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La Responsabilidad Pública y Privada por el Uso e Implementación de Programas con Algoritmos Defectuosos en Colombia, Una Propuesta de Lege Ferenda
No full textPrograma de Doctorado en Estudios Avanzados en Derechos Humanos por la Universidad Carlos III de MadridPresidenta: María Carmen Barranco Avilés.- Secretaria: María Olga Sánchez Martínez.- Vocal: Nicola Lucch
Concerning multivariate Bernstein polynomials and stochastic logic
No full textAmong the applications of the Bernstein polynomials in one variable is their use in solving problems associated with stochastic computing. Taking as a starting point the notion of stochastic logic in the sense of Qian-Riedel-Rosenberg, the aim of this paper is to investigate some necessary and sufficient conditions for guaranteeing whether polynomial operations can be implemented with stochastic logic based on multivariate Bernstein polynomials with coefficients in the unit interval.This research was partially supported by Decanato de Investigación y Desarrollo, Universidad Simón Bolívar, Venezuela, grant DID-USB (S1-ICCB-004-17), and by Comunidad de Madrid (Spain) under the Multiannual Agreement with UC3M in the line of Excellence of University Professors (EPUC3M23), in the context of the 5th. Regional Programme of Research and Technological Innovation (PRICIT). The author thanks the referees for their careful revision of the manuscript. Their comments and suggestions have contributed to improve substantially the presentation of this wor
Optimal Design of Multi-Asset Options
No full textThe combination of stochastic derivative pricing models and downside risk measures often leads to the paradox (risk, return) = (−infinity, +infinity) in a portfolio choice problem. The construction of a portfolio of derivatives with high expected returns and very negative downside risk (henceforth “golden strategy”) has only been studied if all the involved derivatives have the same underlying asset. This paper also considers multi-asset derivatives, gives practical methods to build multi-asset golden strategies for both the expected shortfall and the expectile risk measure, and shows that the use of multi-asset options makes the performance of the obtained golden strategy more efficient. Practical rules are given under the Black–Scholes–Merton multi-dimensional pricing model.This research was partially supported by the Spanish Ministry of Science and Innovation (Project PID2021-125133NB-I00) and the University Carlos III of Madrid (Project 2009/00445/003)
Passivation of galvanized and carbon steels in phosphate mortars manufactured with alternative MgO sources
No full textMagnesium potassium phosphate cements (MKPCs) are cementitious materials that harden simply with water and are very useful for repairing damaged concrete structures. However, obtaining MgO implies high CO2 emissions. In the present study, the MgO is obtained from two different industrial by-products (cyclone dust during the industrial calcination of magnesite and tundish deskulling waste generated in the steel manufacturing), as they can be an ecological alternative to manufacture mortars. The properties of these innovative mortars still deserve further research. Moreover, if the MKPCs need to be used for repairs of reinforced building structures or for applications that could involve embedded metal bars, the ability of these mortars to passivate the metal is another key point that is investigated in the present research. The characteristics of the alternative MKPC mortars, such as curing shrinkages, mechanical properties, porosities and pHs, are compared with those of conventional ordinary Portland cement mortar. Ribbed carbon steel and galvanized steel bars were used as reinforcements. Six different types of reinforced mortar samples were exposed to high relative humidity (RH) for four months and their electrochemical performances were monitored. Both carbon and galvanized steels embedded in the highly ecological MKPC mortars manufactured with MgO from tundish wastes are able to be passive in environments with high RH. However, galvanized and carbon steel bars are not able to reach a stable passivity in mortars made with cyclone dust MgO. Analysis of the pore solutions obtained after pore pressing enable these results to be understood.This study was funded by PID2021-125810OB-C21 and PID2021-125810OB-C22 projects, financed by MCIN/AEI/10.13039/501100011033/and FEDER “Una manera de hacer Europa”. The authors would like to thank the Catalan Government for the quality accreditation and funding given to their research group DIOPMA (2021 SGR 00708)
A Quest for Knowledge
Get PDFIs more novel research always desirable? We develop a model in which knowledge shapes society's policies and guides the search for discoveries. Researchers select a question and how intensely to study it. The novelty of a question determines both the value and difficulty of discovering its answer. We show that the benefits of discoveries are nonmonotone in novelty. Knowledge expands endogenously step-by-step over time. Through a dynamic externality, moonshots research on questions more novel than what is myopically optimal can improve the evolution of knowledge. Moonshots induce research cycles in which subsequent researchers connect the moonshot to previous knowledge.Johannes Schneider gratefully acknowledges financial support from Horizon Europe MSCA Project 101061192; the Agencia Estatal de Investigación (MICIU/AEI /10.13039/501100011033) through grants PID2019-111095RB-I00, PID2020-118022GB-I00, and CEX2021-001181-M; the German Research Foundation (DFG) through CRC TR 224 (Project B03); and Comunidad de Madrid, grantMAD-ECON-POL-CM H2019/HUM-5891. Funding for APC: Universidad Carlos III de Madrid (Agreement CRUE-Madroño 2024)
Exploring commuter stress dynamics through machine learning and double optimization
