Recent additions

  • Urban land cover classification with missing data modalities using deep convolutional neural networks 

    Kampffmeyer, Michael C.; Salberg, Arnt Børre; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-14)
    Automatic urban land cover classification is a fundamental problem in remote sensing, e.g., for environmental monitoring. The problem is highly challenging, as classes generally have high interclass and low intraclass variances. Techniques to improve urban land cover classification performance in remote sensing include fusion of data from different sensors with different data modalities. However, ...
  • A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe 

    Havnes, Ove; Antonsen, Tarjei; Baumgarten, Gerd; Hartquist, Thomas W.; Biebricher, Alexander; Fredriksen, Åshild; Friedrich, Martin; Hedin, Jonas (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-15)
    <p>We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected ...
  • Weather situation during observed ship-icing events off the coast of Northern Norway and the Svalbard archipelago 

    Samuelsen, Eirik Mikal; Graversen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-19)
    Ship icing may lead the ship and crew in great jeopardy. Usually, predictions of such ice build-up are based on the modelling of the heat fluxes capable of freezing sea water originated from wave-ship interactions. This study, on the other hand, follows a different and more general approach by investigating the relationship between the weather situation and icing both using observed parameters from ...
  • Impact of assimilating sea ice concentration, sea ice thickness and snow depth in a coupled ocean-sea ice modelling system 

    Fritzner, Sindre Markus; Graversen, Rune; Christensen, Kai Håkon; Rostosky, Philip; Wang, Keguang (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
    The accuracy of the initial state is very important for the quality of a forecast, and data assimilation is crucial for obtaining the best-possible initial state. For many years, sea-ice concentration was the only parameter used for assimilation into numerical sea-ice models. Sea-ice concentration can easily be observed by satellites, and satellite observations provide a full Arctic coverage. During ...
  • SKIM, a Candidate Satellite Mission Exploring Global Ocean Currents and Waves 

    Ardhuin, Fabrice; Brandt, Peter; Gaultier, Lucile; Donlon, Craig James; Battaglia, Alessandro; Boy, Francois; Casal, Tania; Chapron, Bertrand; Collard, Fabrice; Cravatte, Sophie; Delouis, Jean-Marc; De Witte, Erik; Dibarboure, Gerald; Engen, Geir; Johnsen, Harald; Lique, Camille; López-Dekker, Paco; Maes, Christophe; Martin, Adrien; Marie, Louis; Menemenlis, Dimitris; Nouguier, Frederic; Peureux, Charles; Rampal, Pierre; Ressler, Gerhard; Rio, Marie-Helene; Rommen, Bjorn; Shutler, Jamie D.; Suess, Martin; Tsamados, Michel; Ubelmann, Clement; van Sebille, Erik; van den Oever, Martin; Stammer, Detlef (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-30)
    The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented direct measurements of strong currents, from boundary currents ...
  • Deep Reinforcement Learning for Query-Conditioned Video Summarization 

    Zhang, Yujia; Kampffmeyer, Michael C.; Zhao, Xiaoguang; Tan, Min (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-21)
    Query-conditioned video summarization requires to (1) find a diverse set of video shots/frames that are representative for the whole video, and that (2) the selected shots/frames are related to a given query. Thus it can be tailored to different user interests leading to a better personalized summary and differs from the generic video summarization which only focuses on video content. Our work targets ...
  • Sparse signal recovery in MIMO specular meteor radars with waveform diversity 

    Urco, Miguel; Chau, Jorge Luis; Weber, Tobias; Vierinen, Juha; Volz, Ryan (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-15)
    Since the 1950s, specular meteor radars (SMRs) have been used to study the mesosphere and lower thermosphere (MLT) dynamics. Atmospheric parameters derived from SMRs are highly dependent on the number of detected meteors and the accuracy of the meteors' locations. Recently, incoherent and coherent multiple-input-multiple-output (MIMO) radar approaches combined with waveform diversity have been ...
  • Investigation of exceptionally radar-dark regions on the lunar nearside 

    Tveito, Torbjørn; Vierinen, Juha; Serrano, Alessandra (Conference object; Konferansebidrag, 2019-08)
    Remote sensing of planetary surfaces is an effective method for gaining knowledge of the processes that shape the planetary bodies in our solar system. This is useful for uncovering the environment of the primordial solar system and to study the current state of the upper crusts of the other planets in our neighborhood. A recent 6-meter wavelength polarimetric radar map of the Moon [?] showed ...
  • The Thorpex polar low analysed with AROME-Arctic 

    Stoll, Patrick J.; Valkonen, Teresa M.; Graversen, Rune G.; Noer, Gunnar (Conference object; Konferansebidrag, 2019-04)
  • Observing Mesospheric Turbulence With Specular Meteor Radars: A Novel Method for Estimating Second-Order Statistics of Wind Velocity 

