Recent additions

  • Maximizing Interpretability and Cost-Effectiveness of Surgical Site Infection (SSI) Predictive Models Using Feature-Specific Regularized Logistic Regression on Preoperative Temporal Data 

    Kocbek, Primoz; Fijacko, Nino; Soguero-Ruiz, Cristina; Mikalsen, Karl Øyvind; Maver, Uros; Brzan, Petra Povalej; Stozer, Andraz; Jenssen, Robert; Skrøvseth, Stein Olav; Stiglic, Gregor (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-19)
    This study describes a novel approach to solve the surgical site infection (SSI) classification problem. Feature engineering has traditionally been one of the most important steps in solving complex classification problems, especially in cases with temporal data. The described novel approach is based on abstraction of temporal data recorded in three temporal windows. Maximum likelihood L1-norm ...
  • Isdynamikk i tre mindre fjord-trausystemer langs Finnmarkskysten 

    Skjeldnes, Marie Elise Planting (Master thesis; Mastergradsoppgave, 2019-07-01)
    Multistråle batymetriske data og seismiske profiler fra den vestlige kysten av Finnmark er analysert med formålet om å rekonstruere dynamikken til det Fennoskandiske Isdekket gjennom siste glasiale maksimum, og påfølgende deglasiasjon. Fokuset har vært på tre prograderende kiler i forlengelsen av de glasiale trauene Rolvsøy-, Hjelmsøy- og Måsøytrauet. En seismisk stratigrafi er definert med tre ...
  • Distributed Renewable Generation and Power Flow Control to Improve Power Quality at Northern Senja, Norway 

    Jacobsen, Tobias Thørnquist (Master thesis; Mastergradsoppgave, 2019-06-01)
    Distributed renewable generation and power flow control are promising tech- nologies for increasing power system efficiency. Renewable energy production close to consumption reduces need for transport of power to these locations. The benefits of reactive flow control are well documented, and in recent years the use of energy storage for active power control has increased in relevance. The power ...
  • An Investigation of Magnetic Field Disturbances on the Ground and in the Mesosphere 

    Eriksen, Nina Kristine (Master thesis; Mastergradsoppgave, 2019-05-31)
    Geomagnetic field models can be a useful tool for when and where there are no measurements available, or access is limited, because of a highly spatially uneven magnetometer network around the globe. The same can be said for altitudes above the ground, but below the ionospheric current layer, where there exist no in situ measurements at the point of writing. Modelled geomagnetic disturbances have ...
  • Role of hafnium doping concentration on the structural and surface properties of ZnO surfaces 

    Moser, Toni (Master thesis; Mastergradsoppgave, 2019-05-31)
    The presented thesis deals with the characterisation of hafnium doped zinc oxides with focus on the application as transparent conducting film (TCF) or electron transport layer (ETL) in heterojunction solar cells. Atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electrical and optical methods have been applied to characterise the examined ...
  • A Comparison of Naturally Enhanced Ion Acoustic Lines and Auroral Spectral Line Emissions 

    Hansen, Rikke Hedelund (Master thesis; Mastergradsoppgave, 2019-05-31)
    In this thesis, we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar and a comparison with auroral emissions lines measured with a Meridian Scanning Photometer. NEIALs are short-lived events noticeable in the incoherent scatter spectra as an enhancement in one or both shoulders. It has been assumed that NEIALs are associated with an active red emission ...
  • A red tide in the pack ice of the Arctic Ocean 

    Olsen, Lasse Mork; Duarte, Pedro; Peralta-Ferriz, Cecilia; Kauko, Hanna Maria; Johansson, Malin; Peeken, Ilka; Różańska-Pluta, Magdalena; Tatarek, Agnieszka; Wiktor, Jozef; Fernández-Méndez, Mar; Wagner, Penelope Mae; Pavlov, Alexey K.; Hop, Haakon; Assmy, Phillipp (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-02)
    In the Arctic Ocean ice algae constitute a key ecosystem component and the ice algal spring bloom a critical event in the annual production cycle. The bulk of ice algal biomass is usually found in the bottom few cm of the sea ice and dominated by pennate diatoms attached to the ice matrix. Here we report a red tide of the phototrophic ciliate <i>Mesodinium rubrum</i> located at the ice-water interface ...
  • Dust trajectory simulations around Sun, Vega, and Fomalhaut 

    Stamm, Johann Immanuel; Czechowski, Andrzej; Mann, Ingrid; Baumann, Carsten; Myrvang, Margaretha (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-20)
    <p><i>Context - </i>Vega and Fomalhaut display a thermal emission brightness that can possibly arise from hot dust near the stars, an inner extension of their planetary debris disks. There was brought up an idea that nm-sized dust particles are kept in the vicinity of the stars by electromagnetic forces. This resembles the trapping that model calculations show in the corotating magnetic field in the ...
  • Detection of meteoroid hypervelocity impacts on the Cluster spacecraft: First results 

    Vaverka, Jakub; Pellinen-Wannberg, Asta; Kero, Johan; Mann, Ingrid; De Spiegeleer, Alexandre; Hamrin, Maria; Norberg, Carol; Pitkaenen, Timo (Journal article; Peer reviewed, 2017-06-29)
    We present the first study of dust impact events on one of the Earth‐orbiting Cluster satellites. The events were identified in the measurements of the wide band data (WBD) instrument on board the satellite operating in monopole configuration. Since 2009 the instrument is operating in this configuration due to the loss of three electric probes and is therefore measuring the potential between the ...
  • Backpropagation Neural Networks for Facial Recognition 

