## Search

Now showing items 1-100 of 2556

(Doctoral thesis / Doktoravhandling, 2018)

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

Background
Using high-dimensional penalized regression we studied genome-wide DNA-methylation in bone biopsies of 80 postmenopausal women in relation to their bone mineral density (BMD). The women showed ...

(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 / AcceptedVersion; Peer reviewed, 2018)

Aims
To the best of our knowledge, there are no systematic reviews or meta‐analyses that compare rasagiline, selegiline and safinamide. Therefore, we aimed to perform a drug class review comparing all available monoamine ...

(Master thesis / Masteroppgave, 2018)

The objective of this thesis is to give a description of the rough stochastic volatility modelling based on fractional Brownian motion with Hurst exponent H less than 1/2, as well as the corresponding pricing model. ...

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

We use Matsui and Takeuchi's formula for toric A-discriminants to give algorithms for computing local Euler obstructions and dual degrees of toric surfaces and 3-folds. In particular, we consider weighted projective spaces. ...

(Master thesis / Masteroppgave, 2018)

Given a non-principal ultrafilter, we define and prove properties of ultralimits of measure spaces (including σ-algebras, filtrations and measures), random variables and discrete-time stochastic processes. Among other ...

Modelling of Total Claim Amounts with Regime Switching in the Framework of Generalized Cox Processes

(Master thesis / Masteroppgave, 2018)

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

The classical maximum principle for optimal stochastic control states that if a control û is optimal, then the corresponding Hamiltonian has a maximum at u=û. The first proofs for this result assumed that the control did ...

(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 ...

(Master thesis / Masteroppgave, 2018)

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

Given a finite-dimensional Hilbert space H and a collection of operators between its tensor powers satisfying certain properties, we give a short proof of the existence of a compact quantum group G with a fundamental ...

(Master thesis / Masteroppgave, 2018)

In this thesis we implement and employ a simplex spline basis developed by Cohen, Lyche, and Riesenfeld for the space of C1 quadratic splines on the Powell–Sabin 12-split of a triangle. A matrix recursion is used for ...

(Master thesis / Masteroppgave, 2018)

The timing of cardiac events is essential for the analysis of certain components of myocardial function [36]. Finding an algorithm that detects these timings has therefore been the subject of several studies[36]. In this ...

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

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

Extreme wave statistics of unidirectional and counter-propagating seas are investigated, for the special case of long-crested irregular waves, with laboratory experiments and with numerical simulations using the higher ...

(Master thesis / Masteroppgave, 2018)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

We propose a non-Gaussian operator-valued extension of the Barndorff-Nielsen and Shephard stochastic volatility dynamics, defined as the square-root of an operator-valued Ornstein–Uhlenbeck process with Lévy noise and ...

Approximations of Fractional Brownian Motion Restricted Access

(Master thesis / Masteroppgave, 2018)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

This study presents a statistical analysis of interfacial waves in a turbulent stratified air-water flow inside a 10 cm diameter pipe. Wave elevation measurements were acquired using conductance probes with high sampling ...

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

Stratified air-water flow in a horizontal pipe is investigated experimentally using particle image velocimetry and conductance probes. This flow regime is characterized by a complex interplay between a turbulent airflow ...

(Master thesis / Masteroppgave, 2018)

This thesis investigates cubic hypersurfaces and their Fano schemes. After introducing the Fano schemes through low-dimensional examples, we move on to investigate cubic fourfolds. For the cubic fourfolds, we give complete ...

(Master thesis / Masteroppgave, 2018)

Recommender systems are algorithms that suggest content or products to users on the internet. These are becoming ever more important due to the massive growth of content on popular web sites, yet their design is often only ...

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

This study comprises the analysis and the interpretation of the coherent and the noncoherent parts of a coherent-on-receive microwave radar at grazing incidence conditions. The Doppler measurement is an extension of standard ...

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

The properties of directional distributions in ocean wave spectra are studied, with an emphasis on sea states with bimodal directional distributions in the high-frequency tails of single-peaked wave systems. A peak-splitting ...

Optimal reinsurance - an examination of optimal stop-loss contracts for different lines of business Restricted Access

(Master thesis / Masteroppgave, 2018)

Reinsurance is a risk management tool for insurance companies, as it allows for transferring some of the insurance risk to reinsurance companies. From the insurer's perspective, a reinsurance contract may lead to more ...

