Entity

Time filter

Source Type


Mulero-Martinez J.I.,Technical University of Cartagena
IEEE Transactions on Neural Networks and Learning Systems | Year: 2012

A new Gaussian radial basis function static neurocontroller is presented for stable adaptive tracking control. This is a two-stage controller acting in a supervisory fashion by means of a switch logic and allowing arbitration between a neural network (NN) and a robust proportional-derivative controller. The structure is intended to reduce the effects of the curse of dimensionality in multidimensional systems by fully exploiting the mechanical properties of the robot manipulator. A new factorization of the Coriolis/centripetal matrix is used, leading to an NN model that is much smaller than the dynamic ones. By resorting to the extended multivariate Shannon theorem and the computation of the effective bandwidth of the revolute robot manipulators, the network parameters are tuned. Stability and convergence properties are analyzed. This provides the assurance of reliability and effectiveness to make such controller viable. A robot manipulator with two degrees of freedom is employed to study the adaptive features of the neural control algorithm. Finally, the effectiveness of the proposed method is compared to the nonadaptive case. © 2012 IEEE. Source


Gomez-Tornero J.L.,Technical University of Cartagena
IEEE Antennas and Wireless Propagation Letters | Year: 2011

The theory to analyze and design tapered conformal line-source leaky-wave antennas is described in this letter. The deformation in the radiation pattern associated to the bending of the antenna is accurately predicted, and useful expressions are derived to taper the leaky-mode complex propagation constant in order to restore the high-directive radiated beam scanning at the desired angle. The analysis method and the design approach are validated with full-wave simulations of a curved tapered leaky-wave antenna in hybrid technology. © 2006 IEEE. Source


Reverte C.,Technical University of Cartagena
Corporate Social Responsibility and Environmental Management | Year: 2012

In this paper, we provide evidence on the impact of the quality of corporate social responsibility (CSR) reporting on the cost of equity capital for a sample of Spanish listed firms. We aim to verify whether firms with higher CSR disclosure ratings enjoy significantly lower costs of equity capital, after controlling for the well-known Fama and French risk factors (i.e. beta, market-to-book, and size). Consistent with our main hypothesis, we find a significant negative relationship between CSR disclosure ratings and the cost of equity capital. We also obtain that the negative relationship between CSR reporting quality and the cost of equity capital is more pronounced for those firms operating in environmentally sensitive industries. Our findings contribute to the debate on whether CSR activities are value-enhancing or value-neutral by showing that improved CSR can enhance firm value by reducing the firm's cost of equity capital. This implies that CSR reporting is a part of a firm's communication tools in order to decrease information asymmetries between managers and investors. In other words, mandatory social responsibility reporting is called for in order to produce a more precise valuation of a firm. © 2011 John Wiley & Sons, Ltd and ERP Environment. Source


Otero T.F.,Technical University of Cartagena
Polymer Reviews | Year: 2013

Electro-generations of conducting polymers are fast processes through a complex mechanism of parallel reactions giving mixed materials. The films are three-dimensional electrochemical reactors: reactive macromolecules, ions, and solvent. The film composition and its related properties reviewed here change by oxidation/reduction along several orders of magnitude under control. One reaction shifts different properties (multifunctionality). In one device several reaction driven tools, actuators and sensor, work simultaneously (full integration). The activation energy, the coefficient, and the reaction order shift with the initial state of packing conformations. Trapping charges and conformational energetic states constitute new multivalent chemo-conformational memories, close to brain memory. © 2013 Copyright Taylor and Francis Group, LLC. Source


Lopez-Nicolas A.,Technical University of Cartagena
Tobacco control | Year: 2013

The Spanish government has strengthened tobacco control policies since 2005, including changes in tobacco taxes. Because these changes have targeted cigarettes mainly, the tobacco industry has marketed cheaper alternative tobacco products, offering smokers the possibility to downtrade. This paper traces the evolution of patterns of demand for cigarettes and other tobacco products in Spain over the period 2005-2011 in order to assess the impact of such tax loopholes. The authors use data on tobacco products prices and sales as well as changes in the structure and levels of tobacco taxes to relate tax changes to price changes and subsequent market share changes. Tax reforms have lifted the bottom end of the cigarette price distribution, but the industry has been successful in marketing fine-cut tobacco at cheap prices. There have been partial attempts to correct this asymmetric tax treatment, but these have not avoided a remarkable increase in the market share of fine-cut tobacco. The absence of a minimum tax on quantity for the rest of tobacco products allows the industry to place them as potential future downtrading vehicles. In order to address public health objectives, tax policies should aim to equalise the cost of smoking across different tobacco products. Otherwise the tobacco industry can exploit tax loopholes to market cheap alternatives to cigarettes. This requires all tobacco products to bear a minimum tax on quantity, whose levels need to be adjusted in order to reflect the equivalence between different forms of smoking. Source

Discover hidden collaborations