Examinando por Autor "Ochoa Villegas, Jonathan"
Mostrando 1 - 15 de 15
Resultados por página
Opciones de clasificación
- PublicaciónAcceso abiertoAnálisis de absorción en baja frecuencia que produce el uso de varias capas de material absorbente y diferente distribución mediante método analítico y medición con estándares tipo ISO(2020) Arias Arboleda, Susana; Ochoa Villegas, JonathanAbsorption coefficients represent the capacity of sound absorption acoustic materials. This parameter is estimated from measurements such as those specified in ISO type parameters. As for example, regulation 354 estimates the coefficient of absorption at random incidence through the measurement in reverberant chamber and regulation 10534 estimates the absorption at normal incidence using as a tool a tube of standing waves. Most manufacturers of absorbent materials have the estimated absorption coefficient between the frequencies of 125 Hz to 4000 Hz. The low frequency range is usually not reported since the absorption coefficient is not relevant, although it is also of interest in the implementation and therefore an evaluation is necessary. This project aims to find a methodology that allows, through international methods and analytical methods, to estimate the absorption coefficient at low frequency when the thickness of three absorbent materials increases, Frescasa (glass wool), Acustiplaca (pressed rock wool) and Acustifibra (pressed glass wool). The study focuses on the study of frequencies between 63 Hz to 250 Hz, in addition to this, the effect of estimating the absorption coefficient on different distributions is investigated. For this purpose, panels with several layers of absorbent material have been designed to be measured by ISO 354, placing the panels in two positions, vertical and horizontal. The absorption coefficient is estimated using several layers of absorbent material according to ISO 10534-1 in impedance tube. With the proposed methodology, the measurements in the impedance tube were analyzed according to layers of material to determine how to modify the absorption coefficient as the thickness increases. In a reverberant chamber, measurements can be made with the multilayer panels in a vertical position and in a horizontal position. As an analytical method, the Allard and Champoux absorption model is implemented by varying the thickness of the materials and taking into account the resistivity value for each material. With the results obtained, it was concluded that the thickness of the absorbent materials increases, which represents an increase in the absorption coefficient at low frequencies and is also a physical characteristic that predominates over density. However, it is necessary in future studies to define the feasibility of this method, in order to optimize the strategies that are required in each case of acoustic conditioning that link problems in low frequency.
- PublicaciónAcceso abiertoAnálisis del impacto del ruido, de carácter temporal y tonal, sobre procesos cognitivos mediante auralizaciones referenciadas en un recinto pedagógico de la Universidad San Buenaventura Medellín(2017) Arenas Villegas, Sara María; Ochoa Villegas, JonathanThe project began with the investigation of D. Quintero , who performed the first series of psychological tests, with the intention of evaluating the affection on cognitive processes. From this idea, the pilot experiment by E. Higuita  was born, with some changes in the psychological tests in comparison with the D. Quintero project, the most significant was the type of noise used during the psychological tests. With a protocol to use, thanks to the pilot experiment mentioned above, this project aimed to evaluate a larger sample. Sixty-two people were evaluated, each participant performed psychological tests as Integrated Visual and Auditory Continuous Performance Test, Curve Verbal Memory, Wechsler Memory Scale and Trail Making Test, with noise conditions of 125Hz tonal noise, 500Hz, 3150Hz and intermittent noise. There is a need to evaluate the control group again, which was taken from a previous investigation; this may be due to changes to the sample and the adjustments to the protocol for this investigation. The final results shown a similar act of noise groups evaluated.