No full textTravel dynamics significantly impact commuter stress, influenced by traffic behavior, road conditions, travel modes, distance, and socio-demographic characteristics. Previous research on travel stress often exhibits limitations, including narrow scopes focusing on specific routes, vehicle types, or demographics. This study addresses these constraints by employing a comprehensive approach to analyze the influence of various travel attributes on commuter stress levels. An interview-based dataset was collected to capture the multifaceted experiences of road users. Five tree-based machine learning models–Decision Tree (DT), Random Forests (RF), Extra Trees (ET), Extreme Gradient Boosting (XGBoost), and k-Nearest Neighbor (k-NN)–were deployed for imbalanced multi-class classification. XGBoost demonstrated superior performance with the highest accuracy (73.33%) and precision (75.63%) with a standard deviation of ±5.9. A novel double hyperparameter optimization technique enhanced the prediction accuracy across all models, notably increasing the k-NN classifier’s accuracy to 19.99%. The SHAP (SHapley Additive exPlanations) method was utilized for model interpretability, revealing distance traveled per day as the most influential factor across stress levels, followed by mode of transport, gender, and age for low, medium, and high-stress categories, respectively. The study also examines the impact of features on individual commuter stress levels through random instance selection. This research provides valuable insights into the complex interplay between travel attributes and commuter stress, paving the way for the development of effective stress mitigation strategies and improved travel experiences for all road users
Population dynamics in a Leslie-Gower predator-prey model with proportional prey refuge at low densities
No full textIn this paper we propose a mathematical Leslie-Gower predator-prey model, in which the prey takes refuge from the predator when its population size is below a critical threshold, the functional response of the predator is represented by a Holling II function, and the growth of the prey in the absence of the predator is subject to a semi-saturation parameter that affects its birth curve. Since the model is composed of two vector fields, its qualitative analysis includes, in addition to the determination of the number and stability of the equilibria for each vector field and belonging to the biological sense set, the study of the dynamics in the trajectories close to the dividing curve of the two vector fields in order to determine possible pseudo-equilibria. As a result, if the proposed model has a single inner equilibrium, then there is the possibility of having between one or at least two limit cycles, coexisting or not in both vector fields and around the inner equilibrium. Likewise, the model has a stable pseudo-equilibrium which may be surrounded by at least two limit cycle
Sistema avanzado de percepción para vehículos autónomos basado en cámaras monoculares
No full textLos vehículos autónomos tienen como objetivo revolucionar el transporte proporcionando soluciones de movilidad más seguras, sostenibles y eficientes. Actualmente, estos sistemas se componen de diversos módulos que actúan obteniendo y procesando información para que el vehículo navegue de forma segura por el entorno. Esta tesis se centra en el módulo de percepción, encargada de captar información cruda de los sensores y procesarla de forma que el vehículo sea capaz de comprender la posición de los diversos agentes con los que comparte espacio, mandando esta información al planificador para tomar decisiones mas informadas y seguras. Típicamente, este módulo integra diversos sensores, como LiDAR y cámaras, que pueden presentar limitaciones en ciertos escenarios. La presente tesis propone un sistema de percepción robusto basado en cámaras monoculares para abordar estos desafíos, ofreciendo una solución de apoyo seguro en escenarios en los que el sensor principal, el LiDAR, no está disponible o presenta fallos.
La investigación incluye el diseño e implementación de módulos clave para la estimación de profundidad, detección de objetos en el espacio 3D, y mejoras de robustez del sistema aprovechando técnicas innovadoras como mecanismos de atención y filtros de Kalman. Cada algoritmo diseñado e implementado ha sido comparado frente a bases de datos públicos y otros métodos estado del arte. También se han llevado experimentos y optimizaciones de tiempos de cómputo y recursos para su uso en plataformas reales y se ha comparado la optimización realizada con otro método tradicional de fusión cámara-LiDAR. Los resultados experimentales demuestran que el enfoque propuesto mantiene una alta precisión y robustez en la detección en diversas plataformas y configuraciones de cámaras.
Este trabajo establece una base sólida para futuros avances en tecnologías de percepción monocular, como la integración de redes end-to-end, un subsistema de odometría visual fusionando la imagen RGB y los mapas de profundidad, y la mejora del rendimiento en entornos menos controlados. Con todo ello, esta tesis resalta la importancia del uso de estos sistemas redundantes para incrementar la confianza y la percepción de seguridad de los usuarios finales de los vehículos autónomos.Autonomous vehicles aim to revolutionize transportation by providing safer, more sustainable and efficient mobility solutions. Currently, these systems are composed of several modules that act by obtaining and processing information for the vehicle to navigate safely through the environment. This thesis focuses on the perception module, which is responsible for capturing raw information from sensors and processing it so that the vehicle is able to understand the position of the various agents with which it shares space, sending this information to the planner to make more informed and safer decisions. Typically, this module relies on various sensors, such as LiDAR and cameras, which may present limitations in certain scenarios. This thesis proposes a robust perception system based on monocular cameras, offering a secure failsafe solution in scenarios where the main sensor, LiDAR, is unavailable or faulty.
