Marcelo Tiago - Academia.edu (original) (raw)
Papers by Marcelo Tiago
Ultrasound in Medicine and Biology, Aug 1, 2019
This work presents an affordable and easily customizable methodology for phantom manufacturing, w... more This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcoholÀbased cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.
Conferência Brasileira de Dinâmica, Controle e Aplicações, 2011
Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar... more Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar a ocorrência de acidentes de trabalho no processo de esquartejamento de aves. São apresentados ensaios que comparam os resultados dessa técnica aos obtidos num processo de filtragem, determinando o grau de eficiência de cada um deles.
This work describes the development of a blister detection system for cylindrical precast concret... more This work describes the development of a blister detection system for cylindrical precast concrete samples using the method of acoustic impact. Piezoelectric sensors were employed as transducers and a digital oscilloscope was used to acquire the electrical signals. Comparative analysis between acquired signals from a non-defective sample (reference) and samples with medium-sized defects (30 mℓ and 70 mℓ) were performed. The acquired signals were decomposed using the Discrete Wavelet Transform and analyzed in the frequency domain. The results show that the proposed system can be used to identify defective samples and that the resonance frequency of the acquired signals varies according to the size of the defect inserted in the sample. Resumo: Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova cilíndricos de concreto pré-moldado através do método do impacto acústico. Sensores piezelétricos foram empregados como transdutores e um osciloscópio digital foi utilizado para adquirir os sinais elétricos. Foram realizadas análises comparativas entre os sinais adquiridos a partir de uma amostra sem defeito (referência) e as amostras com defeitos de tamanho médio (30 mℓ e 70 mℓ). Os sinais adquiridos foram decompostos usando a Transformada Wavelet Discreta e analisados no domínio da frequência. Os resultados mostram que o sistema proposto pode ser utilizado para identificar amostrar com defeito e que a frequência de ressonância dos sinais adquiridos varia de acordo com o tamanho do defeito inserido na amostra.
Technical Papers ... Rio Oil & Gas, Sep 26, 2022
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Jul 1, 2020
We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to i... more We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to improve the noise and interference suppression. The rake idea is well-known in wireless communications; it involves constructively combining different multipath components that arrive at the receiver antennas. Unlike spread-spectrum signals used in wireless communications, speech signals are not orthogonal to their shifts. Therefore, we focus on the spatial structure, rather than the temporal. Instead of explicitly estimating the channel, we create correspondences between early echoes in time and image sources in space. These multiple sources of the desired and the interfering signal offer additional spatial diversity that we can exploit in the beamformer design. We present several "intuitive" and optimal formulations of acoustic rake receivers, and show theoretically and numerically that the rake formulation of the maximum signal-to-interference-and-noise ratio beamformer offers significant performance boosts in terms of noise and interference suppression. Beyond signal-to-noise ratio, we observe gains in terms of the perceptual evaluation of speech quality (PESQ) metric for the speech quality. We accompany the paper by the complete simulation and processing chain written in Python. The code and the sound samples are available online at http://lcav.github.io/AcousticRake-Receiver/.
Abstract The continuous technological advances require materials with properties that conventiona... more Abstract The continuous technological advances require materials with properties that conventional material cannot display. Material property combinations are being the focus to the development of composite materials, which are considered a multiphase material that ...
Rio Oil and Gas Expo and Conference
Anais do Congresso Brasileiro de Automática 2020, 2020
Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova... more Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova cilíndricos de concreto pré-moldado através do método do impacto acústico. Sensores piezelétricos foram empregados como transdutores e um osciloscópio digital foi utilizado para adquirir os sinais elétricos. Foram realizadas análises comparativas entre os sinais adquiridos a partir de uma amostra sem defeito (referência) e as amostras com defeitos de tamanho médio (30~ml e 70~ml). Os sinais adquiridos foram decompostos usando a Transformada Wavelet Discreta e analisados no domínio da frequência. Os resultados mostram que o sistema proposto pode ser utilizado para identificar amostrar com defeito e que a frequência de ressonância dos sinais adquiridos varia de acordo com o tamanho do defeito inserido na amostra.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2020
We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to i... more We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to improve the noise and interference suppression. The rake idea is well-known in wireless communications; it involves constructively combining different multipath components that arrive at the receiver antennas. Unlike spread-spectrum signals used in wireless communications, speech signals are not orthogonal to their shifts. Therefore, we focus on the spatial structure, rather than the temporal. Instead of explicitly estimating the channel, we create correspondences between early echoes in time and image sources in space. These multiple sources of the desired and the interfering signal offer additional spatial diversity that we can exploit in the beamformer design. We present several "intuitive" and optimal formulations of acoustic rake receivers, and show theoretically and numerically that the rake formulation of the maximum signal-to-interference-and-noise ratio beamformer offers significant performance boosts in terms of noise and interference suppression. Beyond signal-to-noise ratio, we observe gains in terms of the perceptual evaluation of speech quality (PESQ) metric for the speech quality. We accompany the paper by the complete simulation and processing chain written in Python. The code and the sound samples are available online at http://lcav.github.io/AcousticRake-Receiver/.
