Browsing Artikler, rapporter og annet (datateknologi og beregningsorienterte ingeniørfag) by Title
Now showing items 120 of 60

Additive weighted Lp estimates of some classes of integral operators involving generalized Oinarov kernels
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017) 
Asymptotic Behaviour of Ground States for Mixtures of Ferromagnetic and Antiferromagnetic Interactions in a Dilute Regime
(Journal article; Peer reviewed, 20180430)We consider randomly distributed mixtures of bonds of ferromagnetic and antiferromagnetic type in a twodimensional square lattice with probability 1−p 1−p and p, respectively, according to an i.i.d. random variable. We study minimizers of the corresponding nearestneighbour spin energy on large domains in Z 2 Z2 . We prove that there exists p 0 p0 such that for p≤ p 0 p≤p0 such ... 
Asymptotics of a spectralsieve problem
(Peer reviewed, 20151118)In a bounded domain with a thin periodically punctured interface we study the limit behavior of the bottom of spectrum for a Steklov type spectral problem, the Steklov boundary condition being imposed on the perforation surface. For a certain range of parameters we construct the effective spectral problem and justify the convergence of eigenpairs. 
Boundedness and compactness of a class of Hardy type operators
(Journal article; Tidsskriftartikkel; Peer reviewed, 20161213)We establish characterizations of both boundedness and of compactness of a general class of fractional integral operators involving the RiemannLiouville, Hadamard, and ErdelyiKober operators. In particular, these results imply new results in the theory of Hardy type inequalities. As applications both new and wellknown results are pointed out. 
Design of water shock tube for testing shell materials
(Journal article; Tidsskriftartikkel; Peer reviewed, 20140415)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
(Journal article; Peer reviewed, 20181031)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 closein pulse pressure loading. The closein 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
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017)This paper focuses on alternative grid tariffs for household customers with roof top PVpanels ("prosumers"), and evaluates how alternative grid tariffs might affect the benefit from investing in a roof top PVpanel. The paper further shows how different orientations of the PVpanels can affect the benefits for the prosumers subjected to different grid tariffs (for example a power grid tariff), where ... 
Exact Asymptotic Expansion of Singular Solutions for the (2+1)D Protter Problem
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012) 
Fejér and HermiteHadamard Type Inequalities for NQuasiconvex Functions
(Journal article; Peer reviewed; Tidsskriftartikkel, 20171228)Some new extensions and re finements of Hermite – Hadamard and Fejer type inequalities for functions which are N quasiconvex are derived and discussed. 
Fremtidens fleksible distribusjonsnett : fleksibel nettdrift, forbrukerfleksibilitet, plusskunder og forretningsmodeller
(Research report; Forskningsrapport, 20160215)Denne rapporten er utarbeidet i WP1 og WP2 i prosjektet "Fleksibilitet i fremtidens smarte distribusjonsnett  FlexNett" (20152017). FlexNettprosjektet 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
(Journal article; Tidsskriftartikkel; Peer reviewed, 20181114)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 ... 
Hardytype inequalities in fractional hdiscrete calculus
(Journal article; Tidsskriftartikkel; Peer reviewed, 20180404)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>≤<! ≤ ></mo> <mi><i>p</i></mi> <mo><</mo> <mn>1</mn> ... 
Homogenization of biomechanical models for plant tissues
(Journal article; Peer reviewed; Tidsskriftartikkel, 2017)In this paper homogenization of a mathematical model for plant tissue biomechanics is presented. The microscopic model constitutes a strongly coupled system of reactiondiffusionconvection 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 nonisothermal immiscible incompressible twophase flow in porous media
(Journal article; Peer reviewed, 20180315)In this paper, we consider nonisothermal twophase 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 twophase flow equations, and an ... 
Homogenization of random Navier–Stokestype system for electrorheological fluid
(Peer reviewed, 20151119)The paper deals with homogenization of Navier–Stokestype system describing electrorheological fluid with random characteristics. Under nonstandard growth conditions we construct the homogenized model and prove the convergence result. The structure of the limit equations is also studied. 
Lagrangian and ALE Formulations For Soil Structure Coupling with Explosive Detonation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)Simulation of SoilStructure Interaction becomes more and more the focus of computational engineering in civil and mechanical engineering, where FEM (Finite element Methods) for soil and structural mechanics and Finite Volume for CFD (Computational Fluid Dynamics) are dominant. New advanced formulations have been developed for FSI (Fluid Structure Interaction) applications using ALE (Arbitrary ... 
Local Flexibility Market Design for Aggregators Providing Multiple Flexibility Services at Distribution Network Level
(Journal article; Tidsskriftartikkel; Peer reviewed, 20180402)This paper presents a general description of local flexibility markets as a marketbased management mechanism for aggregators. The high penetration of distributed energy resources introduces new flexibility services like prosumer or community selfbalancing, congestion management and timeofuse optimization. This work is focused on the flexibility framework to enable multiple participants to compete ... 
Matrix factorization of multivariate Bernstein polynomials
(Journal article; Peer reviewed; Tidsskriftartikkel, 2015)Ordinary univariate Bernstein polynomials can be represented in matrix form using factor matrices. In this paper we present the deﬁnition and basic properties of such factor matrices extended from the univariate case to the general case of arbitrary number of variables by using barycentric coordinates in the hypersimplices of respective dimension. The main results in the paper are related to the ... 
Multisource data collection for stateoftheart data analysis from groundproximate images in sea ice classification
(Peer reviewed; Bok; Konferansebidrag; Conference object; Book, 20170808)In modern data analysis it is imperative to use well maintained data sources with curated content. This publication gives an approach for research areas, where there is no such central facility. The specific area used here is sea ice classification from images. The publication is split into two parts. The first part describes the integration of discontinuous sources for different aspects of data ... 
A new discrete Hardytype inequality with kernels and monotone functions
(Peer reviewed, 20151006)A new discrete Hardytype inequality with kernels and monotone functions is proved for the case 1<q<p<∞1<q<p<∞. This result is discussed in a general framework and some applications related to Hölder’s summation method are pointed out.