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New efficient data-driven reduced order models for oscillatory dynamics
No full textA new methodology is presented to construct data-driven reduced order models able to efficiently approximate periodic attractors of dynamical systems depending on one or more parameters. In an offline stage, some sets of temporally equidistant snapshots are computed for a limited number of parameter values. Such computation is performed using a standard numerical solver when the problem is governed by a low-dimensional system of ordinary differential equations. If, instead, the underlying dynamical system is high-dimensional (i.e., governed by partial differential equations), the snapshots are computed relying on a physics-based reduced order model obtained via proper orthogonal decomposition plus Galerkin projection. The snapshot sets are then treated using a recent, very robust data processing method, the higher order dynamic mode decomposition, which permits describing the periodic attractors as synchronized expansions in terms of spatial modes and associated temporal frequencies. Modes and frequencies are effectively interpolated at new parameter values, different from those involved in the offline stage. The online operation of the resulting data-driven reduced order model is very fast, since it requires carrying out only a small number of algebraic computations. The performance of the new method is tested for two representative dynamical systems, namely the three-dimensional Lorenz system and a high-dimensional system describing the electron transport in a semiconductor superlattice.This work has been supported by the Fondo Europeo de Desarrollo Regional, Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación, under grants TRA2016-75075-R and PID2020-112796RB-C22
Misinformation and Support for Vigilantism: An Experiment in India and Pakistan
No full textResearch documentation and data that support the findings of this study are openly available at the American Political Science Review Dataverse: https://doi.org/10.7910/DVN/P1TL97. Analyses are preregistered at OSF (https://bit.ly/3O48nKH).Vigilante violence, often targeting religious and sectarian minorities and preceded by unsubstantiated rumors, has taken the lives of many citizens in India and Pakistan in recent years. Despite its horrific nature, such vigilantism receives popular support. Can reducing the credibility of rumors via corrections decrease support for vigilantism? To answer this question, we field simultaneous, in-person experiments in Punjab, Pakistan, and Uttar Pradesh, India, regions where anti-minority vigilantism has been preceded by misinformation. We find that correcting rumors reduces support for vigilantism and increases the desire to hold vigilantes accountable. This effect is not attenuated by prior distrust toward out-groups. By contrast, information about state and elite behavior does not always shape attitudes toward vigilantism. These findings provide evidence that support for vigilantism can be reduced through the dissemination of credible information, even in polarized settings.This research was funded by Facebook Foundational Integrity & Impact Research
Inertial sensor performance study under magnetic disturbances conditions for human biomechanical analysis
No full textIn the last three decades, human biomechanical analysis has reached new milestones in the field of research. A typical analysis is kinematic, which aims to obtain information on body movement, often expressed as joint ranges or angles. There are two ways to achieve this representation: systems that use markers and optoelectronic cameras, and systems based on inertial sensors. Both technologies are significant in biomechanical analysis, though optoelectronic systems are commonly considered the gold standard. However, this system can limit the area of movement or be affected by light conditions in outdoor places, which is why inertial sensor-based systems allow for greater versatility in outdoor applications.
Inertial sensors typically consist of 9 degrees of freedom, an accelerometer, a gyroscope, and a magnetometer. These three sensors, along with their physical properties and after mathematical implementations, can estimate orientation and subsequently find a biomechanical model. The accelerometer can find the direction of the gravity vector; the magnetometer allows us to find the direction of the Earth's magnetic field, while the gyroscope allows us to find the orientation after carrying out an integration process. Theoretically, sensory fusion allows for a correct orientation estimate. However, in practice, there are limitations to each of the sensors. The magnetometer, in particular, loses the Earth's magnetic field reference in the presence of ferromagnetic elements or sources of magnetic disturbances. These limitations are a driving reason for choosing this technology, as many researchers require correct orientation measurements in laboratories that may have magnetic disturbances. Therefore, finding a method that allows working in environments with magnetic disturbances is necessary.
This research seeks to propose a methodology that allows the use of motion capture systems based on inertial sensors in conditions of magnetic disturbance to perform human biomechanical analysis. To develop this objective, a detailed review of the state-of-the-art on this topic has been started. Subsequently, we built a database to train the models that perform orientation estimation. Furthermore, one of the most exciting proposals may be to include pattern recognition methods, modeling the problem of automatic detection of magnetic disturbances. Finally, we have selected the most outstanding sensory fusion algorithms in the state-of-the-art, in addition to a new algorithm proposed in this work.
