Blar i tittel Mastergradsoppgaver i fysikk

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    • Statistical modelling of polarimetric SAR data 

      Doulgeris, Anthony Paul (Master thesis; Mastergradsoppgave, 2006-06-02)
      A statistical modelling technique is developed to analyse polarimetric synthetic aperture radar (PolSAR) images. Polarimetric SAR data consists of four complex scattering coefficients at each image location, requiring multivariate modelling techniques, and this work focuses on a simple class of multivariate distributions, the scale mixture of Gaussians. Three parametric model families of that ...

    • Stochastic Modelling and Numerical Simulations of Radial Filament Motion and Average Profiles at the Boundary of Fusion Plasmas 

      Paikina, Olga (Master thesis; Mastergradsoppgave, 2022-05-15)
      <p>The boundary region of magnetically confined plasmas is well known to have inherently fluctuating parameters. Advances in experimental measurements and numerical computations have revealed that the fluctuation-driven transport of particles and heat across the magnetic field lines is mainly dominated by the radial motion of blob-like filament structures. These structures, which are localized in ...

    • Stochastic modelling of intermittent scrape-off layer plasma fluctuations 

      Theodorsen, Audun (Master thesis; Mastergradsoppgave, 2015-05-15)
      In the tokamak scrape-off layer, radial motion of blob-like structures is the dominant mechanism for transport of particles and heat. Fixed point probe measurements in the Tokamak à Configuration Variable scrape-off layer reveal highly intermittent fluctuations in the ion saturation current. These measurements are well described by a shot noise process with exponential pulse shapes, exponentially ...

    • Studies of plasma potential with emissive probes in the low temperature plasma experiment NJORD 

      Schregel, Christian-Georg (Master thesis; Mastergradsoppgave, 2012-11-02)
      In this thesis, the concept of an emissive probe has been used to obtain the plasma potential in the low temperature plasma experiment NJORD. An emissive probe is a probe concept in which a wire is heated strong enough to emit a Richardson current. The probe is then swept through several voltage biases and thus, an I-V trace obtained. With the current from the emission and the collected current, ...

    • Super-Resolution Imaging of Sub-Mitochondrial Structures using Structured Illumination Microscopy 

      Opstad, Ida Sundvor (Master thesis; Mastergradsoppgave, 2016-05-15)
      Modern science is based on observation, and its advances are limited by what is possible to observe. For centuries optical microscopy was limited by the diffraction of light, making structures closer together than half the wavelength of light unresolvable. In recent years, the new field of optical nanoscopy has emerged, enabling diffraction-limited structures to be resolved. As opposed to ...

    • Suppression of fingering instabilities in superconductors by magnetic braking 

      Lator, Elijah (Master thesis; Mastergradsoppgave, 2012-11)
      Superconductors are materials that can transport electric current without resistance and loss of energy at low temperature. This thesis is a theoretical investigation problem about the thermomagnetic instability in superconductor and its suppression by deposing a metallic layer.

    • System upgrade and data evaluation of the AIRIS riometer 

      Larsen, Ida Marie (Master thesis; Mastergradsoppgave, 2016-06-06)
      The focus of this thesis has been to investigate how to improve the AIRIS data. This has been done by first of all giving the riometer system an overhaul, checking the wiring and receivers as well as upgrading the riometer computer harddisk. As there has been a lot of issues occurring along the way, the focus finally went to pinpointing exactly what is causing the data quality to be poor and coming ...

    • Temperature and thermal emission of cosmic dust around the Sun, Vega and Fomalhaut 

      Myrvang, Margaretha (Master thesis; Mastergradsoppgave, 2018-05-14)
      Many stars are known to have dust disks, which are created through collisions between planetesimals, comparable to comets and asteroids in our solar system. Cosmic dust around a star absorbs electromagnetic radiation and re-radiates at a longer wavelength, determined by its temperature. The thermal emission of the dust can be observed. In certain systems, including the solar system, some of the dust ...

