## Search

Now showing items 201-300 of 2561

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

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

Compressed sensing is a technique for recovering an unknown sparse signal from a small number of linear measurements. When the measurement matrix is random, the number of measurements required for perfect recovery exhibits ...

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

(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 ...

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

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

The evolution of interfacial waves on a stratified flow was investigated experimentally for air-water flow in a horizontal pipe. Waves were introduced in the liquid level of stratified flow near the pipe entrance using an ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

Simultaneous Particle Image Velocimetry (PIV) measurements of stratified turbulent air/water flow in a horizontal pipe have been performed using water droplets as tracers in the gas-phase. The use of water droplets as ...

Simulating sleep. Restricted Access

(Master thesis / Masteroppgave, 2017)

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

The problem on identification of a limit of an ordinary differential equation with discontinuous drift that perturbed by a zero-noise is considered in multidimensional case. This problem is a classical subject of stochastic ...

(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)

(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)

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 / PublishedVersion; Peer reviewed, 2017)

Nocturnal low-level jets (LLJs) are defined as relative maxima in the vertical profile of the horizontal wind speed at the top of the stable boundary layer. Such peaks constitute major power resources for wind turbines. ...

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

Compound events (CEs) are multivariate extreme events in which the individual contributing variables may not be extreme themselves, but their joint – dependent – occurrence causes an extreme impact. Conventional univariate ...

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

We present a two-factor option-pricing model, which parsimoniously captures the difference in volatility persistences under the historical and risk-neutral probabilities. The model generates an S-shaped pricing kernel that ...

(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 ...

(Master thesis / Masteroppgave, 2017)

(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 / 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.
...

(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 / PublishedVersion; Peer reviewed, 2017)

In this paper, we are interested by advanced backward stochastic differential equations (ABSDEs), in a probability space equipped with a Brownian motion and a single jump process, with a jump at time τ. ABSDEs are BSDEs ...

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

Skatteetaten bruker i dag prediktive metoder til blant annet utvelgelse til kontroll av merverdiavgiftsoppgaver og til å forbedre og effektivisere innkreving av skatter. Dette har vist seg å gi økt proveny og en mer effektiv ...

(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 ...

(Chapter / Bokkapittel / SubmittedVersion, 2017)

A modern ship is a highly complex system, often equipped with thousands of sensors to monitor various features of the system. Traditionally, sensor based component control is rule-based. A temperature threshold could for ...

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

We discuss the construction of robust preconditioners for finite element approximations of Biot’s consolidation model in poroelasticity. More precisely, we study finite element methods based on generalizations of the ...

(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 ...

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

Using a nonlinear evolution equation we examine the dependence of the dispersion of directional surface gravity waves on the Benjamin–Feir index (BFI) and crest length. A parameter for describing the deviation between the ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2017)

In this article we will present a new perspective on the variable order fractional calculus, which allows for differentiation and integration to a variable order, i.e. one differentiates (or integrates) a function along ...

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

A droplet that impacts onto a solid substrate deforms in a complex dynamics. To extract the principal mechanisms that dominate this dynamics, we deploy numerical simulations based on the phase field method. Direct comparison ...

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

We have employed laboratory and numerical experiments in order to investigate propagation of waves in both long and short-crested wave fields in deep water. For long-crested waves with steepness, ϵ = kcac = 0.1 (a fairly ...

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

In this paper, we study a mathematical model of cardiac tissue based on explicit representation of individual cells. In this EMI model, the extracellular (E) space, the cell membrane (M), and the intracellular (I) space ...

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

We study conformal structure and topology of leaves of singular foliations by Riemann surfaces.
The final version of this research has been published in the Journal of Geometric Analysis. © 2017 Springer Verlag

Asymptotics of invariant metrics in the normal direction and a new characterisation of the unit disk

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

We give improvements of estimates of invariant metrics in the normal direction on strictly pseudoconvex domains. Specifically we will give the second term in the expansion of the metrics. This depends on an improved ...

(Master thesis / Masteroppgave, 2017)

Parametric representations of surfaces in Computer-Aided Geometric Design (CAGD) are often based on connected patches with rectangular parameter domains. Given a loop of four space curves and normal-derivative curves, we ...

Alternative models for reinsurance in Solvency II Restricted Access

(Master thesis / Masteroppgave, 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)

We introduce the concept of singular recursive utility. This leads to a kind of singular backward stochastic differential equation (BSDE) which, to the best of our knowledge, has not been studied before. We show conditions ...

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

© European Mathematical Society 2017

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

Background: Excess skin cancer mortality and incidence have been reported among both land-based and offshore petroleum workers. The association between skin cancer and ultraviolet radiation (UVR) exposure has not been ...

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

Very long waves are generated when a ship moves across an appreciable depth change ∆h comparable to the average and relatively shallow water depth h at the location, with ∆h/h ≃ 1. The phenomenon is new and the waves are ...

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

The wave diffraction-radiation problem of a porous geometry of arbitrary shape located in the free surface of a fluid is formulated by a set of integral equations, assuming a linear resistance law at the geometry. The ...

