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Hernández del Olmo, Félix

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0000-0002-0567-9572
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Hernández del Olmo
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Félix
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2018 - 201942020 - 20233
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Mostrando 1 - 7 de 7
  • Miniatura
    Publicación
    An Adaptive, Comprehensive Application to Support Home-Based Visual Training for Children With Low Vision
    (IEEE, 2019) Matas, Yolanda; Santos, Carlos; Hernández del Olmo, Félix; Gaudioso Vázquez, Elena
    Low vision is a visual impairment that cannot be improved by standard vision aids such as glasses. Therefore, to improve their visual skills, people affected by low vision usually follow a visual training program planned and supervised by an expert in this eld. Visual training is especially suitable for children because of their plasticity for learning. However, due to a lack of specialists, training sessions are usually less frequent than optimal. Thus, home-based visual training has emerged as a solution to this problem because it can be undertaken by experts and families together. We implemented the Visual Stimulation on the Internet (EVIN) application, which provides comprehensive visual training tasks through games. It also provides reports on children's performance in these visual training tasks. Although EVIN has shown its usefulness in previous works, two main solutions are needed: (i) a support setup to help experts and families work together to address, among other things, the large variety of exercises and different congurations that can be prescribed and (ii) a rigorous experimental design to compare children trained with EVIN and those trained with traditional materials. To face these challenges, we present an adaptive version of EVIN that provides a new design tool that allows experts to plan visual training tasks through templates in advance. In addition, we developed new metrics and reports to achieve a more accurate assessment of a child's improvement. Among other results, it allowed us to develop an reliable experiment to evaluate signicant improvements in children trained with EVIN.
  • Miniatura
    Publicación
    Tackling the start-up of a reinforcement learning agent for the control of wastewater treatment plants
    (Elsevier, 2018) Hernández del Olmo, Félix; Gaudioso Vázquez, Elena; Dormido Canto, Raquel; Duro Carralero, Natividad
    Reinforcement learning problems involve learning by doing. Therefore, a reinforcement learning agent will have to fail sometimes (while doing) in order to learn. Nevertheless, even with this starting error, introduced at least during the non-optimal learning stage, reinforcement learning can be affordable in some domains like the control of a wastewater treatment plant. However, in wastewater treatment plants, trying to solve the day-to-day problems, plant operators will usually not risk to leave their plant in the hands of an inexperienced and untrained reinforcement learning agent. In fact, it is somewhat obvious that plant operators will require firstly to check that the agent has been trained and that it works as it should at their particular plant. In this paper, we present a solution to this problem by giving a previous instruction to the reinforcement learning agent before we let it act on the plant. In fact, this previous instruction is the key point of the paper. In addition, this instruction is given effortlessly by the plant operator. As we will see, this solution does not just solve the starting up problem of leaving the plant in the hands of an untrained agent, but it also improves the future performance of the agent.
  • Miniatura
    Publicación
    Machine Learning Weather Soft-Sensor for Advanced Control ofWastewater Treatment Plants
    (MDPI, 2019) Hernández del Olmo, Félix; Gaudioso Vázquez, Elena; Duro Carralero, Natividad; Dormido Canto, Raquel
    Control of wastewater treatment plants (WWTPs) is challenging not only because of their high nonlinearity but also because of important external perturbations. One the most relevant of these perturbations is weather. In fact, different weather conditions imply different inflow rates and substance (e.g., N-ammonia, which is among the most important) concentrations. Therefore, weather has traditionally been an important signal that operators take into account to tune WWTP control systems. This signal cannot be directly measured with traditional physical sensors. Nevertheless, machine learning-based soft-sensors can be used to predict non-observable measures by means of available data. In this paper, we present novel research about a new soft-sensor that predicts the current weather signal. This weather prediction differs from traditional weather forecasting since this soft-sensor predicts the weather conditions as an operator does when controling the WWTP. This prediction uses a model based on past WWTP influent states measured by only a few physical and widely applied sensors. The results are encouraging, as we obtained a good accuracy level for a relevant and very useful signal when applied to advanced WWTP control systems.
  • Miniatura
    Publicación
    EVIN, una aplicación adaptativa integral para el entrenamiento visual online de niños con baja visión
    (International Journal of Developmental and Educational Psychology, 2021) Santos Plaza, Carlos Manuel; Matas Martín, Yolanda; Hernández del Olmo, Félix; Gaudioso Vázquez, Elena
    La baja visión es una deficiencia visual que no puede ser mejorada con ayudas ópticas convencionales. No obstante, para incrementar sus habilidades estas personas pueden seguir un programa de entrenamiento visual planificado y supervisado por un experto en este campo. Este entrenamiento es especialmente efectivo en niños, debido a su plasticidad para aprender. Pero, debido a la falta de expertos especializados, las sesiones de entrenamiento son generalmente menos frecuentes de lo que sería conveniente. Los programas de entrenamiento visual online son una solución para mitigar este problema, porque pueden ser llevado a efecto por expertos y familias de forma conjunta. De este modo, desarrollamos la aplicación Estimulación Visual en Internet (EVIN), que proporciona un programa de entrenamiento visual en diferentes tareas a través de juegos. Además, presenta informes de los resultados de los niños durante el entrenamiento. Aunque en trabajos anteriores ya se ha probado la utilidad de EVIN, se ha visto necesaria abordar dos nuevas metas: (i) proporcionar algún tipo de soporte en EVIN que ayude a expertos y familias a trabajar juntos debido, entre otras causas, a la gran variedad de ejercicios y configuraciones que pueden ser prescritas a los niños y, (ii) diseñar un riguroso experimento para comparar el entrenamiento visual en niños con EVIN con el entrenamiento con métodos tradicionales. Para afrontar estos objetivos, presentamos una versión adaptativa de EVIN que proporciona una nueva herramienta que permite al experto planificar el entrenamiento visual usando plantillas de ejercicios prediseñadas. Además, hemos desarrollado nuevas métricas e informes que permiten valorar con mayor precisión los resultados de los niños. Todo ello nos ha permitido desarrollar un experimento para evaluar si se produce mejora significativa en los niños entrenados con EVIN.
