### Examinando por Materia "MULTITUDES"

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Proyecto final de Grado AntSwarm(2012) Goldberg, Daniel; Liendro, José Indalecio; Parisi, DanielMás... "El objetivo general del presente trabajo final es aplicar y desarrollar las herramientas de procesamiento de imágenes y video necesarias para poder analizar los registros adquiridos en los experimentos particulares."Más... Artículo de Publicación Periódica Continuous-space automaton model for pedestrian dynamics(2011-05-11) Baglietto, Gabriel; Parisi, DanielMás... An off-lattice automaton for modeling pedestrian dynamics is presented. Pedestrians are represented by disks with variable radius that evolve following predefined rules. The key feature of our approach is that although positions and velocities are continuous, forces do not need to be calculated. This has the advantage that it allows using a larger time step than in force-based models. The room evacuation problem and circular racetrack simulations quantitatively reproduce the available experimental data, both for the specific flow rate and for the fundamental diagram of pedestrian traffic with an outstanding performance. In this last case, the variation of two free parameters (r min and rmax) of the model accounts for the great variety of experimental fundamental diagrams reported in the literature. Moreover, this variety can be interpreted in terms of these model parameters.Más... Artículo de Publicación Periódica Effect of physical distancing on the speed-density relation in pedestrian dynamics(2021-04) Echeverría Huarte, Iñaki; Garcimartín, Ángel; Parisi, Daniel; Martín-Gómez, CésarMás... "We report experimental results of the speed-density relation emerging in pedestrian dynamics when individuals keep a prescribed safety distance among them. To this end, we characterize the movement of a group of people roaming inside an enclosure varying different experimental parameters: (i) global density, (ii) prescribed walking speed, and (iii) suggested safety distance. Then, by means of the Voronoi diagram we are able to compute the local density associated to each pedestrian, which is afterward correlated with its corresponding velocity at each time. In this way, we discover a strong dependence of the speed-density relation on the experimental conditions, especially with the (prescribed) free speed. We also observe that when pedestrians walk slowly, the speed-density relation depends on the global macroscopic density of the system, and not only on the local one. Finally, we demonstrate that for the same experiment, each pedestrian follows a distinct behavior, thus giving rise to multiple speed-density curves."Más... Artículo de Publicación Periódica Effect of physical distancing on the speed–density relation in pedestrian dynamics(2021-04) Echeverría Huarte, Iñaki; Garcimartín, Ángel; Parisi, Daniel; Cruz Hidalgo, R.; Martín-Gómez, César; Zuriguel, IkerMás... "We report experimental results of the speed-density relation emerging in pedestrian dynamics when individuals keep a prescribed safety distance among them. To this end, we characterize the movement of a group of people roaming inside an enclosure varying different experimental parameters: (i) global density, (ii) prescribed walking speed, and (iii) suggested safety distance. Then, by means of the Voronoi diagram we are able to compute the local density associated to each pedestrian, which is afterward correlated with its corresponding velocity at each time. In this way, we discover a strong dependence of the speed-density relation on the experimental conditions, especially with the (prescribed) free speed. We also observe that when pedestrians walk slowly, the speed-density relation depends on the global macroscopic density of the system, and not only on the local one. Finally, we demonstrate that for the same experiment, each pedestrian follows a distinct behavior, thus giving rise to multiple speed-density curves."Más... Artículo de Publicación Periódica Flow of pedestrians through narrow doors with dierent competitiveness(2016) Garcimartín, Ángel; Parisi, Daniel; Pastor, José Martín; Martín-Gómez, César; Zuriguel, IkerMás... "We report a thorough analysis of the intermittent flow of pedestrians through a narrow door. The observations include five diferent sets of evacuation drills with which we have investigated the efect of door size and competitiveness on the flow dynamics. Although the outcomes are in general compatible with the existence of the faster-is-slower efect, the temporal evolution of the instantaneous flow rate provides evidence of new features. These stress the crucial role of the number of people performing the tests, which has an influence on the obtained results. Once the transients at the beginning and end of the evacuation are removed, we have found that the time lapses between the passage of two consecutive pedestrians display heavy-tailed distributions in all the scenarios studied. Meanwhile, the distribution of burst sizes decays exponentially; this can be linked to a constant probability of finding a long-lasting clog during the evacuation process. Based on these results, a discussion is presented on the caution that should be exercised when measuring or describing the intermittent flow of pedestrians through narrow doors."Más... Tesis de maestría Infraestructura para ciudades inteligentes en la nube: solución para procesamiento de datos de las ciudades, aplicado al estudio de muchedumbres(2017) Rodríguez Bilardo, Marisabel Guadalupe; Muñoz, ClaudioMás... "Este trabajo estudia las alternativas de recolección y análisis de grandes cantidades de datos, de tal manera que sea más accesible para los gobiernos de las ciudades realizar inferencias útiles sobre la vida de los habitantes, que redunden en un mejoramiento de la calidad de vida. Se presenta un método a fin de realizar un prototipo para recolectar información proveniente de crowdsensing, que permite consolidar datos y realizar inferencias y visualización dinámica en tiempo real tomando como base de análisis la información pública de la ciudad de Buenos Aires."Más... Artículo de Publicación Periódica Pedestrian collective motion in competitive room evacuation(2017-12) Garcimartín, Ángel; Pastor, José Martín; Martín-Gómez, César; Parisi, Daniel; Zuriguel, IkerMás... "When a sizable number of people evacuate a room, if the door is not large enough, an accumulation of pedestrians in front of the exit may take place. This is the cause of emerging collective phenomena where the density is believed to be the key variable determining the pedestrian dynamics. Here, we show that when sustained contact among the individuals