Search results for "equation"

Small-time bilinear control of Schrödinger equations with application to rotating linear molecules

2023

In [14] Duca and Nersesyan proved a small-time controllability property of nonlinear Schrödinger equations on a d-dimensional torus $\mathbb{T}^d$. In this paper we study a similar property, in the linear setting, starting from a closed Riemannian manifold. We then focus on the 2-dimensional sphere $S^2$, which models the bilinear control of a rotating linear top: as a corollary, we obtain the approximate controllability in arbitrarily small times among particular eigenfunctions of the Laplacian of $S^2$.

Exponential sums related to Maass forms

2019

We estimate short exponential sums weighted by the Fourier coefficients of a Maass form. This requires working out a certain transformation formula for non-linear exponential sums, which is of independent interest. We also discuss how the results depend on the growth of the Fourier coefficients in question. As a byproduct of these considerations, we can slightly extend the range of validity of a short exponential sum estimate for holomorphic cusp forms. The short estimates allow us to reduce smoothing errors. In particular, we prove an analogue of an approximate functional equation previously proven for holomorphic cusp form coefficients. As an application of these, we remove the logarithm …

Simple algorithms for calculation of the axial‐symmetric heat transport problem in a cylinder

2001

The approximation of axial‐symmetric heat transport problem in a cylinder is based on the finite volume method. In the classical formulation of the finite volume method it is assumed that the flux terms in the control volume are approximated with the finite difference expressions. Then in the 1‐D case the corresponding finite difference scheme for the given source function is not exact. There we propose the exact difference scheme. In 2‐D case the corresponding integrals are approximated using different quadrature formulae. This procedure allows one to reduce the heat transport problem described by a partial differential equation to an initial‐value problem for a system of two ordinary diff…

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.

Diffusion front capturing schemes for a class of Fokker–Planck equations: Application to the relativistic heat equation

2010

In this research work we introduce and analyze an explicit conservative finite difference scheme to approximate the solution of initial-boundary value problems for a class of limited diffusion Fokker-Planck equations under homogeneous Neumann boundary conditions. We show stability and positivity preserving property under a Courant-Friedrichs-Lewy parabolic time step restriction. We focus on the relativistic heat equation as a model problem of the mentioned limited diffusion Fokker-Planck equations. We analyze its dynamics and observe the presence of a singular flux and an implicit combination of nonlinear effects that include anisotropic diffusion and hyperbolic transport. We present numeri…

Measurement invariance of the Behavioural Regulation in Sport Questionnaire when completed by young athletes across five European countries

2013

The purpose of this study was (1) to examine the factorial validity of the Behavioural Regulation Sport in Questionnaire (BRSQ) when completed by young soccer players in the Promoting Adolescent Physical Activity (PAPA) project (9-15 years old) in 5 European countries (France: n = 1248, Greece: n = 1507, Norway: n = 1397, Spain: n = 2245, and England: n = 1372) and (2) test the measurement invariance of its latent factors across these 5 countries.First, we tested the exploratory structural equation model (ESEM) factor analyses, allowing cross-loadings between factors, against the traditional independent clusters confirmatory factor analysis model (ICM-CFA), with all cross-loadings constrain…

Educación XX1 : revista de la Facultad de Educación

2017

Introducción: La institucionalización del Aprendizaje-Servicio (ApS) en la universidad recomienda, en primer lugar, el análisis de la cultura docente del profesorado y su actitud hacia la innovación. Precisamente, lo que este trabajo pretende es aportar un modelo teórico integrador desarrollando tres escalas de evaluación, contrastadas a través de pruebas estadísticas, para el contexto de la enseñanza universitaria en España. Metodología: A fin de elaborar el modelo de medida se aplicaron tres escalas a 1903 profesoras y profesores de 6 universidades españolas: una escala de práctica docente (18 ítems), otra sobre compromiso social de la Universidad (9 ítems), y una tercera, sobre prácticas…

2020

In order to ensure the concentration, compliance and motivation of the participants, a short version of 12 items was extracted from the “Experiences in Close Relationships Questionnaire (ECR)”. Even though this short English version shows equally good validity and reliability as the long version, there have been no representative norm values and psychometric characteristics available for the short version in German. Therefore, the German 12-item ECR was implemented in a representative sample of 1,127 males and 1,237 females (mean age M = 49.93; SD = 12.31) from the general public (N = 2,364). The reliability values of the German 12-item ECR in the representative sample are not as good as th…

A Fair Share of Work: Is Fairness of Task Distribution a Mediator Between Transformational Leadership and Follower Emotional Exhaustion?

2019

Drawing on social resource theory and the norm of equity, this research proposes fairness of task distribution as a mediating mechanism of the well-established relationship between transformational leadership and followers’ well-being, conceptualizing the latter as low emotional exhaustion. Using data from 479 German employees in a three-wave longitudinal study, we found transformational leadership to be related to fair task distribution over time. The perceived fairness of task distribution mediated the relationship between transformational leadership and follower emotional exhaustion (structural equation modeling) when excluding stabilities. Our results also show a reverse causation effec…

Transgenerational innovation capability in family firms

2020

PurposeBased on the theory of dynamic capabilities, the purpose of this study is to examine how generation influences the effect of innovation capability on family business performance. To achieve this purpose, a moderation model is tested using the generational level as the moderating variable.Design/methodology/approachThis study used a sample of 106 family businesses CEOs who were surveyed by mail using the Limesurvey 2.5 platform. The results obtained were analyzed using the second-generation partial least squares (PLS) structural equation model. The MICOM (Measurement Invariance of Composite Models) approach was used to analyze the moderating effect.FindingsThis research sheds lights o…