- Buscar por autor

### Examinando por Autor "Franco Bedoya, Ramiro Esteban"

Mostrando 1 - 11 de 11

###### Resultados por página

###### Opciones de clasificación

- PublicaciónAcceso abiertoAnálisis de resonadores de Helmholtz a partir de la implementación del método de elementos finitos(2019) Duque Salcedo, Andrés Felipe; Franco Bedoya, Ramiro Esteban
Mostrar más The project consists of studying the acoustic and physical behavior of the Helmholtz resonators, which according to their dimensions can have different resonance frequencies. The analysis will be done by means of the finite element method (FEM), whose mathematical calculation model provides greater proximity to a real system; This is achieved through matrix arrays. The studies carried out to date on the finite element method focused on acoustics have been carried out for the modal analysis of enclosures, analysis of acoustic silencers for industrial machinery and is often used in the creation of electroacoustic prototypes, such as loudspeakers and microphones. In addition, this method has the advantage of coupling several physical phenomena, for example obtaining data about the temperature and at the same time the acoustics of some model, that is why this method is implemented for the characterization of acoustic materials such as the Helmholtz resonators. Initially, the equation of an acoustic wave is described, which makes it easier to show what is the behavior of the sound in a general way to later center said equation in a particular case, the Helmholtz resonators, which are described from the Helmholtz equation. After having raised the mathematical and physical problem, we proceed to solve it by the aforementioned method. The main advantages of using FEM to analyze materials such as Helmholtz resonators are in the optimization of this process in terms of time and money. In addition, it is vital to know that this method is recurrent as long as you have a processing capacity in the machines too high. The evaluation of the finite element method is performed in the simulation software comsol multiphysics using two different 3D models of Helmholtz resonators, each with different physical characteristics, the simple cavity resonator and the cavity resonator. simple based on slats. Each of the models will have four designs, two for low frequency and two for low medium frequency, having a total of eight simulationsMostrar más - PublicaciónAcceso abiertoAnálisis del paisaje sonoro y su relación con la contaminación por ruido ambiental para la denominada zona norte de la ciudad de Medellín(2018) Morales Uribe, Andrés; Franco Bedoya, Ramiro Esteban; Espinosa García, William Fernando
Mostrar más This work proposes the development of the analysis of the soundscape for the north zone of Medellin, where five open public spaces were studied, such as: Ruta N, Jardín Botánico, Parque de los Deseos, Parque Explora and Parque Norte. Were developed studios like environmental measures, surveys like subjective test and audio recordings about the environmental sound. The research is developed in 3 key phases, with regular traffic, in the day without car and in the implementation of the environmental pico y placa (23rd, 24th and 25th of march 2017). Founding what the principal source of pollution of the environmental noise is the road trafficMostrar más - PublicaciónAcceso abiertoBanco de pruebas para el análisis de vibraciones en maquinaria(2021) Muriel Hoyos, Jaison; Herrera Arcila, Camilo; Franco Bedoya, Ramiro Esteban
Mostrar más n the field of vibration analysis, in machinery, it is important to generate vibration records in differentmachine states to identify the relationship between the recorded signals and possible failures.A rotary motion machine can be simulated as a Jeffcott rotor. The work presents the main design parametersand the final construction of a test bench, for the analysis of vibrations in machinery. For the design, themechanical theory of vibration modeling was taken into account, as well as the different force diagramsto show how each of its parts interacts. The versatility of the test bench was also taken into account sothat it was possible to induce different failures. Once the design was consolidated, each of the parts wasmachined and the test bench was installed. In addition, a damping configuration was established, withneoprene, at the base; which was determined through a transmissibility analysis.Once the test bench has been implemented, a methodology for measuring and analyzing the vibratorysignals, captured at two non-rotating points, is designed and put into practice with the intention ofidentifying changes in rigidity and mass unbalance, through the orbits described by the center of the axis atthe two measurement points. In addition to this, a test is established to analyze the spectrum generated bythe system shutdown in order to find the possible resonance frequency. Four different operating scenarioswere analyzed, through which the incidence of the length of the axis between the bearings, the incidenceof the variation of the location of the unbalance disc along the axis and the variation of the centrifugalforce produced by the change of masses added to the disc were identified.Finally, it is shown the behavior of the orbits obtained which demonstrated the different unbalancesproduced in the test bench, through which it was discovered that the machine had an intrinsic unbalance.It was also demonstrated that the best configuration of neoprenes was with these located in the base,because they generated the lowest peak level and their transmissibility was low.With this project, a methodology was established for the construction, measurement and analysis ofvibratory signals captured at two non-rotating points of the rotor, which will serve as a basis for futureprojects in which failures different from those analyzed in this project can be analyzedMostrar más - PublicaciónAcceso abiertoComparación de métodos de cálculo para la evaluación del ruido producido por sistemas férreos en condiciones colombianas(2018) Ospina Quiceno, Santiago; Vásquez Arenas, Juan Pablo; Franco Bedoya, Ramiro Esteban; Espinosa García, William Fernando