The research includes the design and implementation of key modules for depth estimation, object detection in 3D space, and system robustness improvements leveraging innovative techniques such as attention mechanisms and Kalman filters. The developed system operates in real time, significantly optimizing computation time and resource usage. Each algorithm designed and implemented has been compared against public databases and other state-of-the-art methods. Experiments have also been carried out using real platforms and comparing the optimization performed with another traditional camera-LiDAR fusion method. Experimental results demonstrate that the proposed approach maintains high accuracy and robustness in detection on various platforms and camera configurations.
This work establishes a solid foundation for future advances in monocular sensing technologies, such as integrating end-to-end networks, a visual odometry method to improve the localization module by fusing the RGB data and the estimated depthmaps, and improving performance in less controlled environments. All in all, this thesis highlights the importance of using these redundant systems to increase the confidence and safety perception of end users of autonomous vehicles.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Ramón Ignacio Barber Castaño.- Secretario: Joshué Manuel Pérez Rastelli.- Vocal: José Eugenio Naranjo Hernánde
Felipe II y el Sacro Imperio: la transición de la "política del Norte", 1559-1570
Get PDFPremio Comité Español de Ciencias HistóricasEl libro analiza cómo se gestionaron los intereses diplomáticos de Felipe II en el Sacro Imperio entre 1559 y 1570, sobre todo en calidad de duque de Borgoña y, en menor medida, como duque de Milán. También explica esos intereses pertenecían mayormente a un subsistema diplomático denominado «política del Norte». En segundo término, explica la razón por la que algunos antiguos servidores de Carlos V, que formaban parte de la representación diplomática de Felipe II ante el Sacro Imperio, fueron desplazados por hombres de la Península Ibérica. En tercer lugar, muestra que la defensa de los intereses jurisdiccionales y confesionales de Felipe II en el Sacro Imperio eran una expresión de dinámicas diplomáticas multilaterales. Finalmente, identifica y explica los temas referidos a la Italia imperial que trataron sus embajadores permanentes en Viena. La investigación muestra que el manejo de los intereses diplomáticos de Felipe II en el Sacro Imperio entre 1559 y 1570 experimentó un proceso de transición. Pasó de un modelo borgoñón a uno hispano que dependía del subsistema diplomático «política del Norte». Este último, casi a modo de una reminiscencia, hundía sus raíces en la tradición de los antiguos duques de Borgoña y dotaba de sentido y organización a los mecanismos empleados por el Rey Prudente. El dinasticismo, la multilateralidad y el desdoblamiento de su representación (duque de Borgoña y de Milán, príncipe extranjero, pariente de los emperadores) fueron sus principales recursos para tratar de alcanzar sus objetivos en el espacio imperial.Este trabajo ha sido financiado con cargo a un proyecto de investigación, titulado «Diplomacia Intercultural Mediterránea de la Monarquía hispana (DIPLOINMED)» [PID2022-139326NB-I00], financiado por MCIN/AEI/10.13039/501100011033/ y “FEDER Una manera de hacer Europa”
Control of wind energy conversion systems with permanent magnet synchronous generator for isolated green hydrogen production
Get PDFThis paper addresses the design and analysis of the control system for a Wind Energy Conversion System (WECS) with a Permanent Magnet Synchronous Generator (PMSG) and its application for isolated green hydrogen production. The designed control maximizes the wind turbine (WT) power generation by regulating the electrolyzer current consumption, where the electrolyzer operates as a controlled load, ensuring power balance in the system and enabling the generation of maximum power from the WECS without the use of any energy storage system. The system involves directly integrating a WECS with an alkaline electrolyzer (AEL), and its configuration includes a WT with a PMSG, an AC/DC voltage source converter (VSC) acting as the generator side converter (GSC), and a DC/DC converter acting as the electrolyzer side converter (ESC) with Maximum Power Point Tracking (MPPT) control for the WT. The proposed control system has been fully modeled and tested through simulations in Matlab/Simulink, demonstrating its reliable performance under variable wind speeds. Simulation results illustrate how, over rated wind speeds, the pitch control limits the rotational speed and power to their maximum values, and at under rated wind speeds, the ESC control regulates the AEL current following the MPPT of the WT, while the GSC control maintains the DC bus voltage at its designated nominal value. Overall, the proposed control system shows robust and effective performance across the entire range of possible operational points, ensuring no wind generation power losses by following the maximum power point.This paper is part of the R&D project” GREENH2CM para el posicionamiento estratégico de la Comunidad de Madrid en el ámbito de la I + D + i sobre hidrogeno verde y pilas de combustible” funded by Community of Madrid, MCIN/AEI/10.13039/501100011033 and, as appropriate, by “ERDF A way of making Europe”, by the “European Union NextGenerationEU/PRTR”