94 research outputs found
Non-linear classifiers applied to EEG analysis for epilepsy seizure detection
This work presents a novel approach for automatic epilepsy seizure detection based on EEG analysis that exploits the underlying non-linear nature of EEG data. In this paper, two main contributions are presented and validated: the use of non-linear classifiers through the so-called kernel trick and the proposal of a Bag-of-Words model for extracting a non-linear feature representation of the input data in an unsupervised manner. The performance of the resulting system is validated with public datasets, previously processed to remove artifacts or external disturbances, but also with private datasets recorded under realistic and non-ideal operating conditions. The use of public datasets caters for comparison purposes whereas the private one shows the performance of the system under realistic circumstances of noise, artifacts, and signals of different amplitudes. Moreover, the proposed solution has been compared to state-of-the-art works not only for pre-processed and public datasets but also with the private datasets. The mean F1-measure shows a 10% improvement over the second-best ranked method including cross-dataset experiments. The obtained results prove the robustness of the proposed solution to more realistic and variable conditions. (C) 2017 Elsevier Ltd. All rights reserved
On the multiplicity of the zero-age main-sequence O star Herschel 36
We present the analysis of high-resolution optical spectroscopic observations
of the zero-age main-sequence O star Herschel 36 spanning six years. This star
is definitely a multiple system, with at least three components detected in its
spectrum. Based on our radial-velocity (RV) study, we propose a picture of a
close massive binary and a more distant companion, most probably in wide orbit
about each other. The orbital solution for the binary, whose components we
identify as O9 V and B0.5 V, is characterized by a period of 1.5415 +/- 0.0006
days. With a spectral type O7.5 V, the third body is the most luminous
component of the system and also presents RV variations with a period close to
498 days. Some possible hypotheses to explain the variability are briefly
addressed and further observations are suggested.Comment: 6 pages, 2 figure
Spectral Variations of Of?p Oblique Magnetic Rotator Candidates in the Magellanic Clouds
Optical spectroscopic monitoring has been conducted of two O stars in the
Small and one in the Large Magellanic Cloud, the spectral characteristics of
which place them in the Of?p category, which has been established in the Galaxy
to consist of oblique magnetic rotators. All of these Magellanic stars show
systematic spectral variations typical of the Of?p class, further strengthening
their magnetic candidacy to the point of virtual certainty. The spectral
variations are related to photometric variations derived from OGLE data by Naze
et al. (2015) in a parallel study, which yields rotational periods for two of
them. Now circular spectropolarimetry is required to measure their fields, and
ultraviolet spectroscopy to further characterize their low-metallicity,
magnetically confined winds, in support of hydrodynamical analyses.Comment: 18 pages, 6 figures, accepted for publication by A
Injecting domain knowledge in multi-objective optimization problems: A semantic approach
In the field of complex problem optimization with me-taheuristics, semantics has been used for modeling different aspects, such as: problem characterization, parameters, decision-maker's preferences, or algorithms. However, there is a lack of approaches where ontologies are ap-plied in a direct way into the optimization process, with the aim of enhancing it by allowing the systematic incorporation of additional domain knowledge. This is due to the high level of abstraction of ontologies, which makes them difficult to be mapped into the code implementing the problems and/or the specific operators of metaheuristics. In this paper, we present a strategy to inject domain knowledge (by reusing existing ontologies or creating a new one) into a problem implementation that will be optimized using a metaheu-ristic. Thus, this approach based on accepted ontologies enables building and exploiting complex computing systems in optimization problems. We describe a methodology to automatically induce user choices (taken from the ontology) into the problem implementations provided by the jMetal op-timization framework. With the aim of illustrating our proposal, we focus on the urban domain. Concretely, We start from defining an ontology repre-senting the domain semantics for a city (e.g., building, bridges, point of inte-rest, routes, etc.) that allows defining a-priori preferences by a decision ma-ker in a standard, reusable, and formal (logic-based) way. We validate our proposal with several instances of two use cases, consisting in bi-objective formulations of the Traveling Salesman Problem (TSP) and the Radio Net-work Design problem (RND), both in the context of an urban scenario. The results of the experiments conducted show how the semantic specification of domain constraints are effectively mapped into feasible solutions of the tackled TSP and RND scenarios. TUniversidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