Mostrar más The principal objective of this thesis was to compare calculation methods for noise estimation by railroads under colombian conditions, the compared methods were: RMR (Holland), Schall 03 (Germany) and CRN (United Kingdom), each one of the methods consider the conditions of the railway network of its country, thats why a comparison was made beetween the calculated levels of each method with measurements made by the engineering faculty in 2015, the places with measured data were Cerrejón, Chiriguaná,Yumbo and Zipaquirá. measurements in Medellin metro were made too by the investigators. The analysis made to the theory of each calculation method obligated to establish equivalents beetween the colombian trains and the trains from the country which the studied method were developed. the calculations were made with SoundPlan 7.3 which is a ambiental noise software bundle that allows the calculation of noise, noise maps and noise impact over Gis map shapes. The results comparison on each situation by the use of the 3 methods, allowed to observe the large differences between measured data and simulated ones, these differences had the same order of proximity, the closest values for every situation were given by the CRN method, then by Schall-03 method, leaving the RMR method as the one that had the greatest deviation with respect to the measurementsMostrar más - PublicaciónAcceso abiertoComparación subjetiva por medio de audífonos de la capacidad de localización de 4 bases de datos de HRTF de libre acceso(2021) Tamayo Arcila, Tobias; Silva Zuluaga, Alejandro; Franco Bedoya, Ramiro Esteban
Mostrar más With the advent of virtual entertainment, the search for increasingly real experiences has led to the creationof stimuli that seek to simulate the sensations obtained from human senses. An example of this is thebinaural audio, which aims to simulate the way in which the human being listens to sound. This typeof audio is produced by means of HRTF filters, which are transfer functions found through the Fouriertransform of the impulse responses captured from the binaural heads (HRIR). The localization capabilityof these may not be very accurate, due both to physical factors of the measured head that are inheritedby the filter, and to differences in the type of playback system which is used and the room in which theuser listens to the produced audio.The purpose of this research work is to design and execute a methodology of subjective tests through aonline form, with the intention of making a comparison between the HRTF filter bases of MIT, IRCAM,SADIE and CIPIC, in terms of their location capability.From the analysis of percentages and indicators of uncertainty and location, it was concluded that nodifferences were found in the location capacity of the databases, except for the CIPIC filter, which has aslightly higher location capacity than the rest. In addition, a low percentage of hits was obtained, whereerrors due to cone of confusion and totally incorrect answers had the greatest influence.Mostrar más - PublicaciónAcceso abiertoDesarrollo de un algoritmo de procesamiento de señales con arreglos de hidrófonos para la ubicación de fuentes subacuáticas(2017) Builes Suárez, Sebastián; Franco Bedoya, Ramiro Esteban
Mostrar más Source location is an important aspect in defense and monitoring in different knowledge areas, in response to the need of developing a tool able to execute this task, the present work proposes the implementation of direction of arrival (DOA) algorithm designed for underwater aplications under the research project of acoustic detection of targets, focusing in advanced methods of beamforming. The algorithms were implemented and validated by the numerical method of pseudo-spectral k-space, Ąnding a high coherency in their responses compared with the theoretical far-Ąeld model. In the design stage three kind of arrays are proposed and tested in controled conditions with no satisfactory results, Ąnding failures and performing an analysis of the methods and arrays by means of array signal processing theory toolsMostrar más - PublicaciónAcceso abiertoDetección, conteo y caracterización de vehículos en vías alternas mediante señales registradas con sismómetros para tiempos determinados(2020) Gallego Guzmán, Sebastián; Flórez López, Alejandro; Franco Bedoya, Ramiro Esteban
Mostrar más The study seeks to detect, count and characterize road traffic events by means of a vehicle measurementimplemented on 3 alternate roads in the Buenos Aires neighborhood of the city of Medell ́ın, using twotypes of seismometer arrangements; linear and two-dimensional, in order to capture its vibration signals,using the Linux operating system, 2 seismic stations and 4 geophones that capture these disturbances.Once the signals are obtained, they are analyzed using two programming languages; Python and Matlab,used to carry out two types of event recognition machine learning from two reference signals that arechosen for the training of the two learning machines. Then, from the measurements in the configuration ofthe two-dimensional and linear reference seismometer arrangements, the results are studied to find whatpercentage of effectiveness they present and the utility in recognizing vehicle capacity; thus determiningwhich of the seismic array configurations is most efficient for capturing road traffic signals.Mostrar más - PublicaciónAcceso abiertoDiseño de sólido resonador para partes del cuerpo (muslos) por medio de pruebas experimentales y elementos finitos(2019) Mora Saldarriaga, María Camila; Franco Bedoya, Ramiro Esteban
