1,654 research outputs found
Optimal Control Realizations of Lagrangian Systems with Symmetry
A new relation among a class of optimal control systems and Lagrangian
systems with symmetry is discussed. It will be shown that a family of solutions
of optimal control systems whose control equation are obtained by means of a
group action are in correspondence with the solutions of a mechanical
Lagrangian system with symmetry. This result also explains the equivalence of
the class of Lagrangian systems with symmetry and optimal control problems
discussed in \cite{Bl98}, \cite{Bl00}.
The explicit realization of this correspondence is obtained by a judicious
use of Clebsch variables and Lin constraints, a technique originally developed
to provide simple realizations of Lagrangian systems with symmetry. It is
noteworthy to point out that this correspondence exchanges the role of state
and control variables for control systems with the configuration and Clebsch
variables for the corresponding Lagrangian system.
These results are illustrated with various simple applications
Simulation of the hydrogen ground state in Stochastic Electrodynamics
Stochastic electrodynamics is a classical theory which assumes that the
physical vacuum consists of classical stochastic fields with average energy
in each mode, i.e., the zero-point Planck spectrum.
While this classical theory explains many quantum phenomena related to harmonic
oscillator problems, hard results on nonlinear systems are still lacking. In
this work the hydrogen ground state is studied by numerically solving the
Abraham -- Lorentz equation in the dipole approximation. First the stochastic
Gaussian field is represented by a sum over Gaussian frequency components, next
the dynamics is solved numerically using OpenCL. The approach improves on work
by Cole and Zou 2003 by treating the full problem and reaching longer
simulation times. The results are compared with a conjecture for the ground
state phase space density. Though short time results suggest a trend towards
confirmation, in all attempted modelings the atom ionises at longer times.Comment: 20 pages, 9 figures. Published version, minor change
Colitis linfoplasmocitaria canina : un hallazgo frecuente en la exploración colonoscópica
En este trabajo se describen los hallazgos clínicos, laboratoriales y colonoscópicos de la colitis linfoplasmocitaria canina, aparte de tratar los aspectos más relevantes sobre su etiopatogenia y diagnóstico, para describir finalmente las pautas de tratamiento del proceso
Mutual information and sensitivity analysis for feature selection in customer targeting: a comparative study
WOS:000454945400004Feature selection is a highly relevant task in any data-driven knowledge discovery project. The present research focuses on analysing the advantages and disadvantages of using mutual information (MI) and data-based sensitivity analysis (DSA) for feature selection in classification problems, by applying both to a bank telemarketing case. A logistic regression model is built on the tuned set of features identified by each of the two techniques as the most influencing set of features on the success of a telemarketing contact, in a total of 13 features for MI and 9 for DSA. The latter performs better for lower values of false positives while the former is slightly better for a higher false-positive ratio. Thus, MI becomes a better choice if the intention is reducing slightly the cost of contacts without risking losing a high number of successes. However, DSA achieved good prediction results with less features.info:eu-repo/semantics/acceptedVersio
Cycle-finite module categories
We describe the structure of module categories of finite dimensional algebras
over an algebraically closed field for which the cycles of nonzero
nonisomorphisms between indecomposable finite dimensional modules are finite
(do not belong to the infinite Jacobson radical of the module category).
Moreover, geometric and homological properties of these module categories are
exhibited
A first-principles study of superconductivity on RbH by doping without applied pressure
The structural, electronic, lattice dynamics, electron-phonon coupling, and
superconducting properties of the alkali-metal hydride RbH, metalized through
electron-doping by the construction of the solid-solution RbSrH,
are systematically analyzed as a function of Sr-content within the framework of
density functional perturbation and Migdal-Eliashberg theories, taking into
account the effect of zero-point energy contribution by the quasi-harmonic
approximation. For the entire studied range of Sr-content, steady increments of
the electron-phonon coupling constant and the superconducting critical
temperature are found with progressive alkaline-earth metal content through
electron-doping, reaching the values of and ~K
with =0.1(0). The steady rise of such quantities as a function of
Sr-content is consequence of the metallization of the hydride as an increase of
density of states at the Fermi level is observed, as well as the softening of
the phonon spectrum, mainly coming from H-optical modes. Our results indicate
that electron-doping on metal-hydrides is an encouraging alternative to look
for superconductivity without applied pressure.Comment: 8 pages, 6 figure
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