Artículos

URI permanente para esta colección

http://hdl.handle.net/20.500.14454/1634

Examinar

Mostrando 1 - 20 de 1035

A 3D ray launching time-frequency channel modeling approach for UWB ranging applications
(Institute of Electrical and Electronics Engineers Inc., 2020-05-21) Otim, Timothy; López Iturri, Peio; Azpilicueta Fernández de las Heras, Leyre; Bahillo, Alfonso; Díez Blanco, Luis Enrique; Falcone, Francisco
Ultrawideband (UWB) has the ability to achieve decimetre level of ranging accuracy, hence, its wider usage nowadays in the field of positioning. In spite of the attractiveness of UWB, its performance is strongly dependent on the propagation channel. In this paper, an analysis of the the UWB channel for ranging applications using an inhouse developed 3D Ray launching (3D RL) algorithm is presented. A parametric study has been performed considering variations of cuboid size resolution of the simulation mesh, in order to analyze convergence impact on estimation accuracy, focusing on Radio frequency (RF) power levels as well as time domain characterization. The RF power results have been used to model the path-loss, small scale fading, and the power delay profile so as to obtain the statistics of the multipath channel as well as time of flight (TOF) estimation values. The results show that the 3D RL is a valuable tool to test UWB systems for ranging applications with a mean accuracy of up to 10 cm in multipath conditions considering complex scatterer distributions within the complete volume of the scenarios under test.
666 itinerarios por la ciudad partida
(Universidad Pontificia Comillas, CESI-JESPRE, 2023) Lanceros Méndez, Patxi
El drama de lo político atraviesa la Divina Comedia de principio a fin, y es uno de sus hilos conductores: formas de gobierno, hábitos sociales, virtudes, pasiones y vicios políticos aparecen censados, analizados y evaluados, con rigor, a lo largo de toda la magna obra. Los sextos cantos de las tres partes de la Commedia —Inferno, Purgatorio y Paradiso— se ocupan de ese drama de forma intensa: como círculos concéntricos, abarcan un espacio cada vez mayor: Florencia, Italia, el —siempre difuso— Imperio (es decir, el mundo políticamente organizado, la oecumene). El presente artículo analiza esos cantos desde una perspectiva que, insistente, da base y unidad al conjunto: la división de la ciudad, la guerra civil
AA5754 aluminium alloy springback reduction by post forming electro plastic effect (PFEPE)
(Elsevier B.V., 2024-11) Lozares Abasolo, Jokin; Otegi Martinez, Nagore; Trinidad Naranjo, Javier; Barrenetxea Iñarra, Manex; Aizpuru Larrañaga, Iosu; Jimbert Lacha, Pedro José; Mendiguren Olaeta, Joseba
Post Forming Electro Plastic Effect (PFEPE) has been proposed as a promising technology for mitigating forming forces and addressing springback challenges in the metal forming industry. However, several research gaps remain unaddressed for the industrialization of this technology. Firstly, there is a lack of experimental validation regarding the impact of stress reduction on springback. Secondly, the potential effect of the skin-effect on the current metrics of stress reduction needs to be evaluated. Additionally, a post-forming electrically assisted elastoplastic material model is necessary for further technology development in stamping processes. This study tackles these challenges by utilizing AA5754H22 as a reference material and integrating a comprehensive experimental campaign with finite element numerical models and empirical material model developments. Our findings confirm that PFEPE facilitates a significant reduction in springback, achieving approximately a 100% reduction. Although the skin-effect introduces non-uniform current flux density distribution, its impact at the macroscopic level is negligible for the studied thin samples. While the numerical results of springback fails to accurately replicate experimental results, the developed material model aligns well with experimental trends.
AA5754–Al2O3 nanocomposite prepared by friction stir processing: microstructural evolution and mechanical performance
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-04) Mohammed, Moustafa M.; Abdullah, Mahmoud E.; Rohim, M. Nafea M.; Kubit, Andrzej; Derazkola, Hamed Aghajani