Mostrar más In the present work, experimental tests were carried out on adults of different body types and gender, both male and female, to obtain the frequencies of less attenuation for the thighs; having as a result for the high part 83Hz, middle part 91 Hz and low part 106 Hz. Subsequently, the design of solid resonators was made for the frequencies obtained for each part of the thighs. To obtain the resonant solids, we studied the solution of the acoustic wave equation in a beam embedded in both ends by initial conditions and the boundary conditions of the system. To validate the results, the numerical simulation was carried out using the finite element method (FEM). According to the results obtained, the design of the resonant solids is useful for the amplification of the vibrations at the frequencies to which they were tunedMostrar más - PublicaciónAcceso abiertoDiseño de sólidos resonadores para el desarrollo de una experiencia interactiva vibrotáctil por medio de pruebas experimentales y elementos finitos(2019) Otálvaro Hoyos, Juan Esteban; Figueroa Cuellar, Daniel Stiven; Franco Bedoya, Ramiro Esteban
Mostrar más In the present paper, experimental tests were carried out on adults of different contextures and gender, both male and female, to obtain the frequencies of less attenuation for the hands, feet and back; Resulting in hands, a frequency of 112 Hz for the palm and 184 Hz for the fingers. For the feet, a frequency of 182 Hz was obtained for the fingers, 75 Hz and 80 Hz for the heel, for the instep 80 Hz, 81 Hz and 93 Hz. Finally, for the back part there are frequencies of 54 Hz for the central part, 65 Hz for the right part and 75 Hz for the left part. Subsequently, the design of solid resonators for the different frequencies was carried out. To obtain the resonant solids, we have studied the solution of the acoustic wave equation in a beam embedded in both ends by the initial conditions and the boundary conditions of the system. To validate the results, the numerical simulation was carried out using the finite element method (FEM), according to the results obtained, the design of the resonant solids is useful for the amplification of the vibrations at the frequencies to which they were tunedMostrar más - PublicaciónAcceso abiertoGeneración de tomografías 2D de la tierra por medio de inversión de onda completa FWI utilizando SPECFEM 2D Cartesian(2020) Pulgarín Suárez, Diego Alexander; Berrío Ríos, David; Franco Bedoya, Ramiro Esteban
Mostrar más This work shows the procedure for the creation of a 2D tomography of the earth from the joint methodcalled full-wave inversion (FWI), for this, two experiments are carried out, the first one on a syntheticterrain called ’Checkers’ and the second one on a real flat terrain. A workflow is established, consistingof a stage of obtaining reference data, one of initial model creation, one of signal preprocessing andfinally one of iterative simulation and optimization. The results of both experiments are presented andan error analysis is made between the synthetic terrain model obtained and the actual synthetic terrainmodel to determine the effectiveness of the proposed workflow. Finally, the real terrain model obtained iscompared with data from two wells previously excavated at the site. The results identify the strengths andweaknesses of the method in terms of distribution of sources and receivers, initial model used, analyzedfrequency bandwidth of the signals and discretization timesMostrar más - PublicaciónAcceso abiertoRepresentación de las propiedades tímbricas y dinámicas de una señal de audio a través de una matriz RGB para la sustitución sensorial del oído a la vista(2021) García Gómez, Andrés; Franco Bedoya, Ramiro Esteban
Mostrar más This thesis shows the development of a method for the visual representation of the timbral and dynamic properties of an audio signal in an RGB matrix, for ear-to-vision sensory substitution in people with hearing disabilities. In the first part, were obtained audio descriptors and a comparison was made between the different types, such as the MFCC, spectral descriptors such as the spectral centroid, spectral flatness, spectral slope among others, descriptors such as the "Chroma Vector" were also used. Which allows identifying musical notes. To obtain these descriptors, the audio characteristics extraction tools included in the Matlab 2020B Audio Toolbox and the Dan Ellis “Chroma Feature Analysis and Synthesis” library were used. Based on the "Chroma Vector" an experimental algorithm was developed, using type IIR filters and later improved with the Q transform. Based on this method, were achieved visual representations in an RGB matrix. These visual representations were inspired by the phenomenon of synesthesia, more precisely sound-color synesthesia (Chromesthesia) and the analogous characteristics between hearing and vision. Visual representations based on this algorithm were obtained, similar to a spectrogram in real time, using the chromatic scale and colors according to this. Such visualizations appear to be useful to observe the temporal evolution of harmony and notes in music and for identifying basic patterns in short voice signals (logatomes). Finally, a subjective visual comparison between similar voice and music signals visualizations was made. a comparison using the “VGGish” neural network was made too, for this using its original input (mel scale filters), and the constant Q spectrum that was obtained as an audio descriptor previously, in this case showing the original input a better performance, but qualitatively it seems that the method chosen in this work visually represents the music and voice signals betterMostrar más