261 research outputs found

    New strategies for the aerodynamic design optimization of aeronautical configurations through soft-computing techniques

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    Premio Extraordinario de Doctorado de la UAH en 2013Lozano Rodríguez, Carlos, codir.This thesis deals with the improvement of the optimization process in the aerodynamic design of aeronautical configurations. Nowadays, this topic is of great importance in order to allow the European aeronautical industry to reduce their development and operational costs, decrease the time-to-market for new aircraft, improve the quality of their products and therefore maintain their competitiveness. Within this thesis, a study of the state-of-the-art of the aerodynamic optimization tools has been performed, and several contributions have been proposed at different levels: -One of the main drawbacks for an industrial application of aerodynamic optimization tools is the huge requirement of computational resources, in particular, for complex optimization problems, current methodological approaches would need more than a year to obtain an optimized aircraft. For this reason, one proposed contribution of this work is focused on reducing the computational cost by the use of different techniques as surrogate modelling, control theory, as well as other more software-related techniques as code optimization and proper domain parallelization, all with the goal of decreasing the cost of the aerodynamic design process. -Other contribution is related to the consideration of the design process as a global optimization problem, and, more specifically, the use of evolutionary algorithms (EAs) to perform a preliminary broad exploration of the design space, due to their ability to obtain global optima. Regarding this, EAs have been hybridized with metamodels (or surrogate models), in order to substitute expensive CFD simulations. In this thesis, an innovative approach for the global aerodynamic optimization of aeronautical configurations is proposed, consisting of an Evolutionary Programming algorithm hybridized with a Support Vector regression algorithm (SVMr) as a metamodel. Specific issues as precision, dataset training size, geometry parameterization sensitivity and techniques for design of experiments are discussed and the potential of the proposed approach to achieve innovative shapes that would not be achieved with traditional methods is assessed. -Then, after a broad exploration of the design space, the optimization process is continued with local gradient-based optimization techniques for a finer improvement of the geometry. Here, an automated optimization framework is presented to address aerodynamic shape design problems. Key aspects of this framework include the use of the adjoint methodology to make the computational requirements independent of the number of design variables, and Computer Aided Design (CAD)-based shape parameterization, which uses the flexibility of Non-Uniform Rational B-Splines (NURBS) to handle complex configurations. The mentioned approach is applied to the optimization of several test cases and the improvements of the proposed strategy and its ability to achieve efficient shapes will complete this study

    New strategies for the aerodynamic design optimization of aeronautical configurations through soft-computing techniques

    Get PDF
    Premio Extraordinario de Doctorado de la UAH en 2013Lozano Rodríguez, Carlos, codir.This thesis deals with the improvement of the optimization process in the aerodynamic design of aeronautical configurations. Nowadays, this topic is of great importance in order to allow the European aeronautical industry to reduce their development and operational costs, decrease the time-to-market for new aircraft, improve the quality of their products and therefore maintain their competitiveness. Within this thesis, a study of the state-of-the-art of the aerodynamic optimization tools has been performed, and several contributions have been proposed at different levels: -One of the main drawbacks for an industrial application of aerodynamic optimization tools is the huge requirement of computational resources, in particular, for complex optimization problems, current methodological approaches would need more than a year to obtain an optimized aircraft. For this reason, one proposed contribution of this work is focused on reducing the computational cost by the use of different techniques as surrogate modelling, control theory, as well as other more software-related techniques as code optimization and proper domain parallelization, all with the goal of decreasing the cost of the aerodynamic design process. -Other contribution is related to the consideration of the design process as a global optimization problem, and, more specifically, the use of evolutionary algorithms (EAs) to perform a preliminary broad exploration of the design space, due to their ability to obtain global optima. Regarding this, EAs have been hybridized with metamodels (or surrogate models), in order to substitute expensive CFD simulations. In this thesis, an innovative approach for the global aerodynamic optimization of aeronautical configurations is proposed, consisting of an Evolutionary Programming algorithm hybridized with a Support Vector regression algorithm (SVMr) as a metamodel. Specific issues as precision, dataset training size, geometry parameterization sensitivity and techniques for design of experiments are discussed and the potential of the proposed approach to achieve innovative shapes that would not be achieved with traditional methods is assessed. -Then, after a broad exploration of the design space, the optimization process is continued with local gradient-based optimization techniques for a finer improvement of the geometry. Here, an automated optimization framework is presented to address aerodynamic shape design problems. Key aspects of this framework include the use of the adjoint methodology to make the computational requirements independent of the number of design variables, and Computer Aided Design (CAD)-based shape parameterization, which uses the flexibility of Non-Uniform Rational B-Splines (NURBS) to handle complex configurations. The mentioned approach is applied to the optimization of several test cases and the improvements of the proposed strategy and its ability to achieve efficient shapes will complete this study