Among the results of this work, the method used for the automatic detection of magnetic disturbances stands out, with success rates close to 99%. On the other hand, after comparing the sensory fusion algorithms, we could show that the method proposed in this work is on par with the methods reported in the state of the art.I want to acknowledge the support provided by the Community of Madrid through the Grant DDII2017-IND2017/TIC-7705, and the Colombian Ministry Minciencias Grant 860.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Jesús Tornero López. - Vocal: José María Azorín Poveda. - Secretario: Jorge Andrés Gómez Garcí
Innovative Approaches to Traffic Anomaly Detection and Classification Using AI
Get PDFVideo anomaly detection plays a crucial role in intelligent transportation systems by enhancing urban mobility and safety. This review provides a comprehensive analysis of recent advancements in artificial intelligence methods applied to traffic anomaly detection, including convolutional and recurrent neural networks (CNNs and RNNs), autoencoders, Transformers, generative adversarial networks (GANs), and multimodal large language models (MLLMs). We compare their performance across real-world applications, highlighting patterns such as the superiority of Transformer-based models in temporal context understanding and the growing use of multimodal inputs for robust detection. Key challenges identified include dependence on large labeled datasets, high computational costs, and limited model interpretability. The review outlines how recent research is addressing these issues through semi-supervised learning, model compression techniques, and explainable AI. We conclude with future directions focusing on scalable, real-time, and interpretable solutions for practical deployment.This research was funded by the Spanish Government through the projects PID2021-128327OA-I00, and TED2021-129374A-I00, and funded by MCIN/AEI/10.13039/501100011033 by the European Union NextGenerationEU/PRTR
Simulación de agentes BDI del papel de la ética en las compras en el supermercado
No full textEste TFG establece una simulación de agentes BDI para simular de qué manera los criterios de tipo ético influyen en la decisión de compra en un supermercado virtual, especificando parámetros como, por ejemplo, las emisiones de CO₂, la sostenibilidad, el grado de intermediación, la calidad y el origen del producto; para ello, se diseña un modelo de consumidor virtual ponderando esos valores al escoger productos, se pone en marcha una red de agentes implementada en Python con la librería SPADE que gestiona dinámicamente el surtido en función de las propias ventas y las de los comercios que se encuentran en los alrededores, y se sientan las bases de una futura aplicación de apoyo a la gestión de supermercados que permita evolucionar y extender esta perspectiva en futuros trabajos.Grado en Ingeniería Informátic
Feasibility and Accuracy of a Dual-Function AR-Guided System for PSI Positioning and Osteotomy Execution in Pelvic Tumour Surgery: A Cadaveric Study
Get PDFObjectives: Pelvic tumor resections demand high surgical precision to ensure clear margins while preserving function. Although patient-specific instruments (PSIs) improve osteotomy accuracy, positioning errors remain a limitation. This study evaluates the feasibility, accuracy, and usability of a novel dual-function augmented reality (AR) system for intraoperative guidance in PSI positioning and osteotomy execution using a head-mounted display (HMD). The system provides dual-function support by assisting both PSI placement and osteotomy execution. Methods: Ten fresh-frozen cadaveric hemipelves underwent AR-assisted internal hemipelvectomy, using customized 3D-printed PSIs and a new in-house AR software integrated into an HMD. Angular and translational deviations between planned and executed osteotomies were measured using postoperative CT analysis. Absolute angular errors were computed from plane normals; translational deviation was assessed as maximum error at the osteotomy corner point in both sagittal (pitch) and coronal (roll) planes. A Wilcoxon signed-rank test and Bland–Altman plots were used to assess intra-workflow cumulative error. Results: The mean absolute angular deviation was 5.11 ± 1.43°, with 86.66% of osteotomies within acceptable thresholds. Maximum pitch and roll deviations were 4.53 ± 1.32 mm and 2.79 ± 0.72 mm, respectively, with 93.33% and 100% of osteotomies meeting translational accuracy criteria. Wilcoxon analysis showed significantly lower angular error when comparing final executed planes to intermediate AR-displayed planes (p < 0.05), supporting improved PSI positioning accuracy with AR guidance. Surgeons rated the system highly (mean satisfaction ≥ 4.0) for usability and clinical utility. Conclusions: This cadaveric study confirms the feasibility and precision of an HMD-based AR system for PSI-guided pelvic osteotomies. The system demonstrated strong accuracy and high surgeon acceptance, highlighting its potential for clinical adoption in complex oncologic procedures.This study has been funded by Agencia Estatal de Investigación (AEI)–Proyectos de Transición Ecológica y Digital 2021 (TED2021-132200B-I00 to JACH), Instituto de Salud Carlos III (ISCIII) through the Biomodels and Biobanks Platform and co-funded by the European Union (PT23/00116 to RPM). We also acknowledge support from the PTI FAB3D, Consejo Superior de Investigaciones Científicas (CSIC), Spain and project FS23/01 Transformación digital en oncología ortopédica (Fundación SECOT, Spain)
Design of coil-wound heat exchangers for molten chloride salt TES in CSP with sodium receiver and sCO2 cycle
