Artículos de Investigación

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  • Publication
    Hacia una televisión más participativa
    (Oxbridge Publishing House Ltd, 2005-10) Lara Padilla, María Tíscar
  • Publication
    El ciudadano en la información periodística de la BBC
    (Oxbridge Publishing House, 2008-10) Lamuedra Graván, María; Lara Padilla, María Tíscar
    El presente artículo analiza la estrategia de la BBC para legitimar su papel como televisión pública a través de un mayor acercamiento a los ciudadanos y una diversificación de los contenidos ante la creciente fragmentación de audiencias. El estudio se basa en una serie de entrevistas a profesionales de los servicios informativos de la BBC sobre su concepto de público y su mirada sobre los ciudadanos. El propósito de este estudio es identificar fórmulas que puedan ayudar a las televisiones públicas españolas a afrontar, en el actual contexto, el reto de su legitimación como televisión de servicio público.
  • Publication
    La crisis de identidad de los periodistas en las televisiones públicas europeas: comparación entre BBC y TVE
    (Universidad Complutense de Madrid, 2009-06-01) Lamuedra Graván, María; Lara Padilla, María Tíscar; Ministerio de Ciencia e Innovación (España)
    El periodismo y los periodistas se enfrentan a una crisis de credibilidad propiciada fundamentalmente por el distanciamiento con su público y el alcance de los ciudadanos a nuevos medios de producción y consumo de información gracias a las nuevas tecnologías digitales. En este artículo se analizan los retos que viven las televisiones públicas en la legitimación de su papel como medio público en este entorno de fuerte competencia comercial. El objeto de estudio se aborda a través de 40 entrevistas en profundidad a profesionales de BBC y TVE y el análisis comparado de sus discursos acerca de su identificación como periodistas, sus ideas sobre qué significa el servicio público y la forma en que conciben la incorporación de los ciudadanos en el proceso periodístico.
  • Publication
    From Court to Books: The Genealogy of the Victorian Debate on the Doctrine of Conspiracies
    (Giuffrè Francis Lefebvre S.p.A., 2011-12-31) Saucedo, Víctor
  • Publication
    College material? whether children's effort or ability drives parents' educational expectations depends on socioeconomic background
    (2024-01-01) Foley, William Michael; Radl, Jonas; European Commission
    Educational expectations of higher-SES families tend to be “sticky” – i.e. consistently high and less responsive to variations in academic aptitude –making them an important mechanism behind educational inequality. In this paper, we highlight the analytical benefits of decomposing academic aptitude into cognitive ability and cognitive effort. While we have robust evidence on how expectations depend on students’ ability, we lack reliable data on the association between expectations and effort, inhibiting understanding of the mechanisms behind educational immobility. We address this lacuna with data from a school-based sample of 816 fifth grade students from Berlin and Madrid, including state-of-the-art behavioural measures of participants’ incentivised disposition to exert effort. Results show that, on average, cognitive effort and ability have equally strong correlations with parents’ expectations that their child attends university. However, while lower-SES parents’ expectations are highly responsive to their children’s effort, higher-SES parents are not at all responsive. Conversely, higher-SES parents’ expectations vary substantially as a function of their children’s cognitive ability, whereas lower-SES parents’ expectations do not respond at all. Further analysis indicates that academic aptitude is largely signalled through grades and, hence, that families of varying socioeconomic backgrounds interpret grades in markedly different ways.
