Examinando por Materia "Análisis de señales"
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- PublicaciónAcceso abiertoAfinador mecatrónico para flauta traversa(2014) Taborda Aramburo, Marco Antonio; Ramírez Rivera, Daniel; García Mayén, HéctorEsta propuesta pretende desarrollar a través de la integración de tecnologías derivadas de la mecánica y la electrónica, una herramienta que permita disminuir la subjetividad humana en el proceso de afinación de la flauta traversa. Se propone desarrollar un dispositivo afinador mecatrónico controlado por software, haciendo un análisis previo de las condiciones que afectan la afinación del instrumento mediante pruebas experimentales, de cuyos resultados puedan ser concluidos parámetros importantes en la etapa de diseño e implementación del dispositivo. El ajuste de afinación del instrumento estará determinado por la comparación entre un tono de referencia generado por un algoritmo implementado en Matlab y una señal capturada definida por la nota La – 440Hz en la digitación estándar del instrumento musical. Partiendo de esta comparación se busca obtener el punto de correlación entre las señales, con el fin de controlar por medio del sistema mecatrónico el ajuste de relación de distancia entre la cabeza y el cuerpo del instrumento.
- PublicaciónAcceso abiertoAnálisis de estrés en la voz utilizando coeficientes cepstrales de Mel y máquina de vectores de soporte(2018) Toro Cerón, Luis Gabriel; Ruiz Sánchez, SantiagoVoice analysis can be done in multiple ways, this processes have evolved through ages, becoming more complex and diversifying the utility of them, Nowadays procedures like detection, recognisement or clasification are based on analyses of the sound signal. This project addresses the recent need of making processes that were initially considered subjectives, automatically, taking into a count of the different factors that might influence them, and always being forward to improve and contribute to the existing processes. The importance of it lies on the versatility of the algorythms, that can be used as well in different areas and for different purposes such as the field of medicine, humanities, social sciences and technology
- PublicaciónAcceso abiertoBanco de pruebas para el análisis de vibraciones en maquinaria(2021) Muriel Hoyos, Jaison; Herrera Arcila, Camilo; Franco Bedoya, Ramiro Estebann 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 analyzed
- PublicaciónAcceso abiertoCaracterización de señales electromiográficas para la clasificación de cuatro movimientos de la mano empleando técnicas temporales y frecuenciales(2016) Cruz Salazar, Mónica Andrea; Aguilar Zapata, Olga María; Acosta Calle, Steven; Flórez Velásquez, Camilo AndrésManipulating bionic prosthesis through electromyographic signals captured in humans or animals, it requires the detection of the existing correlation between the temporal characteristics and/or frequency of the electromyographic (EMG) signals captured with the type of movement executed by the muscle or muscles under study. This features or signal parameters are measured in different time intervals, generating a feature vector V = [V1, V2,...,VN]ERN, , where each parameter Vi ER is measured in the i- tenth time signal. Literature has proposed various techniques to characterized EMG signals that have shown to be very effective in detecting the type or types of movements performed, such as the coefficient technique of the autoregressive model (AR), the Zero Crossing, the temporal behavior of the mean and variance, the Short Time Fourier transform, the wavelet transform signal and the energy behavior in time among others. In this paper we will present the development of some temporary - Frequency techniques for the characteristics extraction of the EMG signals for 4 types of movements performed by a hand (arm supination - pronation, fingers Extension - Flexion) and application of principal component analysis (PCA) technique for the dimensions reduction of the characteristics vectors, in order to use the obtained features for each type of movement in a neural network classifier designed by the work team, which will autonomously discriminate the types of movement from the measurement of the EMG signals of the muscles under consideration. Finally, the experimental measurement of the matrix for the probability of success of the different techniques for characteristics extraction will be performed + Neural Network, to select the technique with greater success rate to be used at a later stage of the project for the online recognition of hand movements.
