Now showing items 97-116 of 160

    • Quantitative analysis of accuracy of voidage computations in CFD-DEM Simulations 

      Khawaja, Hassan Abbas; Scott, Stuart A.; Virk, Muhammad Shakeel; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
    • Railway transition curves: A review of the state-of-the-art and future research 

      Brustad, Tanita Fossli; Dalmo, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-18)
      Transition curves are a useful tool for lateral alignment of railway segments. Their design is important to ensure safe and comfortable travel for passengers and cargo. Well designed transition curves can lead to reduced wear of tracks and vehicles, which is beneficial from a maintenance point of view. Extensive studies have been performed through decades to find transition curves that can replace ...
    • Real-Time Voxel-based 2D to 3D CT Visualisation Framework for Volumetric Capacity Estimation 

      Schuchter, Arthur; Petrarolo, Giovanni; Grießner, Dominik (Journal article; Tidsskriftartikkel, 2022)
      Over the decades medical analyses have grown in importance and practice possibilities. Digital operations like split-image procedures have become an integral part of modern medical practices and are still gaining momentum. Through the application of this technique medical computed tomography (CT) and magnetic resonance imaging scans (MRI) can be converted to three-dimensional bodies. This paper ...
    • Rearrangements and jensen type inequalities related to convexity, superquadracity, strong convexity and 1-quasiconvexity 

      Abramovich, Shoshana; Persson, Lars Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09)
      In this paper we derive and discuss some new theorems related to all rearrangements of a given set in Rn , denoted (x) and use the results to prove some new Jensen type inequalities for convex, superquadratic, strongly convex and 1 -quasiconvex functions.
    • Recent trends in operation modal analysis techniques and its application on a steel truss bridge 

      Singh, Harpal; Grip, Niklas (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      Aging of infrastructure causes many problems with great consequences, essentially economical. Operation modal analysis (OMA) is one of the most crucial techniques used for dynamic analysis of civil engineering structures (e.g. bridges, dams or tunnels). OMA uses various time and frequency domain methods to obtain the modal parameters. The analysis of OMA techniques can be used to detect, locate and ...
    • Recognizing Bedside Events Using Thermal and Ultrasonic Readings 

      Danielsen, Asbjørn; Tørresen, Jim (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-09)
      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 Bennett type inequalities 

      Oguntuase, James A; Persson, Lars-Erik; Adeleke, EO (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      In this paper we discuss, complement and improve some Bennett type inequalities. In particular,we prove a new refinement of a Bennett type inequality using super quadracity argument.
    • Refinements of some classical inequalities via superquadraticity 

      Nikolova, Ludmila; Persson, Lars-Erik; Varošanec, Sanja; Yimer, Markos Fisseha (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-21)
      Some new refined versions of the Jensen, Minkowski, and Hardy inequalities are stated and proved. In particular, these results both generalize and unify several results of this type. Some results are also new for the classical situation.
    • Refinements of some limit hardy-Type Inequalities via Superquadracity 

      Oguntuase, James A; Persson, Lars Erik; Fabelurin, Olanrewaju O; Adeagbo-Sheikh, Abdulaziz G (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-03)
      Refinements of some limit Hardy-type 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 

      Kravetc, Tatiana; Bang, Børre; Dalmo, Rune (Peer reviewed; Chapter; Bokkapittel, 2017-10-18)
      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 

      Lukkassen, Dag; Nguetseng, Gabriel; Nnang, Hubert; Wall, Peter (Journal article; Peer reviewed; Tidsskriftartikkel, 2009)
      We study reiterated homogenization of a nonlinear non-periodic 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 Σ-convergence. 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 

      Meidell, Annette; Olsen, Steve (Forskningsrapport; Research report, 2018-12)
      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 

      Kondratiev, Yuri; Molchanov, Stanislav; Piatnitski, Andrey; Zhizhina, Elena (Journal article; Peer reviewed; Tidsskriftartikkel, 2016-12-02)
      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 Vilenkin-Fourier series on martingale Hardy spaces 

      Blahota, Istvan; Nagy, Karoly; Persson, Lars Erik; Tephnadze, George (Journal article; Peer reviewed, 2018-09-20)
      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 Hp-Lp type inequalities of weighted maximal operators of Vilenkin-Nörlund means and its applications 

      Baramidze, Lasha; Persson, Lars Erik; Tephnadze, G; Wall, P (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.
    • Sharpness of some Hardy-type inequalities 

      Persson, Lars-Erik; Samko, Natasha Gabatsuyevna; Tephnadze, George (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-04)
      The current status concerning Hardy-type inequalities with sharp constants is presented and described in a unified convexity way. In particular, it is then natural to replace the Lebesgue measure dx with the Haar measure . There are also derived some new two-sided Hardy-type inequalities for monotone functions, where not only the two constants are sharp but also the involved function spaces are ...
    • Shock Tube. Detail overview of equipment and instruments in the shock tube experimental setup 

      Khawaja, Hassan Abbas; Kapaya, Juma; Moatamedi, Mojtaba (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 ...
    • Singularly perturbed spectral problems in a thin cylinder with fourier conditions on its bases 

      Piatnitski, Andrey; Rybalko, Volodymyr (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
      The paper deals with the bottom of the spectrum of a singularly perturbed second order elliptic operator defined in a thin cylinder and having locally periodic coefficients in the longitudinal direction. We impose a homogeneous Neumann boundary condition on the lateral surface of the cylinder and a generic homogeneous Fourier condition at its bases. We then show that the asymptotic behavior of the ...
    • Singularly perturbed spectral problems with Neumann boundary conditions 

      Piatnitski, Andrey; Rybalko, A; Rybalko, V (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 ...
    • Some Fourier inequalities for orthogonal systems in Lorentz–Zygmund spaces 

      Akishev, Gabdolla; Persson, Lars Erik; Seger, Andreas (Journal article; Peer reviewed, 2019-06-13)
      A number of classical inequalities and convergence results related to Fourier coefficients with respect to unbounded orthogonal systems are generalized and complemented. All results are given in the case of Lorentz–Zygmund spaces.