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Now showing items 1-100 of 2579

Metoder og metodiske utfordringer for matchede kohortstudier Restricted Access

(Master thesis / Masteroppgave, 2018)

Når man estimerer effekten av en bestemt behandling eller eksponering på utfall i kohortstudier, og observasjonsstudier generelt, gir ikke standard metoder korrekte resultater i nærvær av ukontrollert konfundering. Matching ...

(Doctoral thesis / Doktoravhandling, 2018)

(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 ...

(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 ...

(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)

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 / 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. ...

(Master thesis / Masteroppgave, 2018)

Cancer is a major public health problem worldwide where it is the second leading cause of death. To improve safety and efficacy of anti-cancer drugs with less side effects, nanoparticles (NPs) have been studied heavily. ...

(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 ...

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

We prove some fundamental results like localization, excision, Nisnevich descent, and the regular blow-up formula for the algebraic K-theory of certain stack quotients of schemes with affine group scheme actions. We show ...

(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)

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 ...

(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. ...

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

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 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)

This master thesis will demonstrate how to price perpetual American options with linear programming. American options are used both for hedging and speculation, and being able to price derivatives, without creating arbitrage ...

(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 ...

(Doctoral thesis / Doktoravhandling, 2018)

In this PhD thesis problems of Bayesian model selection and model averaging are addressed in various regression contexts. The approaches developed within the thesis are based on the idea of marginalizing out parameters ...

(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 ...

(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)

(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)

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 ...

(Report / Rapport / SubmittedVersion, 2018)

For large multicomponent systems it is typically too costly to monitor the entire system constantly. In the present paper we consider a case where a component is unobserved in a time interval [0, T]. Here T is a stochastic ...

(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 / 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 ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

Generalized linear mixed models (GLMM) are used for inference and prediction in a wide range of different applications providing a powerful scientific tool. An increasing number of sources of data are becoming available, ...

(Master thesis / Masteroppgave, 2018)

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2018)

Powersum varieties, also called varieties of sums of powers, have provided examples of interesting relations between varieties since their first appearance in the 19th century. One of the most useful tools to study them ...

(Chapter / Bokkapittel / AcceptedVersion; Peer reviewed, 2018)

The main idea of this paper is to use the notion of buffered failure probability from probabilistic structural design, first introduced by Rockafellar & Royset (2010), to introduce buffered environmental contours. Classical ...

(Chapter / Bokkapittel / AcceptedVersion; Peer reviewed, 2018)

Slippery runways represent a significant risk to aircrafts especially during the winter season. In order to apply the appropriate braking action, the pilots need reliable information about the runway conditions. Unfortunately ...

(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)

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)

(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 ...

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

In this paper, we study the dynamics of a certain Hodgkin-Huxley model describing the action potential (AP) of a cardiac muscle cell for a better understanding of the occurrence of a special type of cardiac arrhythmia, 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 ...

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)

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)

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 ...

Reserve modelling in the presence of extreme insurance losses Restricted Access

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

(Master thesis / Masteroppgave, 2018)

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)

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)

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)

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)

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)

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)

(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 ...

(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)

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)

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 / AcceptedVersion; Peer reviewed, 2017)

We construct 2D and 3D finite element de Rham sequences of arbitrary polynomial degrees with extra smoothness. Some of these elements have nodal degrees of freedom and can be considered as generalisations of scalar Hermite ...

(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

(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 / 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)

In this paper, we study a second-order, nonlinear evolution equation with damping arising in elastodynamics. The nonlinear term is monotone and possesses a convex potential but exhibits anisotropic and nonpolynomial growth. ...

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

In this paper, we propose a new multivariate model for the dynamics of regional ocean freight rates. We show that a cointegrated system of regional spot freight rates can be decomposed into a common non-stationary market ...

(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 ...

(Master thesis / Masteroppgave, 2017)

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

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 ...

(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 / 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 / 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)

It is argued that the accuracy of risk aggregation in Solvency II can be improved by updating skewness recursively. A simple scheme based on the log-normal distribution is developed and shown to be superior to the standard ...

(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 ...