The utilization of Al2O3 nanopowder to reinforce AA5754 aluminum alloy through blind holes employing the friction stir processing (FSP) technique to produce an aluminum matrix nanocomposite is explored in this paper. Motivated by the necessity to enhance the strength and ductility of welded joints, the impacts of varying the tool rotational speed (rpm) and blind hole diameter on the microstructure and mechanical properties of the joints are investigated. Experimental characterization techniques including SEM, optical microscopy, microhardness, and tensile tests were employed to analyze the welded joints produced under different processing parameters (tool rotational speeds of 910, 1280, and 1700 rpm, and blind hole diameters of 0, 1, 1.5, and 2 mm). Comparative analyses were conducted against base metal properties and joints without reinforcement powder. It was found that the addition of nanopowder resulted in a decrease in the maximum generated heat during FSP, while also reducing the stir zone size compared to samples without nanopowder. Moreover, enhancements in both the strength and ductility of the joints were observed with the incorporation of Al2O3 nanoparticles. The optimal combination of welding conditions, observed at 1280 rpm rotational speed and 1.5 mm hole diameter, yielded a remarkable ultimate tensile strength of 567 MPa, accompanied by a hardness of 45 HV. These results underscore the potential of nano-Al2O3 reinforcement in significantly improving the mechanical properties of the produced nanocomposite, with implications for advancing the performance of welded structures in various engineering applications
Abnormality detection in nailfold capillary images using deep learning with EfficientNet and cascade transfer learning
(2025-01) Ebadi Jalal, Mona; Emam, Omar S.; Castillo Olea, Cristian; García-Zapirain, Begoña; Elmaghraby, Adel Said
Nailfold Capillaroscopy (NFC) is a simple, non-invasive diagnostic tool used to detect microvascular changes in nailfold. Chronic pathological changes associated with a wide range of systemic diseases, such as diabetes, cardiovascular disorders, and rheumatological conditions like systemic sclerosis, can manifest as observable microvascular changes in the terminal capillaries of nailfolds. The current gold standard relies on experts performing manual evaluations, which is an exhaustive time-intensive, and subjective process. In this study, we demonstrate the viability of a deep learning approach as an automated clinical screening tool. Our dataset consists of NFC images from a total of 225 participants, with normal images accounting for 6% of the dataset. This study introduces a robust framework utilizing cascade transfer learning based on EfficientNet-B0 to differentiate between normal and abnormal cases within NFC images. The results demonstrate that pre-trained EfficientNet-B0 on the ImageNet dataset, followed by transfer learning from domain-specific classes, significantly enhances the classifier's performance in distinguishing between Normal and Abnormal classes. Our proposed model achieved superior performance, with accuracy, precision, recall, F1 score, and ROC_AUC of 1.00, significantly outperforming both models of single transfer learning on the pre-trained EfficientNet-B0 and cascade transfer learning on a convolutional neural network, which each attained an accuracy, precision, recall, and F1 score of 0.67 and a ROC_AUC of 0.83. The framework demonstrates the potential to facilitate early preventive measures and timely interventions that aim to improve healthcare delivery and patients' quality of life.
Achievements and challenges in learning analytics in Spain: the view of SNOLA
(AIESAD (Asociación Iberoamericana de Educación Superior a Distancia), 2020-07-01) Martínez Monés, Alejandra; Dimitriadis Damoulis, Ioannis; Acquila Natale, Emiliano; Álvarez Arana, Ainhoa Izaro; Caeiro Rodríguez, Manuel; Cobos Pérez, Ruth; Conde González, Miguel Ángel; García Peñalvo, Francisco José; Hernández-Leo, Davinia; Menchaca Sierra, Iratxe; Muñoz Merino, Pedro J.; Ros Muñoz, Salvador; Sancho Vinuesa, Teresa