Ultrasound in Medicine & Biology, 2019
This work presents an affordable and easily customizable methodology for phantom manufacturing, w... more This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcoholÀbased cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2019
This work describes the development and tests of a new ultrasonic spectrometer for liquids based ... more This work describes the development and tests of a new ultrasonic spectrometer for liquids based on the use of commercial cuvettes for sample handling. The spectrometer operates in the frequency range from 20 to 80 MHz and gathers some important characteristics, which are its high thermal stability (better than 0.01 o C), by the use of Peltier cells, and practical sample handling with small volume (≤3 ml) samples placed inside cuvettes which can be easily removed from the spectrometer, cleaned/sterilized or simply discarded. Throughtransmission operation is used to measure propagation velocity and attenuation coefficient, and the spectrometer was tested with mixtures of water and NaCl, which have attenuations smaller than that of distilled water, and higher attenuation samples of silicone and castor oil. Backscattering studies of polystyrene particles of 10 and 15 µm-diameters were also conducted, showing the versatility of the instrument.
2009 IEEE International Ultrasonics Symposium, 2009
Abstract The continuous technological advances require materials with properties that conventiona... more Abstract The continuous technological advances require materials with properties that conventional material cannot display. Material property combinations are being the focus to the development of composite materials, which are considered a multiphase material that ...
Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar... more Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar a ocorrência de acidentes de trabalho no processo de esquartejamento de aves. São apresentados ensaios que comparam os resultados dessa técnica aos obtidos num processo de filtragem, determinando o grau de eficiência de cada um deles.
Este trabalho tem como objetivo a compreensao dos processos de representacao espaco- temporal pre... more Este trabalho tem como objetivo a compreensao dos processos de representacao espaco- temporal presentes em Um Filme Falado (obra cinematografica de Manoel de Oliveira) e Viagem a Portugal (obra literaria de Jose Saramago) , desvendando suas implicacoes socio-culturais. O tema da viagem , eixo central de ambas as narrativas, e analisado tendo em vista as percepcoes construidas pelas personagens / viajantes sobre os lugares visitados, seja em Portugal, seja no Mundo Mediterrânico. O olhar investigativo sobre as duas obras torna-se assim um momento privilegiado para a analise sobre os diferentes papeis simbolicos atribuidos pelos autores a presenca da reflexao historica na sociedade portuguesa contemporânea.
Ultrasound in Medicine and Biology, Aug 1, 2019
This work presents an affordable and easily customizable methodology for phantom manufacturing, w... more This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcoholÀbased cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.
Conferência Brasileira de Dinâmica, Controle e Aplicações, 2011
Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar... more Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar a ocorrência de acidentes de trabalho no processo de esquartejamento de aves. São apresentados ensaios que comparam os resultados dessa técnica aos obtidos num processo de filtragem, determinando o grau de eficiência de cada um deles.
This work describes the development of a blister detection system for cylindrical precast concret... more This work describes the development of a blister detection system for cylindrical precast concrete samples using the method of acoustic impact. Piezoelectric sensors were employed as transducers and a digital oscilloscope was used to acquire the electrical signals. Comparative analysis between acquired signals from a non-defective sample (reference) and samples with medium-sized defects (30 mℓ and 70 mℓ) were performed. The acquired signals were decomposed using the Discrete Wavelet Transform and analyzed in the frequency domain. The results show that the proposed system can be used to identify defective samples and that the resonance frequency of the acquired signals varies according to the size of the defect inserted in the sample. Resumo: Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova cilíndricos de concreto pré-moldado através do método do impacto acústico. Sensores piezelétricos foram empregados como transdutores e um osciloscópio digital foi utilizado para adquirir os sinais elétricos. Foram realizadas análises comparativas entre os sinais adquiridos a partir de uma amostra sem defeito (referência) e as amostras com defeitos de tamanho médio (30 mℓ e 70 mℓ). Os sinais adquiridos foram decompostos usando a Transformada Wavelet Discreta e analisados no domínio da frequência. Os resultados mostram que o sistema proposto pode ser utilizado para identificar amostrar com defeito e que a frequência de ressonância dos sinais adquiridos varia de acordo com o tamanho do defeito inserido na amostra.
Technical Papers ... Rio Oil & Gas, Sep 26, 2022
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Jul 1, 2020
We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to i... more We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to improve the noise and interference suppression. The rake idea is well-known in wireless communications; it involves constructively combining different multipath components that arrive at the receiver antennas. Unlike spread-spectrum signals used in wireless communications, speech signals are not orthogonal to their shifts. Therefore, we focus on the spatial structure, rather than the temporal. Instead of explicitly estimating the channel, we create correspondences between early echoes in time and image sources in space. These multiple sources of the desired and the interfering signal offer additional spatial diversity that we can exploit in the beamformer design. We present several "intuitive" and optimal formulations of acoustic rake receivers, and show theoretically and numerically that the rake formulation of the maximum signal-to-interference-and-noise ratio beamformer offers significant performance boosts in terms of noise and interference suppression. Beyond signal-to-noise ratio, we observe gains in terms of the perceptual evaluation of speech quality (PESQ) metric for the speech quality. We accompany the paper by the complete simulation and processing chain written in Python. The code and the sound samples are available online at http://lcav.github.io/AcousticRake-Receiver/.
