Now showing items 12-31 of 93

    • Economic evaluation of the Power grid tariff for households With solar Power installed 

      Sæle, Hanne; Bremdal, Bernt Arild (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      This paper focuses on alternative grid tariffs for household customers with roof top PV-panels ("prosumers"), and evaluates how alternative grid tariffs might affect the benefit from investing in a roof top PV-panel. The paper further shows how different orientations of the PV-panels can affect the benefits for the prosumers subjected to different grid tariffs (for example a power grid tariff), where ...
    • Embeddings of weighted generalized Morrey Spaces into Lebesgue Spaces on fractal sets 

      Samko, Natasha Gabatsuyevna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-19)
      We study embeddings of weighted local and consequently global generalized Morrey spaces defined on a quasi-metric measure set (X, d, μ) of general nature which may be unbounded, into Lebesgue spaces Ls(X), 1 ≤ s ≤ p < ∞. The main motivation for obtaining such an embedding is to have an embedding of non-separable Morrey space into a separable space. In the general setting of quasi-metric measure ...
    • Equivalent integral conditions related to bilinear Hardy-type inequalities 

      Kanjilal, Saikat; Persson, Lars Erik; Shambilova, Guldarya E (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Infinitely many, even scales of, equivalent conditions are derived to characterize the bilinear Hardy-type inequality under various ranges of parameters.
    • Exact Asymptotic Expansion of Singular Solutions for the (2+1)-D Protter Problem 

      Dechevski, Lubomir T (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
    • 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; ...
    • Exploring future C++ features within a geometric modeling context 

      Bratlie, Jostein; Dalmo, Rune (Peer reviewed; Conference object; Chapter, 2019-11)
      The development of the C++ programming language and its standard library has undergone a renaissance since the introduction of the C++11 standard, making the language more relevant than ever, through modern features, simplification and expansion of the standard library. Comparing past and future feature sets (C++17, C++20, ...) similar to comparing different programming languages. In this article ...
    • 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 ...
    • Fejér and Hermite-Hadamard Type Inequalities for N-Quasiconvex Functions 

      Abramovich, S; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-28)
      Some new extensions and re finements of Hermite – Hadamard and Fejer type inequalities for functions which are N -quasiconvex are derived and discussed.
    • 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 ...
    • 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 ...
    • Finite element method application of ERBS triangles 

      Kravetc, Tatiana (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11)
      In this paper we solve an eigenvalue problem on a circular membrane with fixed outer boundary by using a finite element method, where an element is represented as an expo-rational blending triangle. ERBS triangles combine properties of B-spline finite elements and standard polynomial triangular elements. The overlapping of local triangles allows us to provide a flexible handling of the surface while ...
    • The FlexNett Simulator 

      Bremdal, Bernt Arild; Tangrand, Kristoffer (Journal article; Peer reviewed, 2019)
      This paper documents research conducted in the Norwegian FLEXNETT project.<br>It describes a new tool that was developed to study the future impact of prosumers with PV panels on the grid in Norway and the potential energy flexibility that lies with residential prosumers. Systematic use of energy flexibility can be an important instrument for managing peak loads and voltage problems in weak power ...
    • Fremtidens fleksible distribusjonsnett : fleksibel nettdrift, forbrukerfleksibilitet, plusskunder og forretningsmodeller 

      Sæle, Hanne; Bremdal, Bernt Arild; Tøndel, Inger Anne; Istad, Maren Kristine; Foosnæs, Jan Andor; Nordbø, Per Erik; Kirkeby, Henrik; Høverstad, Boye Annfelt; Mathisen, Geir (Research report; Forskningsrapport, 2016-02-15)
      Denne rapporten er utarbeidet i WP1 og WP2 i prosjektet "Fleksibilitet i fremtidens smarte distribusjonsnett - FlexNett" (2015-2017). FlexNett-prosjektet har som målsetting å bidra til økt fleksibilitet i fremtidens smarte distribusjonsnett gjennom å demonstrere og verifisere tekniske og markedsmessige løsninger for fleksibilitet på ulike nivå i nettet til nytte for ulike aktører. <br> Målsettingen ...
    • Geometric Construction of Some Lehmer Means 

      Høibakk, Ralph; Lukkassen, Dag; Meidell, Annette; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-14)
      The main aim of this paper is to contribute to the recently initiated research concerning geometric constructions of means, where the variables are appearing as line segments. The present study shows that all Lehmer means of two variables for integer power k and for k = m 2 , where m is an integer, can be geometrically constructed, that Lehmer means for power k = 0,1 and 2 can be geometrically ...
    • Hardy-type inequalities in fractional h-discrete calculus 

      Persson, Lars Erik; Oinarov, Ryskul; Shaimardan, Serikbol (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-04)
      The first power weighted version of Hardy’s inequality can be rewritten as [<i>mathematical formula</i>] where the constant <i>C</i> =[<i>p</i> / <i>p</i> - <i><b>a</b></i> - 1]<sup><i>p</i></sup> is sharp. This inequality holds in the reversed direction when<math xmlns="http://www.w3.org/1998/Math/MathML"> <mn>0</mn> <mo>&#x2264;<!-- ≤ --></mo> <mi><i>p</i></mi> <mo>&lt;</mo> <mn>1</mn> ...
    • 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.
    • Homogenization of biased convolution type operators 

      Piatnitski, Andrey; Zhizhina, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-07)
      This paper deals with homogenization of parabolic problems for integral convolution type operators with a non-symmetric jump kernel in a periodic elliptic medium. It is shown that the homogenization result holds in moving coordinates. We determine the corresponding effective velocity and prove that the limit operator is a second order parabolic operator with constant coefficients. We also consider ...
    • Homogenization of biomechanical models for plant tissues 

      Piatnitski, Andrey; Ptashnyk, Mariya (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      In this paper homogenization of a mathematical model for plant tissue biomechanics is presented. The microscopic model constitutes a strongly coupled system of reaction-diffusion-convection equations for chemical processes in plant cells, the equations of poroelasticity for elastic deformations of plant cell walls and middle lamella, and Stokes equations for fluid flow inside the cells. The chemical ...
    • Homogenization of Levy-type operators with oscillating coefficients 

      Kassmann, Moritz; Piatnitski, Andrey; Zhizhina, Elena (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-05)
      The paper deals with homogenization of Lévy-type operators with rapidly oscillating coefficients. We consider cases of periodic and random statistically homogeneous micro-structures and show that in the limit we obtain a Lévy-operator. In the periodic case we study both symmetric and non-symmetric kernels whereas in the random case we only investigate symmetric kernels. We also address a nonlinear ...
    • Homogenization of nonisothermal immiscible incompressible two-phase flow in porous media 

      Amaziane, Brahim; Jurak, Murat; Pankratov, Leonid; Piatnitski, Andrey (Journal article; Peer reviewed, 2018-03-15)
      In this paper, we consider nonisothermal two-phase flows through heterogeneous porous media with periodic microstructure. Examples of such models appear in gas migration through engineered and geological barriers for a deep repository for radioactive waste, thermally enhanced oil recovery and geothermal systems. The mathematical model is given by a coupled system of two-phase flow equations, and an ...