## Search

Now showing items 1-100 of 2401

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)

If a number of candidate variables are available, variable selection is a key task aiming to identify those candidates which influence the outcome of interest. Methods as backward elimination, forward selection, etc. are ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)

In biomedical research, boosting-based regression approaches have gained much attention in the last decade. Their intrinsic variable selection procedure and ability to shrink the estimates of the regression coefficients ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

We introduce algebraic dynamical systems, which consist of an action of a right LCM semigroup by injective endomorphisms of a group. To each algebraic dynamical system we associate a C*-algebra and describe it as a semigroup ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

We discuss the internal structure of graph products of right LCM semigroups and prove that there is an abundance of examples without property (AR). Thereby we provide the first examples of right LCM semigroups lacking ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

By a memory mean-field process we mean the solution X(\cdot ) of a stochastic mean-field equation involving not just the current state X(t) and its law \mathcal {L}(X(t)) at time t, but also the state values X(s) and its ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

As modern biotechnologies advance, it has become increasingly frequent that different modalities of high-dimensional molecular data (termed “omics” data in this paper), such as gene expression, methylation, and copy number, ...

The Geometry of the Space of Curves of Genus 2 Restricted Access

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Knowledge about how many fish that have been killed due to bycatch is an important aspect of ensuring a sustainable ecosystem and fishery. We introduce a Bayesian spatio-temporal prediction method for historical bycatch ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Influential points can cause severe problems when deriving a multivariable regression model. A novel approach to check for such points is proposed, based on the variable inclusion matrix, a simple way to summarize results ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

In recent years, renewable energy has gained importance in producing power in many markets. The aim of this article is to model photovoltaic (PV) production for three transmission operators in Germany. PV power can only ...

Sensitivity Analysis of Prices of Claims in Turbulent Markets Restricted Access

(Master thesis / Masteroppgave, 2017)

(Chapter / Bokkapittel / AcceptedVersion; Peer reviewed, 2017)

Environmental contours are widely used as a basis for e.g., ship design. The traditional approach to environmental contours is based on the well-known Rosenblatt transformation. However, due to the effects of this ...

(Master thesis / Masteroppgave, 2017)

The estimation of inverse covariance matrices plays a major role in portfolio optimization, for the global minimum variance portfolio in mean-variance analysis it is the only parameter used to determine the asset allocation. ...

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

Rubin (1987)’s combination formula for variance estimation in multiple imputation (MI) requires a imputation method to be Bayesian-proper. However, many census bureau have heavily relied on non-Bayesian imputations. Bjørnstad ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The Grassmannian Gr(2,5) is embedded in ℙ9 via the Pl\"ucker embedding. The intersection of two general PGL(10)-translates of Gr(2,5) is a Calabi-Yau 3-fold X, and the intersection of the projective duals of the two ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We study the cones of surfaces on varieties of lines on cubic fourfolds and Hilbert schemes of points on K3 surfaces. From this we obtain new examples of nef cycles which fail to be pseudoeffective.

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We consider systems with memory represented by stochastic functional differential equations. Substantially, these are stochastic differential equations with coefficients depending on the past history of the process itself. ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Intrathecal drug and gene vector delivery is a procedure to release a solute within the cerebrospinal fluid. This procedure is currently used in clinical practice and shows promise for treatment of several central nervous ...

(Master thesis / Masteroppgave, 2017)

On the 1st of January 2016, the Solvency II Directive regulating the European insurance industry came into force. Along with a host of reporting requirements, quantitative algorithms for calculating key quantities are ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

For stochastic conservation laws driven by a semilinear noise term, we propose a generalization of the Kružkov entropy condition by allowing the Kružkov constants to be Malliavin differentiable random variables. Existence ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The algebraic connectivity a(G) of a graph G is an important parameter, defined as the second smallest eigenvalue of the Laplacian matrix of G. If T is a tree, a(T) is closely related to the Perron values (spectral radius) ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

A well-known application of Malliavin calculus in mathematical finance is the probabilistic representation of option price sensitivities, the so-called Greeks, as expectation functionals that do not involve the derivative ...

(Research report / Forskningsrapport, 2017)

There are many different numerical methods for solving the Navier-Stokes equations for problems with a free surface. Some examples are volume of fluid (VOF), Marker and cell (MAC), level set, smooth particle hydrodynamics ...

