Recent additions

  • Assessment of Polarimetric Variability by Distance Geometry for Enhanced Classification of Oil Slicks Using SAR 

    Marinoni, Andrea; Espeseth, Martine; Gamba, Paolo; Brekke, Camilla; Eltoft, Torbjørn (Peer reviewed; Chapter; Bokkapittel, 2019-11-14)
    In this paper, we introduce a new approach for investigation of polarimetric Synthetic Aperture Radar (PolSAR) images for oil slick analysis. Our method aims at enhancing discrimination of oil types by exploring the polarimetric features that can be produced by processing PolSAR scenes without dimensionality reduction. Taking advantage of a mixture description of the interactions among classes within ...
  • Lumikot: Fast auroral transients during the growth phase of substorms 

    McKay, Derek; Paavilainen, Tuula; Gustavsson, Björn Johan; Kvammen, Andreas; Partamies, Noora (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-25)
    The development of a magnetospheric substorm may be classified into three phases: growth, expansion, and recovery. The growth phase is important as it includes processes that lead to the expansion. In a recent growth-phase study, a type of fast discrete auroral transient phenomena -- referred to as Lumikot -- were observed. The Lumikot are several kilometers across and move in the high-energy ...
  • Relationship between the source size at the diffuser plane and the longitudinal spatial coherence function of the optical coherence microscopy system 

    Usmani, Kashif; Ahmad, Azeem; Joshi, Rakesh; Dubey, Vishesh Kumar; Butola, Ankit; Mehta, Dalip Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-25)
    Coherence properties of light sources are indispensable for optical coherence microscopy/tomography as they greatly influence the signal-to-noise ratio, axial resolution, and penetration depth of the system. In the present paper, we report the investigation of longitudinal spatial coherence properties of a pseudothermal light source (PTS) as a function of the laser spot size at the rotating diffuser ...
  • Thickness-Dependent Resonant Raman and E' Photoluminescence Spectra of Indium Selenide and Indium Selenide/Graphene Heterostructures 

    Tamalampudi, Srinivasa Reddy; Sankar, Raman; Apostoleris, Harry; Almahri, Mariam Ali; Alfakes, Boulos; Al-Hagri, Abdulrahman; Li, Ru; Gougam, Adel; Almansouri, Ibraheem; Chiesa, Matteo; Lu, Jin-You (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-28)
    Atomically thin, two-dimensional (2D) indium selenide (InSe) has attracted considerable attention because of the dependence of its bandgap on sample thickness, making it suitable for small-scale optoelectronic device applications. In this work, by the use of Raman spectroscopy with three different laser wavelengths, including 488, 532, and 633 nm, representing resonant, near-resonant, and conventional ...
  • Hybrid graphene metasurface for near-infrared absorbers 

    Mahfuzur Rahman, MD; Raza, Aikifa; Younes, Hammad; Alghaferi, Amal; Chiesa, Matteo; Lu, Jin-You (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-19)
    We experimentally demonstrated an amorphous graphene-based metasurface yielding near-infrared super absorber characteristic. The structure is obtained by alternatively combining magnetron-sputtering deposition and graphene transfer coating fabrication techniques. The thickness constraint of the physical vapor–deposited amorphous metallic layer is unlocked and as a result, the as-fabricated graphene-based ...
  • Comparative net energy analysis of renewable electricity and carbon capture and storage 

    Sgouridis, Sgouris; Carbajales-Dale, Michael; Csala, Denes; Chiesa, Matteo; Bardi, Ugo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-08)
    Carbon capture and storage (CCS) for fossil-fuel power plants is perceived as a critical technology for climate mitigation. Nevertheless, limited installed capacity to date raises concerns about the ability of CCS to scale sufficiently. Conversely, scalable renewable electricity installations—solar and wind—are already deployed at scale and have demonstrated a rapid expansion potential. Here we show ...
  • Evaluation of Six Atmospheric Reanalyses over Arctic Sea Ice from Winter to Early Summer 

    Graham, Robert; Cohen, Lana; Ritzhaupt, Nicole; Segger, Benjamin; Graversen, Rune; Rinke, Anette; Walden, Von P.; Granskog, Mats; Hudson, Stephen (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-19)
    This study evaluates the performance of six atmospheric reanalyses (ERA-Interim, ERA5, JRA-55, CFSv2, MERRA-2, and ASRv2) over Arctic sea ice from winter to early summer. The reanalyses are evaluated using observations from the Norwegian Young Sea Ice campaign (N-ICE2015), a 5-month ice drift in pack ice north of Svalbard. N-ICE2015 observations include surface meteorology, vertical profiles from ...
  • High-Throughput Total Internal Reflection Fluorescence and Direct Stochastic Optical Reconstruction Microscopy Using a Photonic Chip 

    Coucheron, David Andre; Helle, Øystein Ivar; Øie, Cristina Ionica; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-16)
    Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced contrast due to optical sectioning. The conventional approach is to use high numerical aperture microscope TIRF objectives for both excitation and collection, severely limiting the field of view and throughput. We present a novel approach to generating ...
  • On the Role of the Atmospheric Energy Transport in 2xCO2-Induced Polar Amplification in CESM1 