- PublicaciónAcceso abiertoAplicación del modelo de predicción de ruido de tráfico CNOSSOS-EU a la estimación de contaminación por ruido de las motos en el Valle de Aburrá(2020) García Paz, Alejandro; Daza Avendaño, Paola Andrea; Ochoa Villegas, JonathanThe new CNOSSOS-EU methodology for the estimation of road traffic noise takes into account of its variables, the input of the two wheeled vehicles (motorcycles) to the strategic noise maps calculation. It is relevant to analyse the affectation of the mentioned category to the results of the levels of acoustic emission in Medellín and its metropolitan area, due to the the increase and high density of motorcycles that currently transit on its roads. Making a design of different vehicular capacity and average speed situations it can be seen the influence of the motorcycles in greater detail in all possible scenarios. Then, is presented the numerical analysis of the CNOSSOS-EU method, simulation of motorcycles in different conditions, as well as, measurements base on ISO standars, analysis and comparison of the result of different methodologies. Finally, the study of the contribution of the generated noise due to motorcycles on Aburrá Valley is made. Additionally, punctual scenarios in the Aburrá Valley are determined for the real analysis of the contributión noise level due to motorcycles. The 4 stages in which the project is developed are presented. These are, first, the numerical analysis of the CNOSSOS-EU method along with SoundPlan simulations in controlled situations and different configurations of vehicular flow. Then, power measurements of different motorcycle models on steady and motion state are made according with ISO 362-2. Later is carried out the comparison of the obtained results to finally make the respective analysis
- PublicaciónAcceso abiertoCaracterización de fuentes de ruido al interior de un centro escolar para estimar el impacto producido dentro de una zona residencial, por medio del software SoundPLAN(2021) Velasquez Arcila, Katherine Andrea; Ochoa Villegas, JonathanThe following work consists of characterizing noise sources inside a school to estimate the impact produced within a residential area. There are currently few studies on the problem of noise emissions generated by leisure activities, such as academic activities. Similarly, in the municipality of Medellín, some institutions are receiving attention because of complaints from residents about the noise generated in these places. The objective of this project was to prepare noise maps where it could estimate the impact produced by noise sources that are found inside a building of an educational institution that is located in a residential area. The noise maps were estimated with different noise indicators, where the evaluated levels varied over time for each indicator.  To carry out the realization of these noise maps, a model of the building of the educational institution is made through the software SoundPLAN, where all the conditions contained within I.E are accommodated to assess the emission levels in order to determine the equivalent A-weighted continuous sound pressure level A ( LAeq,Tin the residential area, where T was determined for different periods in hours in order to estimate the impact with different indicators. Resolution 0627 of 7 April 2006 and the Colombian technical standard NTC 4595 for the evaluation and monitoring of noise from internal sources of the educational institution were taken as reference.
- PublicaciónAcceso abiertoClasificación de escenas acústicas a través de descriptores de audio y máquinas de aprendizaje. Aplicación en escenas de Medellín(2019) Chica Osorio, Carlos Andrés; Yurgaky Valoyes, Dudley; Ochoa Villegas, JonathanIn recent years, automatic learning methods have been paired to obtain models for the analysis and classification of audio signals, such as the support vector machines, Ensemble Classifier, among others. These methods present a problem because they are not very understandable in their internal functioning, since they do not show the user an explanatory structure of how predictions are made and that they are understandable. It is worth mentioning that the models are accurate, but they are not presented properly. There is not a sound bank of the acoustic scenes of the city, it was necessary to record these outside scenes in the field. Audio descriptors such as MFCC and Chroma Vector were used to identify the acoustic scenes together with two SVM algorithms and one Ensemble Classifier. The result was an efficiency rate of 72.22% for the cases of SVM machines (Medium Gaussian and Quadratic), which are satisfactory. On the other hand, the learning machine based on Ensemble Classifier (Boosted Tree) had an Accuracy rate of 55.55%, this being a low performance machine.