  • Publication
    Dielectric tensor of a rectangular arrangement of Ag nanoparticles in anisotropic LiNbO3: Analysis of the negative epsilon conditions
    (Elsevier, 2020-03-15) Cruz Fernández, Rosa María de la; Kanyinda-Malu Kabiena, Clement; Muñoz Santiuste, Juan Enrique; Ministerio de Ministerio de Ciencia e Innovación (España); Comunidad de Madrid
    In the present paper we report the optical response of an ordered array of silver (Ag) nanoparticles (NPs) using the uniaxial 𝐿𝑖𝑁𝑏𝑂3 as a model case. We investigate the anisotropic effects on the effective dielectric tensor taking into account the charges interaction of particles. The Ag NPs dielectric function is described through a modified Drude model whereas the 𝐿𝑖𝑁𝑏𝑂3 dielectric functions are deduced from their experimentally established Sellmeier equations. The effective dielectric tensor components of the ensemble aggregates of Ag NPs and uniaxial 𝐿𝑖𝑁𝑏𝑂3 crystal are treated through the extended Maxwell–Garnett approximation. Following the asymmetric behaviour of uniaxial crystals, Ag NPs are sited in the ordinary plane of the crystal, giving rise to different responses in the 𝑥, 𝑦 and 𝑧 directions of applied electric field. Real and imaginary parts of the effective dielectric tensor components of the aggregate ensemble are investigated in terms of different structural parameters, such as the interparticle spacings, the NPs filling factor and sizes of spherically embedded nanoparticles. We demonstrate that an adequate choice of structural parameters such as NPs sizes, interparticle separation gaps or the filling factor can determine the optical properties of layered Ag–embedded uniaxial crystals such as 𝐿𝑖𝑁𝑏𝑂3. We show that the negative epsilon (NE) condition is satisfied from a critical size of Ag NPs when the filling factor and the interparticles distances (𝑎 and 𝑏) have particular values. This condition defines an interval of energies, called NE range, which clearly depend on values of structural parameters defined in the model. This NE range shows some type of bandwidth anisotropy when it is compared among the 𝑥-, 𝑦-, 𝑧- and 𝑥𝑦-components of the effective dielectric tensor. We analyze some anisotropic features such as the bandwidth and shift resonance energies in the real and imaginary parts of the dielectric tensor when structural parameters change.
  • Publication
    Geometry-related optical properties in vertically aligned GaAs nanowires arrays: A study of sizes and embedding medium effects
    (Elsevier, 2023-10) Cruz Fernández, Rosa María de la; Kanyinda-Malu Kabiena, Clement; Muñoz Santiuste, Juan Enrique; Ministerio de Economía y Competitividad (España); Comunidad de Madrid
    We investigate the effects of the geometrical sizes and surrounding media on the optical properties of a periodic square array of GaAs nanowires (NWs) as candidates for applications on photovoltaic solar cells as well as sensors. As filling media, different insulator materials such as PMMA, Polycarbonate, Polystyrene and PVP are considered in this study. The simulated system is made of three stacked layers along with two semi-infinite air spaces. The stacked layer system is defined by a transparent layer of Indium Tin Oxide (ITO), the active region of GaAs nanowires array embedded into the filling medium and a substrate of Silicon (Si). The multilayer absorbance is simulated by transfer matrix method (TMM); while the GaAs nanowires surrounded by filling medium is treated as an homogeneous layer whose effective dielectric function is described by Bruggeman effective medium theory. For both s- and ppolarizations at normal and oblique incidences, we observe a typical oscillating behavior in the absorbance/reflectance spectra, regardless the type of embedding medium and sizes investigated. For all investigated sizes, we obtain that the absorbance values decrease for longer wavelength. Greater 𝐷∕𝑃 ratio for longer NWs benefit the light trapping with absorbance values up to 80 per cent in the VIS range. For small variations of the refractive index (dielectric constant) of the filling media surrounding GaAs NWs, we observed a perceptible change in their reflectance spectral values at specific wavelengths. On the other hand, the Brewster angle, calculated at the interface of the ITO layer and the effective embedded nanowires composite, is seen to be sensitive to the 𝐷∕𝑃 ratio size, as far as the wavelength is varied. The above numerical results are in good agreement with those reported in the literature by experimental research and sophisticated FDTD simulations in III-V semiconductor nanowires, which demonstrates that our TMM simulations are adequate approximations to account on optical properties in multilayered structures when homogenization of multilayers is required.
