Recent additions

  • 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 ...
  • 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. ...
  • 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 ...
  • 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 ...
  • 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. ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Modelling the evolution of ideal, infinite domain patterns, on a finite domain using a Perfectly Matched Layer 

    Antrushin, Andrey (Master thesis; Mastergradsoppgave, 2016-01-28)
    The Swift-Hohenberg equation is an evolution equation which can produce a Pattern, or a pattern-like picture, to be more precise. For example, it could be used to model some simple natural patterns, like stripes and rolls that one may observe in a Rayleigh-Benard convection experiment. But for any pattern formation obtained by an evolution equation to look ideal, we have to consider this equation ...
  • The Unidirectional Pulse Propagation Equation for Cylindrical Vector modes 

    Nilsen, Vegard (Master thesis; Mastergradsoppgave, 2015-07-27)
    A new model for the unidirectional pulse propagation equations (UPPE) was developed by Per Jacobsen[1], this model is based on the assumption of cylindrical vector (CV) modes. The model will be strong for CV type electrical eld representations where only a few modes will be excited. In this thesis we will investigate the model further. The model will be implemented as a pseudo spectral method where ...
  • Arctic tipping points 

    Smolkova, Valentina (Master thesis; Mastergradsoppgave, 2015-05-15)
    The Arctic is warming much faster than the entire planet, and this causes severe melting of sea ice. However, the climate of different regions of the Earth is interconnected, and changes in the amount of ice in the Arctic can dramatically affect the climate across the whole planet. Some scientists claim that a possible tipping point is the event of the ice-free Arctic Ocean in summer. Certain ...
  • Tipping points and crises in financial markets 

    Shemyakina, Polina (Master thesis; Mastergradsoppgave, 2015-05-15)
    Electricity spot markets and other financial markets are complex systems, and it is difficult to forecast their behaviour, especially uncontrolled and unmanageable situations, such as power crises and deflation of financial bubbles. An energy crisis is any price rise in the supply of energy resources to an economy. It has undesirable consequences, occasionally irreversible. The most known of these ...
  • Simplicial complexes, Demi-matroids, Flag of linear codes and pair of matroids. 

    Zubair, Ali (Master thesis; Mastergradsoppgave, 2015-05-15)
    We first describe linear error-correcting codes, and show how many of their most important properties are determined by their associated matroids . We also introduce the simplicial complex of the independent sets of a matroid. We then proceed to study flags of linear codes, and recall the definition of demi-matroids, and how such demi-matroids associated to flags can describe important properties ...
  • Homological methods applied to theory of codes and matroids 

    Karpova, Anna (Master thesis; Mastergradsoppgave, 2015-05-15)
    In this thesis we first give a survey of linear error-correcting codes, and how many of their most important properties only depend on the matroids derived from their parity check matrices. We also introduce the Stanley-Reisner ring associated to the simplicial complex of the independent sets of a matroid. We then recall in particular how some important properties of linear codes, including their ...
  • Towers of Betti Numbers of Matroids and Weight Distribution of Linear Codes and their Duals 

    Huerga Represa, Violeta (Master thesis; Mastergradsoppgave, 2015-05-15)
    The main notion behind the study of matroids is linear dependence. In this thesis, we give a survey of the concepts and properties of linear error-correcting codes over finite fields being dependent only on the matroids derived from these codes. In particular, the weight distributions of linear codes, and their extensions, over bigger fields are only dependent on the N-graded Betti numbers of these ...
  • Symmetry transformation groups and differential invariants 

    Schneider, Eivind (Master thesis; Mastergradsoppgave, 2014-11-15)
    There exists a local classification of finite-dimensional Lie algebras of vector fields in two complex dimensions. We lift the Lie algebras from this classification to three complex dimensions.
  • Deforming the vacuum. On the physical origin and numerical calculation of the Casimir effect. 

    Mikalsen, Karl Øyvind (Master thesis; Mastergradsoppgave, 2014-05-14)
    A new method for calculating the Casimir force between compact objects was introduced in May 2012 by Per Jakobsen and Isak Kilen. In this method a regularization procedure is used to reduce the pressure to the solution of an integral equation defined on the boundaries of the objects. In this thesis the method is further developed by extending from a 2D to a 3D massless scalar field, subject to ...

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