- PublicaciónAcceso abiertoDesarrollo de un aplicativo tipo Web GIS para la presentación de soundscapes combinado videos 360 y audio espacial(2020) Valencia Viñas, Pablo; Ochoa Villegas, JonathanThe development of a webgis-like application to present soundscapes combining 360-degree videos and ambisonic spatial audio is a project developed at the University of San Buenaventura with the help of the Metropolitan Area of the Aburra Valley (AMVA). Showing noise studies to the community can become complex due to the unknown information and languages that they handle, the map built by means of the mapbox and Qgis applications allows observing the noise sources found in the Aburra Valley and It manages to obtain an audio capture obtained by means of the Ambisonic technique and video captured by means of a 360-degree camera which allows the user to have an immersive experience and can be completely submerged in a point of the city which It allows you to save an image of the intangible heritage of the city or municipality
- PublicaciónAcceso abiertoDesign of a protocol for the measurement of physiological and emotional responses to sound stimuli(2017) Macía Arango, Andrés Felipe; Ochoa Villegas, JonathanA protocol for the measurement of physiological and emotional responses to sound stimuli is presented. The sounds used in the study were created by comparing different methods and possible bandwidths. These sounds correspond to white noise filtered in 3 central frequencies, to know, 125 Hz, 500Hz, and 3150Hz, with a variable bandwidth based on 1/3 octaves. additionally, spatial information was given to the sounds by convolving them with a simulated binaural impulse response. Two experiments were conducted. The first one consisted of 3 sounds created at different sound pressure levels, between 50 dB and 80 dB in 6 steps. It was found that both valence and arousal changed as the level increased, the first one decreasing, and the last one increasing, showing a possible relation between elicited emotions from a sound and its sound pressure level. The second experiment presented both image and sound simultaneously. The sound corresponded to the same described above, at a fixed level of 65dB. The images were two, one with a positive semantic content, and the other with a negative one. Both images were taken from the IAPS (International Affective Picture System). Responses were measured with the self assessment manikin SAM and Noldus FaceReader technology. The results obtained with the SAM were not conclusive, probably due to sample size, experiment design and other factors. The results obtained with the FaceReader showed clear reactions from participants to the audiovisual.
- PublicaciónAcceso abiertoDeterminación del efecto causado en procesos cognitivos por el tiempo de reverberación y ruido de fondo mediante el uso de auralizaciones(2018) Restrepo Dávila, Felipe; Ochoa Villegas, JonathanIn this work, the experimental design was presented in the form of a replica, in which a sample of sixty university students was evaluated in order to determine the effect caused by reverberation time and background noise on the cognitive processes of memory, attention and executive functions, seeking to contrast the results obtained in previous researches. Statistical analysis is presented in order to relate the effect of these acoustic parameters. Five psychological instruments were applied where four of these psychological instruments were auralized taking into account the acoustic conditions measured and the hypothetical treatment of the mini auditorium 2 of the University of San Buenaventura, San Benito Medellín. For the application of the test, the recording room of studio A of the University of San Buenaventura Medellín was used and the psychological instruments were reproduced using the Opsodis binaural reproduction system as specified in the connection diagram of section VII.A and the distribution within the recording room as shown in Figure 8. It was found that the results found in previous theses where the impact of reverberation time and background noise on cognitive processes was evaluated are similar, corroborating in the same way the foreign investigations, where it is proven that background noise and reverberation time significantly affect attention, memory and executive functions, being reverberation time the most affected acoustic parameter. High background noise causes interference in the communication of verbal messages, causing the individual to remain in an unnecessarily high attention span, which can have negative health effects such as fatigue and stress. The long reverberation time in turn causes loss of speech intelligibility, i.e. verbal messages are partially understood or sometimes confused
- PublicaciónAcceso abiertoDiseño y automatización de un sistema para las mediciones de la velocidad del sonido en tejidos de peces(2020) Echeverri Zea, Laura; Ochoa Villegas, JonathanIn this project we disigned a in this project a software was designed for the automatization of the speed of sound c measurements in tissue. With this software measurements of c were carried in water and soft tissue of Atlantic makerel (Scomber scombrus) using the Emitter-Receiver method with Airmar P319 transducers. An average c is found for the calibration set-up of 1502.75m / s with an error of 1.2%, compared with the calculated value, for the soft tissue and average of c 1583.1m / s is measured with an error of 0.8%. For the quality analysis of the signals, three parameters were studied, Total harmonic distortion (THD), for which acceptable values are found below 1.25%, the second parameter is the Zero-Crossing Rate for which the maximum acceptable value is 0.26 and finally the third chosen parameter refers to the error between the first harmonic of the receiving signal vs. the frequency emitted from the generator, for this the acceptable range found is between 1% and 13%
