Search results for "VDP::Mathematics and natural science: 400"
showing 10 items of 421 documents
Oscillation theorems for second-order nonlinear neutral delay differential equations
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/594190 Open Access We analyze the oscillatory behavior of solutions to a class of second-order nonlinear neutral delay differential equations. Our theorems improve a number of related results reported in the literature.
Optimal design of complex passive-damping systems for vibration control of large structures: An energy-to-peak approach
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/510236 Open Access We present a new design strategy that makes it possible to synthesize decentralized output-feedback controllers by solving two successive optimization problems with linear matrix inequality (LMI) constraints. In the initial LMI optimization problem, two auxiliary elements are computed: a standard state-feedback controller, which can be taken as a reference in the performance assessment, and a matrix that facilitates a proper definition of the main LMI optimization problem. Next, by solving the second optimization problem, the …
Recent Advances in Static Output-Feedback Controller Design with Applications to Vibration Control of Large Structures
2014
Published version of an article in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2014.3.4 Open Access In this paper, we present a novel two-step strategy for static output-feedback controller design. In the first step, an optimal state-feedback controller is obtained by means of a linear matrix inequality (LMI) formulation. In the second step, a transformation of the LMI variables is used to derive a suitable LMI formulation for the static output-feedback controller. This design strategy can be applied to a wide range of practical problems, including vibration control of large structures, control of oshore wind turbine…
Dynamic Output Feedback Passive Control of Uncertain Switched Stochastic Systems with Time-Varying Delay
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from Hindawi: http://dx.doi.org/10.1155/2013/281747 Open Access This paper is concerned with the issues of passivity analysis and dynamic output feedback (DOF) passive control for uncertain switched stochastic systems with time-varying delay via multiple storage functions (MSFs) method. Firstly, based on the MSFs method, a sufficient condition for the existence of the passivity of the underlying system is established in terms of linear matrix inequalities (LMIs). Furthermore, the problem of dynamic output feedback passive control is investigated. Based on the obtained passivity condition, a …
„Die Gottesluft der freien Forschung“ – Jacobis Verhältnis zur französischen Mathematik aus politischer Sicht
2013
Published version of an article in the journal: Mitteilungen der Deutschen Mathematiker-Vereinigung (DMV)
Für die Ehre des menschlichen Geistes - Ein neuer Blick auf eine bekannte Kontroverse zwischen Fourier und Jacobi über die Rolle der Anwendungen der …
2013
Published version of an article from the journal: Mitteilungen der Deutschen Mathematiker-Vereinigung (DMV)
Spin transport in ferromagnetic/normal-metal tunnel junction arrays
2012
Published version of an article in the journal: Physical Review B. Also available from the publisher:http://dx.doi.org/10.1103/PhysRevB.85.094421 An array of alternating ferromagnetic and normal-metal islands separated by small tunnel junctions is theoretically investigated in the sequential tunneling regime. A numerical Monte Carlo method is used to calculate the transport properties. The spin-dependent tunneling currents give rise to nonequilibrium spin accumulation on the normal island. The tunneling magneto resistance (TMR) is calculated for a large range of array parameters. The TMR oscillates with bias voltage and can become negative for certain array parameters. We show that the long…
Communication: The absolute shielding scales of oxygen and sulfur revisited
2015
Copyright 2015 AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Journal of Chemical Physics 2015, 142 and may be found at http://dx.doi.org/10.1063/1.4913634 We present an updated semi-experimental absolute shielding scale for the 17O and 33S nuclei. These new shielding scales are based on accurate rotational microwave data for the spin–rotation constants of H2 17O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)], C17O [Cazzoli et al., Phys. Chem. Chem. Phys. 4, 3575 (2002)], and H2 33S [Helgaker et al., J. Chem. Phys. 139, 244308 (2013)] corrected both for v…
Convective Instability in a Horizontal Porous Channel with Permeable and Conducting Side Boundaries
2013
Published version of an article in the journal: Transport in Porous Media. Also available on Science Direct: http://dx.doi.org/10.1007/s11242-013-0198-y The stability analysis of the motionless state of a horizontal porous channel with rectangular cross-section and saturated by a fluid is developed. The heating from below is modelled by a uniform flux, while the top wall is assumed to be isothermal. The side boundaries are considered as permeable and perfectly conducting. The linear stability of the basic state is studied for the normal mode perturbations. The principle of exchange of stabilities is proved, so that only stationary normalmodes need to be considered in the stability analysis.…
The genetic legacy of extreme exploitation in a polar vertebrate
2020
Understanding the effects of human exploitation on the genetic composition of wild populations is important for predicting species persistence and adaptive potential. We therefore investigated the genetic legacy of large-scale commercial harvesting by reconstructing, on a global scale, the recent demographic history of the Antarctic fur seal (Arctocephalus gazella), a species that was hunted to the brink of extinction by 18th and 19th century sealers. Molecular genetic data from over 2,000 individuals sampled from all eight major breeding locations across the species’ circumpolar geographic distribution, show that at least four relict populations around Antarctica survived commercial huntin…