Abstract The continuous technological advances require materials with properties that conventiona... more Abstract The continuous technological advances require materials with properties that conventional material cannot display. Material property combinations are being the focus to the development of composite materials, which are considered a multiphase material that ...
Rio Oil and Gas Expo and Conference
Anais do Congresso Brasileiro de Automática 2020, 2020
Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova... more Este trabalho descreve o desenvolvimento de um sistema para detecção de bolhas em corpos de prova cilíndricos de concreto pré-moldado através do método do impacto acústico. Sensores piezelétricos foram empregados como transdutores e um osciloscópio digital foi utilizado para adquirir os sinais elétricos. Foram realizadas análises comparativas entre os sinais adquiridos a partir de uma amostra sem defeito (referência) e as amostras com defeitos de tamanho médio (30~ml e 70~ml). Os sinais adquiridos foram decompostos usando a Transformada Wavelet Discreta e analisados no domínio da frequência. Os resultados mostram que o sistema proposto pode ser utilizado para identificar amostrar com defeito e que a frequência de ressonância dos sinais adquiridos varia de acordo com o tamanho do defeito inserido na amostra.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2020
We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to i... more We present the concept of an acoustic rake receiver-a microphone beamformer that uses echoes to improve the noise and interference suppression. The rake idea is well-known in wireless communications; it involves constructively combining different multipath components that arrive at the receiver antennas. Unlike spread-spectrum signals used in wireless communications, speech signals are not orthogonal to their shifts. Therefore, we focus on the spatial structure, rather than the temporal. Instead of explicitly estimating the channel, we create correspondences between early echoes in time and image sources in space. These multiple sources of the desired and the interfering signal offer additional spatial diversity that we can exploit in the beamformer design. We present several "intuitive" and optimal formulations of acoustic rake receivers, and show theoretically and numerically that the rake formulation of the maximum signal-to-interference-and-noise ratio beamformer offers significant performance boosts in terms of noise and interference suppression. Beyond signal-to-noise ratio, we observe gains in terms of the perceptual evaluation of speech quality (PESQ) metric for the speech quality. We accompany the paper by the complete simulation and processing chain written in Python. The code and the sound samples are available online at http://lcav.github.io/AcousticRake-Receiver/.
Ultrasound in Medicine & Biology, 2019
This work presents an affordable and easily customizable methodology for phantom manufacturing, w... more This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcoholÀbased cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2019
This work describes the development and tests of a new ultrasonic spectrometer for liquids based ... more This work describes the development and tests of a new ultrasonic spectrometer for liquids based on the use of commercial cuvettes for sample handling. The spectrometer operates in the frequency range from 20 to 80 MHz and gathers some important characteristics, which are its high thermal stability (better than 0.01 o C), by the use of Peltier cells, and practical sample handling with small volume (≤3 ml) samples placed inside cuvettes which can be easily removed from the spectrometer, cleaned/sterilized or simply discarded. Throughtransmission operation is used to measure propagation velocity and attenuation coefficient, and the spectrometer was tested with mixtures of water and NaCl, which have attenuations smaller than that of distilled water, and higher attenuation samples of silicone and castor oil. Backscattering studies of polystyrene particles of 10 and 15 µm-diameters were also conducted, showing the versatility of the instrument.
2009 IEEE International Ultrasonics Symposium, 2009
Abstract The continuous technological advances require materials with properties that conventiona... more Abstract The continuous technological advances require materials with properties that conventional material cannot display. Material property combinations are being the focus to the development of composite materials, which are considered a multiphase material that ...
Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar... more Este trabalho apresenta uma técnica que utiliza a Transformada Wavelet Discreta para caracterizar a ocorrência de acidentes de trabalho no processo de esquartejamento de aves. São apresentados ensaios que comparam os resultados dessa técnica aos obtidos num processo de filtragem, determinando o grau de eficiência de cada um deles.
Este trabalho tem como objetivo a compreensao dos processos de representacao espaco- temporal pre... more Este trabalho tem como objetivo a compreensao dos processos de representacao espaco- temporal presentes em Um Filme Falado (obra cinematografica de Manoel de Oliveira) e Viagem a Portugal (obra literaria de Jose Saramago) , desvendando suas implicacoes socio-culturais. O tema da viagem , eixo central de ambas as narrativas, e analisado tendo em vista as percepcoes construidas pelas personagens / viajantes sobre os lugares visitados, seja em Portugal, seja no Mundo Mediterrânico. O olhar investigativo sobre as duas obras torna-se assim um momento privilegiado para a analise sobre os diferentes papeis simbolicos atribuidos pelos autores a presenca da reflexao historica na sociedade portuguesa contemporânea.