(Master thesis / Masteroppgave, 2017)

The objectives of this thesis have been to model the spot prices in the energy market, to look at the forward curve, and to derive the Greeks from the spread option. The two energy commodities that have been used are power ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

An alternating sign matrix , or ASM, is a (0,±1)(0,±1)-matrix where the nonzero entries in each row and column alternate in sign, and where each row and column sum is 1. We study the convex cone generated by ASMs of order ...

(Master thesis / Masteroppgave, 2017)

Computations in general insurance are often based on models such as the collective risk model, which uses a compound distribution to describe the aggregated losses. A critical part of this model is the un- certainty of ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

We give recursive formulas for the generating elements in the Milnor basis of the mod 2 motivic Steenrod algebra.
This research was first published in the New York Journal of Mathematics © 2017

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We consider the problem of finding a maximum k-regular induced subgraph of a graph G. Theoretical results are established to compare upper bounds obtained from different techniques, including bounds from quadratic programming, ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

In this paper we derive optimal subspaces for Kolmogorov nn-widths in the L2 norm with respect to sets of functions defined by kernels. This enables us to prove the existence of optimal spline subspaces of arbitrarily high ...

(Doctoral thesis / Doktoravhandling, 2017)

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

This article studies singular mean field control problems and singular mean field two-players stochastic differential games. Both sufficient and necessary conditions for the optimal controls and for the Nash equilibrium ...

Nonlinear interpolatory curve subdivision schemes Restricted Access

(Master thesis / Masteroppgave, 2017)

The aim of this thesis is to study the convergence and smoothness of certain nonlinear interpolatory curve subdivision schemes. The emphasis will be on the iterated geometric schemes, which are extensions of the nonlinear ...

(Master thesis / Masteroppgave, 2017)

In this thesis, we study what can be said about Fermat's Last Theorem using only elementary methods. We will study the work of Sophie Germain and Niels Henrik Abel, both who worked with Fermat’s Last Theorem in the early ...

(Master thesis / Masteroppgave, 2017)

This thesis is devoted to presenting and illustrating a novel estimation method offering a way to reduce confounding bias in time-to-event situations. In order to reduce this bias, without having to observe all of the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We consider a scalar conservation law with zero-flux boundary conditions imposed on the boundary of a rectangular multidimensional domain. We study monotone schemes applied to this problem. For the Godunov version of the ...

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Background: Using computational fluid dynamics (CFD) to compute the hemodynamics in cerebral aneurysms has received much attention in the last decade. The usability of these methods depends on the quality of the computations, ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We propose and investigate a valuation model for the income of selling tradeable green certificates (TGCs) in the Swedish–Norwegian market, formulated as a singular stochastic control problem. Our model takes into account ...

(Master thesis / Masteroppgave, 2017)

The main goal of this thesis is to reproduce the article [SW16] by Sims and Williams, categorising the primitive ideal space of the class of Deaconu- Renault groupoid C*-algebras generated by N_0^k-actions. We go through ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We comment on the discretization of the Dirac equation using finite element spaces of differential forms. In order to treat perturbations by low order terms, such as those arising from electromagnetic fields, we develop ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Let ℓ be a prime and q=pν, where p is a prime different from ℓ. We show that the ℓ–completion of the nth stable homotopy group of spheres is a summand of the ℓ–completion of the (n,0) motivic stable homotopy group of spheres ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We show that a Hilbert scheme of conics on a Fano fourfold double cover of P2×P2 ramified along a divisor of bidegree (2,2) admits a P1-fibration with base being a hyper-Kähler fourfold. We investigate the geometry of such ...

(Master thesis / Masteroppgave, 2017)

In this thesis we consider sextactic points on plane algebraic curves and a 2-Hessian curve that identifies these points. This curve was first established by Cayley, and we prove that Cayley's 2-Hessian is wrong. Moreover, ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We lift ambit fields to a class of Hilbert space-valued volatility modulated Volterra processes. We name this class Hambit fields, and show that they can be expressed as a countable sum of weighted real-valued volatility ...

(Chapter / Bokkapittel / SubmittedVersion, 2017)

Electricity infrastructure has become a critical element of modern industrial society. In order to model and analyse this infrastructure, identify weaknesses, and optimize performance, one needs to take into account its ...

