Verificación de identidad en la educación virtual mediante análisis biométrico basado en la dinámica del tecleo

Virtual education has become one of the tools most widely used by students at all educational levels, not just because of its convenience and flexibility, but also because it can expand educational coverage. All these benefits also bring along multiple issues in terms of security and reliability in the evaluation the of student’s knowledge because traditional identity verification strategies, such as the combination of username and password, do not guarantee that the student enrolled in the course really takes the exam. Therefore, a system with a different type of verification strategy should be designed to differentiate valid users from impostors. This study proposes a new verification system based on distances computed among Gaussian Mixture Models created with different writing task. The proposed approach is evaluated in two different modalities namely intrusive verification and non-intrusive verification. The intrusive mode provides a false positive rate of around 16 %, while the non-intrusive mode provides a false positive rate of 12 % In addition, the proposed strategy for non-intrusive verification is compared to a work previously reported in the literature and the results show that our approach reduces the equal error rate in about 24.3 %. The implemented strategy does not need additional hardware; only the computer keyboard is required to complete the user verification, which makes the system attractive, flexible, and practical for virtual education platforms.La educación virtual se ha convertido en una de las herramientas más utilizadas por los estudiantes en todos los niveles educativos, no solo por la comodidad y la flexibilidad, sino también por la posibilidad de ampliar la cobertura educativa en una población. Todos estos beneficios traen consigo múltiples problemas de seguridad y confiabilidad a la hora de evaluar el proceso de aprendizaje del estudiante, ya que las estrategias tradicionales de verificación de identidad, como la combinación de nombre de usuario y contraseña, no garantizan que el estudiante matriculado en el curso realmente realice el examen. Por lo tanto, es necesario diseñar un sistema con otro tipo de estrategia de verificación para diferenciar un usuario válido de un impostor. Este estudio propone un nuevo método de verificación, basado en el cálculo de distancias entre los modelos de mezclas gaussianas creados con diferentes tareas de escritura. El enfoque propuesto es evaluado en dos modalidades diferentes llamadas verificación intrusiva y verificación no intrusiva. El modo intrusivo proporciona una tasa de falsos positivos de 16 %, mientras el modo no intrusivo provee una tasa de falsos positivos de 12 %. Además, la estrategia propuesta para verificación no intrusiva es comparada con un trabajo previamente reportado en la literatura y los resultados muestran que nuestro enfoque reduce la tasa de error en aproximadamente un 24.3 %. La estrategia implementada no necesita hardware adicional, solo es requerido el teclado del computador para realizar la verificación, lo que hace que el sistema sea atractivo y flexible para ser usado en plataformas de educación virtual

Predicting PSR Filters by Transverse Relaxation Enhancements

The paramagnetic spin relaxation (PSR) filter allows the suppression of the NMR resonances of individual components in mixtures according to their Gd3+-complexing ability. The difficulty in predicting this property hampers, however, the widespread application of this filter. Herein we describe that the PSR filter is dominated by the transverse relaxation enhancement (R2p) experienced by nuclei in the presence of Gd3+, so that R2p represents a reliable predictive tool of suppression in the 1D and 2D PSR filter of complex mixtures. The robustness of R2p as a predictive tool in PSR filters has been demonstrated at different magnetic fields and for the 1H, 13C, COSY, and HMQC filtering of commercial multicomponent compositions, including beverages and drugsThis work was financially supported by the Spanish Government (CTQ2012-34790, CTQ2012-33436) and the Xunta de Galicia (CN2011/037). L.F.P. thanks the Portuguese Foundation for Science and Technology (FCT MCTES) for a Ph.D. grant (SFRH/BD/37341/2007)S

Identification of new sources of resistance to RHBV- rice hoja blanca virus

With the aim to find new sources of resistance to rice hoja blanca (white leaf) disease, transmitted by the insect Tagosodes orizicolus, 660 genotypes were evaluated under greenhouse and field conditions. Seven resistant genotypes were identified, and genomic studies were performed to demonstrate that the resistance in these sources is genetically different from that of Fedearroz 2000, which is currently the variety with the most resistance to hoja blanca. These new resistance sources constitute a resource that can be used to sustainably extend hoja blanca disease management throughout all of the rice-growing regions of tropical America. This is the first report of hoja blanca resistance in indica rice and different from that of Fedearroz 2000

Parameter extraction techniques for the analysis and modeling of resistive memories

A revision of the different numerical techniques employed to extract resistive switching (RS) and modeling parameters is presented. The set and reset voltages, commonly used for variability estimation, are calculated for different resistive memory technologies. The methodologies to extract the series resistance and the parameters linked to the charge-flux memristive modeling approach are also described. It is found that the obtained cycle-to-cycle (C2C) variability depends on the numerical technique used. This result is important, and it implies that when analyzing C2C variability, the extraction technique should be described to perform fair comparisons between different resistive memory technologies. In addition to the use of extensive experimental data for different types of resistive memories, we have also included kinetic Monte Carlo (kMC) simulations to study the formation and rupture events of the percolation paths that constitute the conductive filaments (CF) that allow resistive switching operation in filamentary unipolar and bipolar devices.Consejería de Conocimiento, Investigaci ́on y Universidad, Junta de Andalucía (Spain) and the FEDER program for the projects A.TIC.117.UGR18, B-TIC-624-UGR20 and IE2017-5414Ramón y Cajal grant No. RYC2020-030150-IFunding for open access charge: Universidad de Granada/CBU