  • Publication
    Los límites humanitarios al comercio exterior de armas convencionales: algunos apuntes de su importancia para el derecho penal
    (Universidad de Talca, Centro de Estudios en Derecho Penal, 2023-07) Garrocho Salcedo, Ana María
    El comercio exterior de armas convencionales y material de doble uso es una actividad regulada y controlada por el Estado, imprescindible para prevenir desvíos indeseados y evitar un uso indebido por parte del destinatario de las armas. Por esta razón, atendiendo a la peligrosidad potencial que comporta la exportación de armamento, los Estados adoptan el sistema de licencia previa para autorizar su exportación. En el presente trabajo se explora la problemática general de la exportación de armas, subrayando las implicaciones que esta actividad comporta para la paz, la seguridad y la prevención de violaciones graves de los derechos humanos, para seguidamente examinar los límites normativos que la legislación supranacional ha impuesto a los Estados, muy en concreto el Tratado de Comercio de Armas, de 2 de abril de 2013, y la Posición Común de la Unión Europea 2008/944/PESC del Consejo, de 8 de diciembre de 2008, por la que se definen las normas comunes que rigen el control de las exportaciones de tecnología y equipos militares. Asimismo, se analizará el régimen de exportación de armas en España, el problema del secreto del expediente de exportación y las implicaciones que esta regulación puede tener para el Derecho Penal español, especialmente para el delito de contrabando o la prevaricación administrativa de funcionarios. Adicionalmente, el trabajo plantea la necesidad de valorar, de lege ferenda, la inclusión de nuevos tipos penales en el ámbito del control y seguimiento ex post una vez las armas han llegado al lugar de destino. La evitación del desvío indeseado hacia grupos criminales y la comprobación del uso final de las armas son deberes irrenunciables de los Estados y de las empresas del sector, teniendo en cuenta el potencial lesivo del armamento en la convivencia social y en los derechos humanos.
  • Publication
    V2N Service Scaling with Deep Reinforcement Learning
    (Cornell University academic standards, 2023) Shih-Huan Hsu, Cyril; Martín Pérez, Jorge; Papagianni, Chrysa; Grosso, Paola; European Commission; Ministerio de Asuntos Económicos y Transformación Digital (España)
    The fifth generation (5G) of wireless networks is set out to meet the stringent requirements of vehicular use cases. Edge computing resources can aid in this direction by moving processing closer to end-users, reducing latency. However, given the stochastic nature of traffic loads and availability of physical resources, appropriate auto-scaling mechanisms need to be employed to support cost-efficient and performant services. To this end, we employ Deep Reinforcement Learning (DRL) for vertical scaling in Edge computing to support vehicular-tonetwork communications. We address the problem using Deep Deterministic Policy Gradient (DDPG). As DDPG is a model-free off-policy algorithm for learning continuous actions, we introduce a discretization approach to support discrete scaling actions. Thus we address scalability problems inherent to high-dimensional discrete action spaces. Employing a real-world vehicular trace data set, we show that DDPG outperforms existing solutions, reducing (at minimum) the average number of active CPUs by 23% while increasing the long-term reward by 24%.
  • Publication
    Data-centric Service-Based Architecture for Edge-Native 6G Network
    (IEEE, 2023-11-20) Baldoni, Gabriel; Quevedo, José; Magalhaes Guimaraes, Carlos Eduardo; Oliva Delgado, Antonio de la; Corsaro, Angelo; European Commission
    Starting with 5G, mobile networks moved away from the point-to-point model used by previous generations towards a Service-Based Architecture (SBA) focused on a Cloudnative design. While 5G considers the SBA mainly as a central location with a single administrative domain, 6G is expected to become more of a fully-distributed system. This raises the need for flexible service routing capabilities that allow the utilization of the distributed resources available over multiple infrastructures. This paper embraces this vision and explores the utilization of data-centric and dataflow mechanisms for a seamless realization and interaction of composable services in a fully distributed Edgenative 6G architecture. The feasibility and suitability of this vision are showcased through a proof-of-concept prototype, validated over selected 5G workflows u sing d ifferent t echnologies, with results demonstrating the advantages of pursuing data-centric and dataflow approaches.
  • Publication
    Beyond Multi-Access Edge Computing: Essentials to Realize a Mobile, Constrained Edge
    (IEEE, 2024-01) Rojas, Elisa; Guimaraes, Carlos; Oliva Delgado, Antonio de la; Bernardos Cano, Carlos Jesús; Gazda, Robert
    The main purpose of ETSI multi-access edge computing (MEC) is to improve latency and bandwidth consumption by keeping local traffic local while providing computing resources near the end-user. Despite its clear benefits, the next-generation of hyper-distributed applications (e.g., edge robotics, augmented environments, or smart agriculture) will exacerbate latency and bandwidth requirements, posing significant challenges to today's MEC deployments. In this work, we leverage the current study item ETSI GR MEC 036, introducing a lightweight constrained version of a MEC platform that can be deployed in a mobile end terminal or in its closed locality. This work presents design options for cMEC, and explains how it can untangle the aforementioned problems while being architecturally compatible with a full-fledged MEC framework. Finally, key use cases and still open challenges are discussed, including recommendations to extend the current MEC standard toward constrained environments.