    Vierinen, Juha; Chau, Jorge L.; Charuvil, Harikrishnan; Urco, Miguel; Clahsen, Matthias; Avsarkisov, Victor; Marino, Raffaele; Volz, Ryan (Journal article; Peer reviewed, 2019-07)
    There are few observational techniques for measuring the distribution of kinetic energy within the mesosphere with a wide range of spatial and temporal scales. <br>This study describes a method for estimating the three‐dimensional mesospheric wind field correlation function from specular meteor trail echoes. Each radar echo provides a measurement of a one‐dimensional projection of the wind velocity ...
  • Novel specular meteor radar systems using coherent MIMO techniques to study the mesosphere and lower thermosphere 

    Chau, J. L.; Urco, Miguel; Vierinen, Juha; Volz, Ryan; Clahsen, Matthias; Pfeffer, Nico; Trautner, Jörg (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-05)
    Typical specular meteor radars (SMRs) use one transmitting antenna and at least a five-antenna interferometric configuration on reception to study the mesosphere and lower thermosphere (MLT) region. The interferometric configuration allows the measurement of the angle-of-arrival (AOA) of the detected meteor echoes, which in turn is needed to derive atmospheric parameters (e.g., mean winds, momentum ...
  • MOSIDEO/CIRFA Tank Experiments on Behavior and Detection of Oil in Ice 

    Petrich, Christian; O'Sadnick, Megan Eileen; Brekke, Camilla; Myrnes, Marianne; Maus, Sønke; Salomon, Martina Lan; Woelk, Sofie; Grydeland, Tom; Jenssen, Rolf-Ole Rydeng; Eicken, Hajo; Oggier, Marc; Ferro-Famil, Laurent; Harkati, Lekhmissi; Rebane, Ott; Reimer, Nils (Journal article; Tidsskriftartikkel; Peer reviewed; Conference object; Konferansebidrag, 2019-06)
    In the Arctic, presence of sea ice presents a challenge to safe and sustainable operations. To optimize planning and minimize impact of inadvertent oil spills, oil-in-ice experiments were performed at the HSVA Arctic Environmental Test Basin (AETB) from 14 March to 4 April 2017. Following an under-ice spill and simulated springtime warming, the microscopic movement and distribution of oil in the sea ...
  • A low-cost coastal buoy for ice and metocean measurements 

    Petrich, Christian; O'Sadnick, Megan Eileen; Kleven, Øystein; Sæther, Irina Vasiljeva (Journal article; Tidsskriftartikkel; Peer reviewed; Conference object; Konferansebidrag, 2019-06)
    Regionally, an ice cover in fjords of mainland Norway may form and break up repeatedly during winter. Due to relatively high water temperatures, the freeze-up process is expected to be related to freshwater-induced stratification in the fjords in conjunction with low air temperatues. In an attempt to identify the variability of water conditions in the fjords leading up to and during ice cover ...
  • Radar studies of ionospheric dusty plasma phenomena 

    Mann, Ingrid; Gunnarsdottir, Tinna; Häggström, Ingemar; Eren, Saliha; Tjulin, Anders; Myrvang, Margaretha; Rietveld, Mike T; Dalin, Peter; Jozwicki, Dorota; Trollvik, Henriette Marie Tveitnes (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-17)
    We discuss the influence of charged dust on radar observations in the Earth ionosphere. This region in the upper Earth atmosphere can be described as a partially ionized, low‐temperature plasma. Plasma parameters vary by orders of magnitude spatially and in time. Dust particles influence the charge balance, in some cases dusty plasma condition is met. The polar mesospheric echoes are an example of ...
  • Solar Flare Effects on 150-km Echoes Observed Over Jicamarca: WACCM-X Simulations 

    Pedatella, Nick; Chau, Jorge Luis; Vierinen, Juha; Qian, L; Reyes, Pablo; Kudeki, Erhan; Lehmacher, G; Oppenheim, Meers (Journal article; Tidsskriftartikkel; Preprint; Manuskript, 2019-09-11)
    Jicamarca Radio Observatory observations and Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension (WACCM‐X) simulations are used to investigate the effects of the September 7, 2005 X‐17 solar flare on 150‐km echoes, electron densities, and vertical plasma drifts. The solar flare produces a remarkably similar response in the observed 150‐km echoes and simulated electron ...
  • Characterization of color cross-talk of CCD detectors and its influence in multispectral quantitative phase imaging 

    Ahmad, Azeem; Kumar, Anand; Dubey, Vishesh Kumar; Butola, Ankit; Ahluwalia, Balpreet Singh; Mehta, Dalip Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
    Multi-spectral quantitative phase imaging (QPI) is an emerging imaging modality for wavelength dependent studies of several biological and industrial specimens. Simultaneous multi-spectral QPI is generally performed with color CCD cameras. Here, we present a new approach for accurately measuring the color crosstalk of 2D area detectors, without needing prior information about camera specifications. ...
  • 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 ...
  • 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 ...

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