6,565 research outputs found
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 200 mK between the forward and reverse
thermal bias configurations are obtained below 1 K, corresponding to a
rectification ratio 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
Generalized tableaux over arbitrary digraphs and their associated differential equations
We revisit the concepts of acyclic orderings and number of acyclic orderings
of acyclic digraphs in terms of dispositions and counters for arbitrary
multidigraphs. We prove that when we add a sequence of nested directed paths to
a directed graph there is a unique polynomial such that the generatrix function
of the family of counters is the product of the polynomial and the exponential
function. We give an application, by considering a kind of digraphs arranged in
rows introduced by the authors in a previous paper, called dispositional
digraphs, in the particular case in which the digraph has two rows, to obtain
new families of linear differential equations of small order whose coefficients
are polynomials of small degree which admit polynomial solutions. In
particular, we obtain a new differential equation associated to Catalan
numbers, and the corresponding associated polynomials, which are solution of
this differential equation; we term them Catalan differencial equation and
Catalan polynomials, respectively. We prove that the Catalan polynomials
obtained when we connect the directed path to the second vertex of the lower
row of the digraph are orthogonal polynomials for an appropriate weight
function. We characterize the digraphs that maximize the counter of connected
dispositional digraphs and we find a new differential equation associated to
these digraphs. We introduce also dispositions and counters in any multidigraph
with non-strict inequalities in the dispositions, and we find new differential
equations associated to some of them
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
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