Institutt for datateknologi og beregningsorienterte ingeniørfag: Nye registreringer
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Stabilitet i 22kV distribusjonsnett
(Master thesis; Mastergradsoppgave, 2017-05-18)De senere årene har det vært en økning i utbygging av små produksjonsenheter i distribusjonsnettet. I dag benyttes distribusjonsnettet i hovedsak til å fordele kraft fra overliggende nett. En tilknytning av ny produksjon i slike nett vil medføre utfordringer for netteier når det gjelder spenningskvalitet og leveringssikkerhet og krever ofte oppgraderinger for å kunne opprettholde stabil og sikker ... -
Some new Hardy-type inequalities in q-analysis
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-09)We derive necessary and sufficient conditions (of Muckenhoupt-Bradley type) for the validity of q -analogs of (r, p) -weighted Hardy-type inequalities for all possible positive values of the parameters r and p . We also point out some possibilities to further develop the theory of Hardy-type inequalities in this new direction. -
A new discrete Hardy-type inequality with kernels and monotone functions
(Peer reviewed; Journal article; Tidsskriftartikkel, 2015-10-06)A new discrete Hardy-type 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. -
Some new Hardy-type inequalities for Riemann-Liouville fractional q-integral operator
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-09-24)We consider the q-analog of the Riemann-Liouville fractional q-integral operator of order n∈Nn∈N. Some new Hardy-type inequalities for this operator are proved and discussed. -
Time scale Hardy-type inequalities with ‘broken’ exponent p
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-01-16)In this paper, some new Hardy-type inequalities involving ?broken? exponents are derived on arbitrary time scales. Our approach uses both convexity and superquadracity arguments, and the results obtained generalize, complement and provide refinements of some known results in literature -
Asymptotics of a spectral-sieve problem
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-11-18)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. -
Osmosis for non-electrolyte solvents in permeable periodic porous media
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-08)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 ... -
Singularly perturbed spectral problems with Neumann boundary conditions
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-09-07)The paper deals with the Neumann spectral problem for a singularly perturbed second-order elliptic operator with bounded lower order terms. The main goal is to provide a refined description of the limit behaviour of the principal eigenvalue and eigenfunction. Using the logarithmic transformation, we reduce the studied problem to an additive eigenvalue problem for a singularly perturbed Hamilton–Jacobi ... -
Homogenization of random Navier–Stokes-type system for electrorheological fluid
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2015-11-19)The paper deals with homogenization of Navier–Stokes-type system describing electrorheological fluid with random characteristics. Under non-standard growth conditions we construct the homogenized model and prove the convergence result. The structure of the limit equations is also studied. -
A note on the maximal operators of Vilenkin-Nörlund means with non-increasing coefficients
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016)In [14] we investigated some Vilenkin—Nörlund means with non-increasing 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 weak-L1/(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 ... -
Boundedness and compactness of a class of Hardy type operators
(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. -
Some sharp inequalities for integral operators with homogeneous kernel
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-04-09)One goal of this paper is to show that a big number of inequalities for functions in Lp(R+), p ≥ 1, proved from time to time in journal publications are particular cases of some known general results for integral operators with homogeneous kernels including, in particular, the statements on sharp constants. Some new results are also included, e.g. the similar general equivalence result is proved and ... -
Some new estimates of the ‘Jensen gap’
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-02-01) -
Sharp Hp-Lp type inequalities of weighted maximal operators of Vilenkin-Nörlund means and its applications
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-01)We prove and discuss some new Hp-Lp type inequalities of weighted maximal operators of Vilenkin-Nörlund 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 Vilenkin-Nörlund means. As applications, both some well-known and new results are pointed out. -
Weighted Hardy type inequalities for supremum operators on the cones of monotone functions
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-09-28)The complete characterization of the weighted L<sup>p</sup>-L<sup>r</sup> inequalities of supremum operators on the cones of monotone functions for all 0 < p, r≤∞ is given. -
Fremtidens fleksible distribusjonsnett : fleksibel nettdrift, forbrukerfleksibilitet, plusskunder og forretningsmodeller
(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 ... -
Shock Tube. Detail overview of equipment and instruments in the shock tube experimental setup
(Book; Bok, 2015)The shock tube is a device in which a normal shock wave is produced by the interaction of fluids at significantly high-pressure difference. The shock tube is comprised of two sections known as driver and driven sections. These two sections are interacted with the high-speed valve or a bursting disc. When the interaction happens, a shock wave forms almost instantaneously and propagates into the driven ... -
Thermal Properties of SK One Component Polyurethane using Experiments and Multiphysics Simulations
(Conference object; Konferansebidrag, 2016-12-08)This study proposes to determine the thermal conductivity of SK One Component Polyurethane (SKOCP) developed by China Institute of Water Resources & Hydropower Research Beijing IWHR-KHL Co. Ltd. SKOCP provides excellent proof of aging and chemical resistance of this material. It is non-toxic, acts as a good anti-seepage, offers anti-abrasion and good anti-freezing performance. In addition, it has ... -
Study of Acoustics Properties of SK One Component Polyurethane and its Application in Arctic Marine Structures
(Conference object; Konferansebidrag, 2016-12-08)Marine noise reduction tends to be challenging and requires a comprehensive engineering approach. The soundproofing materials for marine noise reduction are usually exposed to high temperatures, potential fluid or oil spills, engine maintenance and a high airflow environment. This work looks into the acoustic proofing properties of a non-toxic material ‘SK One Component Polyurethane’ developed by ... -
Study of Ice Adhesion Behavior of SK One Component Polyurethane
(Conference object; Konferansebidrag, 2016-12)Ice adhesion causes many serious problems such as aircraft accidents, navigational issues on ships, and power loss on wind turbines. These challenges are mainly associated with the acute behavior of ice adhesion. The ice adheres when water seeps into the microscopic pores of the material substrate and freezes, thereby, forming an interlocking mechanism. Therefore, surface roughness has a significant ...