Browsing Artikler, rapporter og annet (datateknologi og beregningsorienterte ingeniørfag) by Title
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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; Peer reviewed; Tidsskriftartikkel, 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; Peer reviewed; Tidsskriftartikkel, 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; Peer reviewed; Tidsskriftartikkel, 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. 
Preevaluation and interactive editing of Bspline and GERBS curves and surfaces
(Peer reviewed; Conference object; Konferansebidrag; Bokkapittel; Chapter, 201712)Interactive computer based geometry editing is very useful for designers and artists. Our goal has been to develop useful tools for geometry editing in a way that increases the ability for creative design. When we interactively editing geometry, we want to see the change happening gradually and smoothly on the screen. Preevaluation is a tool for increasing the speed of the graphics when doing ... 
Predicting Bedside Falls using Current Context
(Peer reviewed; Bokkapittel; Chapter, 20180205)Each year about a third of the elderly aged 65 or older experience a fall. Many of these falls could be avoided if fall risk assessment and prevention tools where available in the daily living situation. Such tools would need to use the current context as input to predict an imminent fall. This paper presents an approach predicting imminent falls using data from a roofmounted infrared array combined ... 
Quantitative analysis of accuracy of voidage computations in CFDDEM Simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012) 
Recognizing Bedside Events Using Thermal and Ultrasonic Readings
(Journal article; Tidsskriftartikkel; Peer reviewed, 20170609)Falls in homes of the elderly, in residential care facilities and in hospitals commonly occur in close proximity to the bed. Most approaches for recognizing falls use cameras, which challenge privacy, or sensor devices attached to the bed or the body to recognize bedside events and bedside falls. We use data collected from a ceiling mounted 80 60 thermal array combined with an ultrasonic sensor ... 
Refinements of some limit hardyType Inequalities via Superquadracity
(Journal article; Tidsskriftartikkel; Peer reviewed, 20171103)Refinements of some limit Hardytype inequalities are derived and discussed using the concept of superquadracity. We also proved that all three constants appearing in the refined inequalities obtained are sharp. The natural turning point of our refined Hardy inequality is p=2 and for this case we have even equality. 
Regression analysis using a blending type spline construction
(Peer reviewed; Bokkapittel; Chapter, 20171018)Regression analysis allows us to track the dynamics of change in measured data and to investigate their properties. A sufficiently good model allows us to predict the behavior of dependent variables with higher accuracy, and to propose a more precise data generation hypothesis. By using polynomial approximation for big data sets with complex dependencies we get piecewise smooth functions. One way ... 
Reiterated homogenization of nonlinear monotone operators in a general deterministic setting
(Journal article; Peer reviewed; Tidsskriftartikkel, 2009)We study reiterated homogenization of a nonlinear nonperiodic elliptic differential operator in a general deterministic setting as opposed to the usual stochastic setting. Our approach proceeds from an appropriate notion of convergence termed reiterated Σconvergence. A general deterministic homogenization theorem is proved and several concrete examples are studied under various structure hypotheses ... 
Rescue of stranded persons. C18. Rescue of stranded passengers in the Arctic
(Forskningsrapport; Chapter, 201812)Since we (the authors) could not be a part of the whole SARex 3 exercise this year, we joined the expedition later than the rest of the participants. We gladly accepted the invitation from the Governor of Svalbard, Kjerstin Askholt, and her staff in Longyearbyen to join their service vessel, MS Polarsyssel, to meet The Norwegian Coast Guard’s vessel, (NOCGV) Svalbard, at the location where the ... 
Resolvent bounds for jump generators
(Journal article; Peer reviewed; Tidsskriftartikkel, 20161202)The paper deals with jump generators with a convolution kernel. Assuming that the kernel decays either exponentially or polynomially, we prove a number of lower and upper bounds for the resolvent of such operators. In particular we focus on sharp estimates of the resolvent kernel for small values of the spectral parameter. We consider two applications of these results. First we obtain pointwise ... 
A sharp boundedness result for restricted maximal operators of VilenkinFourier series on martingale Hardy spaces
(Journal article; Peer reviewed, 20180920)The restricted maximal operators of partial sums with respect to bounded Vilenkin systems are investigated. We derive the maximal subspace of positive numbers, for which this operator is bounded from the Hardy space H p to the Lebesgue space L p for all 0<p≤1 . We also prove that the result is sharp in a particular sense. 
Sharp HpLp type inequalities of weighted maximal operators of VilenkinNörlund means and its applications
(Peer reviewed, 20161001)We prove and discuss some new HpLp type inequalities of weighted maximal operators of VilenkinNörlund means with monotone coefficients. It is also proved that these inequalities are the best possible in a special sense. We also apply these results to prove strong summability for such VilenkinNörlund means. As applications, both some wellknown and new results are pointed out.