King Juan Carlos University
Archivo Abierto Institucional de la Universidad Rey Juan CarlosNot a member yet
28087 research outputs found
Sort by
Manual de prácticas de laboratorio: Análisis morfológico por AFM de fotoresist tras exposición y revelado
No full textEste manual presenta una práctica de laboratorio orientada a la caracterización topográfica de fotorresists expuestos a radiación ultravioleta (UV) mediante Microscopía de Fuerza Atómica (AFM). El objetivo principal es que el estudiantado comprenda la relación entre la dosis de exposición, el enfoque y la morfología final del fotorresist, así como el manejo adecuado del microscopio AFM en modo resonante. Se propone un enfoque didáctico que integra conceptos de litografía óptica, análisis de rugosidad y procesamiento de datos con software libre. Este material está diseñado para ser reutilizable en el Grado en Nanociencia y Nanotecnología, dentro de la asignatura Nanofabricación, fomentando la formación experimental y el aprendizaje autónomo
Quality of Experience Under Huge Load for WebRTC Applications: A Case Study of Three Media Servers
No full textVideoconference applications are becoming increasingly popular, and the demand for these applications is growing. The availability of a standard for building videoconference application on the web, the W3C WebRTC standard, boosted the development of such applications. With so many alternatives available, an impact on quality due to an overload of such applications might cause users to leave and choose another service instead. This makes stress testing mandatory in order to understand the limits of these videoconference solutions and how these limits impact the quality of experience (QoE) of the users. However, most testing tools are not designed to calculate QoE, which is essential for real-time videoconference applications, because QoE calculation is complex and a computationally intensive process. This paper focuses on how load impacts QoE for WebRTC applications and presents OpenVidu QoE and Load Testing Tool (OQLT), a load and stress testing tool for WebRTC applications which measures the QoE of users in videoconference applications. In this work, we make use of this tool to help researchers and practitioners understand the impact of server load on the QoE of users in WebRTC applications, by analyzing three different communication systems: Kurento, Mediasoup, and Pion. We study which quality of service (QoS) metrics can be used to prevent an impact on the QoE of users in these servers. We also analyze different session sizes and topologies to understand the impact of server load on the QoE of users under different circumstances. Our findings show that in two of the three media servers (Kurento and Pion), CPU alone is a good indicator of QoE degradation, whereas for Mediasoup, additional WebRTC metrics are needed, because under high CPU usage Mediasoup can still provide a good QoE to its users. We also found that the behavior of the three media servers under load with respect to the QoE perceived by users is different, which might be important for practitioners, and that not all users are impacted equally by an overload on the server, and how users are impacted under such a load depends as well on the media server. From our extensive analysis of the data collected, we provide detailed implications for practitioners when using WebRTC applications
Water Sources in a Zoological Park Harbor Genetically Diverse Strains of Clostridium Perfringens Type A with Decreased Susceptibility to Metronidazole
No full textThe presence of Clostridium perfringens in water is generally regarded as an indicator of fecal contamination, and exposure to waterborne spores is considered a possible source of infection for animals. We assessed the presence and genetic diversity of C. perfringens in water sources in a zoological park located in Madrid (Spain). A total of 48 water samples from 24 different sources were analyzed, and recovered isolates were toxinotyped, genotyped by fluorophore-enhanced repetitive polymerase chain reaction (rep-PCR) fingerprinting and tested for antimicrobial susceptibility. C. perfringens was recovered from 43.8 % of water samples and 50 % of water sources analyzed. All isolates (n=70) were type A and 42.9% were beta 2-toxigenic (i.e., cpb2+), but none contained the enterotoxin-encoding gene (cpe). Isolates belonged to 15 rep-PCR genotypes and most genetic diversity (88 %) was distributed among isolates obtained from the same sample. Most isolates displayed intermediate susceptibility (57.1 %; MIC=16 mu g ml(-1)) or resistance (5.7 %; MIC >= 32 mu g ml(-1)) to metronidazole. No resistance to other antimicrobials was detected, although some isolates showed elevated MICs to erythromycin and/or linezolid. Finally, a marginally significant association between absence of cpb2 and decreased susceptibility to metronidazole (MIC >= 16 mu gml(-1)) was detected. In conclusion, our results reveal a high prevalence of C. perfringens type A in the studied water reservoirs, which constitutes a health risk for zoo animals. The elevated MICs to metronidazole observed for genetically diverse isolates is a cause of additional concern, but more work is required to clarify the significance of reduced metronidazole susceptibility in environmental strains
Más allá de la sostenibilidad: reflexiones filosóficas para un planeta vulnerable
