Browsing Department of Mathematics by Document Types "Peer reviewed"
Now showing items 1-20 of 207
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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 ... -
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 ... -
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 ... -
Analysis of Control Volume Heterogeneous Multiscale Methods for Single Phase Flow in Porous Media
(Peer reviewed; Journal article, 2014)The standard approximation for the flow-pressure relationship in porous media is Darcy's law that was originally derived for infiltration of water in fine homogeneous sands. Ever since there have been numerous attempts to ... -
Analysis of multi-beam sonar echos of herring schools by means of simulation
(Doctoral thesis; Peer reviewed, 2013-05-31)The synchronized behavior of large schools of fish can be a fascinating sight and has caught the attention of researchers for decades. Schools of thousands, or even millions of fish can seemingly function as a single entity, ... -
Analytical solutions for aquifer thermal energy storage
(Peer reviewed; Journal article, 2017-02)The concept of aquifer thermal energy storage involves injection of water at elevated temperature, and possibly nonambient salinity, into a host aquifer. We consider axisymmetric injection, wherein both the composition and ... -
Application of Vertically-Integrated Models with Subscale Vertical Dynamics to Field Sites for CO2 Sequestration
(Peer reviewed; Journal article, 2014)To address the engineering questions on security issues of geological carbon sequestration (GCS), a broad range of computational models with different levels of complexity have been developed - from multiphase multicomponent ... -
Are Central Bankers Inflation Nutters? An MCMC Estimator of the Long-Memory Parameter in a State Space Model
(Journal article; Peer reviewed, 2019)Inflation targeting is a common monetary policy regime. Inflation targets are often flexible in the sense that the central bank allows inflation to temporarily deviate from the target to avoid causing unnecessary volatility ... -
Assessing Model Uncertainties Through Proper Experimental Design
(Peer reviewed; Journal article, 2013)This paper assesses how parameter uncertainties in the model for rise velocity of CO2 droplets in the ocean cause uncertainties in their rise and dissolution in marine waters. The parameter uncertainties in the rise velocity ... -
Assessing non-linearity in European temperature-sensitive tree-ring data
(Journal article; Peer reviewed, 2020-02)We test the application of parametric, non-parametric, and semi-parametric calibration models for reconstructing summer (June–August) temperature from a set of tree-ring width and density data on the same dendro samples ... -
Association between body height and chronic low back pain: a follow-up in the Nord-Trøndelag Health Study
(Peer reviewed; Journal article, 2015-06-15)Objective: To study potential associations between body height and subsequent occurrence of chronic low back pain (LBP). Design: Prospective cohort study. Setting: The North-Trøndelag Health Study (HUNT). Data were ... -
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 ... -
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 ... -
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 ... -
Bridging the ensemble Kalman filter and particle filters: the adaptive Gaussian mixture filter
(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 ... -
Brill–Noether general K3 surfaces with the maximal number of elliptic pencils of minimal degree
(Journal article; Peer reviewed, 2020)We explicitly construct Brill–Noether general K3 surfaces of genus 4, 6 and 8 having the maximal number of elliptic pencils of degrees 3, 4 and 5, respectively, and study their moduli spaces and moduli maps to the moduli ... -
Brill–Noether theory of squarefree modules supported on a graph
(Peer reviewed; Journal article, 2013-05)We investigate the analogy between squarefree Cohen- Macaulay modules supported on a graph and line bundles on a curve. We prove a Riemann–Roch theorem, we study the Jacobian and gonality of a graph, and we prove Clifford’s ... -
Capturing the coupled hydro-mechanical processes occurring during CO2 injection – example from In Salah
(Peer reviewed; Journal article, 2014)At In Salah, CO2 is removed from the production stream of several natural gas fields and re-injected into a deep and relatively thin saline formation, in three different locations. The observed deformation on the surface ... -
Cell-centered finite volume discretizations for deformable porous media
(Peer reviewed; Journal article, 2014-08-11)The development of cell-centered finite volume discretizations for deformation is motivated by the desire for a compatible approach with the discretization of fluid flow in deformable porous media. We express the conservation ...