(Master thesis / Masteroppgave, 2017)

The traditional, linear representation of the genetic information in populations cause a loss of data, as it can not fully represent sites where the sequences differ. Conversely, a graph may incorporate the variation, ...

(Master thesis / Masteroppgave, 2017)

The mechanical behavior of the heart has been modeled for decades by using continuum mechanics and numerical methods. A widely used, but rarely discussed, assumption is that inertial effects can be neglected in these models. ...

(Master thesis / Masteroppgave, 2017)

OpenFOAM and FEniCS are two solver frameworks for solving computational fluid dynamics problems. The former employs the finite volume method to discretize the governing equations, while the latter employs the finite element ...

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Proper orthogonal decomposition (POD) is applied to distinct data sets in order to characterize the propagation of error arising from basis truncation in the description of turbulence. Experimental data from stereo particle ...

(Research report / Forskningsrapport, 2017)

Detecting fraud using information from social networks Restricted Access

(Master thesis / Masteroppgave, 2017)

With all the technological progress we have witnessed during the last couple of decades, it comes as no surprise that modern fraudsters use highly complex methods to disguise their suspicious activities. Traditional ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The notion of higher order dual varieties of a projective variety, introduced in \cite{P83}, is a natural generalization of the classical notion of projective duality. In this paper we present geometric and combinatorial ...

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

Computational models of fluids, structures, and the interaction between them shows good promise in science and engineering, with nearly infinitely many applications. However, fluid-structure interaction (FSI) is poorly ...

(Master thesis / Masteroppgave, 2017)

Millions of people world wide suffer from asthma, and respiratory diseases are one of the leading causes of death. Patients can be treated or relieved by inhalation of medicine, but the efficiency of the treatment is often ...

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

Målet ved denne artikkelen er å analysere forholdet mellom vri- og flyttespill og symmetrigruppen. Vi skal se sammenhengen mellom gruppeteori og mange populære spill, spesielt når man vil løse spillene

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

The Lagrangian paths, horizontal Lagrangian drift velocity, U L , and the Lagrangian excess period, T L − T 0 , where T L is the Lagrangian period and T 0 the Eulerian linear period, are obtained by ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The attenuation of surface gravity waves is an important process associated with air–sea and wave–current interactions. Here we investigate experimentally the attenuation of monochromatic surface gravity waves due to the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We prove that all moment varieties of univariate Gaussian mixtures have the expected dimension. Our approach rests on intersection theory and Terracini’s classification of defective surfaces. The analogous identifiability ...

(Master thesis / Masteroppgave, 2017)

Environmental contours are used as a basis for e.g., ship designs. The traditional approach to environmental contours is based on the well-known Rosenblatt transformation. However, due to the effects of this transformation ...

(Master thesis / Masteroppgave, 2017)

We consider the bidomain model of cardiac electrophysiology. Departing from a discrete cellular model we derive the bidomain equations by homogenization. Using two-scale convergence we provide a rigorous homogenization ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

This paper proposes a Finite Difference Multilevel Monte Carlo algorithm for degener- ate parabolic convection diffusion equations where the convective and diffusive fluxes are allowed to be random. We establish a notion ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We propose a boundary quotient diagram for right LCM semigroups with property (AR) that generalizes the boundary quotient diagram for N⋊N×. Our approach focuses on two important subsemigroups: the core subsemigroup and the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Background
It has been proposed that future reference genomes should be graph structures in order to better represent the sequence diversity present in a species. However, there is currently no standard ...

(Master thesis / Masteroppgave, 2017)

Muscle ultrasound imaging is a convenient technique to visualize normal and pathological muscle tissue. Studying muscle fascicle pennation angle and fascicle length and their dynamic changes during contraction are important ...

Pricing Freight Derivatives Restricted Access

(Master thesis / Masteroppgave, 2017)

(Research report / Forskningsrapport, 2017)

We consider a Navier-Stokes equation in two and three space dimensions subject to periodic boundary conditions and perturbed by a transport type noise. The perturbation is sufficiently smooth in space, but rough in time. ...

Strong solutions of d-dimensional SDE's with generalized drift and fractional Brownian initial noise

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

In this paper we prove the existence of strong solutions to a SDE with a generalized drift driven by a multidimensional fractional Brownian motion for small Hurst parameters H<1/2. Here the generalized drift is given as ...

