Browsing Department of Mathematics by Title
Now showing items 1-20 of 977
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The 11th Society of Petroleum Engineers Comparative Solution Project: Problem Definition
(Journal article; Peer reviewed, 2024)This article contains the description of, and call for participation in, the 11th Society of Petroleum Engineers Comparative Solution Project (the 11th SPE CSP, https://spe.org/csp). It is motivated by the simulation ... -
2-Deoxy-D-glucose couples mitochondrial DNA replication with mitochondrial fitness and promotes the selection of wild-type over mutant mitochondrial DNA
(Journal article; Peer reviewed, 2021)Pathological variants of human mitochondrial DNA (mtDNA) typically co-exist with wild-type molecules, but the factors driving the selection of each are not understood. Because mitochondrial fitness does not favour the ... -
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 ... -
A 3D computational study of effective medium methods applied to fractured media
(Peer reviewed; Journal article, 2013-10)This work evaluates and improves upon existing effective medium methods for permeability upscaling in fractured media. Specifically, we are concerned with the asymmetric self-consistent, symmetric self-consistent, and ... -
A 3D-1D coupled blood flow and oxygen transport model to generate microvascular networks
(Journal article; Peer reviewed, 2020)In this work, we introduce an algorithmic approach to generate microvascular networks starting from larger vessels that can be reconstructed without noticeable segmentation errors. Contrary to larger vessels, the reconstruction ... -
4D Seismic History Matching Using the Ensemble Kalman Filter (EnKF): Possibilities and Challenges
(Doctoral thesis, 2010-05-27)This research endeavor presents a 4D seismic history matching work flow based on the ensemble Kalman filter (EnKF) methodology. The objective of this work is to investigate the sensitivity of different combinations of ... -
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 ... -
An accelerated staggered scheme for variational phase-field models of brittle fracture
(Journal article; Peer reviewed, 2021)There is currently an increasing interest in developing efficient solvers for variational phase-field models of brittle fracture. The governing equations for this problem originate from a constrained minimization of a ... -
Active and integrated management of water resources throughout CO2 capture and sequestration operations
(Peer reviewed; Journal article, 2011)Most projected climate change mitigation strategies will require a significant expansion of CO2 Capture and Sequestration (CCS) in the next two decades. Four major categories of challenges are being actively researched: ... -
Adaptive asynchronous time-stepping, stopping criteria, and a posteriori error estimates for fixed-stress iterative schemes for coupled poromechanics problems
(Journal article; Peer reviewed, 2020)In this paper we develop adaptive iterative coupling schemes for the Biot system modeling coupled poromechanics problems. We particularly consider the space–time formulation of the fixed-stress iterative scheme, in which ... -
Adaptive Characteristic Operator Splitting Techniques for Convection-Dominated Diffusion Problems in One and Two Space Dimensions
(Department of Applied Mathematics report;85, Research report, 1988-12) -
Adaptive Multiscale Methods Based on A Posteriori Error Estimates
(Master thesis, 2010-06-01)We give an overview of different methods for solving highly heterogeneous elliptic problems with multiscale structure and no intuitive scale separation. We compare different finite element variational multiscale methods ... -
Adaptive parameterization of electric conductivity in inversion of electromagnetic data
(Master thesis, 2012-06-01)We describe a methodology developed for 3-D parameter identification, with focus on large-scale applications such as monitoring subsea oil production and geothermal systems. The methodology is designed to handle challenges ... -
An adaptive solution strategy for Richards' equation
(Journal article; Peer reviewed, 2023)Flow in variably saturated porous media is typically modeled by the Richards equation, a nonlinear elliptic-parabolic equation which is notoriously challenging to solve numerically. In this paper, we propose a robust and ... -
Addressing class imbalance in deep learning for acoustic target classification
(Journal article; Peer reviewed, 2023)Acoustic surveys provide important data for fisheries management. During the surveys, ship-mounted echo sounders send acoustic signals into the water and measure the strength of the reflection, so-called backscatter. ... -
Admissibility conditions for Riemann data in shallow water theory
(Journal article; Peer reviewed, 2020)Consideration is given to the shallow-water equations, a hyperbolic system modeling the propagation of long waves at the surface of an incompressible inviscible fluid of constant depth. It is well known that the solution ... -
Advection Upscaling for Heat Transport in Fractured Geothermal Reservoir
(Master thesis, 2018-06-20)The main objective in this thesis is to give numerical solution for advection term of heat transport equation in fractured geothermal reservoir. To get better insight in the fracture influence on the processes we will ... -
Algebra i første klasse
(Master thesis, 2015-10-12)Oppgaven handler om algebra i første klasse. Hva er tidlig algebra og hvordan kan vi undervise på en slik måte at vi utvikler elevenes algebraiske tenkning? Tidlig algebra er ikke at vi underviser skolealgebra tidligere, ... -
Algebravansker. Hva er årsaken til at elevene syns algebra er vanskelig? Er det hull i grunnleggende kunnskap og/eller misoppfatninger hos elever på videregående skole som gjør at algebra er vanskelig for dem?
(Master thesis, 2017)I denne oppgaven kommer det fram hva årsaken og problemer elever på videregående kan ha i algebra som gjør at de syns algebra er vanskelig, og gjør det dårlig i dette emnet. Resultatene fra TIMSS Advanced i 2015 viser at ... -
An algorithm for internal morging of two subsets with small extra storage requirements.
(Department of Applied Mathematics report;50, Research report, 1974-09)