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    • Improving Doppler frequency estimation from Envisat data 

      Kræmer, Thomas; Johnsen, Harald; Brekke, Camilla (Conference object; Konferansebidrag, 2014)
    • Improving satellite-based monitoring of the polar regions: Identification of research and capacity gaps 

      Gabarró, Carolina; Hughes, Nick; Wilkinson, Jeremy; Bertino, Laurent; Bracher, Astrid; Diehl, Thomas; Dierking, Wolfgang Fritz Otto; Gonzalez-Gambau, Veronica; Lavergne, Thomas; Madurell, Theresa; Malnes, Eirik; Wagner, Penelope Mae (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-17)
      We present a comprehensive review of the current status of remotely sensed and in situ sea ice, ocean, and land parameters acquired over the Arctic and Antarctic and identify current data gaps through comparison with the portfolio of products provided by Copernicus services. While we include several land parameters, the focus of our review is on the marine sector. The analysis is facilitated by the ...
    • Improving sea surface temperature in a regional ocean model through refined sea surface temperature assimilation 

      Iversen, Silje Christine; Sperrevik, Ann Kristin; Goux, Olivier (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-26)
      Infrared (IR) and passive microwave (PMW) satellite sea surface temperature (SST) retrievals are valuable to assimilate into high-resolution regional ocean forecast models. Still, there are issues related to these SSTs that need to be addressed to achieve improved ocean forecasts. Firstly, satellite SST products tend to be biased. Assimilating SSTs from different providers can thus cause the ocean ...
    • Impulse-driven oscillations of the near-Earth's magnetosphere 

      Sato, Hiroatsu; Pecseli, Hans Laszlo; Trulsen, Jan Karsten; Sandholt, Per Even; Farrugia, Charles J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)
      It is argued that a simple model based on magnetic image arguments suffices to give a convincing insight into both the basic static as well as some transient dynamic properties of the near-Earth's magnetosphere, particularly accounting for damped oscillations being excited in response to impulsive perturbations. The parameter variations of the frequency are given. Qualitative results can also be ...
    • In-Silico Evaluation of Glucose Regulation Using Policy Gradient Reinforcement Learning for Patients with Type 1 Diabetes Mellitus 

      Myhre, Jonas Nordhaug; Tejedor Hernandez, Miguel Angel; Launonen, Ilkka Kalervo; El Fathi, Anas; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-11)
      In this paper, we test and evaluate policy gradient reinforcement learning for automated blood glucose control in patients with Type 1 Diabetes Mellitus. Recent research has shown that reinforcement learning is a promising approach to accommodate the need for individualized blood glucose level control algorithms. The motivation for using policy gradient algorithms comes from the fact that adaptively ...
    • Incident Angle Dependence of Sentinel-1 Texture Features for Sea Ice Classification 

      Lohse, Johannes; Doulgeris, Anthony Paul; Dierking, Wolfgang Fritz Otto (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-04)
      Robust and reliable classification of sea ice types in synthetic aperture radar (SAR) images is needed for various operational and environmental applications. Previous studies have investigated the class-dependent decrease in SAR backscatter intensity with incident angle (IA); others have shown the potential of textural information to improve automated image classification. In this work, we investigate ...
    • Incorporating Incidence Angle Variation into Sar Image Segmentation 

      Doulgeris, Anthony Paul; Cristea, Anca (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-05)
      We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing `correction'. It can then be used for supervised and unsupervised image analysis, ...
    • Incorporating Incidence Angle Variation into Sar Image Segmentation 

      Doulgeris, Anthony Paul; Cristea, Anca (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing ‘correction’. It can then be used for supervised and unsupervised image analysis, ...
    • Increasing Multiyear Sea Ice Loss in the Beaufort Sea: A New Export Pathway for the Diminishing Multiyear Ice Cover of the Arctic Ocean 

      Babb, David G; Galley, Ryan; Howell, Stephen; Landy, Jack Christopher; Barber, David G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-16)
      Historically, multiyear sea ice (MYI) covered a majority of the Arctic and circulated through the Beaufort Gyre for years. However, increased ice melt in the Beaufort Sea during the early 2000s was proposed to have severed this circulation. Constructing a regional MYI budget from 1997 to 2021 reveals that MYI import into the Beaufort Sea has increased year-round, yet less MYI now survives through ...
    • Inferring neutral winds in the ionospheric transition region from atmospheric-gravity-wave traveling-ionospheric-disturbance (AGW-TID) observations with the EISCAT VHF radar and the Nordic Meteor Radar Cluster 

      Günzkofer, Florian; Pokhotelov, Dimitry; Stober, Gunter; Mann, Ingrid Brigitte; Vadas, Sharon L.; Becker, Erich; Tjulin, Anders; Kozlovsky, Alexander; Tsutsumi, Masaki; Gulbrandsen, Njål; Nozawa, Satonori; Lester, Mark; Belova, Evgenia; Kero, Johan; Mitchell, Nicholas J.; Borries, Claudia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-18)
      Atmospheric gravity waves and traveling ionospheric disturbances can be observed in the neutral atmosphere and the ionosphere at a wide range of spatial and temporal scales. Especially at medium scales, these oscillations are often not resolved in general circulation models and are parameterized. We show that ionospheric disturbances forced by upward-propagating atmospheric gravity waves can be ...
    • Inferring the Dielectric Properties of Oil Slick from Multifrequency SAR imagery via a Polarimetric Two-Scale Model 

