• The harmonizable representation of complex-valued nonstationary random processes 

      Hindberg, Heidi (Master thesis; Mastergradsoppgave, 2005-06-14)
      In this thesis we study the second-order statistical moment functions that characterizes complex-valued harmonizable processes. A real-valued harmonizable process has four Hermitian second-order functions. These functions are equivalent representations of the second-order statistical quantities of the process. For a complex-valued harmonizable process, however, we need the complementary functions ...
    • The impact of Arctic late summer sea ice variability on mid-latitude autumn and winter weather. 

      Stoll, Patrick (Master thesis; Mastergradsoppgave, 2015-11-18)
      The influence of Arctic summer sea ice area on autumn and winter climate in the extra-tropic Northern hemisphere is investigated. During the last decades, the Arctic has warmed more than twice the global average rate, a phenomenon called the Arctic Amplification (AA). AA involves a remarkable decrease of the Arctic sea ice cover and a decrease of the latitudinal temperature gradient. Both are supposed ...
    • Investigation of inflammatory response of macrophages and trophoblasts using structured illumination microscopy 

      Singh, Rajwinder (Master thesis; Mastergradsoppgave, 2017-05-15)
      Approximately 800 women die from pregnancy or childbirth-related pregnancy complications around the world every day. One of the major reasons for these complications is inflammation following infection. Approximately 40% cases of preterm births occur due to microbial invasion in the genitourinary track. During inflammation, macrophages present at the feto-maternal junction release an increased amount ...
    • Investigation of the ion composition in the topside ionosphere at solar maximum using incoherent scatter technique 

      Shulha, Maryna Oleksiivna (Master thesis; Mastergradsoppgave, 2016-05-15)
      The aim of this study was to investigate the altitudinal and diurnal variations of light ion densities in the topside ionosphere during the 23rd and 24th solar maximums. This made it possible to understand the behavior of the ion composition after extended solar minimum and compare how it differs from the preceding solar maximum. The observed variations are compared with estimates of empirical (IRI) ...
    • Investigation of Thermo-Optical Phase Modulator for Chip Based Structured Illumination Microscopy 

      Das, Sourov Kumar (Master thesis; Mastergradsoppgave, 2018-11-21)
      Optical nanoscopy is an emerging field and enables super-resolution of biological cells. Among the existing nanoscopy techniques, structured illumination microscopy (SIM) is most promising candidate for live cell imaging due to its high-imaging speed, limited photo-toxicity and its suitability with most commonly used fluorophore. One of research focus of the optics group at the department is to ...
    • Investigations of ionospheric disturbances using coherent HF instrumentation 

      Reznychenko, Artem (Master thesis; Mastergradsoppgave, 2016-05-15)
      This work is based on long term monitoring the HF signal data at 9.996 MHz at mid-latitudes from the short radio-path Moscow-Kharkiv and at high-latitudes from the longer radio-path Moscow-Tromso for 2013. The HF signal transmitter is the radio station RWM in Moscow, Russia. The receiver stations are located in Tromso (Norway) and Kharkiv (Ukraine). Using intensity and the Doppler frequency shift ...
    • Kara-Siberian sea ice anomaly and its impact on the atmosphere 

      Balafkan, Nozhan (Master thesis; Mastergradsoppgave, 2018-05-15)
      The behavior of the autumn and winter weather pattern over Europe and Eurasia was investigated during two periods of high and low ice concentration in September over the Kara-Siberian sea. A statistically significant anomalous energy flux from the east Siberian sea to the atmosphere was detected during October of low ice years. Furthermore, an anomalous behavior in the atmospheric circulation was ...
    • Laser diagnostics of the mesospheric magnetic field. Understanding remote laser magnetometry in northern Norway 

      Serrano, Alessandra (Master thesis; Mastergradsoppgave, 2017-05-15)
      This thesis outlines initial motivations and propositions for the Mesospheric Optical Magnetometry (MOM) project, using lidar equipment at ALOMAR observatory in northern Norway to initiate a novel technique for measuring Earth’s magnetic field at approximately 90 km altitude. Included is an in-depth discussion of the physical phenomena within Earth’s mesospheric sodium layer, relevant atomic physics, ...
    • Long-range memory in Earth surface temperatures: spatial scale dependence and land-sea differences 

      Fredriksen, Hege-Beate (Master thesis; Mastergradsoppgave, 2013-05-15)
      The use of long-range memory models as a description of the noise in Earth surface temperatures has increased the recent years, and as a measure of the persistence for such time series we have the Hurst exponent. It is known that sea surface temperatures are more persistent than land temperatures, and that global temperatures are more persistent than local temperatures. We also know that the persistence ...
    • Low-frequency noise power spectrum density characterizing of SiGe HBTs 

      Qi, Peng (Master thesis; Mastergradsoppgave, 2006-06-06)
      The main purposes of this thesis are the Low-Frequency Noise measurement of Silicon-Germanium Heterojunction Bipolar Transistors and its Power Spectrum Density Characterizing. The new generation 375 GHZ SiGe HBTs were measured in this work. We show that most of PSDs of the new generation SiGe HBTs have very ”bumpy” spectra which is contributed by GR noise sources. We investigated their basic ...
    • Måling av plasmadrift i den øvre atmosfære over Ny-Ålesund, Svalbard. 