Get PDFThis paper introduces a novel design for heat exchangers and optimization of operating temperatures in the thermal energy storage (TES) system for next generation (Gen3) concentrated solar power (CSP) plants. The proposed system integrates a sodium receiver, molten chloride salt TES, and a supercritical CO2 (sCO2) power cycle, using coil-wound heat exchangers (CWHEs) to enhance both efficiency and reliability. These heat exchangers are selected for their exceptional robustness under large temperature and pressure variations, enhanced heat transfer, improved part-load performance, reduced dead zones and better temperature control of molten salts. For the first time, CWHEs are designed for Na-Salt and Salt-sCO2 heat exchange, optimizing the TES system for Gen3 CSP plants. The design approach addresses critical reliability challenges, including creep at high temperatures and corrosion of surfaces exposed to the ternary eutectic molten chloride salt mixture MgCl2-KCl-NaCl (wt% 45.98–38.91–15.11). Additionally, a multi-stream model is applied to the CWHEs to capture thermal gradients across coil layers. Furthermore, the operating temperatures of the hot and cold tanks are optimized to minimize the total annual cost (TAC) of the TES system, including CWHEs and salt tanks. This optimization reduces TAC by 6.4 % to 4.2 % across solar multiples ranging from 1 to 2.5. The proposed design and optimization methodology provide an efficient and reliable solution for heat transfer between the sodium receiver, molten chloride salt, and sCO2 cycle, enhancing the performance and viability of Gen3 CSP plants.This research is funded under the projects: grant PID2021-122895OB-I00 funded by MCIN/AEI/10.13039/501100011033 and the ERDF A way of making Europe; grant TED2021-129326B-I00 funded by MCIN/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR; and the scholarship “Ayudas para la formación del profesorado universitario” (FPU-21/01212) awarded by the Spanish Ministerio de Educación, Cultura y Deporte (MECD). Funding for APC: Universidad Carlos III de Madrid (Agreement CRUE-Madroño 2025
Neural lasso: a unifying approach of lasso and neural networks
Get PDFIn recent years, there has been a growing interest in establishing bridges between statistics and neural networks. This article focuses on the adaptation of the widely used lasso algorithm within the context of neural networks. To accomplish this, the network configuration is first designed. After that, in order to estimate the network weights, three optimization algorithms are considered. The first one, called standard neural lasso, employs the conventional procedure for training neural networks. The second optimization algorithm, termed restricted neural lasso, mimics traditional lasso to establish a connection between statistics and machine learning. Finally, a third optimization algorithm, called voting neural lasso was developed. Voting neural lasso offers a novel way of estimating weights by considers the significance of variables across the cross-validation scenarios. Results showed that the conventional approach of training neural networks resulted in a lower performance when the validation set is not sufficiently representative. It was also observed that restricted neural lasso and the traditional lasso obtained equivalent results, which shows the convergence of the neural technique with the statistical one. Finally, the developed voting neural lasso algorithm outperformed the traditional lasso. These results were obtained across diverse training sets, encompassing observations ranging from as few as 47 to as many as 4000, with the number of predictors varying from 9 to 200.This research was partially funded by: Grant TED2021-130980B-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR”. Grant RED2022-134259-T funded by MCIN/AEI/ 10.13039/501100011033. Project “DTS21/00091", funded by Instituto de Salud Carlos III (ISCIII) and co-funded by the European Union. Grant for the requalification of permanent lectures, UC3M, David Delgado-Gómez. Grant PEJ-2021-AI/SAL-21472 funded by Comunidad de Madrid. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature
El cambio climático como nuevo riesgo social
No full textAdemás de la digitalización, el cambio climático constituye el otro gran tipo de riesgo propio de nuestra época. El presente estudio se adentra en su configuración como nuevo riesgo social para, a partir de esta base, analizar el modo en que se articulan las herramientas y estrategias dispuestas para su cobertura. En particular, nos detendremos en las medidas puestas en marcha para hacerle frente, distinguiendo entre aquellas que guardan una más estrecha relación con los Estados del bienestar, es decir, la Seguridad Social o las políticas sociales y las políticas de empleo; de aquellas otras que tienen que ver con las condiciones de trabajo, incluyendo las relacionas con la seguridad y salud laborales. Cerraremos el estudio con unas breves conclusiones desde la perspectiva de las transiciones laborale
A Reasoned Attempt to Mitigate Vibrations in Nonlinear Flexible Systems Influenced by Tractive-Elastic Rolling Contact Friction Through Input Shaping: A Case Study on a Trolley-Pipe Benchmark Transport System
Get PDFThe well-regarded feedforward control strategy known as Input Shaping is aimed at improving the dynamic response of flexible mechanical systems by reducing overshoot and residual vibration amplitude. Its validity has been confirmed by numerous studies dealing with linear system dynamics. However, its application in nonlinear systems, particularly those influenced by tractive–elastic rolling contact friction, remains a challenging and less explored open research area. This paper investigates whether Input Shaping, without tractive rolling friction compensation, can effectively mitigate vibrations in a trolley–pipe benchmark transport system. In this system, the pipe is modeled as a rolling disc attached to the trolley by a spring at its center of mass, while the trolley itself is connected to a guiding body frame by an additional spring acting as a proportional control. The natural frequencies of the system are analytically estimated and numerically verified from a corresponding well-suited multibody model. Thus, tailored two-mode shapers are designed based on simultaneous constraints and the convolution sum, respectively. Through multibody simulations, this study evaluates the performance of Input Shaping under tractive–elastic rolling contact friction conditions. The findings highlight both the potential and limitations of this control method in addressing nonlinear mechanical systems influenced by tractive–elastic rolling contact friction.This research was funded by the Spanish government’s Ministry of Science and Innovation Grant Number PID2020-116984RB-C21