As in other research fields, the development of learning analytics is influenced by the networks of researchers that contribute to it. This paper describes one of such networks: the Spanish Network of Learning Analytics (SNOLA). The paper presents the research lines of the members of SNOLA, as well as the main challenges that learning analytics has to address in the next few years as perceived by these researchers. This analysis is based on SNOLA’s archival data and on a survey carried out to the current members of the network. Although this approach does not cover all the activity related to learning analytics in Spain, the results provide a representative overview of the current state of research related to learning analytics in this context. The paper describes these trends and the main challenges, among which we can point out the need to adopt an ethical commitment with data, to develop systems that respond to the requirements of the end users, and to reach a wider institutional impact.
Action research environments: challenges for their initiation and sustainability
(Springer, 2024-12) Larrea Aranguren, Miren; Finnestrand, Hanne; Aranguren, Mari Jose; Arrona Etxaniz, Ainhoa; Canto Farachala, Martha Patricia; Costamagna, Pablo; Estensoro García, Miren
Las Actitudes educativas del profesorado hacia las altas capacidades: validación de la escala AEPAC
(Grupo FORCE (HUM 386), 2024) Barrenetxea Mínguez, Lucía; Galindo Domínguez, Héctor; Yániz Álvarez de Eulate, Concepción
Para mejorar la formación del profesorado en el ámbito de las altas capacidades (AACC) es importante conocer qué actitudes docentes guían su respuesta educativa. Son varios los instrumentos creados para evaluar las actitudes docentes en este campo, pero es el cuestionario OGE publicado por Gagné (1991) el instrumento más utilizado hoy en día. En el presente estudio señalamos la necesidad de crear un nuevo instrumento y fijamos por objetivo diseñar y validar una escala en español que mida las actitudes educativas del profesorado hacia las AACC. Para ello, se seleccionó el instrumento DATA como base para su traducción y adaptación al español. Tras realizar un análisis exploratorio se observó una falta de consistencia interna, por lo que se reestructuró la escala dando lugar a una nueva formada por tres dimensiones (elitismo, adaptación curricular y aceleración), quienes respondieron 546 docentes desde educación infantil hasta formación profesional. Tras realizar un análisis confirmatorio con la nueva escala se obtuvieron índices favorables de fiabilidad y validez dando como resultado una escala óptima para medir las actitudes educativas del profesorado hacia las AACC
The activation of the temporary protection directive 2001/55/EC for Ukrainian refugees: a demonstration of its uniqueness
(Universidad de Cádiz, 2023) Abrisketa, Joana
The response to the arrival of the Ukrainian population as a consequence of the Russian invasion breaks with the “deterrence paradigm” that has guided the EU’s asylum policies since the end of the Cold War. The flight from Ukraine of 650 000 displaced persons in a period of two weeks –from 24 February to 3 March 2022– led the Council of the EU to recognize “the existence of a mass influx into the Union of displaced persons who have had to leave Ukraine as a consequence of an armed conflict”2. The Council’s unanimous finding of the existence of a “mass influx” situation had never been made before. This article seeks to examine the unprecedented response of the EU through the analysis of the Council Implementing Decision (EU) 2022/382 of 4 March 2022. It concludes that although this is a significant response, it has not succeeded in altering in a general way the approach to the asylum system –far from the principle of solidarity– of the Member States.
Active methodologies: exploring the impact on motivation and psychological variables in physical education
(Frontiers Media SA, 2024-10-07) Valero Valenzuela, Alfonso; Hoyos Cuartas, Luz Amelia; Heredia León, Diego Andrés; León Guereño, Patxi
La actualidad del pensamiento de Gesché en el diálogo entre cristianismo y ciencia
(Universidad de Valladolid, 2024) Martínez Baigorri, Javier; Vásquez Pérez, María Nely ; Viguri Axpe, Miguel Ramón
A lo largo de las últimas décadas un grupo de científicos-teólogos ha desarrollado una reflexión sobre Dios a la luz de la imagen del mundo que nos ofrece la ciencia moderna. En esa tarea emergen como conceptos claves para explicar la acción creadora divina la emergencia y el estudio de la causalidad. Sin duda, el desarrollo de modelos que expliquen dicha acción divina, entre los que destaca el panenteísta, ha supuesto la tarea más importante y se ha resuelto a un nivel filosófico más que teológico. Planteamos en este artículo cómo la teología dogmática de Gesché permite aterrizar desde un punto de vista teológico y confesional la reflexión filosófica.
