Viser treff 321-340 av 1057

    • Snowfall and snow accumulation during the MOSAiC winter and spring seasons 

      Wagner, David N.; Shupe, Matthew D.; Cox, Christopher; Persson, Ola G.; Uttal, Taneil; Frey, Markus M.; Kirchgaessner, Amélie; Schneebeli, Martin; Jaggi, Matthias; MacFarlane, Amy R.; Itkin, Polona; Arndt, Stefanie; Hendricks, Stefan; Krampe, Daniela; Nicolaus, Marcel; Ricker, Robert; Regnery, Julia; Kolabutin, Nikolai; Shimanshuck, Egor; Oggier, Marc; Raphael, Ian; Stroeve, Julienne; Lehning, Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-17)
      Data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition allowed us to investigate the temporal dynamics of snowfall, snow accumulation and erosion in great detail for almost the whole accumulation season (November 2019 to May 2020). We computed cumulative snow water equivalent (SWE) over the sea ice based on snow depth and density retrievals from a ...
    • 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 ...
    • 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 ...
    • Multi-instrument observations of the Pajala fireball: origin, characteristics, and atmospheric implications 

      Vierinen, Juha; Aslaksen, Torstein; Chau, Jorge L.; Gritsevich, Maria; Gustavsson, Bjorn Johan; Kastinen, Daniel; Kero, Johan; Kozlovsky, Alexandre; Kværna, Tormod; Näsholm, Sven Peter; Ulich, Thomas; Vegum, Ketil; Midtskogen, Steinar; Lester, Mark (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-07)
      Meteor observations provide information about Solar System constituents and their influx onto Earth, their interaction processes in the atmosphere, as well as the neutral dynamics of the upper atmosphere. This study presents optical, radar, and infrasound measurements of a daytime fireball that occurred on 4 December 2020 at 13:30 UTC over Northeast Sweden. The fireball was recorded with two video ...
    • Evaluating Landsat-8 and Sentinel-2 Data Consistency for High Spatiotemporal Inland and Coastal Water Quality Monitoring 

      Hafeez, Sidrah; Wong, Man Sing; Abbas, Sawaid; Asim, Muhammad (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-30)
      The synergy of fine-to-moderate-resolutin (i.e., 10–60 m) satellite data of the Landsat-8 Operational Land Imager (OLI) and the Sentinel-2 Multispectral Instrument (MSI) provides a possibility to monitor the dynamics of sensitive aquatic systems. However, it is imperative to assess the spectral consistency of both sensors before developing new algorithms for their combined use. This study evaluates ...
    • History of the Tromsø ionosphere heating facility 

      Rietveld, Michael T.; Stubbe, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-22)
      We present the historical background of the construction of a major ionospheric heating facility, “Heating”, near Tromsø, Norway, in the 1970s by the Max Planck Institute for Aeronomy; we also detail the facility’s subsequent operational history to the present. Heating was built next to the European Incoherent Scatter Scientific Association (EISCAT) incoherent scatter (IS) radar facility and in a ...
    • 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 ...
    • Arecibo measurements of D-region electron densities during sunset and sunrise: implications for atmospheric composition 

      Baumann, Carsten; Kero, Antti; Raizada, Shikha; Rapp, Markus; Sulzer, Michael P.; Verronen, Pekka T.; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-02)
      Earth’s lower ionosphere is the region where terrestrial weather and space weather come together. Here, between 60 and 100 km altitude, solar radiation governs the diurnal cycle of the ionized species. This altitude range is also the place where nanometre-sized dust particles, recondensed from ablated meteoric material, exist and interact with free electrons and ions of the ionosphere. This ...
    • On the Potential of Sequential and Nonsequential Regression Models for Sentinel-1-Based Biomass Prediction in Tanzanian Miombo Forests 

      Björk, Sara Maria; Anfinsen, Stian Normann; Næsset, Erik; Gobakken, Terje; Zahabu, Eliakimu (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-03)
      This study derives regression models for aboveground biomass (AGB) estimation in miombo woodlands of Tanzania that utilize the high availability and low cost of Sentinel-1 data. The limited forest canopy penetration of C-band SAR sensors along with the sparseness of available ground truth restricts their usefulness in traditional AGB regression models. Therefore, we propose to use AGB predictions ...
    • Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet-ocean model using FISOC (v1.1) - ROMSIceShelf (v1.0) - Elmer/Ice (v9.0) 

      Zhao, Chen; Gladstone, Rupert; Galton-Fenzi, Benjamin Keith; Gwyther, David; Hattermann, Tore (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-15)
      Changes in ocean-driven basal melting have a key influence on the stability of ice shelves, the mass loss from the ice sheet, ocean circulation, and global sea level rise. Coupled ice sheet–ocean models play a critical role in understanding future ice sheet evolution and examining the processes governing ice sheet responses to basal melting. However, as a new approach, coupled ice sheet–ocean systems ...
    • Ensemble Conformalized Quantile Regression for Probabilistic Time Series Forecasting 

      Jensen, Vilde; Bianchi, Filippo Maria; Anfinsen, Stian Normann (Journal article; Tidsskriftartikkel, 2022-11-04)
      This article presents a novel probabilistic forecasting method called ensemble conformalized quantile regression (EnCQR). EnCQR constructs distribution-free and approximately marginally valid prediction intervals (PIs), which are suitable for nonstationary and heteroscedastic time series data. EnCQR can be applied on top of a generic forecasting model, including deep learning architectures. EnCQR ...
    • Remote sensing image regression for heterogeneous change detection 