    El Portfolio como estrategia de evaluación compartida de la comprensión lectora

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    El Portfolio, como estrategia de evaluación compartida de la comprensión lectora en el aula de Educación Primaria, motiva al alumno a seleccionar y justificar aquellos trabajos que muestran su esfuerzo y logro en tareas de comprensión, antes, durante o después de la lectura. Se trata de un instrumento de diagnóstico que puede ser usado por los estudiantes para reflexionar sobre cómo construyen significado fortaleciendo de ese modo su desarrollo metacognitivo como lectores. El presente trabajo es una contribución al proceso de implantación en nuestro Instituto del Portfolio Europeo de las Lenguas (PEL), durante el curso 2006/2007, y tiene como objetivos: 1) identificar los fundamentos teóricos que sustentan el uso del Portfolio en el ámbito del desarrollo de la comprensión lectora; 2) concebir el Portfolio como un instrumento de cambio en los procesos de evaluación tradicional, que asumen que evaluar exige casi con exclusividad que el estudiante se limite a memorizar y “re-citar” fragmentos de un texto cualquiera y 3) aportar orientaciones prácticas sobre cómo trabajar con este instrumento de desarrollo de la capacidad lectora. La escasa o nula aplicación de esta estrategia de autoevaluación en la Etapa de Primaria sugiere la necesidad de difundir y promover el uso de este instrumento que suscita en los estudiantes, la responsabilidad y el control sobre su propio proceso de construcción de significado lector.A portfolio approach to collaborative reading assessment in Primary Education is a collection of students’ work gathered by the student across different situations before, during or after reading, showing their effort, progress and achievement in reading comprehension. The portfolio is a diagnostic tool that students use to reflect upon their process of learning to strengthen their metacognitive awareness as readers. As a contribution to the implementation of the European Language Portfolio (ELP), during the academic year 2006-2007 in our School*, the purposes of this article are: (1) to identify the theoretical rationale supporting the use of portfolio in reading comprehension development; (2) to understand the Portfolio as an agent of change and an alternative to traditional ways of assessing reading comprehension that only requires the student factual recall of information, re-citing parts of the text; (3) to provide procedural guidelines for the use of this diagnostic tool in reading comprehension development. The meager application of this strategy in our Primary Schools suggests the need for the promotion of this assessment tool in order for the students to develop a metacognitive and reflective stance, self-assessment, responsibility and control of their own meaning making process of reading.Le Portfolio, utilisé comme stratégie de collaboration dans l’apprentissage de la lectura compréhension à l’école primaire, est source de motivation pour l’élève. Cet outil permet de sélectionner et de justifier plusieurs tâches de compréhension réussies aussi bien avant, que pendant et après la lecture, mettant ainsi en avant les succès accomplis par l’élève. Il s’agit d’un outil de diagnostique pouvant être utilisé par les élèves, afin de réfléchir à leur niveau de compréhension tout en renforçant leur développement métacognitif en tant que lecteurs. Ce document prétend raconter le processus d’implantation au sein de notre Lycée du Portfolio Européen des Langues (PEL), au cours de l’année scolaire 2006/07. Il a pour objectifs : 1) mettre l’accent sur les fondements théoriques sur lesquels s’appuie l’utilisation du Portfolio dans la perspective du développement de la lecture compréhension ; 2) concevoir le Portfolio comme un outil de changement capable de se substituer aux méthodes traditionnelles d’évaluation qui demandent uniquement à l’élève de mémoriser et ré-citer des extraits d’un texte, et 3) fournir des informations pratiques sur la manière d’utiliser cet outil pour développer les capacités de compréhension du texte écrit. L’application de cette stratégie dans nos écoles primaires étant nulle ou rare, cela implique le besoin de promouvoir cet outil, pour que les élèves puissent développer une approche de réflexion métacognitive, l’auto évaluation de leur progression, la prise en responsabilité et le contrôle du processus de construction du sens en tant que lecteurs

