Now showing items 2976-2995 of 4765

    • Oil spill emergency preparedness in the Russian Arctic : a study of the Murmansk region. 

      Ivanova, Maria (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The issue of oil spill emergency response in north-west Russia has become increasingly important following a substantial increase in maritime transport and major offshore developments in Russian waters. This study is an initial effort to outline the public and private agencies and organizations involved in handling oil spills in the Murmansk region and the structure of the oil spill emergency response ...
    • Oil Spill Preparedness and Response in the Arctic. The effect of low temperature on oil spill response operations in the Arctic with respect to overall equipment effectiveness 

      Rolandsen, Markus Helfjord (Master thesis; Mastergradsoppgave, 2018-06-02)
      Effectiveness is an important term in oil spill response operations. Literature often relate to the level of effectiveness connected to either mechanical containment and recovery, in-situ burning or chemical dispersant application. The term effectiveness in oil spill response operations can be related to existing theory and the perspective of Overall Equipment Effectiveness (OEE). The perspective ...
    • Oil-Spill-Response-Oriented Information Products Derived From a Rapid-Repeat Time Series of SAR Images 

      Espeseth, Martine; Jones, Cathleen; Benjamin, Holt; Brekke, Camilla; Skrunes, Stine (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-19)
      New quantitative and semiautomated methods for analyzing oil slick evolution using a time series of L-band synthetic aperture radar (SAR) images with short repeat time are developed and explored. In this study, two methods that are complementary in terms of identifying temporal changes within an oil slick are presented. The two methods reflect two ways of evaluating the oil slicks. The first method ...
    • The Omni-Kernel Architecture: Scheduler Control Over All Resource Consumption in Multi-Core Computing Systems 

      Kvalnes, Åge Andre (Doctoral thesis; Doktorgradsavhandling, 2014-03-13)
      Clouds commonly employ virtual machine technology to leverage and efficiently utilize computational resources in data centers. The workloads encapsulated by virtual machines contend for the resources of their hosting machines and interference from resource sharing can cause unpredictable performance. Despite the use of virtual machine technology, the role of the operating system as an arbiter of ...
    • Omni-Kernel: An Operating System Architecture for Pervasive Monitoring and Scheduling 

      Kvalnes, Åge; Johansen, Dag; Renesse, Robbert van; Schneider, Fred B.; Valvåg, Steffen (Research report; Forskningsrapport, 2013)
      Clouds commonly employ virtual machine technology to leverage and efficiently utilize computational resources in data centers. The workloads encapsulated by virtual machines contend for the resources of their hosting machines, and interference from resource sharing can cause unpredictable performance. Despite the use of virtual machine technology, the role of the operating system as an arbiter of ...
    • On a class of integrable systems of Monge-Ampère type 

      Doubrov, Boris; Ferapontov, Eugene V.; Kruglikov, Boris; Novikov, Vladimir S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-08)
      We investigate a class of multi-dimensional two-component systems of Monge-Ampère type that can be viewed as generalisations of heavenly type equations appearing in a self-dual Ricci-flat geometry. Based on the Jordan-Kronecker theory of the skew-symmetric matrix pencils, a classification of normal forms of such systems is obtained. All two-component systems of Monge-Ampère type turn out to be ...
    • On a class of linearizable planar geodesic webs 

      Goldberg, Vladislav V.; Lychagin, Valentin V. (Working paper; Arbeidsnotat, 2008-12-13)
      We present a complete description of a class of linearizable planar geodesic webs which contain a parallelizable 3-subweb.
    • On Atmospheric Energy Transport by Waves 

      Heiskanen, Tuomas Ilkka Henrikki (Master thesis; Mastergradsoppgave, 2018-12-14)
      Recently a new method, based on a Fourier decomposition in the zonal direction, for studying the atmospheric energy transport contribution by planetary and cyclone scale waves has been proposed. Recent studies based on this show that planetary waves contribute more than cyclone scale waves to the atmospheric energy transport into the Arctic. The planetary waves contribute to the Arctic amplification ...
    • On Automated Classification of Sea Ice Types in SAR Imagery 

      Lohse, Johannes (Doctoral thesis; Doktorgradsavhandling, 2021-03-12)
      With the Arctic sea ice continuously decreasing in both extent and thickness, fast and robust production of reliable ice charts becomes more important to ensure the safety of Arctic operations. This thesis focuses on the development of automated algorithms for the mapping of sea ice from synthetic aperture radar (SAR) images. It presents a thorough background on the topics of sea ice observations ...
    • On C-class equations 

      Čap, Andreas; Doubrov, Boris; The, Dennis (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-29)
      The concept of a C-class of differential equations goes back to E. Cartan with the upshot that generic equations in a C-class can be solved without integration. While Cartan’s definition was in terms of differential invariants being first integrals, all results exhibiting C-classes that we are aware of are based on the fact that a canonical Cartan geometry associated to the equations in the class ...
    • On confinement and plasma acceleration from a small ECR plasma source 