No full textDiferentes cumbres, declaraciones y tratados han permitido la emergencia de una nueva conciencia ambiental planetaria. Los ODS son la cristalización de ese proceso multilateral al enlazar derechos humanos y límites ecológicos, constituyendo la primera hoja de ruta global para un planeta vulnerable. Sin embargo, su logro exige profundizar teóricamente: la transgresión de los límites planetarios revela una crisis ecológica que trasciende la sostenibilidad convencional. El vínculo entre sostenibilidad, derechos humanos y vulnerabilidad requiere un sustrato filosófico que aclare causas epistémicas y cuestione los límites de las tecnociencias. Esa reflexión debe traducir principios declarativos en compromisos vinculantes y fomentar una cultura de la vulnerabilidad humana y no humana. Reconocer un espacio-futuro compartido amplía nuestra responsabilidad intergeneracional y exige una ética de la precaución ante el cambio climático irreversible.La presente publicación es resultado principalmente de la participación en el Programa “Impulso a la investigación de la Universidad Rey Juan Carlos”, y se ha realizado dentro del Proyecto titulado “El vínculo entre sostenibilidad, derechos humanos y vulnerabilidad en la sociedad internacional: sustrato filosófico, contenidos políticos y aplicación normativa” (VULNESOSTE), 2025, siendo así que en ella participan los investigadores de este proyecto (Joaquín Fernández Mateo; Cástor Miguel Díaz Barrado; Claudia Gago Martín; Elena Carolina Díaz Galán; María Sagrario Morán Blanco; Julián García Labrador; y Harold Bertot Triana), así como investigadores que generosamente se han sumado a esta iniciativa (José Miguel Calvillo, Carmen Romero, Alberto José Franco, Covadonga Torres Assiego, Mohcine Karzazi, y Fouziza Benzemmour), a los que agradecemos sinceramente su participación. En esencia, se trata de un proyecto competitivo de la línea de doctores emergentes dentro del convenio entre la Comunidad de Madrid y la Universidad Rey Juan Carlos para el fomento de la investigación y la transferencia de tecnología (2023-2026), con referencia externa: 2024/SOLCON-132182, y referencia interna: AR066; y con una duración desde el 01/01/25 hasta el 31/12/25. El desarrollo del proyecto se puede calificar de exitoso y buena muestra de ello son las reflexiones que se contienen en cada uno de los trabajos científicos que integran esta obra. Asimismo, se debe destacar que, al menos, los trabajos realizados por los miembros del equipo de investigación VULNESOSTE responden también a diversas estancias de investigación en Centros extranjeros que han tenido lugar con el propósito de enriquecer la investigación
Developing an assessment governance framework for urban digital twins: Insights from smart cities
No full textUna revisión de los fundamentos económicos sobre la pobreza
No full textEste artículo recupera algunas reflexiones acerca de la eficiencia de los sistemas que han tratado el problema de la pobreza a lo largo de la historia del pensamiento económico. El análisis recoge dos campos de estudio. En primer lugar estudia brevemente cómo la teoría de la propiedad que va desde la escolástica hasta el siglo XVIII compaginó, por una parte, la eficiencia con equidad y, por otra, eficiencia con pobreza extrema. En segundo lugar, este artículo repasa algunas de las críticas a los sistemas de beneficencia en dos contextos diferentes: el debate del siglo XVI en España y la controversia sobre las leyes de pobres inglesas del siglo XIX
Processing and Learning over Irregular Domains: Multidimensional Signals Defined over Multiple Graphs
No full textGraphs provide a powerful mathematical framework for representing complex systems characterized by entities and their pairwise relationships, with applications ranging across diverse scientific and engineering disciplines. While traditional graph signal processing and Graph Neural Networks (GNNs) have achieved remarkable success, they predominantly focus on signals and learning tasks defined over single, often static and homogeneous, graph structures. However, many real-world phenomena exhibit a richness and complexity that cannot be adequately captured by a unique graph. This dissertation addresses this limitation by exploring the paradigm of multidimensional signals defined over multiple graphs, aiming to develop novel methodologies for both generating meaningful ensembles of graphs and designing advanced GNN architectures that effectively leverage these richer structural representations. The research presented herein confronts several key challenges inherent in multi-graph scenarios. These include the generation of realistic, diverse, and controlled graph structures that can serve as inputs for learning systems; the difficulty of bridging structural and semantic gaps when processing, relating, or transferring information between graphs that differ significantly in node sets, edge