- PublicaciónAcceso abiertoEstimación del coeficiente de absorción en incidencia aleatoria utilizando presión y velocidad de partícula mediante la Sonda Pu de Microflown Technologies(2015) Ochoa Villegas, Jonathan; Tafur Jiménez, Luis AlbertoDentro de los parámetros descritos para algunos materiales acústicos, está expuesto el coeficiente de absorción, el cual de acuerdo con normas y estándares internacionales, como la ISO 354, establece que éste parámetro debe ser medido en una cámara reverberante ya que cuantifica la absorción de un material a incidencia aleatoria, lo cual hace que el valor presentado tienda a ser la absorción que el material tenga al momento de su implementación. En este proyecto, se busca una metodología para estimar el coeficiente de absorción a incidencia normal e incidencia aleatoria, partiendo de mediciones de velocidad de partícula y presión sonora con el uso de la sonda PU diseñada por Microflown Technologies®. Con este fin, se desarrolló un protocolo de medición aplicable a incidencia normal y oblicua que garantiza resultados comparables con otros métodos estandarizados como en el caso de mediciones en tubo de ondas estacionarias para incidencia normal. Con los resultados obtenidos no es posible determinar la incidencia aleatoria, por lo que el estudio se centra en el análisis de las variables, presión y velocidad de partícula, conforme cambia el ángulo de incidencia y su posible influencia en la determinación del coeficiente de absorción en incidencia oblicua.
- PublicaciónAcceso abiertoEvaluación de la influencia de las condiciones acústicas de las aulas en tres ciudades del país en el rendimiento docente y estudiantil(2018) Rodríguez González, Mauricio; Ochoa Villegas, JonathanThis project seeks to evaluate the acoustic conditions of the classrooms located in three cities of the country (Medellin, Bogota and Cali) to determine the acoustic impact they have on the teaching-learning process, the health of the teachers and the student’s cognitive performance. The next job is part of the macro project " Identification of factors of environmental performance (acoustic, thermal and visual) determinants of the mental health of teachers and students of public schools of Bogota, Medellin and Cali: Line bases for the analysis of impact of the public politics according to the norm NTC 4595 " conducted by COLCIENCIAS. To execute this project measurements of background noise, time of reverberation and acoustic isolation were realized in the selected classrooms, and there were obtained results that do not fulfill with the regulations, which makes necessary the development of a process of management of noise to control the acoustic problems that they present in the classrooms of the different schools studied. Keywords: Cognitive process, Background noise, Reverberation time, Acoustic isolation, Acoustic conditioning.
- PublicaciónAcceso abiertoEvaluación de las características acústicas que influyen en el confort acústico de aulas de clase en el rendimiento cognitivo de estudiantes a través del uso de una cabeza artificial(2018) Zuluaga Velásquez, Juan Pablo; Ochoa Villegas, JonathanThe influence of acoustic parameters in a classroom for pedagogical use, on the acoustic comfort of students and their cognitive performance, is affected due to several factors. Surveys carried out for this document on students were analyzed, for subjective evaluation of the subject, and various acoustic characteristics such as: background noise, reverberation time, EDT, STI, RASTI, C50, D50, IACC, which describe objectively the acoustic comfort and are those that are intended to investigate in this document, specifically making use of an artificial head, which represents the way in which they hear and perceive the sound by both ears, the students in the classrooms, in order to raise awareness on the importance of acoustic characteristics inside pedagogical classrooms, their effects on cognitive performance and acoustic comfort. Measurements are made in 10 elementary school classrooms in public institutions in the city of Medellín. In each of the venues binaural audio samples were recorded by means of an artificial head, for the analysis of background noise and reverberation time, in different points of the classroom. The measurements were based on a protocol created for the evaluation of the aforementioned acoustic parameters, by means of a digital tool called Aurora, a set of plug-ins created for Adobe Audition, by which the impulse responses can be measured and manipulated of the room, for the evaluation of the acoustic conditions of the school premises
- PublicaciónAcceso abiertoEvaluación de parámetros acústicos de cinco aulas del colegio sol de oriente y su influencia en los componentes cognitivos de atención y memoria inmediata en estudiantes de sexto grado(2018) Benjumea Penagos, Johan Sebastián; Ochoa Villegas, JonathanIn this project, acoustic conditions of five classrooms from the educational institution "Sol de Oriente" were evaluated. This institution is located at Carrera 23 # 56 EH 200, 13 de November, Medellín, Antioquia. Background noise, reverb time (RT), and speaking transmission index (STI) were the parameters evaluated. Binaural response impulse was conducted to gather the STI, and using an artificial head, the background noise was recoded. In the same way, virtual models of the classroom were made to perform geometric acoustic simulation. The results of the simulation were compared against the measurements. In order to evaluate the attention and short time memory, a subjective test was performed with the help of the Psychology department of San Buenaventura University. The test was performed with two courser of middle schoolers whose age average was 12 years old, which use two of the classrooms used in the data gathering. The result is the analysis of the influence of the acoustic conditions in classrooms in the cognitive processes related to attention and short time memory.
