BRAIN COMPUTER INTERFACE - Application of an Adaptive Bi-stage Classifier based on RBF-HMM

Brain Computer Interface is an emerging technology that allows new output paths to communicate the users intentions without the use of normal output paths, such as muscles or nerves. In order to obtain their objective, BCI devices make use of classifiers which translate inputs from the users brain signals into commands for external devices. This paper describes an adaptive bi-stage classifier. The first stage is based on Radial Basis Function neural networks, which provides sequences of pre-assignations to the second stage, that it is based on three different Hidden Markov Models, each one trained with pre-assignation sequences from the cognitive activities between classifying. The segment of EEG signal is assigned to the HMMwith the highest probability of generating the pre-assignation sequence. The algorithm is tested with real samples of electroencephalografic signal, from five healthy volunteers using the cross-validation method. The results allow to conclude that it is possible to implement this algorithm in an on-line BCI device. The results also shown the huge dependency of the percentage of the correct classification from the user and the setup parameters of the classifier

El problema del coste en la industria hotelera: el servicio de alojamiento

La innegable importancia del sector turístico en nuestro país reclama, en nuestra opinión, un riguroso estudio de los diversos componentes que configuran su oferta final, dentro de la que, sin ningún género de duda, ocupa una importancia destacada la industria hotelera. Ello otorga especial relevancia a todo intento de definición y cálculo de los costes que inciden en la misma, y en particular los servicios de restauración y alojamiento, del último de los cuales nos ocupamos en el presente trabajo.We think that the great importance of tourism bussiness in our country makes necessary the elaboration of a deep study about the different factors that shape the completed offer in the sector. The products dealing with accommodations are undoubtedly an important part within this offer. It involves a special meaning for any attempt to define this sort of products and to calculate the costs that affect them. These last aspects we treat in the present piece of work

A normal metal tunnel-junction heat diode

We propose a low-temperature thermal rectifier consisting of a chain of three tunnel-coupled normal metal electrodes. We show that a large heat rectification is achievable if the thermal symmetry of the structure is broken and the central island can release energy to the phonon bath. The performance of the device is theoretically analyzed and, under the appropriate conditions, temperature differences up to $\sim$ 200 mK between the forward and reverse thermal bias configurations are obtained below 1 K, corresponding to a rectification ratio $\mathcal{R} \sim$ 2000. The simplicity intrinsic to its design joined with the insensitivity to magnetic fields make our device potentially attractive as a fundamental building block in solid-state thermal nanocircuits and in general-purpose cryogenic electronic applications requiring energy management.Comment: 4.5 pages, 4 color figure

Reduced kinetic mechanisms for modelling LPP combustión in gas turbines

Reduced kinetic mechanisms for modelling LPP combustión in gas turbine

Matching and recovering 3D people from multiple views

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper introduces an approach to simultaneously match and recover 3D people from multiple calibrated cameras. To this end, we present an affinity measure between 2D detections across different views that enforces an uncertainty geometric consistency. This similarity is then exploited by a novel multi-view matching algorithm to cluster the detections, being robust against partial observations as well as bad detections and without assuming any prior about the number of people in the scene. After that, the multi-view correspondences are used in order to efficiently infer the 3D pose of each body by means of a 3D pictorial structure model in combination with physico-geometric constraints. Our algorithm is thoroughly evaluated on challenging scenarios where several human bodies are performing different activities which involve complex motions, producing large occlusions in some views and noisy observations. We outperform state-of-the-art results in terms of matching and 3D reconstruction.Peer ReviewedPostprint (author's final draft

El uso de SIG de software libre en una práctica de Biología y Geología de 4º de ESO: los ecosistemas.

Para consolidar el conocimiento del bloque del currículo de Biología y Geología de 4º de la E.S.O. (Educación Secundaria Obligatoria) relacionado con los ecosistemas, hemos desarrollado una metodología docente basada en los Sistemas de Información Geográfica (SIG), en la que el objetivo de los estudiantes es crear un shapefile con atributos espaciales e información ecológica sobre los distintos Parques Nacionales de España mediante su digitalización. Se ejemplifica con el procedimiento concreto del Parque Nacional de Doñana. A través del SIG, con un software gratuito para el centro, se aumenta la interactividad del estudiante con la asignatura, se desarrolla la creatividad y se mejora la capacidad de comprender el espacio, mejorando el proceso de enseñanza-aprendizaje.To consolidate the knowledge curriculum of thematic Block of the 4th year of Biology and Geology of the Spanish Educación Secundaria Obligatoria (E.S.O.), related with the ecosystems, we have developed a teaching methodology based on Geographic Information Systems (GIS). The students aim is to make a shapefile with space attributes and ecological information about the National Parks of Spain by its digitalization. We have given an example of Doñana National Park (Andalucia). Through the use of GIS and a kind of software with no additional charge to the school, student interactivity with the subject is increased, creativity is developed and their ability to understand space is improved. These skills are very useful for the teaching-learning proces

Brain Computer Interface. Comparison of Neural Networks Classifiers.