    Chloroplast damage induced by the inhibition of fatty acid synthesis triggers autophagy in chlamydomonas

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    Fatty acids are synthesized in the stroma of plant and algal chloroplasts by the fatty acid synthase complex. Newly synthesized fatty acids are then used to generate plastidial lipids that are essential for chloroplast structure and function. Here, we show that inhibition of fatty acid synthesis in the model alga Chlamydomonas reinhardtii activates autophagy, a highly conserved catabolic process by which cells degrade intracellular material under adverse conditions to maintain cell homeostasis. Treatment of Chlamydomonas cells with cerulenin, a specific fatty acid synthase inhibitor, stimulated lipidation of the autophagosome protein ATG8 and enhanced autophagic flux. We found that inhibition of fatty acid synthesis decreased monogalactosyldiacylglycerol abundance, increased lutein content, down-regulated photosynthesis, and increased the production of reactive oxygen species. Electron microscopy revealed a high degree of thylakoid membrane stacking in cerulenin-treated cells. Moreover, global transcriptomic analysis of these cells showed an up-regulation of genes encoding chloroplast proteins involved in protein folding and oxidative stress and the induction of major catabolic processes, including autophagy and proteasome pathways. Thus, our results uncovered a link between lipid metabolism, chloroplast integrity, and autophagy through a mechanism that involves the activation of a chloroplast quality control system.Ministerio de Economía y Competitividad BFU2015-68216-PJunta de Andalucía CVI-7336, BIO2015-74432-JI

    Aerodynamic shape optimization of a 3D wing via volumetric B-Splines

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    This paper shows a gradient-based aerodynamic shape optimization of a threedimensional wing using volumetric B-Splines. The wing is enclosed in a volumetric parallelepiped, commonly referred as control box, which can be seen as a rubber box that deforms the enclosed space. The deformation of the wing is provided by the manipulation of the control points, where the gradients are calculated using the continuous adjoint solution. This technique can be applied to arbitrary three dimensional complex designs and provides some advantages over other traditional geometry parameterization methods, such as deformation locality and the ability to handle some geometric constraints

    Ethical challenges in the development of virtual assistants powered by large language models

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    Virtual assistants (VAs) have gained widespread popularity across a wide range of applications, and the integration of Large Language Models (LLMs), such as ChatGPT, has opened up new possibilities for developing even more sophisticated VAs. However, this integration poses new ethical issues and challenges that must be carefully considered, particularly as these systems are increasingly used in public services: transfer of personal data, decision-making transparency, potential biases, and privacy risks. This paper, an extension of the work presented at IberSPEECH 2022, analyzes the current regulatory framework for AI-based VAs in Europe and delves into ethical issues in depth, examining potential benefits and drawbacks of integrating LLMs with VAs. Based on the analysis, this paper argues that the development and use of VAs powered by LLMs should be guided by a set of ethical principles that prioritize transparency, fairness, and harm prevention. The paper presents specific guidelines for the ethical use and development of this technology, including recommendations for data privacy, bias mitigation, and user control. By implementing these guidelines, the potential benefits of VAs powered by LLMs can be fully realized while minimizing the risks of harm and ensuring that ethical considerations are at the forefront of the development process.Agencia Gallega de Innovación (GAIN)Xunta de Galicia | Ref. ED431B 2021/2

    Decreased glycogen synthase kinase-3 levels and activity contribute to Huntington's disease