    Solheim, Inger (Master thesis; Mastergradsoppgave, 1991-12)
    A survey was conducted testing the aptitude of neural networks to recognize human faces. The motivation for this a study is the possibility of designing automatic security systems. Pictures of 511 subjects were collected. The pictures captured both profiles and many natural expressions of the subject. Some of the subjects were wearing glasses, sunglasses or hats in some of the pictures. The images ...
  • Single-input and multiple-output surface acoustic wave sensing for damage quantification in piezoelectric sensors 

    Pamwani, Lavish; Habib, Anowarul; Melandsø, Frank; Ahluwalia, Balpreet Singh; Shelke, Amit (Journal article; Peer reviewed, 2018-06-22)
    The main aim of the paper is damage detection at the microscale in the anisotropic piezoelectric sensors using surface acoustic waves (SAWs). A novel technique based on the single input and multiple output of Rayleigh waves is proposed to detect the microscale cracks/flaws in the sensor. A convex-shaped interdigital transducer is fabricated for excitation of divergent SAWs in the sensor. An angularly ...
  • Ice-water Classification in the Barents Sea from Sentinel-1 EW SLC Images 

    Krokan, August (Master thesis; Mastergradsoppgave, 2019-05-31)
    The focus of this thesis is to do ice-water classification on Sentinel-1 EW SLC imagery using an unsupervised Mixture of Gaussian segmentation algorithm. The classes are automatically labelled as sea ice or water based on the slope of the observed brightness decay from near- to far-range, which is different for sea ice and water. The aim of the thesis is twofold. In the first part, the ability of ...
  • An investigation of the robustness of distance measure-based supervised labelling of segmented remote sensing images 

    Kiærbech, Åshild (Master thesis; Mastergradsoppgave, 2019-06-03)
    Unsupervised clustering methods on remote sensing images have shown good results. However, this type of machine learning needs additional labelling to be an end-to-end classification in the same manner as traditional supervised classification. The automation of the labelling needs further exploration. We want to investigate the robustness of a supervised automatic labelling scheme by comparing a ...
  • On the relationship between global mean temperature in historical runs of Earth system models and equilibrium climate sensitivity 

    Haug, Sofie Flyvholm (Master thesis; Mastergradsoppgave, 2019-05-31)
    Equilibrium climate sensitivity (ECS) measures the long-term global surface temperature response due to a doubling of CO2 in the atmosphere. Estimates of ECS is not well constrained, 1.5-4.5C [Pachauri et al., 2014], and there is a wide spread between different Earth system models (ESMs). Recently it has been suggested that ECS can be constrained using an observed relationship between the statistical ...
  • Target Decomposition of Quad-Polarimetric SAR Images as an Unmixing Problem 

    Norum Danielsen, Daniel (Master thesis; Mastergradsoppgave, 2019-05-31)
    Classic target decomposition methods use scattering space in their approaches. However, the goal for this project is to investigate whether a different approach to retrieve accurate and reliable estimates on the earth composition is possible when using the feature space with covariance matrix-based features. The approach consists of four steps. Generating multidimensional feature space data from ...
  • Arctic Thin Sea Ice Thickness Regression Models for Sentinel-2 

    Skogvold, Øystein Fredriksen (Master thesis; Mastergradsoppgave, 2019-05-31)
    Sea ice thickness is an important parameter for modelling the sea ice mass balance, momentum and gas exchanges, and global energy budget. The interest of studies into thin sea ice has increased as trends in recent years show a increasing abundance in thin first year ice. Existing thin sea ice thickness products operate at resolutions down to 750 meters. Very high resolution (less than 100 meters) ...
  • Coded Signals for High Frequency Ultrasound Imaging 

    Peng, Chengxiang (Master thesis; Mastergradsoppgave, 2019-05-30)
    Degeneration of articular cartilage is known as a serious and painful knee disease seriously affecting people in all ages. The disease also marks the presence of osteoarthritis which is a complex musculoskeletal disorder. A successful assessment of the degeneration status is of great importance for estimating osteoarthritis progression, and thereby beneficial for implementing clinical treatments. ...
  • Correction Strategies for Breathing Induced Motion in PET Images 

    Bakkevoll, Stian (Master thesis; Mastergradsoppgave, 2019-06-03)
    Breathing induced motion highly impacts the quality of PET images. Motion blur impacts important parameters such as standardised uptake value (SUV) and lesion volume. To be able to stage lung cancer correctly, and provide correct treatment, the impact of motion needs to be reduced. There exists techniques to combat the breathing motion, such as elastic motion correction and gating strategies. ...
  • Charging Effects and Detection of Mesospheric Dust with the Instrument SPID on the G-Chaser Rocket 

    Gunnarsdottir, Tinna (Master thesis; Mastergradsoppgave, 2019-06-01)
    Smoke Particle Impact Detector (SPID) is a faraday cup impact probe designed and built by the University of Tromso (UIT). Its main purpose is to measure nanometer sized smoke particles (in-situ) in the atmosphere, and to do that it needs to be launched on a sounding rocket. Its design is an open faraday cup with grids to shield out ambient plasma and a larger slanted impact grid to measure the ...
  • On the Meteoric Smoke Particle Detector SPID: Measurements and analysis from the G-chaser rocket campaign 

    Trollvik, Henriette Marie Tveitnes (Master thesis; Mastergradsoppgave, 2019-06-01)
    The Smoke Particle Impact Detector (SPID), newly designed at the University of Tromsø, was launched from Andøya 09:13 UTC the 13. January 2019. SPID is designed to detect meteoric smoke particles (MSPs) in winter mesospheric conditions. The rocket had a velocity of 1600 ms-1 at ~55 km where the nosecone was separated. At ~ 60km, SPID detected a signal of 17nA on the middle plate. The dynamics of the ...

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