Recent additions

  • On the boundedness of subsequences of Vilenkin-Fejér means on the martingale Hardy spaces 

    Persson, Lars Erik; Tephnadze, George; Tutberidze, Giorgi (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03)
    In this paper we characterize subsequences of Fejér means with respect to Vilenkin systems, which are bounded from the Hardy space <i>H<sub>p</sub></i> to the Lebesgue space <i>L<sub>p</sub></i>, for all 0 < p < 1/2. The result is in a sense sharp.
  • Existence and Uniqueness of Some Cauchy Type Problems in Fractional q-Difference Calculus 

    Shaimardan, S.; Persson, Lars Erik; Tokmagambetov, N.S. (Journal article; Tidsskriftartikkel, 2020)
    In this paper we derive a sufficient condition for the existence of a unique solution of a Cauchy type q-fractional problem (involving the fractional q-derivative of Riemann-Liouville type) for some nonlinear differential equations. The key technique is to first prove that this Cauchy type q-fractional problem is equivalent to a corresponding Volterra q-integral equation. Moreover, we define the ...
  • Utilizing Local Flexibility Resources to Mitigate Grid Challenges at Electric Vehicle Charging Stations 

    Ilieva, Iliana; Bremdal, Bernt Arild (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-12)
    Charging of electric vehicles (EVs) on a large scale can cause problems for the grid. Utilizing local flexibility resources, such as smart charging, stationary battery, vehicle-to-grid applications, and local generation can be an efficient way to contain the grid challenges and mitigate the need for grid reinforcement. Focusing on the INSPIRIA charging station located in Norway, this paper investigates ...
  • Flexibility-Enhancing Charging Station to Support the Integration of Electric Vehicles 

    Ilieva, Iliana; Bremdal, Bernt Arild (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)
    This paper discusses the Inspiria charging station facility in Norway, which enables various charging point operators to offer different charging systems for different purposes and needs. The charging station can be considered a specific case of a shared economy, as users share the same infrastructure and much of the same space. By utilizing new technology and the differences in charging needs in ...
  • Investigating the Polar Code’s function-based requirements for life-saving appliances and arrangements, and the performance of survival equipment in cold climate conditions – test of SOLAS approved desalting apparatus at low temperatures 

    Engtrø, Espen; Sæterdal, Ane (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-21)
    As the sea ice extent steadily decreases, the Arctic region is simultaneously experiencing extensive growth in commercial shipping activities, in areas which previously were considered inaccessible for most ships during large periods of the year, increasing the probability of accidents or incidents occurring. <i>The International Code for Ships Operating in Polar Waters (The Polar Code)</i> states ...
  • Flexibility-Enhancing Charging Station to Support the Integration of Electric Vehicles 

    Ilieva, Iliana; Bremdal, Bernt Arild (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)
    This paper discusses the Inspiria charging station facility in Norway, which enables various charging point operators to offer different charging systems for different purposes and needs. The charging station can be considered a specific case of a shared economy, as users share the same infrastructure and much of the same space. By utilizing new technology and the differences in charging needs in ...
  • A New Development of the Classical Single Ladder Problem via Converting the Ladder to a Staircase 

    Høibakk, Ralph; Lukkassen, Dag; Meidell, Annette; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-08)
    Our purpose is to shed some new light on problems arising from a study of the classical Single Ladder Problem (SLP). The basic idea is to convert the SLP to a corresponding Single Staircase Problem. The main result (Theorem 1) shows that this idea works fine and new results can be obtained by just calculating rational solutions of an algebraic equation. Some examples of such concrete calculations ...
  • Investigating the affordances of a flipped mathematics classroom from an activity theoretical perspective 

    Fredriksen, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-20)
    Flipped Classroom as a pedagogical framework has gained popularity at secondary and tertiary levels of mathematics education, but there is a lack of research based on a solid theoretical foundation. This article considers the flipped mathematics classroom from the perspective of affordances and cultural–historical activity theory. The empirical background is based on semi-structured interview data ...
  • Using Deep Learning Methods to Monitor Non-Observable States in a Building 

    Tangrand, Kristoffer; Bremdal, Bernt Arild (Peer reviewed; Conference object; Konferansebidrag, 2020-02-06)
    This paper presents results from ongoing research with a goal to use a combination of time series from non-intrusive ambient sensors and deep recurrent neural networks to predict room usage at a university campus. Training data was created by collecting measurements from ambient sensors measuring room CO2, humidity, temperature, light, motion and sound, while the ground-truth counts was created ...
  • Exploring Realistic Mathematics Education in a Flipped Classroom Context at the Tertiary Level 