      Sado, Pascal; Fredriksen, Åshild (Conference object; Konferansebidrag, 2019)
      <p>Electron Cyclotron Resonance (ECR) is a technique to create high density, low temperature plasmas that do not depend on a cathode, like arc discharges and are therefore easier to maintain and have a longer lifespan. The use of the Electron Cyclotron Resonance (ECR) for electron heating for Magnetic Nozzle (MN) thrusters have recently received increased interest, as they have been shown to provide ...
    • On Data-Independent Properties for Density-Based Dissimilarity Measures in Hybrid Clustering 

      Møllersen, Kajsa; Dhar, Subhra; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-12)
      Hybrid clustering combines partitional and hierarchical clustering for computational effectiveness and versatility in cluster shape. In such clustering, a dissimilarity measure plays a crucial role in the hierarchical merging. The dissimilarity measure has great impact on the final clustering, and data-independent properties are needed to choose the right dissimilarity measure for the problem ...
    • On derivatives of smooth functions represented in multiwavelet bases 

      Anderson, Joel; Harrison, Robert J.; Sekino, Hideo; Sundahl, Bryan; Beylkin, Gregory; Fann, George I.; Jensen, Stig Rune; Sagert, Irina (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-24)
      We construct high-order derivative operators for smooth functions represented via discontinuous multiwavelet bases. The need for such operators arises in order to avoid artifacts when computing functionals involving high-order derivatives of solutions of integral equations. Previously high-order derivatives had to be formed by repeated application of a first-derivative operator that, while uniquely ...
    • On Edge Cloud Service Provision with Distributed Home Servers 

      Khan, Muhammed Amin; Freitag, Felix (Conference object; Konferansebidrag, 2017-12-28)
      Edge computing has been proposed for new types of cloud services, which need computing infrastructure at the network edge. Driven by important use cases from the Internet of Things (IoT) domain, edge cloud computing has also a huge business potential. Edge computing devices are already operational in many industrial and consumer-oriented scenarios. A typical characteristic of these solutions is, ...
    • On elementary particles as representations of the Poincaré group 

      Martínez Marín, Pau (Master thesis; Mastergradsoppgave, 2023-08-14)
      This thesis is concerned with the definition of elementary particles as irreducible projective unitary representations of the Poincaré group. During the contents of this work, we will introduce the relevant prerequisites and results. Concerning differential geometry, we will discuss smooth manifolds, Lie groups and Lie algebras. About quantum mechanics, we will introduce Hilbert spaces and the basic ...
    • On evaluation metrics for medical applications of artificial intelligence 

      Hicks, Steven A.; Strumke, Inga; Thambawita, Vajira L B; Hammou, Malek; Riegler, Michael Alexander; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-08)
      Clinicians and software developers need to understand how proposed machine learning (ML) models could improve patient care. No single metric captures all the desirable properties of a model, which is why several metrics are typically reported to summarize a model’s performance. Unfortunately, these measures are not easily understandable by many clinicians. Moreover, comparison of models across studies ...
    • On hybrid classification using model assisted posterior estimates 

      Ghosh, Anil K.; Godtliebsen, Fred (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Traditional parametric and nonparametric classifiers used for statistical pattern recognition have their own strengths and limitations. While parametric methods assume some specific parametric models for density functions or posterior probabilities of competing classes, nonparametric methods are free from such assumptions. So, when these model assumptions are correct, parametric methods outperform ...
    • On Importance of Off-Diagonal Elements in the Polarimetric Covariance Matrix: A Sea Ice Application Perspective 

      Ratha, Debanshu; Doulgeris, Anthony Paul; Marinoni, Andrea; Eltoft, Torbjørn (Conference object; Konferansebidrag, 2023-06)
    • On integrability of certain rank 2 sub-Riemannian structures 

      Kruglikov, Boris; Vollmer, Andreas; Lukes-Gerakopoulos, Georgios (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-01)
      We discuss rank 2 sub-Riemannian structures on low-dimensional manifolds and prove that some of these structures in dimensions 6, 7 and 8 have a maximal amount of symmetry but no integrals polynomial in momenta of low degrees, except for those coming from the Killing vector fields and the Hamiltonian, thus indicating nonintegrability of the corresponding geodesic flows.
    • On Jordan classes for Vinberg's theta-groups 

      Santi, Andrea; Carnovale, Giovanna; Esposito, Francesco (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-23)
      V. L. Popov has recently introduced an analogue of Jordan classes (packets or decomposition classes) for the action of a θ-group (G0, V), showing that they are finitely-many, locally-closed, irreducible unions of G0-orbits of constant dimension partitioning V. We carry out a local study of their closures showing that Jordan classes are smooth and that their closure is a union of Jordan classes. We ...