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Now showing items 1-100 of 2563

(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 ...

(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 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)

Let A be an n × n (0, ∗)-matrix, so each entry is 0 or ∗. An A-interval matrix is a (0, 1)-matrix obtained from A by choosing some ∗’s so that in every interval of consecutive ∗’s, in a row or column of A, exactly one ∗ ...

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

We investigate the Smith Normal Form (SNF) of alternating sign matrices (ASMs) and related matrices of 0’s and 1’s ((0, 1)-matrices). We identify certain classes of ASMs and (0, 1)-matrices whose SNFs are (0, 1)-matrices. ...

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

In this paper we show that, with respect to the L2 norm, three classes of functions in Hr(0,1) , defined by certain boundary conditions, admit optimal spline spaces of all degrees ≥r−1 , and all these spline spaces ...

(Master thesis / Masteroppgave, 2018)

(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 ...

(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, 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. ...

(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 ...

(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)

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)

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)

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 ...

(Doctoral thesis / Doktoravhandling, 2018)

Quantum groups are a noncommutative extension of the notion of a group and first appeared in the context of quantum mechanics. Now the theory of quantum groups has further developed and has become interesting in its own ...

Approximations of Fractional Brownian Motion Restricted Access

(Master thesis / Masteroppgave, 2018)

(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)

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 ...

(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 ...

(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)

(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 ...

(Master thesis / Masteroppgave, 2018)

(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 ...

(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 ...

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)

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)

(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 ...

Reserve modelling in the presence of extreme insurance losses Restricted Access

(Master thesis / Masteroppgave, 2018)

(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)

(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 ...

(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)

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)

(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)

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)

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)

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)

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)

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 ...

Geometric and topological analysis of cortical folding Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

(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)

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)

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

In this paper, we study strongly robust optimal control problems under volatility uncertainty. In the G-framework, we adapt the stochastic maximum principle to find necessary and sufficient conditions for the existence of ...

(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 / SubmittedVersion, 2017)

We study methods for solving stochastic control problems of systems offorward–backward mean-field equations with delay, in finite and infinite time horizon.Necessary and sufficient maximum principles under partial information ...

(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 prove a version of Onsager’s conjecture on the conservation of energy for the incompressible Euler equations in the context of statistical solutions, as introduced recently by Fjordholm et al. (2017). As a byproduct, ...

(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 ...

(Master thesis / Masteroppgave, 2017)

In this thesis we give an introduction to the Minimal Model Program and the Morrison-Kawamata cone conjecture. We then present some known results on anticanonical hypersurfaces building up to the result proven by Kollár ...

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

Wind field ensembles from six CMIP5 models force wave model time slices of the northeast Atlantic over the last three decades of the 20th and the 21st centuries. The future wave climate is investigated by considering the ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

An alternating sign matrix, or ASM, is a (0, ±1)-matrix where the nonzero entries in each row and column alternate in sign. We generalize this notion to hypermatrices: an n × n × n hypermatrix A = [aijk] is an alternating ...

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

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

(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 ...

(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. ...

(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 ...

(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)

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

The final publication is available at IOS Press.

(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 ...

(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 / AcceptedVersion; Peer reviewed, 2017)

In this paper we establish the unisolvence of any interlacing pair of rectangular grids of points with respect to a large class of associated polynomial spaces. This includes interpolation on Padua points and the schemes ...

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

Given a discrete quantum group H with a finite normal quantum subgroup G, we show that any positive, possibly unbounded, harmonic function on H with respect to an irreducible invariant random walk is G-invariant. This ...

(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)

The seller’s risk-indifference price evaluation is studied. We propose a dynamic risk-indifference pricing criteria derived from a fully- dynamic family of risk measures on the L_p-spaces for p ∈ [1, ∞]. The concept of ...

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

Given a rigid C∗ -tensor category C with simple unit and a probability measure µ on the set of isomorphism classes of its simple objects, we define the Poisson boundary of (C, µ). This is a new C∗ -tensor category P, ...

(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 ...

(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 study the problem of convergence to the boundary in the setting of random walks on discrete quantum groups. Convergence to the boundary is established for random walks on SU\q(2). Furthermore, we will define the Martin ...

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

Waves propagating below drift ice were observed in the North-West Barents Sea. In-situ measurements of ice and water characteristics were performed with the equipment deployed on the ice and in the water below the ice ...

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

The spatial and temporal development of shear-induced overturning billows associated with breaking internal solitary waves is studied by means of a combined laboratory and numerical investigation. The waves are generated ...

(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)

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 ...