Now showing items 21-40 of 45

    • Modelling laser-matter interactions using resonant states 

      Juhász, Dávid (Master thesis; Mastergradsoppgave, 2016-05-12)
      Studying how light interacts with materials has become important for many technological applications from optical communication to developing of new materials. Therefore scientists have always tried to improve their understanding of these effects. The primary goal has always been to microscopically describe the pertinent processes. This paper provides a brief introduction into the interactions of ...
    • High frequency financial time series prediction: machine learning approach 

      Zankova, Ekaterina (Master thesis; Mastergradsoppgave, 2016-05-13)
      Machine learning is a rapidly evolving subfield of computer science. It has enormous amount of applications. One of the application domains is financial data analysis. Machine learning was usually applied for analysis and forecasting of daily financial time series. Availability of high frequency financial data became another challenge with its own specifics and difficulties. Regressors, being a ...
    • Insulating the Vacuum. Calculating the Casimir force using the boundary integral method with von Neumann boundary conditions 

      Utheim, Marius (Master thesis; Mastergradsoppgave, 2016-08-15)
      In 2012, a new method for calculating the Casimir force between compact objects was developed, expressing the force in terms of a boundary integral equation. The case of perfectly conducting objects with Dirichlet boundary conditions in two dimensions was treated by Isak Kilen. The method was later extended to three dimensions by Karl Øyvind Mikalsen. The contribution of this thesis will be to ...
    • Separable representations of the Poisson, Helmholtz and complex Helmholtz kernels 

      Bjørgve, Magnar (Master thesis; Mastergradsoppgave, 2017-02-15)
      For high accuracy applications of integral operators in higher dimensions the complexity of operation and storage usually grows exponentially with dimensions. One method that has proven successful for handling these difficulties are the separation of the integral kernels as linear combinations of products of one-dimensional kernels, commonly referred to as separation of variables. In this ...
    • A complex contour based perfectly matched layer applied to a pattern generating model equation. 

      Jenssen, Amund (Master thesis; Mastergradsoppgave, 2017-02-17)
      The observable universe consists of several non equilibrium systems that generate spatiotemporal behaviour in the form of various patterns. As the elementary laws of physics and chemistry are unable to explain the pattern forming behaviour of such systems, scientists have turned to desktop experiments and model equations to gain further insight. The model equations that generate numerical solutions ...
    • Almost affine codes and matroids 

      Diachkov, Konstantin (Master thesis; Mastergradsoppgave, 2017-05-15)
      In this thesis we study various types of block codes, like linear, mutlti-linear, almost affine codes. We also look at how these codes can be described by associated matroids. In addition we look at flags (chains) of codes and see how their behavior can be described using demi-matroids. We also introduce weight polynomials for almost affine codes.
    • On the Ewald-Oseen scattering formulation for linear and nonlinear transient wave scattering 

      Kuzmina, Anastasiia (Master thesis; Mastergradsoppgave, 2017-05-16)
      In this thesis work we develop and apply EOS formulation to three scattering problems: two of them are 1D problems and one is 2D. The first chapter comprises EOS formulations and numerical implementation for 1D scattering problems. Also in this chapter we use different numerical methods to solve test problem and choose the most stable and accurate method for solving of the given 1D problems. ...
    • Modern climate-economic models and climate policies 

      Grabovskaia, Sofiia (Master thesis; Mastergradsoppgave, 2018-05-15)
      The problem of climate change is one of the most discussed problems nowadays. The global warming has an unquestionable influence on the economic growth of the different countries, and, consequently, on the whole world economics. The climate economics thus is an actual topic to study. Moreover, it is important to predict how the climate will change over the next century and which resulting outcomes ...
    • Modelling high intensity laser pulse propagation in air using the modified Korteweg-de Vries equation 

      Rørnes, Bjarne (Master thesis; Mastergradsoppgave, 2018-06-01)
      Ultrafast laser pulse experiments and applications are entering a phase that challenges the validity of mathematical models utilised to model longer pulses in nonlinear optics. This thesis aims to propose a possible mathematical model for high intensity laser pulse propagation in air through a multiple scales expansion of Maxwell’s equations and discuss a method on how to solve the corresponding ...
    • Mathematics of Viral Infections: A Review of Modeling Approaches and A Case-Study for Dengue Dynamics 

      Yong, Chung Han (Master thesis; Mastergradsoppgave, 2018-09-20)
      In this thesis we use mathematical models to study the mechanisms by which diseases spread. Transmission dynamics is modelled by the class of SIR models, where the abbreviation stands for susceptible (S), infected (I) and recovered (R). These models are also called compartmental models, and they serve as the basic mathematical framework for understanding the complex dynamics of infectious diseases. ...
    • Group Cohomology and Extensions 

