Browsing Artikler, rapporter og annet (datateknologi og beregningsorienterte ingeniørfag) by Title
Now showing items 5675 of 91

Railway transition curves: A review of the stateoftheart and future research
(Journal article; Tidsskriftartikkel; Peer reviewed, 20200518)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 ... 
Recent trends in operation modal analysis techniques and its application on a steel truss bridge
(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
(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; Chapter; Bokkapittel, 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. 
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 highpressure difference. The shock tube is comprised of two sections known as driver and driven sections. These two sections are interacted with the highspeed 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
(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
(Peer reviewed, 20150907)The paper deals with the Neumann spectral problem for a singularly perturbed secondorder 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
(Journal article; Peer reviewed, 20190613)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. 
Some inequalities for Cesàro means of double VilenkinFourier series
(Journal article; Peer reviewed; Tidsskriftartikkel, 20181219)In this paper, we state and prove some new inequalities related to the rate of Lp approximation by Cesàro means of the quadratic partial sums of double Vilenkin–Fourier series of functions from Lp. 
Some inequalities related to strong convergence of Riesz logarithmic means
(Journal article; Tidsskriftartikkel; Peer reviewed, 20200323)In this paper we derive a new strong convergence theorem of Riesz logarithmic means of the onedimensional Vilenkin–Fourier (Walsh–Fourier) series. The corresponding inequality is pointed out and it is also proved that the inequality is in a sense sharp, at least for the case with Walsh–Fourier series. 
Some new estimates of the ‘Jensen gap’
(Peer reviewed, 20160201) 
Some new Fourier inequalities for unbounded orthogonal systems in LorentzZygmund spaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 20200320)In this paper we prove some essential complements of the paper (J. Inequal. Appl. 2019:171, 2019) on the same theme. We prove some new Fourier inequalities in the case of the Lorentz–Zygmund function spaces L q,r (logL ) α Lq,r(logL)α involved and in the case with an unbounded orthonormal system. More exactly, in this paper we prove and discuss some new Fourier inequalities of this type for ... 
Some new Hardytype inequalities for RiemannLiouville fractional qintegral operator
(Peer reviewed, 20150924)We consider the qanalog of the RiemannLiouville fractional qintegral operator of order n∈Nn∈N. Some new Hardytype inequalities for this operator are proved and discussed. 
Some new Hardytype inequalities in qanalysis
(Peer reviewed, 201609)We derive necessary and sufficient conditions (of MuckenhouptBradley type) for the validity of q analogs of (r, p) weighted Hardytype inequalities for all possible positive values of the parameters r and p . We also point out some possibilities to further develop the theory of Hardytype inequalities in this new direction.