(Master thesis / Masteroppgave, 2018)

Compressed sensing is the study of solving underdetermined systems of linear equations with unique sparse solutions. In addition to this, applications of compressed sensing require that the number of rows of the measurement ...

(Master thesis / Masteroppgave, 2018)

In this thesis, we consider the mod 2 homology of Q≥0S0 as an E∞ space and show the
following. The homologies H*Q≥0S0 and H*C∞S0 are isomorphic as free commutative
/2-algebras. The homology H*Q≥0S0 is generated as an ...

(Master thesis / Masteroppgave, 2018)

Modeling of the blood flow in and around aneurysms with computational fluid dynamics (CFD) is important to better understand why aneurysms form and rupture. CFD modeling requires an accurate representation of the ...

(Master thesis / Masteroppgave, 2018)

The recent results on non-uniqueness of the Euler equations, all based on the theory developed in the papers by Camillo De Lellis and László Székelyhidi Jr., are believed to be connected to the theory of turbulent fluid ...

(Master thesis / Masteroppgave, 2018)

This graduate thesis has been devoted to the examination of spectral methods. The object of the research is to analyse the accuracy and precision of different numerical schemes developed on the basis of mathematical models ...

(Master thesis / Masteroppgave, 2018)

In this master thesis we will prove Dirichlet's theorem on primes in arithmetic progressions. The theorem states that there are an infinite number of primes in every primitive residue class modulo any positive number q, ...

(Master thesis / Masteroppgave, 2018)

Longitudinal data arise when repeated measurements are taken on individuals over time. Commonly used models for such data are multivariate linear models, linear mixed effect models and generalised linear mixed models. This ...

(Master thesis / Masteroppgave, 2018)

A Heron triangle is a triangle with integer sides and integer area. A rational triangle is a triangle with rational sides and area. We will set out to prove van Luijks Theorem, that there exist infinitely many non-similar ...

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

Applying the computational fluid dynamics software openFoam, we study dead water resistance on a barge. Dead water resistance is the extra drag due to internal waves in the interface between salt water and fresh water. For ...

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

Solvency II er et forsikringsdirektiv som kontrollerer all forsikringsdrift i EU/EØS. Direktivet innebærer kontrollering av kapitalreserven, SCR, for hver av forsikringsselskapets porteføljer. Dette for å sikre forbrukerens ...

Hvor er jeg? Kan jeg regne det ut? Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

In this thesis, we consider models for survival data with a high-dimensional covariate space. Most models used for such datasets are based on the Cox regression model, of which a critical assumption is that the hazard ...

(Master thesis / Masteroppgave, 2018)

Usikkerhet rundt menneskers fremtidige levealder resulterer i stor risiko for livsforsikringsselskap. Retningslinene for kalkulering av slik risiko er satt av EU-kommisjonen og heter Solvency II. Denne oppgaven vil presenteres ...

(Master thesis / Masteroppgave, 2018)

Computational fluid dynamics, with the software OpenFOAM, has ben used to investi- gate the dead water phenomenon. Investigation was done by simulating a barge moving in stratified waters. Comparison of the turbulence ...

Geometric and topological analysis of cortical folding Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

Regression analysis is a commonly used approach to modelling the relationships between dependent and independent variables. When estimating the coefficients of a regression model, the least squares estimator is often used, ...

(Master thesis / Masteroppgave, 2018)

Denne oppgaven handler om beregning av risiko for forsikringsutbetalinger ved vindkatastrofer, og hvordan Solvency II gir en forenklet måte å beregne kapitalkrav som skal sikre selskapene fra insolvens med 99.5% sikkerhet. ...

(Master thesis / Masteroppgave, 2018)

The bidomain and monodomain models describing cardiac electrophysiology are computationally demanding to solve. Employing efficient numerical methods is therefore important for the practical use of these models. In this ...

(Master thesis / Masteroppgave, 2018)

Ventricular fibrillation (VF) occurs in ~10 % of myocardial infarction (MI) patients. These patients have higher in-hospital mortality and increased risk to lethal arrhythmias. The susceptibility for VF during acute MI and ...

(Master thesis / Masteroppgave, 2018)

In this thesis we begin by looking at polynomials of m n x n matrices invariant under simultaneous conjugation. Thereafter we connect the invariant polynomials to simple representations of noncommutative plane curves, ...