      Mikalsen, Egil Børge (Master thesis; Mastergradsoppgave, 1977-11)
      Oppgaven bygger på målinger av plasmadrift i den øvre atmosfære over Ny-Ålesund, Svalbard. Som målemetode er brukt "spaced receivers" metoden. I kap. 2 er satt opp modeller for solvind, magnetosfære og ionosfære og en ser på fenomen som forplanter seg fra solvinden til ionosfæren. Ved hjelp av disse modeller beregnes så drift av plasma i ionosfæren. I kap. 3 beskrives målemetoden. Diffraksjonsmekanismen ...
    • Measuring Wind Using the Internal Stabilisation System of a Quadrotor Drone 

      Simma, Magdalena (Master thesis; Mastergradsoppgave, 2018-05-15)
      This thesis proposes a method of measuring wind using the data logged by the autopilot of a quadrotor drone. The approach is fundamentally different from other attempts found in the literature. Theoretical equations from works on quadrotor control are utilised and supplemented to form the theoretical framework. Static thrust tests provide the necessary parameters for calculating wind estimates. ...
    • Modeling Ice-shelf Ocean Interaction at Petermann Glacier, Greenland 

      Bao, Weiyang (Master thesis; Mastergradsoppgave, 2017-05-15)
      Petermann Glacier drains about 4% of the Greenland ice sheet area, with at least 80% of its mass loss through basal melting of the floating ice shelf. Utilizing a high-resolution coupled ice-shelf-ocean model, we aim at understanding the ocean circulation in Nares Strait and the mechanism of oceanic heat supply below the ice shelf as well as quantifying the basal mass loss. The numerical model is ...
    • Multi-sensor data fusion and feature extraction for forest applications 

      Yitayew, Temesgen Gebrie (Mastergradsoppgave; Master thesis, 2012-05-15)
      The purpose of this study was to extract, evaluate and select different multi-frequency polarimetric SAR and multi-spectral optical features to demonstrate the benefit of multi-sensor data fusion for forest applications. Multi-frequency fully Polarimetric SAR data at P-, L- and C-band and multi-spectral Landsat TM data acquired over the Nezer forest in France were used for demonstration. The scene ...
    • A multiwavelet approach to the direct solution of the Poisson equation: implementation and optimization 

      Jensen, Stig Rune (Master thesis; Mastergradsoppgave, 2009-11-15)
      This work is presenting a fully numerical approach for the direct solution of the Poisson equation for the electrostatic potential given by an arbitrary charge density. Efficient solution of this equation is important in many fields of science, where the current work is dealing with nuclear and electronic potential calculations, used in the field of computational chemistry. The equation is solved ...
    • Numerical computations of turbulent motions in magnetized plasmas 

      Decristoforo, Gregor (Master thesis; Mastergradsoppgave, 2016-05-18)
      Intermittent fluctuations and turbulence-induced transport of magnetically confined fusion plasmas are investigated by numerical computations. A reduced fluid model describing the evolution of plasma pressure and electric drift vorticity in a two-dimensional plane perpendicular to the magnetic field is derived. A numerical simulation code implemented on graphical processing units is presented. We ...
    • Numerical Simulations of Turbulence at the Boundary of Fusion Plasma 

      Jäntti, Henrik (Mastergradsoppgave; Master thesis, 2022-05-15)
      Numerical simulations of reduced fluid models describing magnetized plasmas have previously been used to study the boundary of fusion plasmas extensively. A common approximation applied to these models is the so-called Boussinesq approximation. One of the requirements for the Boussinesq approximation to be applicable is that the background particle density is significantly higher than the fluctuations ...
    • Numerical studies of radial filament motion in toroidally confined plasmas 

      Kube, Ralph (Master thesis; Mastergradsoppgave, 2010-05)
      Numerical studies of radial filament motions in the SOL of toroidally confined plasmas are studies. We use a two dimensional two-field model to characterize blob-like structures in the radial-poloidal domain. These structures are observed to achieve velocities in the order of the ion acoustic velocity in the SOL of tokamaks and other toroidal confinement devices. By numerical means we find a ...
    • A numerical study of planar elliptical antennas applied to ultrawideband (UWB) imaging of breast tissue 

      Brelum, Sindre Holsbøe (Master thesis; Mastergradsoppgave, 2008-08)
      The thesis discusses the possibility of using ultrawideband (UWB) radar to detect breast cancer. At the present time, X-ray mammography and ultrasound are the golden standard imaging techniques for detection and evaluation of breast cancer, but they both have their limitations. UWB radar utilizes the difference in dielectric properties between a tumor and the surrounding healthy tissue. By interpreting ...
    • Observations of auroral plasma lines 

      Grydeland, Tom (Master thesis; Mastergradsoppgave, 1998-03-01)
      The thesis describes observations of strongly enhanced incoherent scatter plasma lines in the auroral ionosphere which were made with the EISCAT UHF radar in 1985. The linear theory of plasma instabilities is reviewed, and several possible explanations are discussed. The observations were found to be of insufficient resolution to unambiguously resolve which one would be the correct explanation. ...