Actualidad institucional y económica de España en el marco de la Unión Europea (enero de 2024)
(Universidad de Deusto = Deustuko Unibertsitatea, Instituto de Estudios Europeos, 2024) Iñarritu, Beatriz
Actualidad institucional y económica de España en el marco de la Unión Europea (febrero de 2025)
(Universidad de Deusto = Deustuko Unibertsitatea, Instituto de Estudios Europeos, 2025) Rodríguez Talavera, Pablo
El segundo semestre de 2024 ha marcado un período de transformaciones clave para la Unión Europea (UE), tanto a nivel político como económico. La configuración del nuevo Parlamento Europeo y la Comisión Europea estableció una agenda renovada centrada en la sostenibilidad, la cohesión social y la transición digital. Hungría, en su papel como presidencia rotatoria del Consejo de la UE, ha liderado iniciativas enfocadas en reducir disparidades regionales, mejorar la conectividad digital y abordar la seguridad alimentaria en un contexto de tensiones globales. Entre los hitos destacados se encuentran los avances en el proceso de adhesión de Ucrania y Moldavia, consolidando su integración en el bloque europeo. Además, la UE ha reforzado sus relaciones internacionales mediante acuerdos estratégicos en África y Asia Central, y su liderazgo climático ha quedado de manifiesto durante la cumbre climática de Bruselas, donde se establecieron metas ambiciosas para reducir las emisiones de carbono. Estas acciones subrayan el compromiso de la UE con el desarrollo sostenible, la seguridad energética y la integración económica global
Actualidad institucional y económica de España en el marco de la Unión Europea (julio de 2024)
(Universidad de Deusto = Deustuko Unibertsitatea, Instituto de Estudios Europeos, 2024) Rodríguez Talavera, Pablo
Adaptación de la herramienta COMDID-C al euskera
(Sociedad de Estudios Vascos = Eusko Ikaskuntza, 2023) Arteta Elguezua, Joseba; Villardón Gallego, Lourdes ; Bezanilla, María José
Debido a la necesidad de disponer de herramientas para la evaluación de la Competencia Digital Docente (CDD) en la lengua vehicular del sistema educativo, el objetivo de este estudio es disponer de un cuestionario en euskera, la lengua de instrucción del País Vasco (Spain). Con este fin se ha llevado a cabo la adaptación a la lengua vasca de la herramienta COMDID-C
Adaptation and validation of the Spanish version of the Being a Mother scale
(PeerJ Inc., 2024) Riera Martín, Anna; Oliver Roig, Antonio; Cormenzana, Susana; Richart Martínez, Miguel; Martínez Pampliega, Ana
Background. Becoming a mother is a very important process because of the impact it can have on women and their families. Currently, there is no validated questionnaire that evaluates the process of becoming a mother in the Spanish population. Moreover, no consistent results have been obtained to identify significant differences between primiparous and multiparous mothers. Aim. (1) Linguistic and metric validation of the Being a Mother scale (BaM-13) in the Spanish population, (2) analysis of possible differences between primiparous and multiparous mothers’ experience of motherhood. Methods. Instrumental design. In 2016–2017, a sample of 579 mothers with children between 6 and 11 months of age completed the Spanish version of BaM-13. The instrument was translated using forward and back translation. Construct validity, internal consistency, and criterion validity were empirically analyzed. Results. Factorial analyses showed that the scale presented two adequate factors. Internal consistency of the global scale (α = 0.818, ω = 0.861), the Postnatal bonding factor (α = 0.773, ω = 0.784), and the Adult’s experience factor (α = 0.710, ω = 0.721) was adequate. Significant associations were found with postpartum depression (r = 0.560), parental competence (r = −0.584) and postnatal bonding (r = −0.327). In terms of parity, primiparous mothers have greater difficulty in postnatal bonding, compared to multiparous mothers (p = 0.006). Conclusions. The Spanish version of the BaM-13 scale is valid for measuring mothers’ experience of motherhood in a wide range of domains. The findings of the study show the importance of considering parity in the experience of becoming a mother, highlighting the approach to postnatal bonding in primiparous mothers. Additionally, we underline that it should not be assumed that multiparous mothers experience fewer difficulties in their motherhood process.