  • Miniatura
    Publicación
    Automatic assignment of reviewers in an online peer assessment task based on social interactions
    (Wiley Online Library, 2019) Anaya, Antonio R.; Luque Gallego, Manuel; Letón Molina, Emilio; Hernández del Olmo, Félix
    Online peer assessment tasks are very popular and have unique characteristics that improve learning and encourage social interactions in a distance education environment. Unfortunately, social factors have usually been ignored in the process of selecting reviewers for online peer assessment tasks. We hypothesise that this fact could have some influence on the lack of engagement and participation by some learners. For this reason, we propose an approach in which social network analysis techniques, expert criteria, and Bayesian reasoning are applied to select reviewers with the objective of increasing participation in peer review tasks. The approach is divided into two elements. On the one hand, we have developed an influence diagram template that structures a set of proposed social network analysis variables in accordance with expert criteria. This influence diagram template can be easily updated for any course simply by eliciting a minimal set of parameters. On the other hand, we have instantiated the proposed influence diagram template to produce an influence diagram network to quantify the quality of reviewer assignment for an online peer assessment task. In an online experiment, we verified that the consideration of social factors can increase participation in a peer assessment task.
  • Miniatura
    Publicación
    Advanced Control by Reinforcement Learning for Wastewater Treatment Plants: A Comparison with Traditional Approaches
    (MDPI, 2023) Gorrotxategi Zipitria, Mikel; Hernández del Olmo, Félix; Gaudioso Vázquez, Elena; Duro Carralero, Natividad; Dormido Canto, Raquel
    Control mechanisms for biological treatment of wastewater treatment plants are mostly based on PIDS. However, their performance is far from optimal due to the high non-linearity of the biological and changing processes involved. Therefore, more advanced control techniques are proposed in the literature (e.g., using artificial intelligence techniques). However, these new control techniques have not been compared to the traditional approaches that are actually being used in real plants. To this end, in this paper, we present a comparison of the PID control configurations currently applied to control the dissolved oxygen concentration (in the active sludge process) against a reinforcement learning agent. Our results show that it is possible to have a very competitive operating cost budget when these innovative techniques are applied.
  • Miniatura
    Publicación
    Machine learning algorithm to characterize antimicrobial resistance associated with the International Space Station surface microbiome
    (BioMed Central (Springer), 2022) Madrigal, Pedro; Singh, Nitin K.; Wood, Jason M.; Mason, Christopher E.; Venkateswaran, Kasthuri; Beheshti, Afshin; Gaudioso Vázquez, Elena; Hernández del Olmo, Félix
    Background: Antimicrobial resistance (AMR) has a detrimental impact on human health on Earth and it is equally concerning in other environments such as space habitat due to microgravity, radiation and confinement, especially for long-distance space travel. The International Space Station (ISS) is ideal for investigating microbial diversity and virulence associated with spaceflight. The shotgun metagenomics data of the ISS generated during the Microbial Tracking–1 (MT-1) project and resulting metagenome-assembled genomes (MAGs) across three flights in eight different locations during 12 months were used in this study. The objective of this study was to identify the AMR genes associated with whole genomes of 226 cultivable strains, 21 shotgun metagenome sequences, and 24 MAGs retrieved from the ISS environmental samples that were treated with propidium monoazide (PMA; viable microbes). Results: We have analyzed the data using a deep learning model, allowing us to go beyond traditional cut-offs based only on high DNA sequence similarity and extending the catalog of AMR genes. Our results in PMA treated samples revealed AMR dominance in the last flight for Kalamiella piersonii, a bacteria related to urinary tract infection in humans. The analysis of 226 pure strains isolated from the MT-1 project revealed hundreds of antibiotic resistance genes from many isolates, including two top-ranking species that corresponded to strains of Enterobacter bugandensis and Bacillus cereus. Computational predictions were experimentally validated by antibiotic resistance profiles in these two species, showing a high degree of concordance. Specifically, disc assay data confirmed the high resistance of these two pathogens to various beta-lactam antibiotics. Conclusion: Overall, our computational predictions and validation analyses demonstrate the advantages of machine learning to uncover concealed AMR determinants in metagenomics datasets, expanding the understanding of the ISS environmental microbiomes and their pathogenic potential in humans.