    Graversen, Rune; Langen, Peter L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-12)
    A doubling of the atmospheric CO<sub>2</sub> content leads to global warming that is amplified in the polar regions. The CO<sub>2</sub> forcing also leads to a change of the atmospheric energy transport. This transport change affects the local warming induced by the CO<sub>2</sub> forcing. Using the Community Earth System Model (CESM), the direct response to the transport change is investigated. ...
  • Patch Size Evolution During Pulsating Aurora 

    Partamies, Noora; Bolmgren, Karl; Heino, Erkka; Ivchenko, Nickolay; Borovsky, Joseph E.; Sundberg, Hanna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-30)
    We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1–2 hr. An automatic routine has been developed to detect patches in the all‐sky camera images. ...
  • Observation of mesospheric dust and ionospheric conditions during the G-chaser rocket campaign 

    Trollvik, Henriette Marie Tveitnes; Gunnarsdottir, Tinna; Mann, Ingrid; Olsen, Sveinung viggo; Restad, Erlend; Antonsen, Tarjei; Fredriksen, Åshild; Eilertsen, Yngve; Havnes, Ole; Hansen, Rikke; Floer, Markus; Bjørk, Arne; Bootby, Christopher; Latteck, Ralph (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10)
    SPID, Smoke Particle Impact Detector, is a Faraday cup detector designed to measure nanometer-sized meteoric smoke particles during rocket flights. We report measurements made with SPID during the G-Chaser student rocket campaign 13 January 2019 and describe the design of the SPID instruments. Model calculations of dust trajectories within the detector result in an effective crosssection of 0.97 for ...
  • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1A/B 

    Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-17)
    Synthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The ...
  • On-Site Ribosome Remodeling by Locally Synthesized Ribosomal Proteins in Axons 

    Shigeoka, Toshiaki; Koppers, Max; Wong, Hovy Ho Wai; Lin, Julie Qiaojin; Cagnetta, Roberta; Dwivedy, Asha; de Freitas Nascimento, Janaina; van Tartwijk, Francesca W.; Ströhl, Florian; Cioni, Jean Michel; Schaeffer, Julia; Carrington, Mark; Kaminski, Clemens F.; Jung, Hosung; Harris, William A.; Holt, Christine E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-10)
    Ribosome assembly occurs mainly in the nucleolus, yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a sequence motif, ...
  • Partially spatially coherent digital holographic microscopy and machine learning for quantitative analysis of human spermatozoa under oxidative stress condition 

    Dubey, Vishesh Kumar; Popova, Daria; Ahmad, Azeem; Acharya, Ganesh; Basnet, Purusotam; Mehta, Dalip Singh; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-05)
    Semen quality assessed by sperm count and sperm cell characteristics such as morphology and motility, is considered to be the main determinant of men’s reproductive health. Therefore, sperm cell selection is vital in assisted reproductive technology (ART) used for the treatment of infertility. Conventional bright field optical microscopy is widely utilized for the imaging and selection of sperm cells ...
  • Noisy multi-label semi-supervised dimensionality reduction 

    Mikalsen, Karl Øyvind; Soguero-Ruiz, Cristina; Bianchi, Filippo Maria; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
    Noisy labeled data represent a rich source of information that often are easily accessible and cheap to obtain, but label noise might also have many negative consequences if not accounted for. How to fully utilize noisy labels has been studied extensively within the framework of standard supervised machine learning over a period of several decades. However, very little research has been conducted ...
  • Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2, and Sentinel-1A/B 

    Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel, 2020)
  • Uncertainty and interpretability in convolutional neural networks for semantic segmentation of colorectal polyps 

    Jenssen, Robert; Kampffmeyer, Michael C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-20)
    Colorectal polyps are known to be potential precursors to colorectal cancer, which is one of the leading causes of cancer-related deaths on a global scale. Early detection and prevention of colorectal cancer is primarily enabled through manual screenings, where the intestines of a patient is visually examined. Such a procedure can be challenging and exhausting for the person performing the screening. ...
  • Plasma fluctuations in the scrape-off layer and at the divertor target in Alcator C-Mod and their relationship to divertor collisionality and density shoulder formation 

    Kuang, AQ; LaBombard, Brian; Brunner, D; Garcia, Odd Erik; Kube, Ralph; Theodorsen, Audun (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-15)
    Experiments indicate that the formation of density shoulders in the far scrape-off layer (SOL) is associated with an increase in cross-field transport and the propagation of coherent structures of high density known as blobs. It has been suggested that far SOL divertor collisionality (Λ<sub>div</sub>) may be a controlling parameter in this physics, which could be challenging for heat flux mitigation ...
  • Super-condenser enables labelfree nanoscopy 

    Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Mela, Ioanna; Osterrieth, Johannes W.M; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-22)
    Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a <i>super-condenser</i> featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the ...
  • An Optimal Decision-Tree Design Strategy and Its Application to Sea Ice Classification from SAR Imagery 

    Lohse, Johannes; Doulgeris, Anthony Paul; Dierking, Wolfgang Fritz Otto (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-03)
    We introduce the fully automatic design of a numerically optimized decision-tree algorithm and demonstrate its application to sea ice classification from SAR data. In the decision tree, an initial multi-class classification problem is split up into a sequence of binary problems. Each branch of the tree separates one single class from all other remaining classes, using a class-specific selected feature ...

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