(Master thesis / Masteroppgave, 2018)

The field of compressive sensing is a modern field in applied mathematics which receives a lot of attention. In this thesis, we will give some insight into the iterative algorithms used in compressive sensing. We will study ...

Can computing help in learning linear algebra? Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

Reserve modelling in the presence of extreme insurance losses Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

(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 ...

(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, ...

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

We show that the Cuntz splice induces stably isomorphic graph C∗-algebras. This result is a key step towards the recent complete classification of unital graph C∗-algebras both with respect to K-theoretical classification ...

(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 / 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)

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

Background: Recent large-scale undertakings such as ENCODE and Roadmap Epigenomics have generated experimental data mapped to the human reference genome (as genomic tracks) representing a variety of functional elements ...

(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 ...

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

We use representation theory and Bott’s theorem to show vanishing of higher cotangent cohomology modules for the homogeneous coordinate ring of Grassmannians in the Plücker embedding. As a by-product, we answer a question ...

Distinct DNA methylation profiles in bone and blood of osteoporotic and healthy postmenopausal women

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

DNA methylation affects expression of associated genes and may contribute to the missing genetic effects from genome-wide association studies of osteoporosis. To improve insight into the mechanisms of postmenopausal ...

(Master thesis / Masteroppgave, 2017)

CFD analysis of a cone grid applied to a flat plate, with mesh generation script.

(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 ...

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

(Master thesis / Masteroppgave, 2017)

(Journal article / Tidsskriftartikkel / PublishedVersion, 2017)

Beginner student courses in mathematics in higher education have had high failure rates across the country. A national study [1] conducted by the Norwegian Association of Higher Education Institutions (UHR) in 2013 showed ...

(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 / PublishedVersion; Peer reviewed, 2017)

(Master thesis / Masteroppgave, 2017)

In this thesis we study the construction of wavelets for the Cuntz--Krieger $C^{\ast}$-algebras as developed by M. Marcolli and A. Paolucci in [MP11]. We identify and correct some errors in the construction, as well as ...

(Master thesis / Masteroppgave, 2017)

(Master thesis / Masteroppgave, 2017)

We build a mathematical model for the risk involved when a person makes a binding fixed-price offer to buy or sell something that fluctuates in value. This situation often arises in financial markets, where such an offer ...

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

The nonlinear shallow water model is widely used in the study of tsunami propagation, but an increasing number of studies are dedicated to the dispersion dynamics of tsunamis. If the wave dispersion becomes important, ...

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

-stability for entropy solutions of nonlinear degenerate parabolic convection–diffusion equations with discontinuous coefficients, Skr. K. Nor. Vidensk. Selsk. 3 (2003) 1–49], singles out the vanishing viscosity solution ...

(Master thesis / Masteroppgave, 2017)

In this thesis we analyze spread functions in the cointegrated market, with dynamics based on different combinations of Brownian motions and Ornstein-Uhlenbeck processes, and their structural differences. Theoretical and ...

(Master thesis / Masteroppgave, 2017)

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

The final publication is available at IOS Press through http://dx.doi.org/10.3233/COM-170081

(Master thesis / Masteroppgave, 2017)

Conventional 2D medical ultrasound imaging is based on analyzing the backscatter (echoes) from multiple, focused, transmitted acoustic beams. Most imaging systems are very similar in the way they create and record beams. ...

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

Computational models of cardiac mechanics, personalized to a patient, offer access to mechanical information above and beyond direct medical imaging. Additionally, such models can be used to optimize and plan therapies ...

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

The air-sea gas transfer velocity k is frequently estimated as an empirical function of wind speed. However, it is widely recognized that k depends on processes other than wind speed alone. The small-eddy model, which ...

(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 / 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 ...

(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 ...

(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 ...

(Master thesis / Masteroppgave, 2017)

(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 ...

(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 ...

(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 ...

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

The recent price coupling of many European electricity markets has triggered a fundamental change in the interaction of day-ahead prices, challenging additionally the modeling of the joint behavior of prices in interconnected ...

(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) ...

(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)

Given an action α of a discrete group G on a unital C∗ -algebra A, we introduce a natural concept of α -negative definiteness for functions from G to A, and examine some of the first consequences of such a notion. ...

(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 ...

(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)

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 ...