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Now showing items 1-100 of 691

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

The sparseness promoted by the total variation norm is utilized to achieve superresolution amplitude-variation-with-offset (AVO) inversion. The total variation norm promotes solutions that have constant values within ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We describe a method for geophysical inversion of seismic amplitude data, we argue that this type of inversion is a natural extension of the processing flow. The methodology is related to digital image-video restoration ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

New methods for time-to-event prediction are proposed by extending the Cox proportional hazards model with neural networks. Building on methodology from nested case-control studies, we propose a loss function that scales ...

(Research report / Forskningsrapport, 2019)

Based on a study of isolated restrained columns, and two-column panel frames, the often complicated mechanics of moment formations in the members are studdied using elastic second-order theory for the purpose of establishing ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

The purpose of this paper is to study the following topics and the relation between them: (i) Optimal singular control of mean-field stochastic differential equations with memory; (ii) reflected advanced mean-field backward ...

(Research report / Forskningsrapport, 2019)

Columns in sway frames may be divided into laterally ``supporting (bracing) sway columns'', which can resist applied lateral shears, and ``supported (braced) sway columns'', which must have negative shears from the rest ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We compute the 1-line of stable homotopy groups of motivic spheres over fields of characteristic not two in terms of hermitian and Milnor K-groups. This is achieved by solving questions about convergence and differentials ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

We study optimal control of stochastic Volterra integral equations (SVIE) with jumps by using Hida-Malliavin calculus.
We give conditions under which there exist unique solutions of such equations.
Then we prove both a ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We use a white noise approach to study the problem of optimal insider control of a stochastic delay equation driven by a Brownian motion B and a Poisson random measure N. In particular, we use Hida-Malliavin calculus and ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Background: Omics data can be very informative in survival analysis and may improve the prognostic ability of classical models based on clinical risk factors for various diseases, for example breast cancer. Recent research ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

In this paper, we present and analyze a new mixed finite element formulation of a general family of quasi-static multiple-network poroelasticity (MPET) equations. The MPET equations describe flow and deformation in an ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

A central problem in traffic management is that of scheduling the movements of vehicles so as to minimize the cost of the schedule. It arises in important applications such as train timetabling, rescheduling, delay and ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We prove that the integral Hodge conjecture holds for 1-cycles on irreducible holomorphic symplectic varieties of K3[n]-type and of generalized Kummer type. As an application, we give a new proof of the integral Hodge ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We develop cointegration for multivariate continuous-time stochastic processes, both in finite and infinite dimension. Our definition and analysis are based on factor processes and operators mapping to the space of prices ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

In this paper, we extend the focused information criterion (FIC) to copula models. Copulas are often used for applications where the joint tail behavior of the variables is of particular interest, and selecting a copula ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

The bidomain system of degenerate reaction–diffusion equations is a well-established spatial model of electrical activity in cardiac tissue, with “reaction” linked to the cellular action potential and “diffusion” representing ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Life expectancies at birth are routinely computed from period life tables. When mortality is falling, such period life expectancies will typically underestimate real life expectancies, that is, life expectancies for birth ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We introduce and analyze the full [Formula: see text] and the reduced [Formula: see text] Nica–Toeplitz algebra associated to an ideal [Formula: see text] in a right-tensor [Formula: see text]-precategory [Formula: see ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We investigate a class of scalar conservation laws on manifolds driven by multiplicative Gaussian (Itô) noise. The Cauchy problem defined on a Riemanian manifold is shown to be well-posed. We prove existence of generalized ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We propose novel modifications to an anomaly detection methodology based on multivariate signal reconstruction followed by residuals analysis. The reconstructions are made using Auto Associative Kernel Regression (AAKR), ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

We show that two approaches to equivariant deformation of C[Formula: see text]-algebras by actions of negatively curved Kählerian Lie groups, one based on oscillatory integrals and the other on quantizations maps defined ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We compare three different models of two phase flow in a porous medium; the standard Darcy/Buckley–Leverett model, the Brinkman model and the Helmholtz model. These three models are all singular perturbations of the inviscid ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Internal solitary waves (ISWs) propagating in a stably stratified two‐layer fluid in which the upper boundary condition changes from open water to ice are studied for grease, level, and nilas ice. The ISW‐induced current ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Given a free unitary quantum group G = Au(F), with F not a unitary 2-by-2 matrix, we show that the Martin boundary of the dual of G with respect to any G-Gˆ-invariant, irreducible, finite range quantum random walk coincides ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Principal component analysis (PCA) is often used in anomaly detection and statistical process control tasks. For bivariate normal data, we prove that the minor projection (the least varying projection) of the PCA‐rotated ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