- 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 EstebanSource 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 tools
- PublicaciónAcceso abiertoDiseño de una herramienta para la gestión de derechos de autor de una pieza fonográfica, mediante la transcripción automática de melodías, usando Music Information Retrieval(2019) Correa Ruiz, Juan Pablo; Mato Méndez, Fernando JoséBy the end of the 80`s and early 90’s, the very first investigations and tangible products from MIR (Music Information Retrieval) were released. MIR would be an interdisciplinary science, that would take charge of extracting musical information from digital processing of its signal; the possibility of giving to a computer a piece of a song, and this computer finding its tempo, harmony, melody, music scale, seems to be impossible, and not only from musical field, from engineering it also could extract each instrument from a record, find applied processes within the mix, discrimination between speech and music, among others. The social and commercial impact extends itself to generate playlists from the data rendered by the computer. By that time, the most significant reaches for this new science was not applying it on a list of audio files hosted inside a local computer`s hard disk, but taking it to the internet to create a freer data base that would allow the access to a millions of music files. In this degree work, multiple MIR methods will be investigated, and used to fragment and analyze the audio signal through mathematical autocorrelations, Fourier and Hilbert transform and parabolic interpolations, extracting musical information, such as beats per minute and musical notes from signal spectre to transcribe a melody automatically. This final product will serve as a tool for musical piece registration on Sociedad de Autores y Compositores de Colombia, as it is the legal identity of a piece.
- PublicaciónAcceso abiertoEvaluación de técnicas de reducción de ruido basadas en wavelets orientadas al procesamiento de señales bioacústicas(2018) Gómez Echavarría, Alejandro; Ugarte Macías, Juan PabloThis research project assesses and proposes different strategies for noise reduction based on the undecimated discrete wavelet transform to process noisy bioacoustic signals. The proposed strategies are based on different criteria for estimating the level of noise present in the signal to perform a soft thresholding on the deatail coefficients obtained from the wavelet decomposition. The proposed algorithms, called LAstd, LDstd and LDmad, use the standard deviation of the last approximation, the standard deviation of each detail at each level and the median absolute deviation to estimate the noise level respectively. The strategies are compared with Stein's unbiased risk threshold estimation method (SURE) implemented with the Matlab function wden from the wavelet toolbox which uses the discrete wavelet transform. Three sets of data were used to assess the algorithms. In a first approach, the strategies were evaluated using different owl calls with different additive noise profiles and amplitudes. To test the tolerance of the algorithms to ambient noise, a data set of fragments with acoustic events of high biological activity were extracted from field recordings. Finally, the algorithms were tested with the full recordings of the Colombian ecosystems which contained the acoustic events. The results were quantified using the signal-to-noise ratio and the spectral entropy. To complement the results, a visual analysis of the spectrograms of the processed signals was made. The methodology LAstd obtained an excellent performance when processing the owl calls contaminated with white Gaussian noise, however it is not tolerant to colored noise and narrow band noise. On the other hand, the methodologies LDstd and LDmad show a better performance in signals with colored noise, demonstrating their ability to process field recordings with ambient noise. The implementation of a smoothing parameter “q” for the thresholding in the proposed methodologies allowed to adjust the processing to avoid the loss of important information, giving to the algorithms versatility to perform well in different scenarios
- PublicaciónAcceso abiertoRobot hexápodo para la detección de minas antipersona artesanales tipo jeringa(2014) Botero Gómez, Santiago; Cárdenas Torres, Andrés MauricioEsta investigación propone utilizar un robot hexápodo, instrumentado que emule el caminar de un insecto en topografías montañosas del territorio Colombiano especialmente en la región Antioqueña, el cual será controlado remotamente mediante dos módulos Xbee serie 2 para la detección de minas antipersona a partir del cambio de temperatura generado por el cabezal de la jeringa de material plástico respecto a la vegetación presente a su alrededor. El cambio de temperatura como método de detección planteado en este trabajo se basa en resultados encontrados experimentalmente, se propone utilizar el sensor infrarrojo de temperatura MLX90614. La programación y el análisis de los datos que entreguen los sensores serán interpretados por la plataforma arduino debido a sus características apropiadas para el completo desarrollo de este proyecto. Entre los resultados esperados se encuentra el mejoramiento de la secuencia de control del robot hexápodo mediante dos joystick análogos, además del algoritmo para tener una medición exacta de la temperatura
- PublicaciónAcceso abiertoSistema Mecatrónico para la Interpretación de la Lengua de Señas Colombiana(2011) Benjumea Herrera, Juan Sebastián; Gil Arboleda, Sebastián; Cárdenas Torres, Andrés MauricioLa ciencia y la tecnología están tomando parte en la difícil tarea de ayudar a la comunidad en situación de discapacidad, entre los esfuerzos que se han hecho a nivel mundial para eliminar dichas barreras comunicativas, sobresalen los sintetizadores de voz, que se encargan de convertir en sonido las palabras que el usuario escribe a través del teclado y que se visualizan en una pequeña pantalla. Pero en la tecnología, nada está lo suficientemente bien hecho como para no tratar de mejorarlo, es así como se busca la evolución de los sintetizadores de voz, pero ya no controlados con los dedos sino con el cerebro directamente.