      Breivik, Markus Nordvoll (Master thesis; Mastergradsoppgave, 2019-08-31)
      The goal of this thesis is to classify all extensions where the kernel has order p^s and the cokernel has order p^t, p is a prime, and 1 ≤ s,t ≤ 2. We determine (up to weak congruence) the different combinations of kernel, cokernel and operators, and for each case, calculate the second cohomology group. By comparing resolutions, we get an explicit correspondence between the second cohomology group ...
    • The Four Faces of Hyperelliptic curves 

      Boyne, Marcus L. (Master thesis; Mastergradsoppgave, 2020-05-13)
      In this thesis we will look at elliptic and hyperelliptic curves. There are three abelian groups that are isomorphic to hyperelliptic curves. The Jacobian of hyperelliptic curves, the ideal class group and the form class group, will all be defined and given abelian group structure. We will give an algorithm for point addition and point doubling done exclusively in the jacobian of the curve. ...
    • A bidirectional pulse propagation model for extreme nonlinear optics: derivation and implementation. 

      Korzeniowska, Magdalena (Master thesis; Mastergradsoppgave, 2020-05-13)
      With growing capabilities of high-intensity laser beams to generate ultra-short pulses of light, the simulation of pulse propagation in nonlinear media is expected to catch up with the front-line experimental setups. Among the challenges of nonlinear material response modeling is the ability to capture the back-scatter effect - a phenomenon inherently elusive for the well-established methods of ...
    • A boundary integral approach to the modeling of surface waves in a wave tank 

      Thygesen, Sander Bøe (Master thesis; Mastergradsoppgave, 2020-06-14)
      Boundary integral equations (BIEs) are used to model surface waves in a wave tank. Assuming an ideal fluid, the velocity of the fluid can be considered as a potential flow and be modeled by the Laplace equation on the domain. The domain in this case will be a section of a wave channel with an incoming wave from the right, a rigid bottom, a reflective wall on the right and a time varying surface that ...
    • Joint Invariants of Symplectic and Contact Lie Algebra Actions 

      Andreassen, Fredrik (Master thesis; Mastergradsoppgave, 2020-06-23)
      By restricting generating functions of infinitesimal symmetries of symplectic and contact vector spaces to quadratic forms, we obtain a finite-dimensional Lie subalgebra, consisting of vector fields isomorphic to the linear symplectic or conformal symplectic algebra. This allows us to look for joint invariants of the diagonal action of g on product manifolds. We find an explicit recipe for creating ...
    • Differential Invariants of Symplectic and Contact Lie Algebra Actions 

      Jensen, Jørn Olav (Master thesis; Mastergradsoppgave, 2020-06-23)
      In this thesis we consider the equivalence problem for symplectic and conformal symplectic group actions on submanifolds and functions. We solve the equivalence problem for general submanifolds by means of computing differential invariants and describing all the invariants of the associated group action by appealing to the Lie-Tresse theorem.
    • Ice-albedo tipping points in a diffusive energy-balance model with land and ocean 

      Hilbertsen, Kristian Bergum (Mastergradsoppgave; Master thesis, 2021-01-20)
      The ice-albedo feedback is associated with the nonlinearity in the climate system, due to the sudden change in albedo between ice-free and ice-covered surfaces. This nonlinearity can potentially cause abrupt and dramatic shifts in the climate, referred to as tipping points. It is also believed that this mechanism has contributed significantly to the precipitous losses of Arctic sea ice, which have ...
    • Symmetric Ideals 

      Lien, Arne (Mastergradsoppgave; Master thesis, 2021-05-14)
      Polynomials appear in many different fields such as statistics, physics and optimization. However, when the degrees or the number of variables are high, it generally becomes quite difficult to solve polynomials or to optimize polynomial functions. An approach that can often be helpful to reduce the complexity of such problems is to study symmetries in the problems. A relatively new field, that has ...
    • Individual-Based Modeling of COVID-19 Vaccine Strategies 

      Skagseth, Håvard Mikal (Master thesis; Mastergradsoppgave, 2021-06-01)
      COVID-19 is a respiratory disease with influenza-like symptoms originating from Wuhan, China, towards the end of 2019. There has been developed multiple vaccines to contain the virus and to protect the most vulnerable people in society. In this thesis we look at two different vaccination strategies to prevent most deaths and years of life lost. We conclude that the safest and most consistent strategy ...
    • Real Plane Algebraic Curves 

      González García, Pedro (Master thesis; Mastergradsoppgave, 2021-06-18)
      This master thesis studies several properties of real plane algebraic curves, focusing on the case of even degree. The question of the relative positions of the connected components of real plane algebraic curves originates in Hilbert's sixteenth problem which, despite its prominence, is still open in the case of higher degree curves. The goal of this thesis is an exposition of fundamental ...