Brain Computer Interface is an emerging technology that allows new output paths to communicate the user’s intentions without use of normal output ways, such as muscles or nerves (Wolpaw, J. R.; et al., 2002).In order to obtain its objective BCI devices shall make use of classifier which translate the inputs provided by user’s brain signal to commands for external devices. The primary uses of this technology will benefit persons with some kind blocking disease as for example: ALS, brainstem stroke, severe cerebral palsy (Donchin et al., 2000).This report describes three different classifiers based on three different types of neural networks: Radial Basis Functions RBF, Probabilistic Neural Networks PNN, and Multi-Layer Perceptions MLP. The report compares the results produced by them in order to obtain conclusions to apply to an on-line BCI device; it also describes the experimental procedure followed in the experiments. As result of the tests carried out on five healthy volunteers an estimation of the success rate for each type of classifier, the type and architecture of the classifier, and filtering windows are established

Feedback effect analysis by comparison of discrimination capability of On-line and Off-line experimental procedures based on LDA

This paper analyses the user’s feedback influence in the mental task discrimination capability through the comparison of results obtained from Off-line and On-line Brain Computer Interface experimental procedures. Experiments performed under these two paradigms were carried out by five male volunteers. In order to develop a wearable BCI device only two electrodes in C3 and C4 zones have been used for electroencephalographic signal acquisition. These procedures apply seven different types of preprocessing windows and Linear Discrimination Analysis technique to reduce the dimension of the feature space before the quantification of the discrimination capability between the proposed mental activities. The discrimination capability is quantified through statistical analysis, based on bilateral contrast test, between the population of the LDA transformed feature vectors

Influence of the notch-sharpening technique on styrene-acrylonitrile fracture behavior

The Centre Catala del Plastic and Universidad Rey Juan Carlos laboratories joined forces to investigate the effect of the notch-sharpening technique on the fracture parameters of styrene-acrylonitrile. Contact notch-sharpening techniques, such as razor tapping, razor sliding, and razor broaching, and a noncontact procedure, femtolaser, were analyzed. The fracture values of the samples with notches sharpened via contact techniques were divided into two groups: one with pop-in and the other with no pop-in in the load-displacement records; this resulted in the lowest and highest fracture toughnesses, respectively. The fracture parameters of the specimens with notches sharpened via a femtolaser were between those of the samples with notches sharpened via contact procedures in which pop-in occurred and those in which it did not. To explain these results, the crack front of the nontested specimens after sharpening was investigated in depth, we identified the type of damage and measured its size and the crack tip radii. The morphology of the crack front was related to the fractographic study.Postprint (author's final draft

Laminar mixing in diluted and undiluted fuel jets upstream from lifted flames

The boundary-layer approximation is used to describe the frozen mixing process taking place when a fuel jet of radius a discharges into stagnant air. The results are applicable to the calculation of lifted flames stabilized in round laminar jets with relatively large Reynolds numbers, Re, for which the proposed formulation provides a detailed description for the velocity and composition fields encountered by the propagating triple flame formed at the base of the lifted flame. The problem is integrated for relevant values of the flow parameters, including values of the stoichiometric air-to-fuel mass ratio S of order unity, when the lifted flame is located in the region of jet development, corresponding to distances from the injector of order Re a. Further attention is given to the relevant case S ≫ 1, corresponding to typical conditions of undilute hydrocarbon-air flames, for which the resulting lifted flames are stabilized at relatively large distances from the injector, of order S Re a. It is seen that Schlichting asymptotic solution, which corresponds to a point source of momentum, is then applicable to describe the mixing process upstream from the lifted flame. Improved accuracy is sought by introducing expansions for the velocity components and for the reactant mass fractions in powers of S-1. The resulting development shows in particular that the first-order correction to the leading-order solution is equivalent to the introduction of a virtual origin for the axial coordinate. It is shown that the magnitude of the required translation, which is equal for the velocity and composition fields, must be determined from continuity considerations. As an illustrative example, the resulting description is used to calculate flame fronts with S ≫ 1 in the thermal-diffusive approximation