      Luppino, Luigi Tommaso; Bianchi, Filippo Maria; Moser, Gabriele; Anfinsen, Stian Normann (Conference object; Konferansebidrag, 2018-11-01)
      Change detection in heterogeneous multitemporal satellite images is an emerging topic in remote sensing. In this paper we propose a framework, based on image regression, to perform change detection in heterogeneous multitemporal satellite images, which has become a main topic in remote sensing. Our method learns a transformation to map the first image to the domain of the other image, and vice versa. ...
    • Automatic Detection of Low-Backscatter Targets in the Arctic Using Wide Swath Sentinel-1 Imagery 

      Cristea, Anca; Johansson, Malin; Doulgeris, Anthony Paul; Brekke, Camilla (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-12)
      Low backscatter signatures in synthetic aperture radar (SAR) imagery are characteristic to surfaces that are highly smooth and specular reflective of microwave radiation. In the Arctic, these typically represent newly formed sea ice, oil spills, and localized weather phenomena such as low wind or rain cells. The operational monitoring of low backscatter targets can benefit from a stronger integration ...
    • Mission Performance Trade-offs of Battery-powered sUAS 

      Hovenburg, Anthony Reinier; Johansen, Tor Arne; Storvold, Rune (Chapter; Bokkapittel, 2017-07-27)
      A sensitivity analysis is presented on the influence of the weight, altitude and speed of battery-powered sUAS on the resulting stall speed, endurance and range. To aid in the determination of the aircraft performance prior to flight, a method is being brought forth that quantifies the impact of these mission parameters. As a case study the P31015 sUAS is used. The P31015 is a concept model of a ...
    • Uncertainty-Aware Deep Ensembles for Reliable and Explainable Predictions of Clinical Time Series 

      Wickstrøm, Kristoffer Knutsen; Mikalsen, Karl Øyvind; Kampffmeyer, Michael; Revhaug, Arthur; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-07)
      Deep learning-based support systems have demonstrated encouraging results in numerous clinical applications involving the processing of time series data. While such systems often are very accurate, they have no inherent mechanism for explaining what influenced the predictions, which is critical for clinical tasks. However, existing explainability techniques lack an important component for trustworthy ...
    • Multifocus microscopy with optically sectioned axial superresolution 

      Ströhl, Florian; Hansen, Daniel Henry; Nager Grifo, Mireia; Birgisdottir, Åsa Birna (Journal article; Tidsskriftartikkel, 2022)
      Multifocus microscopy enables recording of entire volumes in a single camera exposure. In dense samples, multifocus microscopy is severely hampered by background haze. Here, we introduce a scalable multifocus method that incorporates optical sectioning and offers axial superresolution capabilities. In our method, a dithered oblique light-sheet scans the sample volume during a single exposure, while ...
    • A year-round satellite sea-ice thickness record from CryoSat-2 

      Landy, Jack Christopher; Dawson, Geoffrey; Tsamados, Michel; Bushuk, Mitchell; Stroeve, Julienne C.; Howell, Stephen; Krumpen, Thomas; Babb, David G.; Komarov, Alexander S.; Heorton, Harold; Belter, H. Jakob; Aksenov, Yevgeny (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-14)
      Arctic sea ice is diminishing with climate warming at a rate unmatched for at least 1,000 years. As the receding ice pack raises commercial interest in the Arctic, it has become more variable and mobile, which increases safety risks to maritime users. Satellite observations of sea-ice thickness are currently unavailable during the crucial melt period from May to September, when they would be most ...
    • RS-HeRR: a rough set-based Hebbian rule reduction neuro-fuzzy system 

      Liu, Feng; Sekh, Arif Ahmed; Quek, Chai; Ng, Geok See; Prasad, Dilip K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-01)
      Interpretabilty is one of the desired characteristics in various classification task. Rule-based system and fuzzy logic can be used for interpretation in classification. The main drawback of rule-based system is that it may contain large complex rules for classification and sometimes it becomes very difficult in interpretation. Rule reduction is also difficult for various reasons. Removing important ...
    • Oscillations:Linear theory and applications in AFM 

      Olukan, Tuza Adeyemi; Santos, Sergio; Elsherbiny, Lamia; Chiesa, Matteo (Research report; Forskningsrapport, 2022)
      The theory of oscillations can be studied from a mathematical point of view in terms of differential equations. The differential equation is written and then the solution or solutions worked out and mathematically analysed. Provided physical, economic, social, or other phenomena can be modelled in terms of equivalent differential equations, the solutions and results are applicable to all phenomena ...
    • Multifocus microscopy with optical sectioning and high axial resolution 

      Ströhl, Florian; Hansen, Daniel Henry; Nàger, Mireia; Birgisdottir, Åsa birna (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
      Multifocus microscopy enables recording of entire volumes in a single camera 11 exposure. In dense samples, multifocus microscopy is severely hampered by background haze. 12 Here, we introduce a scalable multifocus method that incorporates optical sectioning and offers 13 improved axial resolution capabilities. In our method, a dithered oblique light-sheet scans the 14 sample volume during a ...