structures, or resolutions; and the need to enhance GNN expressivity and adaptability to effectively utilize information from multiple complex graphs, especially in scenarios involving non-aligned nodes, settings with incomplete node features or challenging data characteristics like heterophily. To address these challenges, this dissertation makes four primary contributions, each corresponding to one or more peer-reviewed publications. The first set of contributions focuses on advancing graph generative modeling. Recognizing the need for generating graphs that not only mimic observed data but also adhere to specific structural requirements, we introduce Graph Guided Diffusion (GGDiff). This novel framework unifies multiple guidance strategies for conditional graph generation using diffusion models, interpreting the process as a stochastic control problem. GGDiff enables zero-shot guidance of pre-trained diffusion models under both differentiable and non-differentiable reward functions, facilitating the generation of graphs constrained by desired properties, such as motif counts or fairness metrics. This work significantly expands the toolkit available for creating graph data, enabling the utilization of the generated graphs for downstream tasks. Complementing this graph generation setting, we explore graph generation through the lens of graphons, which are limit objects for dense graph sequences. We propose a scalable graphon estimation method that directly recovers the graphon via moment matching using implicit neural representations. This approach bypasses the complexities of latent variable modeling and costly metric optimizations, offering theoretical guarantees on estimation accuracy. We also introduce MomentMixup, a data augmentation technique in the moment space to enhance graph-based learning tasks. These two generative methodologies provide powerful tools for creating diverse and principled graph structures, laying the groundwork for more sophisticated multi-graph learning. The second set of contributions delves into novel GNN architectures designed to operate effectively in multi-graph and complex single-graph settings. We first propose a flexible GNN architecture to handle tasks where input and output signals are defined on two entirely different graphs, which may possess distinct node sets and topologies. This Input-Output GNN (IO-GNN) framework features a three-block design (an input GNN, a latent space transformation, and an output GNN) allowing for effective signal mapping and representation learning across disparate graph domains. The framework also accomodates a self-supervised learning approach, inspired by canonical correlation analysis, demonstrating the utility of leveraging information from multiple graph structures to learn informative latent representations. Finally, we address the issue of GNN performance degradation on heterophilic graphs, where connected nodes often have different labels. We introduce Structure-Guided GNN (SG-GNN), an architecture that leverages structural attributes (such as role-based or global properties) to construct alternative graph views. These structural graphs are designed to exhibit higher homophily, and SG-GNN adaptively learns to weigh the contributions from the original graph and these new views. This approach significantly improves performance on heterophilic benchmarks by providing GNNs with more relevant neighbor information, and highlights the benefit of considering multiple graph perspectives even for tasks initially proposed to operate on a single primary graph. Complementing this focus on leveraging existing structure for better learning, we also demonstrate that similar structural attributes can be used in scenarios with missing data, successfully being used to interpolate entirely unavailable node features by identifying local structural similarities.
Taken collectively, the contributions of this dissertation establish a comprehensive suite of tools and methodologies for the generation of, and learning over, multiple and complex graph structures. By developing principled graph generative models and innovative GNN architectures, this work pushes the boundaries of how we can process and understand multidimensional signals defined over multiple graphs. The findings demonstrate the significant potential of moving beyond single-graph paradigms, opening new avenues for tackling complex real-world problems where data is inherently structured through multiple, interacting underlying structures. In summary, this research provides both theoretical insights and practical algorithms that contribute to the broader advancement of machine learning on graphs.Doctoral Program in Information and Communication TechnologiesTesis Doctoral leída en la Universidad Rey Juan Carlos de Madrid en 2025. Directores: Antonio García Marqué
I Jornadas Internacionales Interdisciplinares: Salud mental perinatal y crianza. Caminos hacia el bienestar integral. Libro de Actas
No full textLibro de Actas de las I Jornadas Internacionales Interdisciplinares: Salud mental perinatal y crianza. Caminos hacia el bienestar integral que tuvieron lugar el 3 de noviembre de 2025.En este año celebramos, por primera vez, las Jornadas Internacionales Interdisciplinares: Salud Mental Perinatal y Crianza. Estas jornadas surgen de la iniciativa de dos profesores e investigadores de la Universidad Rey Juan Carlos que, desde perspectivas y grupos de investigación diferentes, han coincidido en su interés y pasión por el estudio y cuidado de las personas en esta etapa tan importante de la vida. Consideramos necesario reunirnos, junto con otros profesionales del campo, para compartir y debatir acerca de los avances y necesidades que se están experimentando actualmente en esta área, cada vez más relevante.
