Search results for " posterior"
showing 10 items of 221 documents
A posteriori error control for Maxwell and elliptic type problems
2014
A posteriori error estimates for variational problems in the theory of viscous fluids
2016
The papers included in the thesis are focused on functional type a posteriori error estimates for the Stokes problem, the Stokes problem with friction type boundary conditions, the Oseen problem, and the anti-plane Bingham problem. In the summary of the thesis we consider only the Oseen problem. The papers present and justify special forms of these estimates which are suitable for the approximations generated by the Uzawa algorithm. The estimates are of two main types. Estimates of the first type use exact solutions obtained on the steps of the Uzawa algorithm. They show how errors encompassed in Uzawa approximations behave and have mainly theoretical meaning. Estimates of the second type o…
Transcranial Magnetic Stimulation Trains at 1 Hz Frequency of the Right Posterior Parietal Cortex Facilitate Recognition Memory
2021
Neuroimaging, neuropsychological, and brain stimulation studies have led to contrasting findings regarding the potential roles of the lateral parietal lobe in episodic memory. Studies using brain stimulation methods reported in the literature do not offer unequivocal findings on the interactions with stimulation location (left vs. right hemisphere) or timing of the stimulation (encoding vs. retrieval). To address these issues, active and sham 1 Hz repetitive transcranial magnetic stimulation (rTMS) trains of 600 stimuli were applied over the right or left posterior parietal cortex (PPC) before the encoding or before the retrieval phase of a recognition memory task of unknown faces in a grou…
Estimates of the modeling error generated by homogenization of an elliptic boundary value problem
2016
Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)
Un modelo de control en la dirección estratégica
2002
A partir de la evolución de las fases del proceso estratégico, presentamos un desarrollo de la fase de control como elemento clave de la Dirección Estratégica. Tras una revisión de la literatura, se propone un modelo integrado que permite aplicar el control estratégico en organizaciones complejas, o lo que es lo mismo, la posibilidad de afrontar con éxito estudios empíricos que nos permitan identificar las dificultades reales en la aplicación de los sistemas de control, más allà del “cuadro de mando” al uso en los trabajos de consultoría. En la última parte del trabajo, se toma como base la revisión realizada por Langfield-Smith porque nos permite completar el estudio con una propuesta de t…
Sobre la identidad y procedencia del poeta Filóxeno y la autoría del ditirambo ???????
2019
El presente estudio pretende resolver la controversia en torno a la identidad y procedencia del poeta Filóxeno, célebre ditirambógrafo del siglo V-IV a.C. Para ello, hemos recopilado todos los testimonios que citan a personajes con el nombre de Filóxeno desde la primera mención de Aristófanes. La investigación ha revelado que existen varios individuos con el mismo nombre y rasgos comunes. No obstante, el examen de estos testimonios revela la existencia de un único autor de ditirambos: Filóxeno de Citera. Además, creemos que este poeta fue el autor del ditirambo ???????, que algunos editores atribuyeron falsamente a Filóxeno de Léucade. Posteriormente, reflexionamos sobre la identidad de Fil…
Active disturbance rejection control of linear induction motor
2017
This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input-output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodelling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, t…
Residual a posteriori error estimation for frictional contact with Nitsche method
2023
We consider frictional contact problems in small strain elasticity discretized with finite elements and Nitsche method. Both bilateral and unilateral contact problems are taken into account, as well as both Tresca and Coulomb models for the friction. We derive residual a posteriori error estimates for each friction model, following [Chouly et al, IMA J. Numer. Anal. (38) 2018, pp. 921-954]. For the incomplete variant of Nitsche, we prove an upper bound for the dual norm of the residual, for Tresca and Coulomb friction, without any extra regularity and without a saturation assumption. Numerical experiments allow to assess the accuracy of the estimates and their interest for adaptive meshing …
Semi-discrete Galerkin approximation method applied to initial boundary value problems for Maxwell's equations in anisotropic, inhomogeneous media
1981
SynopsisIn this paper the semi-discrete Galerkin approximation of initial boundary value problems for Maxwell's equations is analysed. For the electric field a hyperbolic system of equations is first derived. The standard Galerkin method is applied to this system and a priori error estimates are established for the approximation.
A posteriori error estimates for time-dependent reaction-diffusion problems based on the Payne-Weinberger inequality
2015
We consider evolutionary reaction-diffusion problem with mixed Dirichlet--Robin boundary conditions. For this class of problems, we derive two-sided estimates of the distance between any function in the admissible energy space and exact solution of the problem. The estimates (majorants and minorants) are explicitly computable and do not contain unknown functions or constants. Moreover, it is proved that the estimates are equivalent to the energy norm of the deviation from the exact solution.