An elastic sheet that deforms near a solid substrate in a viscous fluid is a situation relevant to various dynamical processes in biology, geophysics, and engineering. Here, we study the relaxation dynamics of an elastic ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We consider a model for flow of liquid and gas in a pipe. We assume that the gas is ideal and that the liquid is incompressible. Under this assumption the resulting system of equations, expressing conservation of mass and ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

The utility of flow simulations relies on the robustness of computational fluid dynamics (CFD) solvers and reproducibility of results. The aim of this study was to validate the Oasis CFD solver against in vitro experimental ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Our purpose of this paper is to study stochastic control problems for systems driven by mean-field stochastic differential equations with elephant memory, in the sense that the system (like the elephants) never forgets its ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Risk measure is a fundamental concept in finance and in the insurance industry. It is used to adjust life insurance rates. In this article, we will study dynamic risk measures by means of backward stochastic Volterra ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

This work introduces a general concept of center for graphs, built on the model of the characteristic set ([12], [14]) of trees. We define it as the set of cycles in a specific directed graph associated with the original ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

The collected current by spherical and cylindrical Langmuir probes immersed in an unmagnetized and collisionless non-Maxwellian plasma at rest are theoretically studied, and analytical expressions for the currents of ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We perform an experimental analysis of two-phase stratified wavy pipe flow, with the aim to detect and quantify the effect of small scale wave breaking. Particle image velocimetry is employed to analyze the velocity fields ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We study the equilibrium in the model proposed by Kyle (Econometrica 53(6):1315–1335, 1985) and extended to the continuous-time setting by Back (Rev Financ Stud 5(3):387–409, 1992). The novelty of this paper is that we ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We present the first application of an Artificial Neural Network trained through a Deep Reinforcement Learning agent to perform active flow control. It is shown that, in a 2D simulation of the Kármán vortex street at ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

In this paper we study the Ostrovsky–Hunter equation for the case where the flux function f(x, u) may depend on the spatial variable with certain smoothness. Our main results are that if the flux function is smooth enough ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

This paper is devoted to the multivariate estimation of a vector of Poisson means. A novel loss function that penalises bad estimates of each of the parameters and also the sum (or equivalently the mean) of the parameters ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We consider Tchebycheffian spline spaces over planar T-meshes and we study their dimension. We show that the structure of extended Tchebycheff spaces allows us to fully generalize the dimension upper bounds known in the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Data integration, i.e. the use of different sources of information for data analysis, is becoming one of the most important topics in modern statistics. Especially in, but not limited to, biomedical applications, a relevant ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Atlantic cod (Gadus morhua) is an ecologically important species with a wide‐spread distribution in the North Atlantic Ocean, yet little is known about the diversity of its intestinal microbiome in its natural habitat. No ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We study vehicular traffic on a road with multiple lanes and dense, unidirectional traffic following the traditional Lighthill--Whitham--Richards model where the velocity in each lane depends only on the density in the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We prove a necessary and sufficient condition in terms of the barycenters of a collection of polytopes for existence of coupled Kähler–Einstein metrics on toric Fano manifolds. This confirms the toric case of a coupled ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Kinetic simulation results are presented to study the response of multi-Needle Langmuir Probes of the type used on many satellites. Simulations of isolated probes are used to parametrize the current collected as a function ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Doctoral thesis / Doktoravhandling, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Stratified gas–liquid flow is a flow regime typically encountered in multiphase pipelines. The understanding and modeling of this regime is of engineering importance especially for the oil and gas industry. In this work, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Graph-based representations are considered to be the future for reference genomes, as they allow integrated representation of the steadily increasing data on individual variation. Currently available tools allow de novo ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Given a Stein manifold with the density property, we show that under a suitable topological condition it is possible to prescribe derivatives at a finite number of points to automorphisms depending holomorphically on a ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We show that there is a unique hypersurface of minimal degree passing through the non-faces of a polytope which is defined by a simple hyperplane arrangement. This generalizes the construction of the adjoint curve of a ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We construct a holomorphic embedding ϕ:B3→C3 such that ϕ(B3) is not Runge in any strictly larger domain. As a consequence, S≠S1 for n=3.

(Chapter / Bokkapittel / PublishedVersion; Peer reviewed, 2019)

Seismic exploration in complex geological settings and shallow geological targets has led to a demand for higher spatial and temporal resolution in the final migrated image. Seismic data from conventional marine acquisition ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

The solution of the continuous time filtering problem can be represented as a ratio of two expectations of certain functionals of the signal process that are parametrized by the observation path. We introduce a class of ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Datasets encountered when examining deeper issues in ecology and evolution are often complex. This calls for careful strategies for both model building, model selection, and model averaging. Our paper aims at motivating, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

