Viser treff 235-254 av 1261

    • Deep Semisupervised Teacher–Student Model Based on Label Propagation for Sea Ice Classification 

      Khaleghian, Salman; Ullah, Habib; Kræmer, Thomas; Eltoft, Torbjørn; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-14)
      In this article, we propose a novelteacher–student-based label propagation deep semisupervised learning (TSLP-SSL) method for sea ice classification based on Sentinel-1 synthetic aperture radar data. For sea ice classification, labeling the data precisely is very time consuming and requires expert knowledge. Our method efficiently learns sea ice characteristics from a limited number of labeled samples ...
    • Delt situasjonsforståelse under søk og redning i nordområdene 

      Haugstveit, Ida Maria; Skjetne, Jan Håvard; Walderhaug, Ståle; Antonsen, yngve; Ellingsen, May-Britt; Håheim-Saers, Nils; Heggelund, Yngve; Anfinsen, Stian Normann (Research report; Forskningsrapport, 2016-05-03)
      Prosjektets mål er å bidra til økt kunnskap om hvordan etablere delt situasjonsforståelse mellom sentrale aktører innen SAR i Nordområdet. Prosjektgruppa har arbeidet ut ifra en menneske-teknologi-organisasjon (MTO) tilnærming og hvor vi har sett på <br>1) menneskelige og organisatoriske faktorer og <br>2) tekniske faktorer som virker inn på etableringen av delt situasjonsforståelse mellom aktører.<br> ...
    • Demonstrating low Raman background in UV-written SiO2 waveguides 

      Jensen, Mathias Novik; Gates, James C.; Flint, Alex I.; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-06)
      Raman spectroscopy can give a chemical ’fingerprint’ from both inorganic and organic samples, and has become a viable method of measuring the chemical composition of single biological particles. In parallel, integration of waveguides and microfluidics allows for the creation of miniaturized optical sensors in lab-on-a-chip devices. The prospect of combining integrated optics and Raman spectroscopy ...
    • Demystifying speckle field interference microscopy 

      Ahmad, Azeem; Jayakumar, Nikhil; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-27)
      Dynamic speckle illumination (DSI) has recently attracted strong attention in the feld of biomedical imaging as it pushes the limits of interference microscopy (IM) in terms of phase sensitivity, and spatial and temporal resolution compared to conventional light source illumination. To date, despite conspicuous advantages, it has not been extensively implemented in the feld of phase imaging due ...
    • Dense dilated convolutions merging network for land cover classification 

      Liu, Qinghui; Kampffmeyer, Michael; Jenssen, Robert; Salberg, Arnt Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-06)
      Land cover classification of remote sensing images is a challenging task due to limited amounts of annotated data, highly imbalanced classes, frequent incorrect pixel-level annotations, and an inherent complexity in the semantic segmentation task. In this article, we propose a novel architecture called the dense dilated convolutions' merging network (DDCM-Net) to address this task. The proposed ...
    • The Departure from Mixed-Layer Similarity During the Afternoon Decay of Turbulence in the Free-Convective Boundary Layer: Results from Large-Eddy Simulations 

      Elguernaoui, Omar; Reuder, Joachim; Li, Dan; Maronga, Bjørn; Bakhoday Paskyabi, Mostafa; Wolf, Tobias; Esau, Igor (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-21)
      This study analyses the departure of the velocity-variances profiles from their quasi-steady state described by the mixed-layer similarity, using large-eddy simulations with different prescribed shapes and time scales of the surface kinematic heat flux decay. Within the descriptive frames where the time is tracked solely by the forcing time scale (either constant or time-dependent) describing the ...
    • Depositional environments of the Upper Triassic Snadd Formation on the Loppa High, SW Barents Sea 

      Johansen, Stian André (Master thesis; Mastergradsoppgave, 2016-06-01)
      This thesis has focused on the depositional environments of the Upper Triassic Snadd Formation. This formation covers the time-period Ladinian to early Norian with multiple marine regressions and transgressions, resulting in depositional environments ranging from offshore marine shelf to a coastal plain. A 3D seismic dataset and its correlating well have been studied and a refined seismic stratigraphic ...
    • Derivation of vertical wavelengths of gravity waves in the MLT-region from multispectral airglow observations 

