Now showing items 7-26 of 91

    • Blending functions based on trigonometric and polynomial approximations of the Fabius function 

      Olofsen, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Most simple blending functions are polynomials, while more advanced blending functions are, for example, rational or expo-rational fractions. The Fabius function has the required properties of a blending function, but is a nowhere analytic function and cannot be calculated exactly everywhere on the required domain. We present a new set of trigonometric and polynomial blending functions with the shape ...
    • Boundedness and compactness of a class of Hardy type operators 

      Abylayeva, AAkbota M; Oinarov, Ryskul; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-13)
      We establish characterizations of both boundedness and of compactness of a general class of fractional integral operators involving the Riemann-Liouville, Hadamard, and Erdelyi-Kober operators. In particular, these results imply new results in the theory of Hardy type inequalities. As applications both new and well-known results are pointed out.
    • 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 ...
    • Design of water shock tube for testing shell materials 

      Ji, Hongjuan; Mustafa, Mohamad; Khawaja, Hassan Abbas; Ewan, Bruce C.; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-04-15)
      This paper presents design considerations for a shock tube experimental rig used to investigate the dynamic failure mechanisms of shell geometries subjected to water shock impact loading. In such setup, it is desirable that the drive pressure used within the tube can provide a wide range of impulsive loads on the test structures and some flexibility can be achieved on the applied pulse durations. ...
    • Dynamic plastic response of beams subjected to localised pulse loads 

      Thil, Nicolas; Mehreganian, Navid; Moatamedi, Mojtaba; Louca, Luke A.; Soleiman Fallah, Arash (Journal article; Peer reviewed, 2018-10-31)
      Localised blast loads give rise to high gradients of overpressure detrimental to structural elements as beams and plates. This article presents an analytical study on the dynamic plastic response of beams made of a ductile metallic material due to close-in pulse pressure loading. The close-in pressure load is characterised by a spatially varying function constant over a central region and exponentially ...
    • 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 ...
    • 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.