Now showing items 381-400 of 1276

    • seMLP: Self-Evolving Multi-Layer Perceptron in Stock Trading Decision Making 

      Jun, S.W; Sekh, Arif Ahmed; Quek, Chai; Prasad, Dilip K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-24)
      There is a growing interest in automatic crafting of neural network architectures as opposed to expert tuning to fnd the best architecture. On the other hand, the problem of stock trading is considered one of the most dynamic systems that heavily depends on complex trends of the individual company. This paper proposes a novel self-evolving neural network system called self-evolving Multi-Layer ...
    • Revealing the Quasi-Periodic Crystallographic Structure of Self-Assembled SnTiS3 Misfit Compound 

      Rajput, Nitul S.; Baik, Hionsuck; Lu, Jin-You; Tamalampudi, Srinivasa Reddy; Sankar, Raman; Al Ghaferi, Amal; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-28)
      Chemical vapor transport synthesis of SnTiS3 yields a self-assembled heterostructure of two distinct constituent materials, the semiconductor SnS and the semimetal TiS2. The misfit layer compound, although thermodynamically stable, is structurally complex, and precise understanding of the structure is necessary for designing nanoengineered heterojunction compound devices or for theoretical studies. ...
    • Determination of the Azimuthal Extent of Coherent E-Region Scatter Using the ICEBEAR Linear Receiver Array 

      Huyghebaert, Devin Ray; McWilliams, Kathryn A.; Hussey, Glenn; Galeschuk, Draven; Chau, Jorge L.; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-07)
      The Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar (ICEBEAR) is a VHF coherent scatter radar that operates with a field-of-view centered on 58°N, 106°W and measures characteristics of ionospheric E-region plasma density irregularities. The initial operations of ICEBEAR utilized a wavelength-spaced linear receiving array to determine the angle of arrival of the ionospheric ...
    • Investigating the Ubiquitous Presence of Nanometric Water Films on Surfaces 

      Santos Hernandez, Sergio; Amadei, Carlo Alberto; Lai, Chia-Yun; Olukan, Tuza Adeyemi; Lu, Jin-You; Font, Josep; Barcons, Victor; Verdaguer, Albert; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-25)
      When we speak of nanometric water films on surfaces we are speaking about a truly ubiquitous phenomenon in nature. All surfaces exposed to ambient conditions are covered by a thin film of water that affects or mediates surface chemistry, general physical-chemical processes on surfaces, and even solid–solid interactions. We have investigated this phenomenon for over a decade by exploiting dynamic ...
    • Improved Arctic Sea Ice Freeboard Retrieval From Satellite Altimetry Using Optimized Sea Surface Decorrelation Scales 

      Landy, Jack Christopher; Bouffard, Jerome; Wilson, Chris; Rynders, Stefanie; Aksenov, Yevgeny; Tsamados, Michel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-18)
      A growing number of studies are concluding that the resilience of the Arctic sea ice cover in a warming climate is essentially controlled by its thickness. Satellite radar and laser altimeters have allowed us to routinely monitor sea ice thickness across most of the Arctic Ocean for several decades. However, a key uncertainty remaining in the sea ice thickness retrieval is the error on the sea surface ...
    • The computational complexity of understanding binary classifier decisions 

      Wäldchen, Stephan; Macdonald, Jan; Hauch, Sascha; Kutyniok, Gitta Astrid Hildegard (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-21)
      For a d-ary Boolean function Φ: {0, 1}<sup>d</sup> → {0, 1} and an assignment to its variables x = (x<sub>1</sub>, x<sub>2</sub>, . . . , x<sub>d</sub>) we consider the problem of finding those subsets of the variables that are sufficient to determine the function value with a given probability δ. This is motivated by the task of interpreting predictions of binary classifiers described as Boolean ...
    • Multimodal on-chip nanoscopy and quantitative phase imaging reveals the nanoscale morphology of liver sinusoidal endothelial cells 

      Butola, Ankit; Coucheron, David Andre; Szafranska, Karolina; Ahmad, Azeem; Mao, Hong; Tinguely, Jean-Claude; McCourt, Peter Anthony; Paramasivam, Senthilkumaran; Mehta, Dalip Singh; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-23)
      Visualization of three-dimensional (3D) morphological changes in the subcellular structures of a biological specimen is a major challenge in life science. Here, we present an integrated chip-based optical nanoscopy combined with quantitative phase microscopy (QPM) to obtain 3D morphology of liver sinusoidal endothelial cells (LSEC). LSEC have unique morphology with small nanopores (50-300 nm in ...
    • First Studies of Mesosphere and Lower Thermosphere Dynamics Using a Multistatic Specular Meteor Radar Network Over Southern Patagonia 

      Conte, J. F.; Chau, Jorge L.; Urco, Juan M.; Latteck, Ralph; Vierinen, Juha; Salvador, Jacobo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-18)
      This paper presents for the first time results on winds, tides, gradients of horizontal winds, and momentum fluxes at mesosphere and lower thermosphere altitudes over southern Patagonia, one of the most dynamically active regions in the world. For this purpose, measurements provided by SIMONe Argentina are investigated. SIMONe Argentina is a novel multistatic specular meteor radar system ...
    • Physics-based machine learning for subcellular segmentation in living cells 

