Search results for "vite"
showing 10 items of 3463 documents
Convergent dynamics of optimal nonlinear damping control
2021
Following Demidovich's concept and definition of convergent systems, we analyze the optimal nonlinear damping control, recently proposed [1] for the second-order systems. Targeting the problem of output regulation, correspondingly tracking of $\mathcal{C}^1$-trajectories, it is shown that all solutions of the control system are globally uniformly asymptotically stable. The existence of the unique limit solution in the origin of the control error and its time derivative coordinates are shown in the sense of Demidovich's convergent dynamics. Explanative numerical examples are also provided along with analysis.
The onset of convection in a two-layered porous medium with anisotropic permeability
2019
We consider convection in a horizontal porous layer of uniform thickness which is heated from below and which is composed of two anisotropic sublayers with principal axes lying in the three coordinate directions. The aim is to determine criteria for the onset of convection by finding the critical Rayleigh number, wavenumber and roll orientation relative to the coordinate axes. The full set of nondimensional parameters has at least six members even when the sublayers are considered to be thermally isotropic, and therefore, we select some special cases in order to illuminate the type of qualitative behaviour which may be expected. One such case is where the anisotropic sublayers are identical…
Onset of Convection in an Inclined Anisotropic Porous Layer with Internal Heat Generation
2019
The onset of convection in an inclined porous layer which is heated internally by a uniform distribution of heat sources is considered. We investigate the combined effects of inclination, anisotropy and internal heat generation on the linear instability of the basic parallel flow. When the Rayleigh number is sufficiently large, instability occurs and a convective motion is set up. It turns out that the preferred motion at convection onset depends quite strongly on the anisotropy ratio, &xi
Delta- and Daugavet points in Banach spaces
2020
AbstractA Δ-pointxof a Banach space is a norm-one element that is arbitrarily close to convex combinations of elements in the unit ball that are almost at distance 2 fromx. If, in addition, every point in the unit ball is arbitrarily close to such convex combinations,xis a Daugavet point. A Banach spaceXhas the Daugavet property if and only if every norm-one element is a Daugavet point. We show that Δ- and Daugavet points are the same inL1-spaces, inL1-preduals, as well as in a big class of Müntz spaces. We also provide an example of a Banach space where all points on the unit sphere are Δ-points, but none of them are Daugavet points. We also study the property that the unit ball is the clo…
Daugavet- and delta-points in Banach spaces with unconditional bases
2020
We study the existence of Daugavet- and delta-points in the unit sphere of Banach spaces with a 1 1 -unconditional basis. A norm one element x x in a Banach space is a Daugavet-point (resp. delta-point) if every element in the unit ball (resp. x x itself) is in the closed convex hull of unit ball elements that are almost at distance 2 2 from x x . A Banach space has the Daugavet property (resp. diametral local diameter two property) if and only if every norm one element is a Daugavet-point (resp. delta-point). It is well-known that a Banach space with the Daugavet property does not have an unconditional basis. Similarly spaces with the diametral local diameter two property do not have an un…
Exploring Realistic Mathematics Education in a Flipped Classroom Context at the Tertiary Level
2020
AbstractFlipped classroom (FC) pedagogical frameworks have recently gained considerable popularity, especially at secondary school levels. However, there are rich opportunities to explore FC at tertiary levels, but progress on the area requires instructors’ attention to well-designed tasks for students’ collaborative learning. Realistic Mathematics Education (RME) provides a foundation for the development of such tasks. This article advances research on the role of task design in a FC context by considering how RME heuristics may be developed to include the out-of-class phase, where students prepare for in-class work with videos. This adaption, named flipped RME classroom design, is explore…
Robust coordinated control algorithm for multiple marine vessels with external disturbances
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/597195 Open Access The problem of coordinated control for multiple marine vessels in the presence of external disturbances is considered in this paper. A robust coordinated control algorithm is proposed for multiple marine vessels. The proposed robust coordinated control algorithm is divided into two parts. The first part develops an extended state observer to estimate the disturbances of marine vessels. The second part presents a robust coordinated control algorithm based on the output of the extended state observer. Furthermore, the rob…
Seernes opplevelse av nettbaserte gudstjenester
2021
Author's accepted manuscript. When the corona pandemic became a fact, many parishes within the Church of Norway chose to start video streaming of services as a substitute for gatherings in the church. This article is based on a survey done among viewers of these broadcasts and sheds light on how online worship services were received. The findings from the survey show that the viewers value recognizability and authenticity, but at the same time expect the service to be adapted to the medium since the situation of viewing on a screen is quite different from being in a church.
Digital knowledge sharing and creative performance: Work from home during the COVID-19 pandemic
2021
Abstract The outbreak of the COVID-19 pandemic and the resulting social distancing requirements have led to major disruptions in the world of work. The outcomes of the enforced and large-scale work from home (WFH) practices are currently largely unexplored. This study aims to address this gap in the research by investigating the external and internal digital knowledge sharing (DKS) and creative performance (CP) of employees under these extraordinary circumstances. The social capital theory was utilized as the theoretical lens for examining the associations of DKS and CP with demographic, individual, and organizational factors. An online cross-sectional survey was carried out among knowledge…
Online mathematics teaching and learning during the COVID-19 pandemic: The perspective of lecturers and students
2021
The global spread of the novel coronavirus, Covid-19, reached Norway at the end of February 2020. MatRIC, Centre for Research, Innovation and Coordination of Mathematics Teaching conducted a national survey in Norwegian higher education institutions (HEIs) during June-July 2020 to explore lecturers’ and students’ experiences of online mathematics teaching and learning and to enable sharing of solutions to the challenges encountered. One hundred and twenty-seven students and eighteen lecturers participated in this survey. In this presentation, we will share some of the findings of the survey in relation to the following two themes: challenges of learning and teaching mathematics online, and …