Browsing Artikler, rapporter og annet (datateknologi og beregningsorienterte ingeniørfag) by Title
Now showing items 1332 of 64

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; 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 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; Tidsskriftartikkel; Peer reviewed, 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; Konferansebidrag; Bok; 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. 
A NEW GENERALIZATION OF BOAS THEOREM FOR SOME LORENTZ SPACES Λq(ω)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018)Let Λq( ω ), q > 0, denote the Lorentz space equipped with the (quasi) norm [<i>MATHEMATICAL FORMULA</I>] for a function f on [0,1] and with ω positive and equipped with some additional growth properties. A generalization of Boas theorem in the form of a twosided inequality is obtained in the case of both general regular system [<i>MATHEMATICAL FORMULA</I>] and generalized Lorentz Λq( ω ) spaces 
A new look at classical inequalities involving Banach lattice norms
(Journal article; Tidsskriftartikkel; Peer reviewed, 20171208)Some classical inequalities are known also in a more general form of Banach lattice norms and/or in continuous forms (i.e., for ‘continuous’ many functions are involved instead of finite many as in the classical situation). The main aim of this paper is to initiate a more consequent study of classical inequalities in this more general frame. We already here contribute by discussing some results of ... 
A note on the maximal operators of VilenkinNörlund means with nonincreasing coefficients
(Peer reviewed, 2016)In [14] we investigated some Vilenkin—Nörlund means with nonincreasing coefficients. In particular, it was proved that under some special conditions the maximal operators of such summabily methods are bounded from the Hardy space H1/(1+α) to the space weakL1/(1+α), (0 < α ≦ 1). In this paper we construct a martingale in the space H1/(1+α), which satisfies the conditions considered in [14], and so ... 
Numerical simulation of the dynamic response in pulseloaded fibre–metallaminated plates
(Journal article; Tidsskriftartikkel; Peer reviewed, 20160727)This article presents a threedimensional constitutive model to replicate the dynamic response of blastloaded fibre–metal laminates made of 20240 aluminium alloy and woven composite (glass fibre–reinforced polypropylene). Simulation of the dynamic response is challenging when extreme localised loads are of concern and requires reliable material constitutive models as well as accurate modelling ... 
On geometric construction of some power means
(Journal article; Peer reviewed, 20181127)In the homogenization theory, there are many examples where the effective conductivities of composite structures are power means of the local conductivities. The main aim of this paper is to initiate research concerning geometric construction of some power means of three or more variables. We contribute by giving methods for the geometric construction of the harmonic mean $ P_{1} $ and the arithmetic ... 
On heat conduction in domains containing noncoaxial cylinders
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)We consider heat conduction in domains containing noncoaxial cylinders. In particular, we present some regularity results for the solution and consider criteria which ensure the single valueness of the corresponding complex potential. Examples are discussed. In addition, we present some classes of cases where the parameters describing the solution are rational. Alternative ways of calculating the ... 
On Some Power Means and Their Geometric Constructions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018)The main aim of this paper is to further develop the recently initiatedresearch concerning geometric construction of some power means wherethe variables are appearing as line segments. It will be demonstratedthat the arithmetic mean, the harmonic mean and the quadratic meancan be constructed for any number of variables and that all power meanswhere the number of variables are n = 2m, m 1 2 N for all ... 
Osmosis for nonelectrolyte solvents in permeable periodic porous media
(Peer reviewed, 201608)The paper gives a rigorous description, based on mathematical homogenization theory, for flows of solvents with not charged solute particles under osmotic pressure for periodic porous media permeable for solute particles. The effective Darcy type equations for the flow under osmotic pressure distributed within the porous media are derived. The effective Darcy law contains an additional flux term ... 
Periodic homogenization of nonlocal operators with a convolutiontype kernel
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)The paper deals with a homogenization problem for a nonlocal linear operator with a kernel of convolution type in a medium with a periodic structure. We consider the natural diﬀusive scaling of this operator and study the limit behavior of the rescaled operators as the scaling parameter tends to 0. More precisely we show that in the topology of resolvent convergence the family of rescaled operators ... 
Pointwise estimates for heat kernels of convolutiontype operators
(Journal article; Peer reviewed; Tidsskriftartikkel, 20180416)We study the large‐time behaviour of the fundamental solution of parabolic equations with an elliptic part being non‐local convolution‐type operator. We assume that this operator is a generator of a Markov jump process, and that its convolution kernel decays at least exponentially at infinity. The fundamental solution shows rather different asymptotic behaviour depending on whether  x  ≲ t , or t ... 
Potential type operators in PDEs and their applications
(Journal article; Peer reviewed; Tidsskriftartikkel, 201701)We prove the boundedness of Potential operator in weighted generalized Morrey space in terms of MatuszewskaOrlicz indices of weights and apply this result to the Hemholtz equation in ℝ<sup>3</sup> with a free term in such a space. We also give a short overview of some typical situations when Potential type operators arise when solving PDEs.