Paz es entender lo que somos: prácticas socioculturales de paz en Quibdó

This paper presents the research findings of the project Socio-cultural Practices of Peace in Quibdó (Prácticas socioculturales de paz en Quibdó), which aims to contribute to understanding peacebuilding out of the daily life of communities from the capital of Chocó. A contextualized analysis of Quibdó is proposed regarding peacebuilding from cultural practices. This qualitative research study unfolds a hermeneutic phenomenological methodology. The information analysis was carried out by triangulating information, with primary and secondary sources, through ten semi-structured, in-depth interviews. The axial and categorical coding was carried out using the ATLAS.ti software, version 7.5. The study found that the recognition of peace from a territorial approach based on daily cultural practices allows both resignification of memory and appropriation of social environment, historical memory and non-violence. The study concludes that socio-cultural practices of peace make it possible to demonstrate the vindication of the "Afro" and the "Chocoano", thus recognizing the need to integrate aspects such as gender, ethnicity and social commitment in coexistence with others.El artículo presenta los resultados de investigación del proyecto «Prácticas socioculturales de paz en Quibdó», que busca contribuir a la comprensión de la construcción de paz desde la cotidianidad de las comunidades de la capital del Chocó. Se plantea un análisis contextualizado de Quibdó frente a la construcción de paz desde las prácticas culturales. El enfoque es cualitativo, desde una metodología hermenéutico-fenomenológica. El análisis de la información se realizó a partir de la triangulación de información con fuentes primarias y secundarias a través de diez entrevistas semiestructuradas a profundidad. La codificación axial y categorial se realizó mediante el software ATLAS.ti, versión 7.5. Se encontró que el reconocimiento de la paz desde un enfoque territorial a partir de prácticas culturales cotidianas permite la resignificación de la memoria y la apropiación del entorno social, la memoria histórica y la no violencia. Se concluye que las prácticas socioculturales de paz permiten evidenciar la reivindicación de lo «afro» y lo «chocoano», reconociendo la necesidad de integrar aspectos como el género, lo étnico y el compromiso social en coexistencia con los otros

Genetic diversity of Ectocarpus (Ectocarpales, Phaeophyceae) in Peru and northern Chile, the area of origin of the genome-sequenced strain

International audienceThe origin of the Ectocarpus strain used for genome sequencing (the ‘genome strain’) was Peru, where no Ectocarpus had been reported previously. To study the genetic diversity in the region and to increase the number of individuals from this area available for genetic experiments, 119 new Ectocarpus strains were isolated from eight localities along the 3000 km of coastline from central Peru to central Chile.Internal transcribed spacer 1 (ITS1) genotyping revealed nine different genotypes, five of which were endemic to the area studied and three of which were previously unknown.Individuals of the same genotype as the genome strain occurred from Peru to northernmost Chile, representing 61% of the samples in this area, from which five more genotypes were isolated. Further south, down to central Chile, most individuals belonged to Ectocarpus siliculosus, Ectocarpus fasciculatus and Ectocarpus crouaniorum. In sexual crosses, the genome strain and the new isolates of the same genotype were fully compatible.Sequences from four nuclear and cytoplasmic genetic markers (ITS1, ITS2, Rubisco spacer and Cytochrome‐c oxidase subunit 3 (cox3)) separated the genome strain from the known species of Ectocarpus. It may in future be recognized as a separate species

Visual 3-D SLAM from UAVs

The aim of the paper is to present, test and discuss the implementation of Visual SLAM techniques to images taken from Unmanned Aerial Vehicles (UAVs) outdoors, in partially structured environments. Every issue of the whole process is discussed in order to obtain more accurate localization and mapping from UAVs flights. Firstly, the issues related to the visual features of objects in the scene, their distance to the UAV, and the related image acquisition system and their calibration are evaluated for improving the whole process. Other important, considered issues are related to the image processing techniques, such as interest point detection, the matching procedure and the scaling factor. The whole system has been tested using the COLIBRI mini UAV in partially structured environments. The results that have been obtained for localization, tested against the GPS information of the flights, show that Visual SLAM delivers reliable localization and mapping that makes it suitable for some outdoors applications when flying UAVs

El paro nacional camionero del 2016 : Un estudio de caso sobre el impacto en precios

El paro camionero ocurrido en Colombia durante el 2016 ha sido catalogado como uno de los más largos de la historia de Colombia, en el cual durante 46 días la mayor parte de los transportadores suspendieron actividades. Este texto realiza un análisis de

Variability estimation in resistive switching devices, a numerical and kinetic Monte Carlo perspective

Acknowledgments The authors thank the support of the Spanish Ministry of Science, Innovation and Universities and the FEDER program through projects TEC2017-84321-C4-1-R, TEC2017-84321-C4-3-R, and projects A.TIC.117.UGR18, IE2017-5414 and B.TIC.624.UGR20 funded by the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and the FEDER program. Funding for open access charge: Universidad de Granada/CBUAWe have analyzed variability in resistive memories (Resistive Random Access Memories, RRAMs) making use of advanced numerical techniques to process experimental measurements and simulations based on the kinetic Monte Carlo technique. The devices employed in the study were fabricated using the TiN/Ti/HfO2/W stack. The switching parameters were obtained making use of new developed extraction methods. The appropriateness of the advanced parameter extraction methodologies has been checked by comparison to kinetic Monte Carlo simulations; in particular, the reset and set events have been studied and detected. The data obtained were employed to shed light on the resistive switching operation and the cycle-to-cycle variability. It has been shown that variability depends on the numerical technique employed to obtain the set and reset voltages, therefore, this issue must be taken into consideration in RS characterization and modeling studies. The proposed techniques are complementary and depending on the technology and the curves shape the features of a particular method could make it to be the most appropriate.Spanish Ministry of Science, Innovation and Universities and the FEDER program through projects TEC2017-84321-C4-1-R, TEC2017-84321-C4-3-RConsejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and the FEDER program, projects A.TIC.117.UGR18, IE2017-5414 and B.TIC.624.UGR20Funding for open access charge: Universidad de Granada/CBU