  • Publication
    IEEE 802.11az Indoor Positioning with mmWave
    (IEEE Explore, 2023-12-18) Picazo Martinez, Pablo; Barroso Fernandez, Carlos; Martín Pérez, Jorge; Groshev, Milan; Oliva Delgado, Antonio de la; Ministerio de Ciencia e Innovación (España)
    Last years we have witnessed the uprising of location-based applications, which depend on the device's capabilities to accurately obtain their position. IEEE 802.11, foretelling the need for such applications, started the IEEE 802.11az work on Next Generation Positioning. Although this standard provides positioning enhancements for sub-6 GHz and mmWave bands, high accuracy in the order of centimeters can only be obtained in the latter band, thanks to the high temporal resolution from the multi-GHz bandwidth. This work presents the new techniques provided by IEEE 802.11az for enhanced secured positioning in the mmWave band. Additionally, this paper assesses 802.11az mmWave accuracy using a novel trigonometry solution, compares it with advanced positioning solutions, and identifies open research challenges.
  • Publication
    Baseline pupil size does not correlate with fluid intelligence: a laboratory study with children and adults
    (2024-03) Lorente Labrado, Patricia; Ruuskanen, Veera; Mathôt, Sebastiaan; Crespo, Antonio; Radl, Jonas; European Commission
    Recent studies have investigated resting-state, or baseline, pupil size as a general measure of cognitive abilities, based on the previous finding that larger pupils might be predictive of higher general intelligence or working memory capacity. However, evidence for such relationships has been mixed, and all previous studies thus far have focused on adult samples. The present study adds to this debate by examining the correlation between fluid intelligence and baseline pupil size in a sample of both children (10 years old) and adults (their parents). Importantly, our sample is representative in terms of socioeconomic background, which was not the case in previous studies, thus addressing concerns about sample selection and variability. We did not find evidence for a relationship of fluid intelligence with baseline pupil size or with pupil-size variability, neither for children nor adults. Therefore, our results do not replicate the relationship between cognitive abilities and baseline pupil size as reported in previous research.
  • Publication
    Software Vulnerability Detection under Poisoning Attacks using CNN-based Image Processing
    (2024-02-15) González Manzano, Lorena; García Alfaro, Joaquín; Comunidad de Madrid; Ministerio de Ciencia, Innovación y Universidades (España)
    Design flows, code errors, or inadequate counter measures may occur in software development. Some of them lead to vulnerabilities in the code, opening the door to attacks. Assorted techniques are developed to detect vulnerable code samples, making artificial intelligence techniques, such as Machine Learning (ML), a common practice. Nonetheless, the security of ML is a major concern. This includes the the case of ML-based detection whose training process is affected by data poisoning. More generally, vulnerability detection can be evaded unless poisoning attacks are properly handled. This paper tackles this problem. A novel vulnerability detection system based on ML-based image processing, using Convolutional Neural Network (CNN), is proposed. The system, hereinafter called IVul, is evaluated under the presence of backdoor attacks, a precise type of poisoning in which a pattern is introduced in the training data to alter the expected behavior of the learned models. IVul is evaluated with more than three thousand code samples associated with two representative programming languages (C# and PHP). IVul outperforms other comparable state-of-the-art vulnerability detectors in the literature, reaching 82% to 99% detection accuracy. Besides, results show that the type of attack may affect a particular language more than another, though, in general, PHP is more resilient to proposed attacks than C#.
