Search results for "STABILITY"
showing 10 items of 3085 documents
A fully adaptive wavelet algorithm for parabolic partial differential equations
2001
We present a fully adaptive numerical scheme for the resolution of parabolic equations. It is based on wavelet approximations of functions and operators. Following the numerical analysis in the case of linear equations, we derive a numerical algorithm essentially based on convolution operators that can be efficiently implemented as soon as a natural condition on the space of approximation is satisfied. The algorithm is extended to semi-linear equations with time dependent (adapted) spaces of approximation. Numerical experiments deal with the heat equation as well as the Burgers equation.
Weighting non-covalent forces in the molecular recognition of C60. Relevance of concave–convex complementarity
2008
The relative contributions of several weak intermolecular forces to the overall stability of the complexes formed between structurally related receptors and [60]fullerene are compared, revealing a discernible contribution from concave–convex complementarity. Viruela Martin, Pedro Manuel, Pedro.M.Viruela@uv.es ; Viruela Martin, Rafael, Rafael.Viruela@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es
Polarization Modulation Instability in Dispersion-Engineered Photonic Crystal Fibers
2021
Generation of widely spaced polarization modulation instability (PMI) sidebands in a wide collection of photonic crystal fibers (PCF), including liquid-filled PCFs, is reported. The contribution of chromatic dispersion and birefringence to the net linear phase mismatch of PMI is investigated in all-normal dispersion PCFs and in PCFs with one (or two) zero dispersion wavelengths. Large frequency shift sidebands are demonstrated experimentally. Suitable fabrication parameters for air-filled and liquid-filled PCFs are proposed as guidelines for the development of dual-wavelength light sources based on PMI.
Pricing to market behaviour in European car markets
2003
Abstract This paper investigates PTM behaviour in European car markets for a period of great interest (1993–98), taking into account the role of invoicing currency. The results indicate that local currency price stability is a strong and pervasive phenomenon across products independently of the invoicing currency. The paper offers robustness checks, tests and arguments that justify the interpretation of this finding, at least in part, as evidence of PTM. It implies the existence of market segmentation and price discrimination, despite the completion of the single market programme on 1 January 1993.
Factor structure and stability of a quality questionnaire within a postgraduate program
2017
En este trabajo se describe un instrumento basado en el uso de una técnica de análisis factorial con el fin de medir la calidad de la educación a través de una muestra de estudiantes de postgrado de una universidad pública española. El instrumento tiene unas aceptables propiedades psicométricas (fiabilidad y validez). En cuanto a la solución factorial, tres dimensiones principales se han determinado: la importancia dada a la materia; recursos educativos y conocimiento de la materia (anterior y posterior). Es importante destacar que estas tres dimensiones se han detectado consistentemente en todo el análisis factorial: muestra total y cursos separados. Estas tres dimensiones deben ser consid…
Femoral neck's fracture in Fahr's Syndorme
2016
Fahr's syndrome is a rare neurological diseas characterized by the presence of idiopathic deposition of calcium in aeras of the brain that control movements.
Success factors of Polish family businesses
2017
This article presents the results of a study carried out among family businesses operating in Poland. It is intended to supplement previously generated knowledge in the area of the operation of family businesses in the specific socio-economic and legal conditions in Poland. The objective was to collate the opinions of entrepreneurs regarding the need for visibility of the family and the family business status in business relations and the marketing activities of enterprises. The data were collected using in-depth interviews with the Polish family business owners. This paper outlines the conclusion of the study with respect to success factors such as: the trust among the family members, flex…
Twisting and buckling: A new undulation mechanism for artificial swimmers
2012
Among the various locomotion strategies of the animal kingdom, the undulation locomotion is of particular interest for biomimetic applications. In this paper, we present an artificial swimmer set into motion by a new and non-trivial undulation mechanism, based on the twisting and buckling of its body. The swimmer consists of a long cylinder of ferrogel which is polarized transversely and in opposite directions at each extremity. When it is placed on a water film and submitted to a transverse oscillating magnetic field, the worm-like swimmer undulates and swims. Whereas symmetry breaking is due to the field gradient, the undulations of the worm result from a torsional buckling instability as…
Optimal Flight Path Determination in Turbulent Air: A Modified EKF Approach
2017
By using the Extended Kalman Filter an accurate path following in turbulent air is performed. The procedure employs simultaneously two different EKFs: the first one estimates disturbances, the second one affords to determine the necessary controls displacements for rejecting those ones. To tune the EKFs an optimization algorithm has been designed to automatically determine Process Noise Covariance and Measurement Noise Covariance matrices. The first filter, by using instrumental measurements gathered in turbulent air, estimates wind components. The second one obtains command laws able to follow the desired flight path. To perform this task aerodynamic coefficients have been modified. Such a…
Full- and reduced-order filter design for discrete-time T-S fuzzy systems with time-varying delay
2012
This paper is focused on the problem of ℋ ∞ filtering for a class of discrete-time T-S fuzzy time-varying delay systems. Our interest is how to design full- and reduced-order filters that guarantee the filtering error system to be asymptotically stable with a prescribed ℋ ∞ performance. Sufficient conditions for the obtained filtering error system are proposed by applying an input-output approach and a two-term approximation method, which is employed to approximate the time-varying delay. The corresponding full and reduced-order filter design is cast into a convex optimization problem, which can be efficiently solved by standard numerical algorithms.