methods for constraint-based models
(Doctoral thesis, 2021-02-05)This dissertation is a partial fulfillment of the requirements for the degree of Doctor of Philosophy (PhD). This study is carried out at the Department of Mathematics, University of Bergen. The subject of the thesis is ... -
Bayesian Variational Methods in Carbon Storage Monitoring
(Doctoral thesis, 2021-01-19)This thesis explores the use of deep learning and variational inference in Carbon Capture and Storage (CCS) monitoring. It consists of an introductory part and three scientific papers. The first chapter introduces CCS and ... -
Binary time series classification with Bayesian convolutional neural networks when monitoring for marine gas discharges
(Journal article; Peer reviewed, 2020-06-19)The world’s oceans are under stress from climate change, acidification and other human activities, and the UN has declared 2021–2030 as the decade for marine science. To monitor the marine waters, with the purpose of ... -
Horizontal holonomy and foliated manifolds
(Journal article; Peer reviewed, 2019)We introduce horizontal holonomy groups, which are groups defined using parallel transport only along curves tangent to a given subbundle D of the tangent bundle. We provide explicit means of computing these holonomy groups ...
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