El desarrollo de la competencia de liderazgo en adolescentes en la ciudad de Tijuana
La presente investigación se centró en describir el desarrollo del liderazgo en cinco componentes en adolescentes en la ciudad de Tijuana teniendo como base la teorÃa del liderazgo transformacional, con un enfoque mixto CUAN y CUAL en un diseño exploratorio por etapas consecutivas. Para la primera etapa se elaboró una lÃnea base del liderazgo con una muestra de 165 adolescentes. En la segunda etapa participaron 11 adolescentes en un programa diseñado para la formación de lÃderes seleccionando a 5 de ellos para la muestra. Los principales resultados: los adolescentes tienen un conocimiento sobre sà mismos y saben enunciar sus fortalezas y debilidades, son positivos y optimistas. En general se consideran personas llenas de energÃa y curiosidad. Se muestran signos de una transición de la etapa de desarrollo moral convencional a los post-convencional. Sus valores son los religiosos, ecológicos y afectivos. Transitan de una estrategia cognitiva de tipo intuitiva a una sensorial, lo que demuestra el paso del pensamiento concreto al abstracto. Hay signos de una mayor concientización sobre las consecuencias de sus actos, asà como de la capacidad de autogestión. Tienen un conocimiento general sobre lo que es un lÃder, se perciben como lÃderes y las caracterÃsticas que deben desarrolla
Algoritmo Evolutivo Multi-Objectivo para la Toma de Decisiones Interactiva en Optimización Dinámica
Debido al creciente interés en el análisis de datos en streaming en entornos Big Data para la toma de decisiones, cada vez es más común la aparición de problemas de optimización dinámica que involucran dos o más objetivos en conflicto. Sin embargo, los enfoques que combinan optimización dinámica multi-objetivo con la articulación de preferencias para la toma de decisiones son todavÃa escasos. En este artÃculo, proponemos un nuevo algoritmo de optimización dinámica multi-objetivo llamado InDM2, que permite incorporar preferencias del experto (humano) de cara a la toma de decisiones para guiar el proceso de búsqueda. Con InDM2, el decisor no solo puede expresar sus preferencias mediante uno o más puntos de referencia (que definen la la región de interés deseada), sino que estos puntos también se pueden modificar de manera interactiva. La propuesta incorpora métodos para mostrar gráficamente las diferentes aproximaciones de la región de interés obtenidas durante el proceso de optimización. El decisor puede asà inspeccionar y cambiar, en tiempo de optimización, la región de interés de acuerdo con la información mostrada. Las principales caracterÃsticas de InDM2 son descritas y se analiza su funcionamiento mediante casos de uso académicos.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Spectral classification and properties of the O Vz stars in the Galactic O-Star Spectroscopic Survey (GOSSS)
On the basis of the Galactic O-Star Spectroscopic Survey (GOSSS), a detailed
systematic investigation of the O Vz stars is presented. The currently used
spectral classification criteria are rediscussed, and the Vz phenomenon is
recalibrated through the addition of a quantitative criterion based on the
equivalent widths of the He I 4471, He II 4542, and He II 4686 spectral lines.
The GOSSS O Vz and O V populations resulting from the newly adopted spectral
classification criteria are comparatively analyzed. The locations of the O Vz
stars are probed, showing a concentration of the most extreme cases toward the
youngest star forming regions. The occurrence of the Vz spectral peculiarity in
a solar-metallicity environment, as predicted by the fastwind code, is also
investigated, confirming the importance of taking into account several
processes for the correct interpretation of the phenomenon.Comment: Accepted for publication in The Astronomical Journa
Phenotypic and genotypic profile of clinical and animal multidrug-resistant Salmonella enterica isolates from Mexico
Descripción de Salmonella enterica multirresistenteAims: The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug-resistant (MDR) isolates from food-producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico).
Methods and Results: A total of 243 isolates were evaluated in terms of antimicrobial resistance (AMR) and related genes through a disk diffusion method and PCR respectively; we found 16 MDR isolates, all of them harbouring the blaCMY gene but not qnr genes, these isolates represent less than 10% of the collection. The pulsed-field gel electrophoresis revealed a
higher genotypic similitude within isolates of State of Mexico than Jalisco.
Conclusions: A low percentage of Salmonella isolates were resistant to relevant antibiotics in human health, nevertheless, the AMR and involved genes were similar despite the different serovars and origin of the isolates.
Significance and Impact of the Study: This investigation rovided an insight of the current status of AMR of Salmonella isolates in two States of Mexico and pinpoint the genes involved in AMR and their epidemiological relationship, the information could help to determine an adequate therapy in human and eterinary medicine
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