- PublicaciónAcceso abiertoExploración de materiales para sistemas de control pasivo de ruido implementado a diseño acústico bioclimático con potencial uso en la construcción sostenible(2019) Villa Muñoz, Laura; Ochoa Villegas, JonathanThe concern about noise levels inside enclosure has increased in recent years. Therefore, it has dabbled in the search for a solution, the passive noise control has been a simple and effective answer for it. The passive noise control is a solution for de noise levels that can be found in the enclosure, because this is in charge of decreases them. The noise levels that affects an enclosure it’s due to ambient noise that is around it, this is influenced by several factors, such as: the industry, the traffic and the other factors that are there in the environment. The passive noise control can be implemented on any of the noise points (source – way – receptor), which is particularly, useful according to what people needs, to decrease noise levels inside enclosure the most effective is to monitor the facades, this control must be done with materials with acoustic characteristics, such as, sound reduction index and absorption coefficient. The most frequently implemented materials for the noise control are wool, drywall and concrete, although efficient in terms of absorption, these materials do not have optimal characteristics to be part of the bioclimatic design. The bioclimatic consider sustainable materials as optimal for any type of construction, because they do not pollute and help improve oxygen. The objective of this investigation is to find the acoustic characteristics on a different type of material than conventional, which are not contaminant, and besides, accomplish with adequate acoustic characteristics to replace the conventional ones. The methodology to be developed will start in the search and characterization material. By means of the P-U lead, for later get a cost-benefit analysis of the material implementation. With the obtained data through measurements and calculations it is evident that the green walls are a potential tool for the passive control of noise with bioclimatic design, since they meet the bioclimatic characteristics of comfort and has attenuations throughout the frequency range if it is a composite partition that is accompanied by concrete, or in high frequencies if the only installation is a vertical garden.
- PublicaciónAcceso abiertoModelado acústico a través de métodos numéricos para la generación de propuestas de intervención en aulas de clase(2018) Zemanate Silva, Oscar Fabián; Ochoa Villegas, JonathanThe work below consist of the generation of intervention proposals in architectural acoustics for classrooms in public institutions in the colombian cities Medellín, Bogotá and Cali under the project: Identificación de factores de desempeño ambiental (acústico, térmico y visual) determinantes de la salud mental de docentes y estudiantes de escuelas públicas en Bogotá, Medellín y Cali: Línea base para el análisis de la política pública según la norma NTC 4595. For this end a 14 classrooms sample was taken distributed in the three cities mentioned before. The work is divided in three phases and its results are based in geometric acoustics simulations in CATT-Acoustics v.9. The first phase aims to give an initial acoustics diagnosis for each one of the classrooms using simulations. It was found that In the most part of the classrooms the objectives proposed by this investigation were not accomplished: Reverberation time less than 1 second ant STI values greater than 0,6. The second phase take simulation results and with this data and architectural analysis of the classroom (geometry and materiality) gives an architectural proposal in the walls which aims to increase the room’s absorption by adding absorbent panels. In the third phase new simulations are done, this time with the intervention proposal. This simulation let the investigation to verify that the intervention works and works for the most of the rooms