  • Publication
    How socioeconomic status shapes cognitive effort: A laboratory study among fifth graders
    (2024-03) Radl, Jonas; Apascaritei, Paula; Foley, William; Kröger, Lea; Lorente Labrado, Patricia; Palacios Abad, Alberto; Solga, Heike; Stuhler, Jan Leonard; Swarr, Madeline Lee; European Commission
    Effort is essential both to normative and sociological theories of stratification. But social scientific research has tended to treat effort as a missing variable or to measure it unreliably with self-reports. An emerging consensus in cognitive science identifies effort with executive function, i.e. the mental processes controlling conscious activity. Executive function can be measured using behavioral tasks, opening new avenues towards understanding the link between effort and stratification. However, while most large-N sociological studies lack behavioral measures of effort, most cognitive science studies rely on small convenience samples and omit the crucial role of incentives. We implemented a laboratory study with over 1,300 fifth-grade students. The experimental design features three "real-effort" tasks, each of which taps into different domains of executive function. Effort was elicited under three incentive conditions: (i) unincentivized (no reward); (ii) piece-rate (material reward); and (iii) tournament (material plus status reward). Overall, we find a positive association between parental socio-economic status and children's cognitive effort. However, the magnitude of this gap is surprisingly modest. Moreover, the effect of social origin on effort is largest in the unincentivized condition and shrinks when effort is extrinsically motivated. We discuss implications of how material scarcity shapes cognitive effort under different incentives.
  • Publication
    On-Board Small-Scale Object Detection for Unmanned Aerial Vehicles (UAVs)
    (MDPI, 2023-05-01) Saeed, Zubair; Yousaf, Mohammed Haron; Ahmed, Rehan; Velastin Carroza, Sergio Alejandro; Viriri, Serestina
    Object detection is a critical task that becomes difficult when dealing with onboard detection using aerial images and computer vision technique. The main challenges with aerial images are small target sizes, low resolution, occlusion, attitude, and scale variations, which affect the performance of many object detectors. The accuracy of the detection and the efficiency of the inference are always trade-offs. We modified the architecture of CenterNet and used different CNN-based backbones of ResNet18, ResNet34, ResNet50, ResNet101, ResNet152, Res2Net50, Res2Net101, DLA-34, and hourglass14. A comparison of the modified CenterNet with nine CNN-based backbones is conducted and validated using three challenging datasets, i.e., VisDrone, Stanford Drone dataset (SSD), and AU-AIR. We also implemented well-known off-the-shelf object detectors, i.e., YoloV1 to YoloV7, SSD-MobileNet-V2, and Faster RCNN. The proposed approach and state-of-the-art object detectors are optimized and then implemented on cross-edge platforms, i.e., NVIDIA Jetson Xavier, NVIDIA Jetson Nano, and Neuro Compute Stick 2 (NCS2). A detailed comparison of performance between edge platforms is provided. Our modified CenterNet combination with hourglass as a backbone achieved 91.62%, 75.61%, and 34.82% mAP using the validation sets of AU-AIR, SSD, and VisDrone datasets, respectively. An FPS of 40.02 was achieved using the ResNet18 backbone. We also compared our approach with the latest cutting-edge research and found promising results for both discrete GPU and edge platforms.
  • Publication
    Federal and state audits do not increase compliance with a grant program to improve municipal infrastructure: A pre-registered field experiment
    (Elsevier, 2023-05-01) De La O, Ana; Fernández Vázquez, Pablo Alberto; Martel Garcia, Fernando
    Government audits usually have a broad mandate to monitor compliance with program rules. We conducted a field experiment in collaboration with Mexico"s Superior Auditor of the Federation to investigate if federal or state audits increase municipal compliance with the allocation, reporting, and transparency rules of an intergovernmental grant to improve local infrastructure. We randomly assigned 85 municipalities to be audited by a federal auditor, a state one, or a control group. We find that audits do not increase compliance and examine the reasons behind this none effect. Drawing from audit reports and a survey of municipal administrators, we show that, even though audits produced verifiable information and increased expectations of future audits, their effect on administrators" perceived career prospects was limited. We conclude with a discussion of the policy implications of our results
  • Publication
    Forum: Spanish Online Resources for Spanish and Latin American History
    (Association for Spanish and Portuguese Historical Studies, 2016) Martínez, Roger Louis
    The mid-2010s are a challenging period to investigate digital collections precisely because they exist as patchwork of emerging collections that are incompletely indexed, and thus it is difficult to appreciate their significance. For diligent researchers who employ a robust digital search methodology, there are substantial opportunities to locate and reveal high-dispersed and fragmentary histories. This researcher proposes six essential approaches to researching electronic collections based on personal expertise in physically researching in almost thirty Spanish private, local, church, provincial, and national archives and libraries, as well as countless digital collections.