      Sekh, Arif Ahmed; Opstad, Ida Sundvor; Godtliebsen, Gustav; Birgisdottir, Åsa Birna; Ahluwalia, Balpreet Singh; Agarwal, Krishna; Prasad, Dilip K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-15)
      Segmenting subcellular structures in living cells from fluorescence microscope images is a ground truth (GT)-deficient problem. The microscopes’ three-dimensional blurring function, finite optical resolution due to light diffraction, finite pixel resolution and the complex morphological manifestations of the structures all contribute to GT-hardness. Unsupervised segmentation approaches are quite ...
    • Multiobjective optimization of a hybrid wind/solar battery energy system in the Arctic 

      Nguyen, Tuan Thanh; Boström, Tobias Kristoffer (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-30)
      This paper presents an optimal design of a hybrid wind turbine/PV/battery energy system for a household application using a multiobjective optimization approach, namely, particle swarm optimization (PSO). The ultimately optimal component selection of the hybrid renewable energy system (HRES) is suggested by comprehensively investigating the effects of various factors on the cost-reliability relation, ...
    • Multiresolution Dynamic Mode Decomposition (mrDMD) of Elastic Waves for Damage Localisation in Piezoelectric Ceramic 

      Kalimullah, Nur MM; Shelke, Amit; Habib, Anowarul (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-27)
      The performance of piezoelectric sensors deteriorated due to the presence of defect, delamination, and corrosion that needed to be diagnosed for the effective implementation of the structural health monitoring (SHM) framework. A novel experimental approach based on Coulomb coupling is devised to visualise the interaction of ultrasonic waves with microscale defects in the Lead Zirconate Titanate ...
    • 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 ...
    • Electron Density Depletion Region Observed in the Polar Cap Ionosphere 

      Bjoland, Lindis Merete; Ogawa, Y.; Løvhaug, Unni Pia; Lorentzen, Dag Arne; Hatch, Spencer Mark; Oksavik, Kjellmar (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-16)
      This paper presents and discusses electron density depletion regions observed with the incoherent scatter EISCAT Svalbard Radar (ESR) located at 75.43°N geomagnetic latitude. The data include several decades of measurements, which make them suitable for studying statistical features and characteristics of the ionospheric parameters. Here we focus on the electron density depletions and their dependence ...
    • 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 ...
    • Sol-Gel Thin Film Processing for Integrated Waveguide Sensors 

      Alberti, Sebastian; Jagerska, Jana (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-05)
      Integrated opto-chemical sensors present great advantages in comparison to the current lab equipment. They bring portability, reduced costs, facilitate in-situ measurements, as well as largely reduced sample volumes. In this quest, standard processing protocols over established materials, such as silicon nitride, silicon, silicon dioxide, titanium oxide, and even a wide variety of polymers have so ...
    • Modelling the influence of meteoric smoke particles on artificial heating in the D-region 

      Myrvang, Margaretha; Baumann, Carsten; Mann, Ingrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-17)
      We investigate if the presence of meteoric smoke particles (MSPs) influences the electron temperature during artificial heating in the D-region. By transferring the energy of powerful high-frequency radio waves into thermal energy of electrons, artificial heating increases the electron temperature. Artificial heating depends on the height variation of electron density. The presence of MSPs can ...
    • Ocean Applications 

      Migliaccio, M.; Nunziata, F.; Marino, A.D.; Brekke, Camilla; Skrunes, Stine (Chapter; Bokkapittel, 2021-05-11)
      In this chapter, the most promising techniques to observe oil slicks and to detect metallic targets at sea using polarimetric synthetic aperture radar (SAR) data are reviewed and critically analysed. The detection of oil slicks in SAR data is made difficult not only by the presence of speckle but also by the presence of, e.g. biogenic films, low-wind areas, rain cells, currents, etc., which increase ...
    • Comparison between mirror Langmuir probe and gas-puff imaging measurements of intermittent fluctuations in the Alcator C-Mod scrape-off layer 

      Kube, Ralph; Theodorsen, Audun; Garcia, Odd Erik; Brunner, D; Labombard, B; Terry, James L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-30)
      Statistical properties of the scrape-off layer plasma fluctuations are studied in ohmically heated plasmas in the Alcator C-Mod tokamak. For the first time, plasma fluctuations as well as parameters that describe the fluctuations are compared across measurements from a mirror Langmuir probe (MLP) and from gas-puff imaging (GPI) that sample the same plasma discharge. This comparison is complemented ...
    • High spatial and temporal resolution L- and C-band Synthetic Aperture Radar data analysis from the yearlong MOSAiC expedition 

      Johansson, Malin; Singha, Suman; Spreen, Gunnar; Howell, Stephen; Sobue, Shin-ichi; Davidson, Malcolm (Conference object; Konferansebidrag, 2021-04)
      In the yearlong MOSAIC expedition (2019-2020) R/V Polarstern drifted with sea ice through the Arctic Ocean, with the goal to continually monitor changes in the coupled ocean-ice-atmosphere system throughout the seasons. A substantial amount of synthetic aperture radar (SAR) satellite images overlapping the campaign was collected. Here, we investigate the change in polarimetric features over sea ice ...
    • The Structure of Climate Variability Across Scales 

      Franzke, Christian L.E.; Barbosa, Susana; Blender, Richard; Fredriksen, Hege-Beate; Laepple, Thomas; Lambert, Fabrice; Nilsen, Tine; Rypdal, Kristoffer; Rypdal, Martin; Scotto, Manuel G; Vannitsem, Stephane; Watkins, Nicholas W.; Yang, Lichao; Yuan, Naiming (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-05)
      One of the most intriguing facets of the climate system is that it exhibits variability across all temporal and spatial scales; pronounced examples are temperature and precipitation. The structure of this variability, however, is not arbitrary. Over certain spatial and temporal ranges, it can be described by scaling relationships in the form of power laws in probability density distributions and ...