    Fredriksen, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-01)
    Flipped classroom (FC) pedagogical frameworks have recently gained considerable popularity, especially at secondary school levels. However, there are rich opportunities to explore FC at tertiary levels, but progress on the area requires instructors’ attention to well-designed tasks for students’ collaborative learning. Realistic Mathematics Education (RME) provides a foundation for the development ...
  • User-Friendly MES Interfaces: Recommendations for an AI-Based Chatbot Assistance in Industry 4.0 Shop Floors 

    Mantravadi, Soujanya; Jansson, Andreas Dyrøy; Møller, Charles (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-04)
    The purpose of this paper is to study an Industry 4.0 scenario of ‘technical assistance’ and use manufacturing execution systems (MES) to address the need for easy information extraction on the shop floor. We identify specific requirements for a user-friendly MES interface to develop (and test) an approach for technical assistance and introduce a chatbot with a prediction system as an interface layer ...
  • Asymptotics of fundamental solutions for time fractional equations with convolution kernels 

    Kondratiev, Yuri; Piatnitski, Andrey; Zhizhina, Elena (Journal article; Peer reviewed, 2020-09-11)
    The paper deals with the large time asymptotic of the fundamental solution for a time fractional evolution equation with a convolution type operator. In this equation we use a Caputo time derivative of order α ∈ (0, 1), and assume that the convolution kernel of the spatial operator is symmetric, integrable and shows a super-exponential decay at infinity. Under these assumptions we describe the ...
  • Altering perceptions, visualizing sub-ground metal objects 

    Pedersen, Aleksander (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06)
    Smart phones and sensor technology represent a key part of everyday life and are being used in areas such as safety, training, healthcare and others. Utilizing an array of internal sensors and a metal detector requires an evaluation of the precision of the measurements and performance reviews. Metal detectors are versatile, with uses in healthcare as well as recreational, but a common issue often ...
  • Finite element application of ERBS extraction 

    Kravetc, Tatiana; Dalmo, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-24)
    In this paper we explore ERBS extraction in application to a heat conduction problem.Two types of basis functions are considered: B-spline and expo-rational B-spline (ERBS)combined with Bernstein polynomials. The first one is a global basis defined on a subdomain whose size is related to the spline degree, while the second one is a strictlylocal basis under the local geometry. While all the coefficients ...
  • Bruk av droner i nordområdene 

    Bakken, Trond; Johnsen, Stig Ole; Holmstrøm, Sture; Merz, Mariann; Transeth, Aksel Andreas; Grøtli, Esten Ingar; Risholm, Petter; Storvold, Rune (Research report; Forskningsrapport, 2020-05-13)
    Formålet med denne rapporten er å vise eksempler på bruk av fjernstyrte og autonome droner i petroleumssektoren og vise hvilke utviklingstrender innen droneteknologi som er viktige. Utfordringer og muligheter for bruk av droner i nordområdene er spesielt vektlagt. Teknologi for og anvendelser av flyvende droner, droner på havoverflaten og droner under vann er behandlet i denne rapporten. Rapporten ...
  • A field study of sensors for winter road assessment 

    Brustad, Tanita Fossli; Pedersen, Aleksander; Bang, Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-02)
    Winter road assessment is a research field with considerable progress over the last 10 years. Various sensors and methods have been tested and analysed, often in a laboratory setting, in order to come up with robust and valid assessment tools that can be used to warn the driver, road users in general, and maintenance personnel of critical conditions. In this paper we compare the field measurements ...
  • Local refinement of ERBS curves 

    Dalmo, Rune (Journal article; Peer reviewed; Chapter, 2013-12-31)
    Expo-rational B-splines (ERBS) provide a blending type construction where local functions at each knot are blended together by infinitely smooth basis functions. In this work we consider some specific ERBS curves that are approximations of parametric curves. We study local refinement to increase flexibility by inserting local control curves at points of interest on the ERBS curve. Inserting knots ...
  • Exploring benefits of using blending splines as transition curves 

    Brustad, Tanita Fossli; Dalmo, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-19)
    Track geometry is a fundamental subject in railway construction. With the demand for increased capacity in terms of load and speed, the need for suitable transitions between consecutive track sections is highly relevant. Properly constructed transition curves lead to improved travel comfort, increased safety, and reduced wear. The well known clothoid curve is widely used as a transition curve; ...
  • A study on hybrid sensor technology in winter road assessment 

    Pedersen, Aleksander; Brustad, Tanita Fossli (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-23)
    Road conditions during the winter months in Nordic countries can be highly unstable. Slippery roads combined with heavy haul traffic and ordinary road users can create dangerous, even lethal, situations if road maintenance is unsuccessful. Accidents and critical road conditions may lead to blocked roads, putting strain on a limited number of main roads in many regions, and may in the worst case ...
  • Hardy-type inequalities over balls in R^N for some bilinear and iterated operators 

    Jain, Pankaj; Kanjilal, Saikat; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
    Some new multidimensional Hardy-type inequalites are proved and discussed. The cases with bilinear and iterated operators are considered and some equivalence theorems are proved.

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