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Versatile instruments assembled from off-the-shelf sensors and open-source electronics are used to record wave propagation and damping measured by Inertial Motion Units (IMUs) in a grease ice slick near the shore in ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

Traditional programs based on feature engineering are under performing on a steadily increasing number of tasks compared with Artificial Neural Networks (ANNs), in particular for image analysis. Image analysis is widely ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Landslides are the second-most important cause of tsunamis after earthquakes, and their potential for generating large tsunamis depend on the slide process. Among the world's largest submarine landslides is the Storegga ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

In this paper we construct a new type of noise of fractional nature that has a strong regularizing effect on differential equations. We consider an equation with this noise with a highly irregular coefficient. We employ a ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

In this paper, we study weak solutions to the following nonlinear parabolic partial differential equation ∂tu−diva(x,t,∇u)+λ(|u|p(x,t)−2u)=0inΩT, where λ≥0 and ∂tu denote the partial derivative of u with respect to the ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Background
We have previously reported a high incidence of colorectal cancer (CRC) in carriers of pathogenic MLH1 variants (path_MLH1) despite follow-up with colonoscopy including polypectomy.
...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

We study congruences of lines $X_\omega $ defined by a sufficiently general choice of an alternating 3-form $\omega $ in $n+1$ dimensions, as Fano manifolds of index $3$ and dimension $n-1$. These congruences include the ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We study the problem of optimal insider control of an SPDE (a stochastic evolution equation) driven by a Brownian motion and a Poisson random measure. Our optimal control problem is new in two ways:
- The controller has ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We show that a cubic fourfold F that is apolar to a Veronese surface has the property that its variety of power sums V SP ( F, 10) is singular along a K 3 surface of genus 20 which is the variety of power sums of a sextic ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

We study how the geometry of a projective variety X is reflected in the positivity properties of the diagonal ΔX considered as a cycle on X×X. We analyze when the diagonal is big, when it is nef, and when it is rigid. In ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Using Macaulay’s correspondence we study the family of Artinian Gorenstein local algebras with fixed symmetric Hilbert function decomposition. As an application we give a new lower bound for the dimension of cactus varieties ...

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

In this thesis results from numerical simulations of long wave run-up on composite beaches are presented along with the analytical solution to the linear problem. The purpose of this study is to find out which parts of the ...

Simulating sleep. Restricted Access

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

The directional wave spectra in sea ice are an important aspect of wave evolution and can provide insights into the dominant components of wave dissipation, that is, dissipation due to scattering or dissipation due to ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

We determine the structure of equilibrium states for a natural dynamics on the boundary quotient diagram of C*-algebras for a large class of right LCM semigroups. The approach is based on abstract properties of the semigroup ...

(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)

Let GG be an affine group scheme over a noetherian commutative ring RR. We show that every GG-equivariant vector bundle on an affine toric scheme over RR with GG-action is equivariantly extended from Spec ( R ) Spec(R) for ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)

Time change is a powerful technique for generating noises and providing flexible models. In the framework of time changed Brownian and Poisson random measures we study the existence and uniqueness of a solution to a general ...

(Chapter / Bokkapittel / SubmittedVersion, 2017)

With the shenfun Python module (github.com/spectralDNS/shenfun) an effort is made towards automating the implementation of the spectral Galerkin method for simple tensor product domains, consisting of (currently) one ...

(Master thesis / Masteroppgave, 2017)

This thesis investigates the appliance of the finite element method to long wave propagation in channels. Weak formulations of potential- and velocity based Boussinesq equations were derived, with the normal dependent ...

(Doctoral thesis / Doktoravhandling, 2016)

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

In the Barents Sea and adjacent water, fishing grounds are closed for shrimp fishing by the Norwegian Directorate of Fisheries Monitoring and Surveillance Service (MSS) if the expected number of juvenile fish caught are ...

(Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2016)

We prove that the Farrell–Jones assembly map for connective algebraic K -theory is rationally injective, under mild homological finiteness conditions on the group and assuming that a weak version of the Leopoldt–Schneider ...

(Master thesis / Masteroppgave, 2016)

In this thesis we will study the phase space, Ph(A), for an associative k-algebra A. The phase space can be considered as a noncommutative tangent bundle. We will derive algebraic notions of points, curves, tangent vectors ...