This is a follow-up to a paper with the same title and by the same authors. In that paper, all groups were assumed to be abelian, and we are now aiming to generalize the results to nonabelian groups. The motivating point ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Clinical studies of patients with schizophrenia and a history of violence are challenging both from an ethical and practical perspective, and the neurobiological underpinnings remain largely unknown. We here present a ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Cox’s proportional hazards regression model is the standard method for modelling censored life-time data with covariates. In its standard form, this method relies on a semiparametric proportional hazards structure, leaving ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Consider the problem of minimizing a quadratic objective subject to quadratic equations. We study the semialgebraic region of objective functions for which this problem is solved by its semidefinite relaxation. For the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Abstract. We introduce an improved formulation of the double-multiple streamtube (DMST) model for the prediction of the flow quantities of vertical axis wind turbines (VAWT). The improvement of the new formulation lies in ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Planning maritime surveillance activities in military operations and long-term defense planning is a huge task that is done manually today. Because maritime surveillance resources are extremely expensive, the potential ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

The category of finite Milnor-Witt correspondences, introduced by Calmès and Fasel, provides a new type of correspondences closer to the motivic homotopy theoretic framework than Suslin-Voevodsky's finite correspondences. ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Water wave attenuation by grease ice is a key mechanism for the polar regions, as waves in ice influence many phenomena such as ice drift, ice breaking and ice formation. However, the models presented so far in the literature ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

An inherent problem with microfluidic filters is the tendency to clog, especially when applied to cells due to their geometrical complexity, deformability, and tendency to adhere to surfaces. In this work, we handle live ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

The notion of a generalized scale emerged in recent joint work with Afsar–Brownlowe–Larsen on equilibrium states on C*-algebras of right Least Common Multiple (LCM) monoids, where it features as the key datum for the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Clicking data, which exists in abundance and contains objective user preference information, is widely used to produce personalized recommendations in web-based applications. Current popular recommendation algorithms, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

We present a Bayesian model for multi-resolution component separation for cosmic microwave background (CMB) applications based on Wiener filtering and/or computation of constrained realizations, extending a previously ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Multiphase flow simulations were run in OpenFOAM utilizing InterFoam, a volume of fluid type solver. A concentric annulus geometry was constructed and periodic boundary conditions were applied to alleviate the requirement ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

In an article from 1865, Arthur Cayley claims that given a plane algebraic curve there exists an associated 2-Hessian curve that intersects it in its sextactic points. In this paper we fix an error in Cayley's calculations ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

For spaces of constant, linear, and quadratic splines of maximal smoothness on the Powell–Sabin 12-split of a triangle, the so-called S-bases were recently introduced. These are simplex spline bases with B-spline-like ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

In [IMA J. Numer. Anal., 29 (2009), pp. 24--42], Nielsen, Tveito, and Hackbusch study the operator generated by using the inverse of the Laplacian as the preconditioner for second order elliptic PDEs $-\nabla \cdot (k(x) ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

The posterior predictive p value (ppp) was invented as a Bayesian counterpart to classical p values. The methodology can be applied to discrepancy measures involving both data and parameters and can, hence, be targeted to ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Current theories suggest that waste solutes are cleared from the brain via cerebrospinal fluid (CSF) flow, driven by pressure pulsations of possibly both cardiac and respiratory origin. In this study, we explored the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Coupled multiphysics problems often give rise to interface conditions naturally formulated in fractional Sobolev spaces. Here, both positive and negative fractionality are common. When designing efficient solvers for ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)

Appendages of seeds, fruits and other diaspores (dispersal units) are essential for their wind dispersal, as they act as wings and enable them to fly. Whirling fruits generate an auto-gyrating motion from their sepals, a ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Deep Reinforcement Learning (DRL) has recently been proposed as a methodology to discover complex active flow control strategies [Rabault et al., “Artificial neural networks trained through deep reinforcement learning ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

We consider a stochastic hydroelectric power plant management problem in discrete time with arbitrary scenario space. The inflow to the system is some stochastic process, representing the precipitation to each dam. The ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

This paper studies a duopoly investment model with uncertainty. There are two alternative irreversible investments. The first firm to invest gets a monopoly benefit for a specified period of time. The second firm to invest ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

In this paper we study mean–variance hedging under the -expectation framework. Our analysis is carried out by exploiting the -martingale representation theorem and the related probabilistic tools, in a continuous financial ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

The Neumann problem of linear elasticity is singular with a kernel formed by the rigid motions of the body. There are several tricks that are commonly used to obtain a nonsingular linear system. However, they often cause ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

We expand the celebrated Alòs decomposition formula of the call price under the Heston model in a Taylor type series of in nite stochastic terms. This expansion is a di erent representation of a formula given in a recent ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Several cardiovascular diseases are caused from localised abnormal blood flow such as in the case of stenosis or aneurysms. Prevailing theories propose that the development is caused by abnormal wall shear stress in focused ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2019)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)

Let G be an undirected simple graph. The signless Laplacian spread of G is defined as the maximum distance of pairs of its signless Laplacian eigenvalues. This paper establishes some new bounds, both lower and upper, for ...