      Quigley, Cornelius; Brekke, Camilla; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel, 2021-04)
      We apply a polarimetric two-scale model to multifrequency synthetic aperture radar imagery of verified oil slicks measured by DLRs F-SAR instrument, which can acquire high spatial resolution and high signal-to-noise data. The purpose, is to determine the permittivity of the scattering surface via an inversion procedure. The ocean surface is modelled as an ensemble of randomly orientated, tilted ...
    • Inflammatory response of macrophages and trophoblasts investigated using structured illumination microscopy and quantitative phase microscopy 

      Singh, Rajwinder; Wolfson, Deanna Lynn; Dubey, Vishesh; Ahmad, Azeem; Acharya, Ganesh; Mehta, Dalip Singh; Basnet, Purusotam; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09)
      <i>Introduction</i>: The super-resolution capability of structured illumination microscopy (SIM) (100 nm) enables 3D imaging of mitochondria, and label-free quantitative phase microscopy (QPM) provides nanoscale quantitative phase values relating to cellular thickness and the refractive index of cellular content.
    • The Influence of NegEx on ICD-10 Code Prediction in Swedish: How is the Performance of BERT and SVM Models Affected by Negations? 

      Budrionis, Andrius; Chomutare, Taridzo; Olsen Svenning, Therese; Dalianis, Hercules (Journal article; Tidsskriftartikkel, 2022-08-22)
      Clinical text contains many negated concepts since the physician excludes irrelevant symptoms when reasoning and concluding about the diagnosis. This study investigates the machine interpretation of negated symptoms and diagnoses using a rule-based negation detector and its influence on downstream text classification task. The study focuses on the effect of negated concepts and NegEx preprocessing ...
    • The influence of solar system oscillation on the variability of the total solar irradiance 

      Yndestad, Harald; Solheim, Jan Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-30)
      Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, ...
    • The influence of surface charge on the coalescence of ice and dust particles in the mesosphere 

      Baptiste, Joshua; Williamsen, Connor; Fox, John; Stace, Anthony, J.; Hassan, Muhammad; Braun, Stefanie; Mann, Ingrid; Besley, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-09)
      Agglomeration of charged ice and dust particles in the mesosphere and lower thermosphere is studied using a classical electrostatic approach, which is extended to capture the induced polarisation of surface charge. Collision outcomes are predicted whilst varying the particle size, charge, dielectric constant, relative kinetic energy, collision geometry and the coefficient of restitution. In addition ...
    • The influence of surface charge on the coalescence of ice and dust particles in the mesosphere and lower thermosphere 

      Baptiste, Joshua; Williamson, Connor; Fox, John; Stace, Anthony J.; Hassan, Muhammad; Braun, Stefanie; Stamm, Benjamin; Mann, Ingrid; Besley, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-09)
      Agglomeration of charged ice and dust particles in the mesosphere and lower thermosphere is studied using a classical electrostatic approach, which is extended to capture the induced polarisation of surface charge. Collision outcomes are predicted whilst varying the particle size, charge, dielectric constant, relative kinetic energy, collision geometry and the coefficient of restitution. In ...
    • Innføring av studentaktive arbeidsformer i seminarundervisningen. Hvilken betydning har dette på læringsutbyttet og klassemiljøet? 

      Netland, Kjell Øystein; Sivertsen, Annfrid; Olufsen, Magne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-08)
      I denne studien ønsket vi å undersøke hvordan innføring av studentaktive læringsformer i seminarundervisningen påvirket det faglige læringsutbyttet og klassemiljøet i STEM-fag (science, technology, engineering and mathematics). Et randomisert kontrollert studie ble gjennomført i seminarundervisningen i to innføringsemner i fysikk og kjemi ved UiT Norges arktiske universitet. I emnene fulgte ...
    • Insights into TiO<inf>2</inf>thin film photodegradation from Kelvin Probe AFM maps 

      Olukan, Tuza Adeyemi; Sydorenko, Jekaterina; Katerski, Atanas; Al Mahri, Mariam; Lai, Chia-Yun; Al-Hagri, Abdulrahman; Santos Hernandez, Sergio; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-29)
      The synthesis of TiO2 thin films by the chemical spray pyrolysis method at different titanium isopropoxide (TTIP) to acetylacetone (AcacH) ratios has been shown to lead to the highest photodegradation at 1 (TTIP):8 (AcacH). These films hold promise in the field of indoor pollution treatment. Carbon incorporation into the surface and into the TiO2 lattice could be responsible for the observed ...
    • Instant Volume Microscopy of Organoids with SOLIS 

      Ströhl, Florian (Journal article; Tidsskriftartikkel, 2023)
      Advancements in microscopy techniques have revolutionized our ability to explore the intricacies of biological systems, with engineered human heart tissue (EHT) being a particularly challenging target. In this article, we will have an in-depth look at the award-winning SOLIS technique (scanned oblique light-sheet instant-volume sectioning), a new twist on multifocus fluorescence microscopy. Through ...
    • Integrated analysis of multi-sensor datasets and oil drift simulations - a free floating oil experiment in the open ocean 

      Brekke, Camilla; Espeseth, Martine; Dagestad, Knut-Frode; Röhrs, Johannes; Hole, Lars Robert; Reigber, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-20)
      A free‐floating oil spill experiment (two oil types) in the open ocean is described, and the results from slick characterization through integrated analysis of drift simulations with remote sensing and in situ data are discussed. We compare oil drift simulations (OpenOil), applying various configurations of wind, wave, and current information, with the observed slick positions and shape. We describe ...