    • Temperature sensitivity of waveguide Mach-Zehnder interferometer 

      Sokolov, Viktor (Master thesis; Mastergradsoppgave, 2013-05-31)
      This thesis is part of a project that aims to develop a sensor for the detection of methane in the air and in water based on a waveguide Mach-Zehnder interferometer. The main application of this sensor is monitoring the environment and the ability to detect a leakage of methane. The development of a sensor includes analysis of operational conditions. In this project one of the greatest concerns is ...

    • Thermal analysis of PTC heaters. Thermography of PTC and Peltier heaters. Labview® based control and Matlab® Simulink simulations of PTC heaters. 

      Taimur, Madiha (Master thesis; Mastergradsoppgave, 2018-06-15)
      A large variety of heating devices are being used in the industry. Two widely used smart heating devices are discussed in this study. These heating devices are Peltier/thermoelectric (TE) and Positive Temperature Coefficient (PTC) resistive heater. This study provides detailed experimentation of PTC heater and Peltier device at room conditions and cold environment. The thermal response of both ...

    • Time Series Forecasting with Recurrent Neural Networks in Presence of Missing Data 

      Choi, Changkyu (Master thesis; Mastergradsoppgave, 2018-11-24)
      In many applications, time series forecasting plays an irreplaceable role in time-varying systems such as energy markets, financial markets, and so on. Predicting the dynamic of time-varying systems is essential but is a difficult task because it depends on not only the nature of the system but also on external influences, such as environmental conditions and social and economic status. Recurrent ...

    • Towards Unsupervised Domain Adaptation for Diabetic Retinopathy Detection in the Tromsø Eye Study 

      Størdal, Magnus (Mastergradsoppgave; Master thesis, 2021-05-29)
      Diabetic retinopathy (DR) is an eye disease which affects a third of the diabetic population. It is a preventable disease, but requires early detection for efficient treatment. While there has been increasing interest in applying deep learning techniques for DR detection in order to aid practitioners make more accurate diagnosis, these efforts are mainly focused on datasets that have been collected ...

    • Trapping of Nanoparticles with Optical Waveguides 

      Dullo, Firehun Tsige (Master thesis; Mastergradsoppgave, 2011-05-18)
      Over the last few years, the notion that links optical trapping with strong intensity of light (high energy photon) not only forced the modification of optical tweezer, but it also open up the door for evanescent wave field trapping. While optical tweezer is merely suitable for trapping micro-sized particles, trapping by evanescent field of a channel waveguide enables both micro and nanosized particles ...

    • Type-I ion outflow from the high latitude ionosphere 

      Argese, Chiara (Master thesis; Mastergradsoppgave, 2013-11-15)
      The aim of this thesis is to study type-I ion outflows in the high latitude ionosphere. Type-I ion outflows are characterized by strong perpendicular electric fields, enhanced and anisotropic ion temperatures and low electron densities below 300 km, indicating small amounts of hard particle precipitation. We scanned data from the EISCAT Madrigal database over a period of 10 years (January 2000 - ...

    • Uncertainty Modeling and Interpretability in Convolutional Neural Networks for Polyp Segmentation. 

      Wickstrøm, Kristoffer Knutsen (Master thesis; Mastergradsoppgave, 2018-05-14)
      Colorectal cancer is one of the leading causes of cancer-related deaths worldwide, with prevention commonly done through regular colonoscopy screenings. During a colonoscopy, physicians manually inspect the colon of a patient using a camera in search for polyps, which are known to be possible precursors to colorectal cancer. Seeing that a colonoscopy is a manual procedure, it can be susceptible to ...

    • The volume distribution of artificial aurora induced by HF radio waves in the ionosphere 

      Kvammen, Andreas (Master thesis; Mastergradsoppgave, 2016-08-15)
      This thesis presents three-dimensional modelling of artificial aurora in the ionospheric F layer, induced by high frequency (HF) O-mode radio waves from the EISCAT heating facility. Understanding how HF radio waves produces enhanced emission in the ionosphere has been one of the one of the major motivations for conducting heating experiments during the last decades. A key element for understanding ...