Adaptive robot behavior based on human comfort using reinforcement learning
(Institute of Electrical and Electronics Engineers Inc., 2024) González Santocildes, Asier; Vazquez, Juan-Ignacio ; Eguíluz, Andoni
This study explores the potential of training robots using reinforcement learning (RL) to adapt their behavior based on human comfort levels during tasks. An experimental environment has been developed and made available to the research community, facilitating the replication of these experiments. The results demonstrate that adjusting a single comfort-related input parameter during training leads to significant variations in the robot's behavior. Detailed discussions of the reward functions and obtained results validate these behavioral adaptations, confirming that robots can dynamically respond to human needs, thereby enhancing human-robot interaction. While the study highlights the effectiveness of this approach, it also raises the question of real-time comfort measurement, suggesting various systems for future exploration. These findings contribute to the development of more intuitive and emotionally responsive robots, offering new possibilities for future research in advancing human-robot interaction.
Addendum: Local elliptic regularity for the Dirichlet fractional Laplacian
(Walter de Gruyter GmbH, 2017) Biccari, Umberto; Warma, Mahamadi; Zuazua, Enrique
In [1], for 1 < p < 1
Adineko pertsonekin estrategia lagunkoiak garatzeko kosorkuntza eta koprodukzio-ekimenak aztertuz: Euskal Autonomia Erkidegoko hiru hiriburuetatik ikasten
(Gobierno Vasco = Eusko Jaurlaritza, 2024-04) Zuñiga, Martín; Buffel, Tine; Arrieta, Felix
Euskal Autonomia Erkidegoan gertatzen ari den zahartze-prozesuak bultzatuta, Pertsona Adinduekin Hiri eta Komunitate Lagunkoiak ekimena lehen-mailako erreferente politiko bihurtu da lurraldean zahartze-politikak garatzeko. Artikulu honek azterketa kualitatibo baten bitartez aztertzen du nola autonomia erkidegoko hiru hiriburuak adineko pertsonen aldeko estrategiak ezartzen ari diren, kosorkuntza- eta koprodukzio-prozesuei begira. Parte hartzeko prozesu horien garapenean gaur egun dituzten erronkak aztertzen ditu artikuluak. Gure ikerketak iradokitzen du inplikazio politikoak, beharrezkoa bada ere, ez duela zentzurik, baldin eta estrategia alderdi interesdun garrantzitsuenen lanean integratzen ez bada. Gainera, adinekoak gehiago errespetatzeko orduan komunitateek duten arrakasta, neurri handi batean, pertsona adinduak, gizarte-azterkeriari aurre egin behar diotenak barne, etorkizuneko ikerkuntzan eta politiketan funtsezko eragile gisa parte hartzen duten ala ez, adinekoak errespetatzen dituzten garapenen inguruan
Adoption of digital technologies and backshoring decisions: is there a link?
(Springer, 2021-12) Kamp, Bart; Gibaja Martíns, Juan José
The present paper assesses whether the adoption of Industry 4.0 technologies can be related to backshoring. It does so by -firstly- investigating the implementation of such technologies by industrial firms with foreign production plants, the experiences and intentions of these firms regarding the location of production activities, and -secondly- by analyzing backshoring cases among them. It finds that backshoring is a rare phenomenon, and it is questionable whether there is a correlation, left alone causality, between the adoption of digital technologies in home-based manufacturing sites and backshoring hitherto. And while the future may hold more backshoring movements in store, they may not be primarily due to the adoption of Industry 4.0 technologies at home-based plants. Instead, other (foreign) location-specific factors seem to have greater weight in the decision-making processes around backshoring operations. I.e., deteriorating sales forecasts in offshore places where firms have production activities, increases in institutional uncertainty in such places, rationalization of global production apparatuses, and/or a lack of possibilities to deploy foreign manufacturing activities and output for third markets. Also against the backdrop of events like the outbreak of Covid19 and the uncertainty-raising effect it has on international business, the trade-off between producing off-shore or bringing manufacturing activities back home is not likely to depend on technology adoption levels at home and abroad either.

Examinar

Examinando Artículos por Título

Resultados por página

Opciones de ordenación