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Nodal Geometry and Growth of Solutions to Elliptic Partial Differential Equations
(Doctoral theses at NTNU;2022:216, Doctoral thesis, 2022)In this thesis we will study zeros and growth properties of solutions to elliptic PDEs. In particular, we first study zeros of linear combination of Laplace-Beltrami eigenfunctions via a growth estimate for positive solutions ... -
Noise removal in synthetically generated diffusion tensor imaging data using a denoising autoencoder
(Bachelor thesis, 2020)Diffusjonstensor avbildning (DTI) er en populær medisinsk avbildningsteknikk som kartlegger diffusjonen av vannmolekyler i biologisk vev. Målte DTI-data er forurenset av støy, og temaet for dette prosjektet var å utforske ... -
Noise-driven bifurcations in a neural field system modelling networks of grid cells
(Peer reviewed; Journal article, 2022)The activity generated by an ensemble of neurons is affected by various noise sources. It is a well-recognised challenge to understand the effects of noise on the stability of such networks. We demonstrate that the patterns ... -
Non-existence of Classical Solutions with Finite Energy to the Cauchy Problem of the Compressible Navier–Stokes Equations
(Journal article; Peer reviewed, 2018)The well-posedness of classical solutions with finite energy to the compressible Navier–Stokes equations (CNS) subject to arbitrarily large and smooth initial data is a challenging problem. In the case when the fluid density ... -
Non-Interactive Zero-Knowledge Proofs with Fine-Grained Security
(Peer reviewed; Journal article, 2022)We construct the first non-interactive zero-knowledge (NIZK) proof systems in the fine-grained setting where adversaries’ resources are bounded and honest users have no more resources than an adversary. More concretely, ... -
Non-linear Newton Solver for a Polymer Two-phase System Using Interface-localized Trust Regions
(Chapter, 2017)Models of polymer flooding account for several processes such as concentration dependent viscosity, adsorption, incomplete mixing, inaccessible pore space, and reduced permeability effects, which altogether gives strongly ... -
Non-parametric Regression in Machine Learning: A Comparison of the Probabilistic and Algorithmic Approach
(Bachelor thesis, 2022)Termen ikke-parametrisk regresjon omhandler et stort antall maskinlærings teknikker som spår fremtidige hendelser av naturlige prosesser ved å bruke funksjoner som er mer fleksible enn deres parametriske motparter. Man kan ... -
Non-uniform dependence on initial data for equations of Whitham type
(Journal article, 2019)We consider the Cauchy problem ∂tu + u∂xu + L(∂xu) = 0, u(0, x) = u0(x) for a class of Fourier multiplier operators L, and prove that the solution map u0 7→ u(t) is not uniformly continuous in Hs on the real line or on the ... -
Noncommutative Geometry in Wireless Communication Applications
(Master thesis, 2018)The theory of time-frequency analysis is introduced, and basic results on modulation spaces are proved. We describe Gabor frames and prove results which are relevant to application in wireless communication. We outline a ... -
Noncommutative Gröbner bases in Polly Cracker cryptosystems
(Master thesis, 2009)We present the noncommutative version of the Polly Cracker cryptosystem, which is more promising than the commutative version. This is partly because many of the ideals in a free (noncommutative) algebra have an infinite ... -
Nonhomogeneous Poisson process with nonparametric frailty and covariates
(Journal article; Peer reviewed, 2017)The nonhomogeneous Poisson process is commonly used in the modeling of failure times of complex repairable systems. In practice there may be a substantial heterogeneity in the failure behavior among apparently identical ... -
Nonlinear Acoustic Waves in Heterogeneous Materials
(Master thesis, 2015)This thesis concerns the partial differential equations governing acoustic wave propagation in heterogeneous materials. We start with an investigation of the standard Eulerian formulation of the equations, and point out ... -
Nonlinear anisotropic degenerate parabolic-hyperbolic equations with stochastic forcing
(Journal article; Peer reviewed, 2021) -
Nonlinear domain decomposition scheme for sequential fully implicit formulation of compositional multiphase flow
(Journal article; Peer reviewed, 2019)New sequential fully implicit (SFI) methods for compositional flow simulation have been recently investigated. These SFI schemes decouple the fully coupled problem into separate pressure and transport problems and have ... -
Nonlinear fractional convection-diffusion equations, with nonlocal and nonlinear fractional diffusion
(Master thesis, 2013)We study nonlinear fractional convection-diffusion equations with nonlocal and nonlinear fractional diffusion. By the idea of Kru\v{z}kov (1970), entropy sub- and supersolutions are defined in order to prove well-posedness ... -
Nonlinear Gauss-Seidel solvers with higher order for black-oil models
(Chapter, 2018)The fully implicit method is the most commonly used approach to solve black-oil problems in reservoir simulation. The method requires repeated linearization of large nonlinear systems and produces ill-conditioned linear ... -
Nonlinear integro-differential Equations: Numerical Solutions by using Spectral Methods
(Master thesis, 2013)This article deals with numerical solutions of nonlinear integro-differential convection-diffusion equations using spectral methods. More specifically, the spectral vanishing viscosity method is introduced and analyzed to ... -
Nonlinear phase unwinding
(Master thesis, 2018)We start of by studying Hardy spaces and Blaschke products. Then we look at a natural nonlinear analogue of Fourier series called the unwinding series. It is obtained through iterative Blaschke factorization and unwinds ... -
Nonlinear Two-Point Flux Approximation Schemes for Reservoir Simulation
(Master thesis, 2018)The main objective of this thesis has been to investigate some methods for simulating CO2 storage and hydrocarbon recovery on complex polyhedral grids, with main focus on the nonlinear two-point flux approximation method. ... -
Nonlocal and monotone techniques in dispersive equations and inverse problems
(Doctoral theses at NTNU;2022:151, Doctoral thesis, 2022)