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    © The Author 2015. Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by brain atrophy particularly in striatum leading to personality changes, chorea and dementia. Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase in the crossroad of many signaling pathways that is highly pleiotropic as it phosphorylates more than hundred substrates including structural, metabolic, and signaling proteins. Increased GSK-3 activity is believed to contribute to the pathogenesis of neurodegenerative diseases like Alzheimer's disease and GSK-3 inhibitors have been postulated as therapeutic agents for neurodegeneration. Regarding HD, GSK-3 inhibitors have shown beneficial effects in cell and invertebrate animal models but no evident efficacy in mouse models. Intriguingly, those studies were performed without interrogating GSK-3 level and activity in HD brain. Herewe aim to explore the level and also the enzymatic activity of GSK-3 in the striatum and other less affected brain regions of HD patients and of the R6/1 mouse model to then elucidate the possible contribution of its alteration to HD pathogenesis by genetic manipulation in mice.We report a dramatic decrease in GSK-3 levels and activity in striatum and cortex of HD patients with similar results in the mouse model. Correction of the GSK-3 deficit inHDmice, by combining with transgenic mice with conditional GSK-3 expression, resulted in amelioration of their brain atrophy and behavioral motor and learning deficits. Thus, our results demonstrate that decreased brain GSK-3 contributes to HD neurological phenotype and open new therapeutic opportunities based on increasing GSK-3 activity or attenuating the harmful consequences of its decrease.This work was supported by Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CiberNed-Instituto de salud Carlos III) and by grants from Ministerio de Ciencia (MEC, MICINN, MINECO), Comunidad Autónoma de Madrid and Fundación Ramón Areces. A.M.Peer Reviewe

    Effect of exercise on bone health in children and adolescents with cancer during and after oncological treatment: A systematic review and meta-analysis

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    Background: Although regular physical activity and exercise programs might improve bone health caused by oncological treatment and the disease itself, it remains unknown the pooled effect of exercise interventions following frequency, intensity, time and type prescriptions. Objective: This systematic review and meta-analysis aimed to synthesise evidence regarding the effectiveness of exercise interventions on bone health in children and adolescents with cancer during and after oncological treatment. Methods: A systematic search was conducted in the MEDLINE (via PubMed), Web of Science and Scopus databases from November 2021 to January 2022. Randomised controlled trials (RCTs) and non-RCTs reporting pre-post changes of the effectiveness of exercise interventions on DXA-measured bone parameters in young population (1–19 years) during or after oncological treatment were included. Pooled (ESs) and 95% confidence intervals (95%CIs) were calculated. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results: A total of eight trials with 341 participants were included. The metaanalyses did not reveal a statistically significant increase in whole body areal bone mineral density (ES = 0.10; 95%CI: −0.14, 0.34), lumbar spine (ES = 0.03; 95%CI: −0.21, 0.26) or femoral neck (ES = 0.10; 95%CI: −0.37, 0.56). Similarly, during the oncological treatment phase the ES was 0.04 (95%CI: −0.17, 0.25) and after the ES was 0.07 (95%CI: −0.20, 0.33). Conclusion: To date, exercise interventions have been inappropriate and therefore, ineffective to illustrate any beneficial effect on bone health in children and adolescents with cancer during and after oncological treatment.Spanish Ministry of Science and Innovation (ref: PID2020-117302RA-I00La Caixa Foundation (ref: LCF/BQ/PR19/11700007)the University of Granada Plan Propio de Investigación 2021-Excellence actions: Unit of Excellence on Exercise, Nutrition and Health (UCEENS)CIBEROBN, Centro de Investigación Biomédica en Red (CB22/03/ 00058Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea – European Regional Development Fund. AM-P is recipient of a predoctoral fellowship (FPU20/05530) by the Spanish Ministry of Education, Culture and Sport. EU-G is supported by the Maria Zambrano fellowship by the Ministerio de Universidades y la Unión Europea—NextGenerationEU

    Practical Characterization of Cell-Electrode Electrical Models in Bio-Impedance Assays

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    This paper presents the fitting process followed to adjust the parameters of the electrical model associated to a cell-electrode system in Electrical Cell-substrate Impedance Spectroscopy (ECIS) technique, to the experimental results from cell-culture assays. A new parameter matching procedure is proposed, under the basis of both, mismatching between electrodes and time-evolution observed in the system response, as consequence of electrode fabrication processes and electrochemical performance of electrode-solution interface, respectively. The obtained results agree with experimental performance, and enable the evaluation of the cell number in a culture, by using the electrical measurements observed at the oscillation parameters in the test circuits employed.Ministerio de Economía y Competitividad TEC2013-46242-C3-1-
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