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

1. Identifying the spatial scale of population structuring is critical for the conservation of natural populations and for drawing accurate ecological inferences. However, population studies often use spatially aggregated ...

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

Multistate monotone systems are used to describe technological or biological systems when the system itself and its components can perform at different operationally meaningful levels. This generalizes the binary monotone ...

(Doctoral thesis / Doktoravhandling, 2016)

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

Detailed observations of the diurnal jet, a surface intensification of the wind-driven current associated with the diurnal cycle of sea surface temperature (SST), were obtained during August and September 2012 in the ...

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

The paper discusses the development of a frequency dependent directional spread from an initial condition of frequency-independence. The study applies basin directional measurements from the Maritime Research Institute ...

(Master thesis / Masteroppgave, 2016)

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

(Doctoral thesis / Doktoravhandling, 2016)

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

Watson and Holmes propose ways of investigating robustness of statistical decisions by examining certain neighbourhoods around a posterior distribution. This may partly amount to ad hoc modelling of extra uncertainty. ...

(Master thesis / Masteroppgave, 2016)

Reserving against future claims and settlements is vital for insurance companies, in the sense that it influences how they may price their products and the solvency of the insurance company. This thesis will present and ...

(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 ...

(Master thesis / Masteroppgave, 2016)

This thesis presents an experimental investigation on the occurrence of freak waves in a bimodal sea. The bimodal sea consisted of two wave systems traveling in the same direction, with different peak frequencies f_{Pj} ...

(Master thesis / Masteroppgave, 2016)

In this thesis we simulate a new model, formulated as a nonlinear filtering problem with a generalized Cox process, for the modeling of transition rates in life insurance. This allows for a time-continuous model which may ...

(Master thesis / Masteroppgave, 2016)

The study of generic quartic symmetroids in projective 3-space dates back to Cayley, but little is known about the special specimens. This thesis sets out to survey the possibilities in the non-generic case. We prove that ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

Biot's consolidation model in poroelasticity has a number of applications in science, medicine, and engineering. The model depends on various parameters, and in practical applications these parameters range over several ...

(Master thesis / Masteroppgave, 2016)

This master thesis presents a laboratory investigation of wave slamming forces on a vertical cylinder in deep and intermediate water. The technique of frequency focusing of the incoming wave field allows for generation of ...

(Master thesis / Masteroppgave, 2016)

We have used the level - set function to divide a computational domain into a solid region and a fluid region to create an idealized model of blood flow in narrow cerebral arteries to simulate the mechanotransduction in ...

(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 / PublishedVersion; Peer reviewed, 2016)

Dynamical downscaling of earth system models is intended to produce high-resolution climate information at regional to local scales. Current models, while adequate for describing temperature distributions at relatively ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

We combine stochastic control methods, white noise analysis, and Hida–Malliavin calculus applied to the Donsker delta functional to obtain explicit representations of semimartingale decompositions under enlargement of ...

(Master thesis / Masteroppgave, 2016)

In this thesis, we consider applications of directed algebraic topology in optimization theory, by representing directed graphs as directed topological spaces. We review the classical max-flow min-cut theorem and a ...

Modellering av norske kortrenter - Med Levy semistasjonære prosseser Restricted Access

(Master thesis / Masteroppgave, 2016)

Monotone regression in high (and lower) dimensions Restricted Access

(Master thesis / Masteroppgave, 2016)

In this thesis, we first present an overview of monotone regression, both in the classical setting and in the high dimensional setting. High dimensional data means that the number of covariates, p, exceeds the number of ...

(Master thesis / Masteroppgave, 2016)

In their article, "Continuity of the Spectrum of a Field of Self-Adjoint Operators", Beckus and Bellissard discuss the following problem: Given a family of bounded, self-adjoint linear operators indexed by a parameter t ...

(Master thesis / Masteroppgave, 2016)

Parallellaksiomet er det eneste aksiomet der hyperbolsk geometri skiller seg fra euklidsk. Mens det i euklidsk geometri er en unik linje som går gjennom et gitt punkt og er parallell med en gitt linje, finnes det i hyperbolsk ...

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

We study stochastic differential games of jump diffusions, where the players have access to inside information. Our approach is based on anticipative stochastic calculus, white noise, Hida–Malliavin calculus, forward ...

(Master thesis / Masteroppgave, 2016)

(Master thesis / Masteroppgave, 2016)

The spread of salmon lice has long been and continues to be an increasing problem for the fish farming industry, causing economic and environmental problems. In this thesis, in cooperation with the Norwegian Veterinary ...

(Master thesis / Masteroppgave, 2016)

(Master thesis / Masteroppgave, 2016)

(Master thesis / Masteroppgave, 2016)

Målet med denne masteroppgaven er å se på teorien som ligger til grunn for en rangeringsmodell kalt Offense-Defense Modellen. Jeg skriver om matriseskaleringer og dobbeltstokastiske matriser som ender med Sinkhorn-Knopp ...