La etapa perinatal conlleva numerosos cambios y situaciones nuevas que impactan en la salud mental de quienes deciden formar una familia. En este ámbito, muchos profesionales desempeñan un rol crucial en el acompañamiento de madres y padres durante todo el proceso. Desde la puesta en marcha de un proceso de fertilidad, pasando por la gestación, el parto, la lactancia y hasta los primeros momentos de la crianza, profesionales como matronas, ginecólogos, obstetras, psicólogos, terapeutas ocupacionales y educadores, entre otros, ponen sus conocimientos y habilidades al servicio de las familias.
Por ello, consideramos que las jornadas debían ser interdisciplinares, con una representación amplia de profesionales e investigadores del sector. Además, la Facultad de Ciencias de la Salud de la Universidad Rey Juan Carlos era el lugar idóneo para este evento, y agradecemos enormemente los espacios facilitados para su realización.
El programa ha sido diseñado cuidadosamente para incluir un amplio rango de situaciones y experiencias dentro del ámbito perinatal, con el objetivo de ofrecer una visión lo más completa posible del trabajo desempeñado en esta área. Los ponentes provienen tanto del ámbito profesional como del académico, de distintas universidades nacionales e internacionales, lo que sin duda enriquecerá la experiencia de todos los asistentes. Aunque contenido, como corresponde a una primera edición, el programa aborda múltiples etapas y actores en la etapa perinatal desde distintas perspectivas de las ciencias de la salud.
Queremos expresar nuestro más profundo agradecimiento a todos los ponentes que confiaron en la realización de estas jornadas y contribuyeron de manera fundamental a que se hicieran realidad
Risks in Children's Digital Visibility and Vulnerability: Sharenting in France, Italy, Spain, and the United Kingdom
No full textSharenting has become a common practice in which parents publicly share aspects of their children's lives on social media platforms. This study explores how parent influencers manage their children's visibility, vulnerability, and privacy, as well as the underlying purposes of sharenting. Methodology: Through a comparative approach, the practices of 12 parent influencers—mothers and fathers—from France, Italy, Spain, and the United Kingdom are examined. A total of 1,789 posts on Instagram and TikTok are analysed using content analysis. Results: Cultural differences are identified in the representation of parental roles: mothers take on a leading role, particularly in Italy, while French male influencers frequently depict involved fatherhood. A concerning trend is observed regarding the lack of safeguards to protect children's identities, increasing the risks associated with their digital exposure. Sharenting is not primarily commercial – the UK is the country where children are most used for promotional purposes – nor is it a space for parental support. Discussions: This study critically examines how mediated parenthood and child representation are negotiated in contemporary digital communication. Conclusions: Influencers, as parents, construct self-representations of themselves as caring and competent caregivers embedded within the logics of digital entertainment
Contratación pública básica para los diferentes operadores jurídicos y económicos
No full textLa presente obra, escrita por un equipo de autores multidisciplinar de expertos en derecho y contratación pública, constituye una guía esencial para comprender los principios, procesos y normativas que rigen la contratación del sector público en España. Su objetivo es ofrecer una herramienta clara y accesible que facilite la comprensión de un ámbito cada vez más complejo y determinante para el desarrollo económico y social como es la Contratación Pública.
Utilidad para los operadores jurídicos y económicos
La contratación pública es un pilar fundamental en la actividad administrativa y en la dinamización del sector económico. Por ello, esta obra resulta indispensable para distintos actores:
• Empresas y profesionales: Permite a las empresas privadas, especialmente a pymes y emprendedores, conocer las oportunidades que ofrece el sector público y cómo acceder a licitaciones y dar sus primeros pasos con garantías.
• Administraciones públicas: Proporciona a los gestores y técnicos administrativos una referencia para aplicar correctamente la normativa vigente y optimizar los procedimientos de contratación.
• Abogados y asesores jurídicos: Sirve como herramienta de consulta para la interpretación y aplicación de la Ley de Contratos del Sector Público, facilitando la defensa de los intereses de sus clientes en procesos de licitación y recursos.
• Estudiantes y académicos: Es una fuente de conocimiento imprescindible para quienes se están formando y quiera conocer los fundamentos básicos de la Contratación