Search results for "Names"
showing 10 items of 6843 documents
Application of Wavelet Networks to Adaptive Control of Robotic Manipulators
2011
Published version of a chapter in the book: Intelligent Robotics and Applications. Also available from the publisher at; http://dx.doi.org/10.1007/978-3-642-25489-5_39 In this paper, a wavelet-based adaptive control is proposed for a class of robotic manipulators, which consist of nonlinearities for friction effects and uncertain terms as disturbances. The controller is calculated by using a mixed of feedback linearization technique, supervisory control and H∞ control. In addition, the parameter adaptive laws of the wavelet network are developed using a Lyapunov-based design. It is also shown that both system tracking stability and convergence of the error estimation can be guaranteed in th…
ean-Square Filtering for Polynomial System States Confused with Poisson Noises over Polynomial Observations
2011
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.2011.2.1 In this paper, the mean-square filtering problem for polynomial system states confused with white Poisson noises over polynomial observations is studied proceeding from the general expression for the stochastic Ito differentials of the mean-square estimate and the error variance. In contrast to the previously obtained results, the paper deals with the general case of nonlinear polynomial states and observations with white Poisson noises. As a result, the Ito differentials for the mean-square estimate and error variance corre- spon…
The Riemann sum method for the design of sum-of-cisoids simulators for Rayleigh fading channels in non-isotropic scattering environments
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/ICUMT.2009.5345371 In this paper, we introduce the Riemann sum method (RSM) as an effective tool for the design of sum-of-cisoids (SOC) simulators for narrowband mobile Rayleigh fading channels under non-isotropic scattering conditions. We show that the RSM results in an excellent approximation of…
Spatial correlations of vacuum fluctuations and the Casimir-Polder potential
2003
We calculate the Casimir-Polder intermolecular potential using an effective Hamiltonian recently introduced. We show that the potential can be expressed in terms of the dynamical polarizabilities of the two atoms and the equal-time spatial correlation of the electric field in the vacuum state. This gives support to an interesting physical model recently proposed in the literature, where the potential is obtained from the classical interaction between the instantaneous atomic dipoles induced and correlated by the vacuum fluctuations. Also, the results obtained suggest a more general validity of this intuitive model, for example when external boundaries or thermal fields are present.
Ab initio calculations of the transfer parameters and coulombic repulsion and estimation of their effects on the electron delocalization and magnetic…
2003
International audience; In this work, we present ab initio calculations on embedded fragments that permit to extract the value of the effective electron transfer integral and coulombic repulsion between W nearest neighbour atoms in a mixed-valence αPW12O40 Keggin polyoxoanion. This allows us to perform a quantitative study of the influence of these two parameters on the magnetic properties of Keggin polyoxoanions reduced by two electrons. We surprisingly find that the electron transfer between edge-sharing and corner-sharing WO6 octahedra have very close values, and show that the punctual charges estimation of coulombic repulsion may not be accurate enough to study the electronic distributi…
Role of the electron transfer and magnetic exchange interactions in the magnetic properties of mixed-valence polyoxovanadate complexes.
2008
International audience; Modeling the properties of high-nuclearity, high-electron-population, mixed-valence (MV) magnetic systems remains one of the open challenges in molecular magnetism. In this work, we analyze the magnetic properties of a series of polyoxovananadate clusters of formula [V 18O 42] (12-) and [V 18O 42] (4-). The first compound is a fully localized spin cluster that contains 18 unpaired electrons located at the metal sites, while the second one is a MV cluster with 10 unpaired electrons largely delocalized over the 18 metal sites. A theoretical model that takes into account the interplay between electron transfer and magnetic exchange interactions is developed to explain t…
Rydberg or Valence? The Long-Standing Question in the UV Absorption Spectrum of 1,1′-Bicyclohexylidene
2008
The electronic excited states of the olefin 1,1'-bicylohexylidene (BCH) are investigated using multiconfigurational complete active space self-consistent-field second order perturbation theory in its multi-state version (MS-CASPT2). Our calculations undoubtedly show that the bulk of the intensity of the two unusually intense bands of the UV absorption of BCH measured with maxima at 5.95 eV and 6.82 eV in the vapor phase are due to a single pi pi* valence excitation. Sharp peaks reported in the vicinity of the low-energy feature in the gas phase correspond to the beginning of the pi 3s(R) Rydberg series. By locating the origin of the pi pi* band at 5.63 eV, the intensity and broadening of th…
A theoretical study of the electronic spectrum of cis-stilbene
1999
Abstract The valence and Rydberg electronic excited singlet states of cis -stilbene have been studied using multiconfigurational second-order perturbation theory (CASPT2). The study includes a geometry determination of the ground state. The geometry of the lowest 1 B state has also been optimized, leading to a structure where the two benzyl groups are nearly perpendicular. The calculated vertical spectrum is in agreement with the occurrence of three main bands in the observed one-photon absorption spectrum. Below the relatively intense transition to the 2 1 B (HOMO→LUMO) state at 4.61 eV, two weak transitions have been computed at 4.11–4.45 eV, which correspond to transitions to the 1 1 B a…
Low-Frequency Relaxation Phenomena in α-LiIO3: The Nature and Role of Defects
2002
The lithium iodate ionic conduction in the polar c-axis direction is studied between 35 and 470 K for crystals grown in various conditions. So far, to separate processes induced by the nature of electrodes, the impedance spectroscopy technique had been used at room temperature with both metallic and ideally polarizable insulating electrodes, so that a relaxation of space charges was clearly identified. Here, the temperature dependence of the hopping ionic conductivity exhibits quite different activation energies well related to the growth conditions. Following low-temperature Raman and thermodynamic experiments, a new approach based on a vacancy diffusion mechanism is proposed. Experimental…
Electron trapping centres and cross sections in LiNbO3studied by57Co Mössbauer emission spectroscopy
1999
Fast electron trapping processes and aliovalent charge states following the 57Co(EC)57Fe decay are studied in undoped, 5.4 mol% Mg-doped and 0.1 mol% Fe-doped LiNbO3 in various thermochemical reduction (TCR) states. Static 57Co Mossbauer emission spectra of congruent Mg:LiNbO3 recorded at T = 4.2 K in external magnetic field of 4.6 T are presented. Trapping cross section ratios are derived for Fe3+Li, Nb5+Li and Mg2+Li. A method to determine trap concentrations for TCR states of LiNbO3 is outlined. The electron-capture distance of the traps is found to be 2.7±1.4 nm. As this is much smaller than the 6 keV Auger-electron penetration depth, it is concluded that the distribution of the alioval…