(Master thesis / Masteroppgave, 2016)

Norway has been suffering from numerous natural disasters throughout its history. In order to be able to compensate losses caused by natural disasters such as storm, flood, earthquake, avalanche or other natural disasters, ...

(Master thesis / Masteroppgave, 2016)

Denne oppgaven er skrevet i faget MAT5930L, som er det siste faget i Lektorprogrammet ved UiO. Emnet er Euklids Elementer. Vi ser på noen av proposisjonene i de tre første bøkene av Elementer. Her fokuserer vi på hvordan ...

(Master thesis / Masteroppgave, 2016)

Syringomyelia is a progressive disease where fluid filled cavities develop inside the spinal cord, and is frequently seen together with Chiari Malformation I (CMI). CMI is characterized by downwards displacements of the ...

(Master thesis / Masteroppgave, 2016)

Optimal stopping problems and the weak variational inequalites Restricted Access

(Master thesis / Masteroppgave, 2016)

This thesis studies a relationship between solving optimal stopping problems and solving the weak variational inequalites. We prove a theorem that presents conditions under which the weak variatonal inequalities have a ...

An ambitmodell for swaper. Restricted Access

(Master thesis / Masteroppgave, 2016)

(Master thesis / Masteroppgave, 2016)

(Master thesis / Masteroppgave, 2016)

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

Objective A number of observational studies have shown an inverse association between circulating 25-hydroxyvitamin D and total mortality, but a reverse J-shaped association has also been reported. In a large nested ...

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

In the present paper, a three-component, stationary, multistate flow network system is studied. Detailed costs and incomes are specified. The aim is to minimize the expected total net loss with respect to the expected times ...

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

We prove that if a closed subset X of the Baire space is searchable in the sense of Escardó [Logical Methods in Computer Science 4(3) (2008), 3], and by a functional definable in Gödel’s T, then X is countable, and the ...

(Master thesis / Masteroppgave, 2016)

An important aspect in portfolio optimization is the quantification of risk. Variance was the starting point, as proposed by Harry Markowitz in the 1950’s, but it’s obviously flawed since it measures high returns as risk. ...

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

We introduce the notion of accurate foundation sets and the accurate refinement property for right LCM semigroups. For right LCM semigroups with this property, we derive a more explicit presentation of the boundary quotient. ...

Customer Duration and Profitability in General Insurance Restricted Access

(Master thesis / Masteroppgave, 2016)

In general insurance, the expected duration of a customer relationship is of great interest since retaining an existing customer is much cheaper than acquiring a new one from an administrative point of view. The expected ...

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

libRadtran is a widely used software package for radiative transfer calculations. It allows one to compute (polarized) radiances, irradiance, and actinic fluxes in the solar and thermal spectral regions. libRadtran has ...

(Master thesis / Masteroppgave, 2016)

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

For many high-dimensional studies, additional information on the variables, like (genomic) annotation or external p-values, is available. In the context of binary and continuous prediction, we develop a method for adaptive ...

(Master thesis / Masteroppgave, 2016)

Denne oppgaven studerer Reed-Solomon-koder og ser på hvordan dekoding av disse kan relateres til å finne potenssumdekomposisjoner av polynomer, hvilket kan tolkes geometrisk som å finne et sekantplan til den rasjonale ...

(Master thesis / Masteroppgave, 2016)

This thesis aims to study the risk measure Conditional Value-at-Risk and analyse an optimization problem of maximizing expected return subject to this risk measure. The analysis include performing Fourier-Motzkin eliminations ...

(Master thesis / Masteroppgave, 2016)

Avhandlingen er en del av en større forskning på bimodal sjø. Det er gjort eksperimenter med vindsjø sammen med dønnning, samt bikromatisk bølge bestående av en kort bølge ridende på dønning er genrert i bølgetanken. Det ...

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

We show that a pseudoeffective R-divisor has numerical dimension 0 if it is numerically trivial on a subvariety with ample normal bundle. This implies that the cycle class of a curve with ample normal bundle is big, which ...

Linear stability of the boundary layer under internal solitary waves Restricted Access

(Master thesis / Masteroppgave, 2016)

(Chapter / Bokkapittel / PublishedVersion; Peer reviewed, 2016)

We introduce Bichromatic Synthetic Schlieren (BiCSS) for instantaneous surface measurements, in where we use two simultaneous images taken at blue and near infrared wavelengths, making use of that refractive index variation ...

(Journal article / Tidsskriftartikkel / SubmittedVersion, 2016)

Direct Numerical Simulations (DNS) of the Navier Stokes equations is an invaluable research tool in fluid dynamics. Still, there are few publicly available research codes and, due to the heavy number crunching implied, ...

(Research report / Forskningsrapport, 2016)

(Master thesis / Masteroppgave, 2016)

Traditionally the compressive sensing theory have been focusing on the three principles of sparsity, incoherence and uniform random subsampling. Recent years research have shown that these principles yield insufficient ...

(Master thesis / Masteroppgave, 2016)

The numerical solution of differential equations is an algorithmic process with various parameters controlling the accuracy, stability and computational time of the simulation. In Computational Fluid Mechanics (CFD) there ...