994 research outputs found

    Towards a Shared Control Navigation Function:Efficiency Based Command Modulation

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    This paper presents a novel shared control algorithm for robotized wheelchairs. The proposed algorithm is a new method to extend autonomous navigation techniques into the shared control domain. It reactively combines user’s and robot’s commands into a continuous function that approximates a classic Navigation Function (NF) by weighting input commands with NF constraints. Our approach overcomes the main drawbacks of NFs -calculus complexity and limitations on environment modeling- so it can be used in dynamic unstructured environments. It also benefits from NF properties: convergence to destination, smooth paths and safe navigation. Due to the user’s contribution to control, our function is not strictly a NF, so we call it a pseudo-navigation function (PNF) instead.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Matter-antimatter asymmetry without departure from thermal equilibrium

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    We explore the possibility of baryogenesis without departure from thermal equilibrium. A possible scenario is found, though it contains strong constraints on the size of the CPTCPT violation (CPTVCPTV) effects and on the role of the BB (baryon number) nonconserving interactions which are needed for it.Comment: Revtex, 4page

    Curved momentum space, locality, and generalized space-time

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    We establish the correspondence between two apparently unrelated but in fact comple-mentary approaches of a relativistic deformed kinematics: the geometric properties of momentum space and the loss of absolute locality in canonical space-time, which can be restored with the intro-duction of a generalized space-time. This correspondence is made explicit for the case of ¿-Poincaré kinematics and compared with its properties in the Hopf algebra framework. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Spacetime and deformations of special relativistic kinematics

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    A deformation of special relativistic kinematics (possible signal of a theory of quantum gravity at low energies) leads to a modification of the notion of spacetime. At the classical level, this modification is required when one considers a model including single- or multi-interaction processes, for which absolute locality in terms of canonical spacetime coordinates is lost. We discuss the different alternatives for observable effects in the propagation of a particle over very large distances that emerge from the new notion of spacetime. A central ingredient in the discussion is the cluster decomposition principle, which can be used to favor some alternatives over the others

    GNUsmail: Open framework for on-line email classification

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    Real-time classification of massive email data is a challenging task that presents its own particular difficulties. Since email data presents an important temporal component, several problems arise: emails arrive continuously, and the criteria used to classify those emails can change, so the learning algorithms have to be able to deal with concept drift. Our problem is more general than spam detection, which has received much more attention in the literature. In this paper we present GNUsmail, an open-source extensible framework for email classification, which structure supports incremental and on-line learning. This framework enables the incorporation of algorithms developed by other researchers, such as those included in WEKA and MOA. We evaluate this framework, characterized by two overlapping phases (pre-processing and learning), using the ENRON dataset, and we compare the results achieved by WEKA and MOA algorithms

    Microencapsulation Yield Assessment Using TGA

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    In this study, microcapsules containing different contents of different kinds of fragrances and with a regular spherical shape, 2,0–8,0 µm diameter, were synthesized in various core:shell ratios. Mint and cuir fragrances were successfully encapsulated in poly(urea-formaldehyde) (PUF) shell via in-situ polymerization. This was confirmed by optical microscope, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) studies. By observation from thermogravimetric analysis (TGA), it was found a relation between thermal gravimetric curves and the amount of fragrance encapsulated, which was later contrasted by ultraviolet-visible spectroscopy. In this way, comparatively, the yield percentage values can be quantitatively defined with a sufficient degree of accuracy by TGA methodPostprint (author's final draft

    Toward a less natural gas dependent energy mix in Spain: Crowding-out effects of shifting to biomass power generationAnális

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    This paper estimates the impact of a hypothetical change in Spain's energy mix on a number of productive sectors. The change would be brought about by substituting power generation from natural gas with generation from biomass. The total amount of electricity supplied has been calculated to remain constant so that a crowding-out effect would be derived from the displacement of one technology with another. An inputeoutput (IO) framework has been used to estimate the overall economic impact on 26 productive sectors included on Spain's 2007 IO Table. Based on the available literature, the consideration of net impact improves the analysis. The results show that the overall net impact across all productive sectors of this change in the energy mix would be positive and equal to about 0.5% for the period. Higher impacts were measured for the ‘Electricity power and Electricity Supply’ sector (15.4%) followed by the ‘Agriculture, Hunting, Forestry’ sector (7.1%). Only the ‘Gas generation and Gas supply’ sector showed a negative impact (e2.5%), which is consistent with the reduced use of natural gas. The overall calculated total impact for Spain's productive sector was equal to V 8074.95 million at the 2007-equivalent value

    Développement de la compétence d'apprendre à apprendre à travers de méthodologies narratives chez des étudiants non traditionnels

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    Cette communication présente le développement et les résultats d'un projet multilatéral européen Erasmus (Innovative Solutions to Acquire Learning to Learn/INSTALL). Ce projet a développé entre 2011 et 2014 activités de recherche et intervention dans quatre pays (l'Italie, la Roumanie, l'Irlande et l'Espagne), dans le but de développer la compétence clef d'apprendre à apprendre et la réflexivité dans des étudiants universitaires non traditionnels et avec du retard académique. Le projet est fondé sur le développement de ressources personnelles et de l'agentivité des étudiants, sur la base du concept de mentalisation. Les Itinéraires de Médiation Narrative travaillent à partir de quatre modules narratifs (Métaphorique, Iconographique, Écriture et Corporel). Les résultats confirment que la formation INSTALL a produit un accroissement significatif de la capacité réflexive ou de mentalisation dans tous les groupes d'étudiants. Cet accroissement a été mesuré par une échelle de réflexivité.Unión Europea 517750-LLP-1-IT-ERASMUS-ESI

    Manganese and zinc in acidic agricultural soils from Central Spain: Distribution and phytoavailability prediction with chemical extraction tests

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    The extractability and distribution of manganese (Mn) and zinc (Zn) were evaluated in acidic agricultural soils from Central Spain. Both single (0.1 M hydrochloride [HCl] and 0.05 M ethylenediaminetetraacetate [EDTA]) and sequential extraction procedures (SEP) (modified Tessier procedure and Community Bureau of Reference [BCR] protocol) were applied to 29 representative soils that belong to the Alfisol, Inceptisol, and Entisol orders. Average relative Mn extractabilities with respect to the total content (16.6% for HCl and 31.9% for EDTA) were higher than those of Zn (7.7% for HCl and 6.5% for EDTA). Manganese was mainly released in the oxide-bound phase of both SEP (33.1% for modified Tessier and 48.9% for BCR), whereas Zn was predominantly found in the residual fraction (49.1% for modified Tessier and 31.4% for BCR). Significant correlations were only found between the amounts of extractable Zn and the oxide-bound fraction in both SEP. Few relationships were established between Zn fractions extracted by the BCR procedure and those obtained with the Tessier method. Both metal concentrations in spring barley (Hordeum vulgare L., cv Beka) grown in 11 selected soils and the calculated soil/plant transfer coefficients (soil/plant concentration factor (CF), mean values of 31.2 for Mn and 196 for Zn) were poorly (or not at all) correlated with the different extracted soil fractions (single and sequential). A number of empirical equations have been obtained by regression analyses to predict the Mn and Zn uptake by barley, with soil metal forms and some soil characteristics as components (pH for Mn and organic matter for Zn). Values of R2 in the equations were relatively low (<68%). Single-extraction techniques produced worse results than SEP for the evaluation of Mn phytoavailability. The modified Tessier procedure provided better predictions of Zn uptake by plants than BCR, but not better than those obtained with the HCl extraction method
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