      Schmidt, Carsten; Dunker, Tim; Lichtenstern, Sabrina; Scheer, Jürgen; Wüst, Sabine; Hoppe, Ulf-Peter; Bittner, Michael (Journal article; Tidsskriftartikkel; Peer reviewed; Preprint; Manuskript, 2018-03-06)
      <p>We present the derivation of gravity wave vertical wavelengths from OH airglow observations of different vibrational transitions. It utilizes small phase shifts regularly observed between the OH(3-1) and OH(4-2) intensities in the spectra of the GRIPS (GRound-based Infrared P-branch Spectrometer) instruments, which record the OH airglow emissions in the wavelength range from 1.5  μm to 1.6  μm ...
    • Deriving high contrast fluorescence microscopy images through low contrast noisy image stacks 

      Acuna Maldonado, Sebastian Andres; ROY, MAYANK; Villegas, Luis; Dubey, Vishesh Kumar; Ahluwalia, Balpreet Singh; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-11)
      Contrast in fluorescence microscopy images allows for the differentiation between different structures by their difference in intensities. However, factors such as point-spread function and noise may reduce it, affecting its interpretability. We identified that fluctuation of emitters in a stack of images can be exploited to achieve increased contrast when compared to the average and Richardson-Lucy ...
    • Design and experimental investigation of charge amplifiers for ultrasonic transducers 

      Hansen, Svein Kristian Esp (Master thesis; Mastergradsoppgave, 2014-06-02)
      Amplifiers are used in all types of electrical circuits to boost signal and there is a huge variety in designs used for different applications. For ultrasonic applications our group has previously used commercial available transimpedance amplifiers that converts a current to a voltage, but these amplifiers have a linear response over its frequency range. To preserve as much information as ...
    • Design and Implementation of a Software Defined Ionosonde. A contribution to the development of distributed arrays of small instruments 

      Floer, Markus (Master thesis; Mastergradsoppgave, 2020-06-29)
      In order to make advances in studies of mesoscale ionospheric phenomena, a new type of ionosonde is needed. This ionosonde should be relatively inexpensive and small form factor. It should also be well suited for operation in a network of transmit and receiver sites that are operated cooperatively in order to measure vertical and oblique paths between multiple transmitters and receivers in the ...
    • Design and implementation of an oblique ionosonde receiver. For studies of spatial and temporal ionospheric structures 

      Floberg, Jens (Mastergradsoppgave; Master thesis, 2022-05-27)
      The study of the ionosphere has been of central interest since its discovery in the early 20th century. In later decades there has been an increasing appreciation and need for understanding the spatial and temporal structure of the ionosphere and how the structure is affected by various processes in the atmosphere. An important process in this context is that of atmospheric gravity waves ...
    • Design, implementering og evaluering av et trådløst medisinsk radiometer basert på IEEE 802.15.4-standarden og Zigbee. 

      Johansen, Amund Kronen (Master thesis; Mastergradsoppgave, 2009-06-01)
      Brystkreft er den vanligste kreftformen for kvinner og overlevelsesraten er betydelig høyere ved tidlig deteksjon. De vanligste undersøkelsesmetodene (mammografi, ultralyd, MRI) er basert på aktive metoder som medfører en viss strålingsfare. Et enkelt, ikke-invasivt instrument som baserer seg på passive metoder er derfor motivasjonen for denne masteroppgaven. Oppgaven beskriver en konseptuell ...
    • A detailed investigation of a geological CO2-storage reservoir 

      Hatland, Anna Maria (Master thesis; Mastergradsoppgave, 2015-05-31)
      Increased CO2-concentrations within the atmosphere of the Earth have encouraged development of “carbon capture and storage” (CCS). It is important to avoid global warming, and CO2 may be stored within geological formations in the subsurface. This thesis focuses on the possibilities of storing CO2 in a reservoir of Middle Triassic-Middle Jurassic age in The Nordkapp Basin, The Southern Barents ...
    • Detailed mapping of faults and fractures along Vestnesa ridge 