exists, density is not enough to describe the evacuation, and propose that at least another variable-such as the kinetic stress-is required. We recorded evacuation drills with different degrees of competitiveness where the individuals are allowed to moderately push each other in their way out. We obtain the density, velocity and kinetic stress fields over time, showing that competitiveness strongly affects them and evidencing patterns which have been never observed in previous (low pressure) evacuation experiments. For the highest competitiveness scenario, we detect the development of sudden collective motions. These movements are related to a notable increase of the kinetic stress and a reduction of the velocity towards the door, but do not depend on the density."Más... Artículo de Publicación Periódica Pedestrian dynamics at the running of the bulls evidences an inaccessible region in the fundamental diagram(2021-09) Parisi, Daniel; Sartorio, Alan G.; Colonnello, Joaquín R.; Garcimartín, Ángel; Pugnaloni, Luis Ariel; Zuriguel, IkerMás... "We characterize the dynamics of runners in the famous “Running of the Bulls” Festival by computing the individual and global velocities and densities, as well as the crowd pressure. In contrast with all previously studied pedestrian systems, we unveil a unique regime in which speed increases with density that can be understood in terms of a time-dependent desired velocity of the runners. Also, we discover the existence of an inaccessible region in the speed–density state diagram that is explained by falls of runners. With all these ingredients, we propose a generalization of the pedestrian fundamental diagram for a scenario in which people with different desired speeds coexist."Más... Artículo de Publicación Periódica People counting using visible and infrared images(2020-10) Biagini, Martín; Filipic, Joaquín; Mas, Ignacio; Pose, Claudio D.; Giribet, Juan I.; Parisi, DanielMás... "We propose the use of convolutional neural networks (CNN) for counting and positioning people in visible and infrared images. Our data set is made of semi-artificial images created from real photographs taken from a drone using a dual FLIR camera. We compare the performance between CNN’s using 3 (RGB) and 4 (RGB+IR) channels, both under different lighting conditions. The 4-channel network responds better in all situations, particularly in cases of poor visible illumination that can be found in night scenarios. The proposed methodology could be applied to real situations when an extensive databank of 4-channel images will be available."Más... Proyecto final de Grado People counting using visible and infrared images(2020-10-19) Biagini, Martín; Filipic, Joaquín; Parisi, DanielMás... "We propose the use of convolutional neural networks that consider as input four channels images (RGB+IR) for counting and positioning people in images. Our data set was made of images based on photographs taken from a drone using a dual FLIR camera. Comparison between 3 (RGB) and 4 (RGB+IR) channels are studied for different lightning conditions. The four channel network performs better in all situations, particularly in cases of poor visible illumination that can be found in real night scenarios. The average precision of this network on a testing data set (independent from the training one) is approximately 1 cm in nding the positions of pedestrians (from 15 and 30 m altitude images) and 0.0001% in the relative counting error."Más... Artículo de Publicación Periódica Physical distance characterization using pedestrian dynamics simulation(2022-01-22) Parisi, Daniel; Patterson, Germán; Pagni, Lucio; Osimani, Lucía; Bacigalupo, Tomás; Godfrid, Juan; Bergagna, Federico M.; Brizi, Manuel Rodríguez; Momesso, Pedro; Gómez, Fermín; Lozano, Jimena; Baader, Juan M.; Ribas, Ignacio; Astiz Meyer, Facundo; Di Luca, Miguel; Barrera, Nicolás Enrique; Keimel Álvarez, Ezequiel Martín; Herrán Oyhanarte, Maite Mercedes; Pingarilho, Pedro Remigio; Zuberbuhler, Ximena; Gorostiaga, FelipeMás... In the present work we study how the number of simulated customers (occupancy) af-fects social distance in an ideal supermarket, considering realistic typical dimensions and processing times (product selection and checkout). From the simulated trajectories we measure social distance events of less than 2 m, and their duration. Among other observ-ables, we define a physical distance coefficient that informs how many events (of a given duration) each agent experiences.Más... Artículo de Publicación Periódica Redefining the role of obstacles in pedestrian evacuation(2018) Garcimartín, Ángel; Maza, Diego; Pastor, José Martín; Parisi, Daniel; Martín-Gómez, César; Zuriguel, IkerMás... "The placement of obstacles in front of doors is believed to be an effective strategy to increase the flow of pedestrians, hence improving the evacuation process. Since it was first suggested, this counterintuitive feature is considered a hallmark of pedestrian flows through bottlenecks. Indeed, despite the little experimental evidence, the placement of an obstacle has been hailed as the panacea for solving evacuation problems. In this work, we challenge this idea and experimentally demonstrate that the pedestrians flow rate is not necessarily altered by the presence of an obstacle. This result—which is at odds with recent demonstrations on its suitability for the cases of granular media, sheep and mice differs from the outcomes of most of existing numerical models, and warns about the risks of carelessly extrapolating animal behaviour to humans. Our experimental findings also reveal an unnoticed phenomenon in relation with the crowd movement in front of the exit: in competitive evacuations, an obstacle attenuates the development of collective transversal rushes, which are hazardous as they might cause falls."Más... Artículo de Publicación Periódica Simulating competitive egress of noncircular pedestrians(2017-04) Cruz Hidalgo, R.; Parisi, Daniel; Zuriguel, IkerMás... "We present a numerical framework to simulate pedestrian dynamics in highly competitive conditions by means of a force-based model implemented with spherocylindrical particles instead of the traditional, symmetric disks. This modification of the individuals’ shape allows one to naturally reproduce recent experimental findings of room evacuations through narrow doors in situations where the contact pressure among the pedestrians was rather large. In particular, we obtain a power-law tail distribution of the time lapses between the passage of consecutive individuals. In addition, we show that this improvement leads to new features where the particles’ rotation acquires great significance."Más...