On-line support vector machines for function approximation

This paper describes an on-line method for building epsilon-insensitive support vector machines for regression as described in (Vapnik, 1995). The method is an extension of the method developed by (Cauwenberghs & Poggio, 2000) for building incremental support vector machines for classification. Machines obtained by using this approach are equivalent to the ones obtained by applying exact methods like quadratic programming, but they are obtained more quickly and allow the incremental addition of new points, removal of existing points and update of target values for existing data. This development opens the application of SVM regression to areas such as on-line prediction of temporal series or generalization of value functions in reinforcement learning.Postprint (published version

Short-range stationary patterns and long-range disorder in an evolution equation for one-dimensional interfaces

A novel local evolution equation for one-dimensional interfaces is derived in the context of erosion by ion beam sputtering. We present numerical simulations of this equation which show interrupted coarsening in which an ordered cell pattern develops with constant wavelength and amplitude at intermediate distances, while the profile is disordered and rough at larger distances. Moreover, for a wide range of parameters the lateral extent of ordered domains ranges up to tens of cells. This behavior is new in the context of dynamics of surfaces or interfaces with morphological instabilities. We also provide analytical estimates for the stationary pattern wavelength and mean growth velocity

Enabling Practical IPsec authentication for the Internet

On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops (First International Workshop on Information Security (IS'06), OTM Federated Conferences and workshops). Montpellier, Oct,/Nov. 2006There is a strong consensus about the need for IPsec, although its use is not widespread for end-to-end communications. One of the main reasons for this is the difficulty for authenticating two end-hosts that do not share a secret or do not rely on a common Certification Authority. In this paper we propose a modification to IKE to use reverse DNS and DNSSEC (named DNSSEC-to-IKE) to provide end-to-end authentication to Internet hosts that do not share any secret, without requiring the deployment of a new infrastructure. We perform a comparative analysis in terms of requirements, provided security and performance with state-of-the-art IKE authentication methods and with a recent proposal for IPv6 based on CGA. We conclude that DNSSEC-to-IKE enables the use of IPsec in a broad range of scenarios in which it was not applicable, at the price of offering slightly less security and incurring in higher performance costs.Universidad de Montpellier IIPublicad

Non-linear ripple dynamics on amorphous surfaces patterned by ion-beam sputtering

Erosion by ion-beam sputtering (IBS) of amorphous targets at off-normal incidence frequently produces a (nanometric) rippled surface pattern, strongly resembling macroscopic ripples on aeolian sand dunes. Suitable generalization of continuum descriptions of the latter allows us to describe theoretically for the first time the main nonlinear features of ripple dynamics by IBS, namely, wavelength coarsening and non-uniform propagation velocity, that agree with similar results in experiments and discrete models. These properties are seen to be the anisotropic counterparts of in-plane ordering and (interrupted) pattern coarsening in IBS experiments on rotating substrates and at normal incidence.Comment: 5 pages, 3 figure

Educación para el desarrollo sostenible, con énfasis en la movilidad y su efecto en la elección de modos de transporte menos contaminantes y eficientes

The high use of car has created some traffic problems and air pollution in cities like Quito. Sustainable Development is an option to reduce these problems. Recent studies have shown little or low correlation of pro-environmental attitudes and pro-environmental behavior. This study tried to show the impact of a sustainable mobility workshop (tms) in young 8th grade students of Quito. The first chi-square analysis showed significant differences between students of experimental group (GE) and control group (GC) who had higher scores on tests of sustainable mobility (x ² = 51.00, p 2.0) indicated that GE has a higher percentage of students whit better grades (86.81%) compared to the percentage of GC (13.19%) who did not receive tms. The second chi-square analysis also showed significant differences between students of experimental group (GE) and control group (GC) who prefer to move in less polluting modes of transport (x ² = 12.00 p 2.0) indicated that GE has a higher percentage of students who prefer to move in less polluting transport modes (83.61%) compared to the percentage of GC (16.39%).En la actualidad el uso indiscriminado del automóvil ha generado en las ciudades algunos problemas como congestión vehicular y contaminación del aire. El concepto de Desarrollo Sostenible se visualiza como una opción para contrarrestar dichos problemas. Estudios recientes han demostrado poca o baja relación entre actitud y comportamiento pro- ambiental. Sin embargo, otros estudios han podido observar relación entre valores y conducta pro-ambiental. La teoría de la Activación de la Norma Moral de Schwartz es una de las más sólidas en el estudio del comportamiento ambiental. El presente estudio analizó la influencia de un Taller de Movilidad Sostenible (TMS) sobre la elección de modos de transporte menos contaminantes en jóvenes de 8vo de Básica del Colegio Don Bosco, de la ciudad de Quito. El primer análisis Chi Cuadrado mostró que existen diferencias significativas entre los estudiantes, que obtuvieron mejores calificaciones en las pruebas de Conocimiento sobre Movilidad Sostenible, del grupo experimental (GE) y los del grupo de control (GC) (X² = 51,00; p 2.0) indicaron que el GE tiene un mayor porcentaje de estudiantes que obtuvieron una mejor calificación (86.81%) comparado con el porcentaje del GC (13.19%), quienes no recibieron el TMS. De igual manera, el segundo análisis Chi Cuadrado mostró que existen diferencias significativas entre los estudiantes que preferirían movilizarse en modos de trasporte menos contaminantes para ir al colegio del GE, de acuerdo a la Encuesta de Movilidad y los del GC (X² = 12,00; p 2.0) indicaron que el GE tiene un mayor porcentaje de estudiantes que preferirían movilizarse en modos de transporte menos contaminantes (83.61%) comparado con el porcentaje del GC (16.39%)