      Roman, Andrei (Master thesis; Mastergradsoppgave, 2017-05-31)
      This master thesis is focused on studying the Vestnesa Ridge located west of Svalbard. The Vestnesa Ridge is a 100 km long and about 3 km wide sediment drift located on the recently uplifted Svalbard margin. The crest of the ridge is represented with numerous pockmarks with different size, orientation and elongation. High resolution seismic data connected pockmarks with acoustic chimneys and faults ...
    • Detecting and Interpreting Faults in Vulnerable Power Grids With Machine Learning 

      Chiesa, Matteo; Bianchi, Filippo Maria; Eikeland, Odin Foldvik; Holmstrand, Inga Setså; Bakkejord, Sigurd (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-10)
      Unscheduled power disturbances cause severe consequences both for customers and grid operators. To defend against such events, it is necessary to identify the causes of interruptions in the power distribution network. In this work, we focus on the power grid of a Norwegian community in the Arctic that experiences several faults whose sources are unknown. First, we construct a data set consisting ...
    • Detecting EV Charging From Hourly Smart Meter Data 

      Barkost, Per Harald (Master thesis; Mastergradsoppgave, 2020-05-15)
      Detecting electrical vehicle (EV) charging from smart meter data (EV detection) is a highly relevant problem for the distribution system operators (DSOs), especially with the expected growth of EVs worldwide. There are several reasons why DSOs may want to detect EV charging. In the present day, the main motivation is to reduce the total load on the grid in high demand periods. This can be achieved ...
    • Detecting the linear and non-linear causal links for disturbances in the power grid 

      Foldvik Eikeland, Odin; Bianchi, Filippo Maria; Holmstrand, Inga Setsa; Bakkejord, Sigurd; Chiesa, Matteo (Chapter; Bokkapittel, 2021)
      Unscheduled power disturbances cause severe consequences for customers and grid operators. To avoid suchevents, it is important to identify the causes and localize the sources of the disturbances in the power distribution network. In this work, we focus on a specific power grid in the Arctic region of Northern Norway that experiences an increased frequency of failures of unspecified origin.
    • Detecting Unhealthy Comments in Norwegian using BERT 

      Warholm, Joakim (Mastergradsoppgave; Master thesis, 2021-05-28)
      In this work we present a new Norwegian labeled dataset of 7078 comments for unhealthy comment detection. The dataset is used to fine-tune a BERT model, and demonstrates that BERT has the ability to detect subtle forms of toxicity, also in Norwegian. We compare how the different newly released Norwegian BERT models perform when fine-tuned on our dataset, and we also experiment with how English data ...
    • The Detection and Attribution of Northern Hemisphere Land Surface Warming (1850–2018) in Terms of Human and Natural Factors: Challenges of Inadequate Data 

      Soon, Willie; Connolly, Ronan; Connolly, Michael; Akasofu, Syun-Ichi; Baliunas, Sallie; Berglund, Johan; Bianchini, Antonio; Briggs, William M.; Butler, C.J.; Cionco, Rodolfo Gustavo; Crok, Marcel; Elias, Ana G.; Fedorov, Valery M.; Gervais, François; Harde, Hermann; Henry, Gregory W.; Hoyt, Douglas V.; Humlum, Ole; Legates, David R.; Lupo, Anthony R.; Maruyama, Shigenori; Moore, Patrick; Ogurtsov, Maxim; ÓhAiseadha, Coilín; Oliveira, Marcos J.; Park, Seok-Soon; Qiu, Shican; Quinn, Gerré; Scafetta, Nicola; Solheim, Jan Erik; Steele, Jim; Szarka, László; Tanaka, Hiroshi L.; Taylor, Mitchell K.; Vahrenholt, Fritz; Velasco Herrera, Víctor M.; Zhang, Weijia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-28)
      A statistical analysis was applied to Northern Hemisphere land surface temperatures (1850–2018) to try to identify the main drivers of the observed warming since the mid-19th century. Two different temperature estimates were considered—a rural and urban blend (that matches almost exactly with most current estimates) and a rural-only estimate. The rural and urban blend indicates a long-term warming ...