Publications

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    ABSTRACT: Exposure-response relationships have been widely studied using A weighted equivalent sound pressure level measured outside building environments in contrast with field surveys. On one hand low frequencies are minimized by A-weighted filter network. On the other hand low frequencies are predominant even inside buildings for some of the most salient sources in many cities (i.e. road traffic). These relationships do not consider that people spend a large part of their time inside building environments. The spread of the exposure-response relationships can, presumably, be reduced by relating people response to the noise spectrum levels inside building environments instead of the outdoors Leq,A. Outdoors spectral maps can be georeferenced using geographical information systems. Then the indoors spectrum for each building can be estimated if the georeferenced data of façades and interiors properties were available. Furthermore city planners can use the outdoors spectral maps to estimate the adequate sound insulation of façades for new projects. In this article a georeferenced spectral map of a part of the city of Rosario, Argentina is developed using inexpensive resources and some interesting tools for this purpose are presented using technical computing software. Different forms of presenting the data are analyzed in relation to the requirements of different agents, public, city planners, Geographical Information Systems users, etc.
    Mecánica Computacional. 11/2011; XXX(4):3075-3085.
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    F Marengo-Rodriguez, E Accolti, F Miyara
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    ABSTRACT: While a huge amount of literature has been devoted to the study of traffic noise, its aural simulation has received much less attention. Such simulation enables the determination of the sound both outside and inside buildings by means of proper filters. In recent years, a technique based on sound recording of each isolated vehicle in a fixed station, followed by Doppler compensation and noise characterization has been developed. Although this technique takes into account each source more precisely (such as engine and exhaust noise with load effect) as well as aerodynamic noise, it depends on the emission of a pilot tone from the source. This tone allows for the retrieval of the vehicle speed. In this paper, a new Doppler compensation method is proposed, based on the vehicle speed estimation from the tones contained in the recorded signal. This technique may be applied to any vehicle as far as it is reasonably isolated from other vehicles, it does not contaminate the signal of interest, and it needs no pilot tone emission from the source, making the method more practical. For aural simulation, a new model based on a polar scheme is considered and proposed. In this paper, the proposed method is assessed with experimental data, and results are compared with those of other existing techniques.
    Mecanica Computacional. 01/2011; XXX (41):3187-3199.
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    ABSTRACT: Signal acquisition in acoustical metrology is an increasing need in research and fieldwork. Many specialists think that new indicators should be introduced to describe effects of noise arising from features such as spectrum, semantic content and psychoacoustic properties of noise, all of which require a knowledge of the time history of signal. While there are several instrumentation grade recorders (some of which are optional upgrades for recent models of sound meters), they are usually expensive. The possibility of using a relatively inexpensive digital recorder (Zoom H4) in combination with the calibrated output signal of a precision sound level meter is explored. The major concern arises from the high frequency effects of the antialiasing filter of the analog to digital converter. Three units of the same model of digital recorder were extensively tested as regards frequency response, noise, distortion and transient response at two sampling rates, 44100 Hz and 96000 Hz. Electrical signals applied at the recorder input were monitored with a volt meter and an oscilloscope, while the recorded digital signal was transferred to a computer for software analysis. Tests reveal that the recorder is suitable for use as part of a measurement setup.
    Proceedings of the 39th International Congress and Exposition on Noise Control Engineering, INTERNOISE 2010; 01/2010
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    Fernando A Marengo Rodriguez, Alejandro Federico, Guillermo H Kaufmann
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    ABSTRACT: We present an optical phase measurement method based on the Hilbert transform for the analysis of a time series of speckle interferograms modulated by a temporal carrier. We discuss the influence of nonmodulating pixels, modulation loss, and noise that affect the bias and modulation intensities of the interferometric signal and propose the application of the empirical mode decomposition method for its minimization. We also show the equivalence between the phase recovery approaches that are based on the Hilbert and the Fourier transforms. Finally, we present a numerical comparison between these methods using computer-simulated speckle interferograms modulated with a temporal carrier.
    Applied Optics 04/2008; 47(9):1310-6. · 1.69 Impact Factor
  • F. A. Marengo Rodríguez, A. Federico, G. H. Kaufmann
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    ABSTRACT: When the phase distribution is evaluated in temporal speckle pattern interferometry by means of the Hilbert transform method, the accuracy of the estimation is conditioned by the influence of the variations of the bias and the modulation intensities, since these parameters must be selected heuristically. In this work we present a novel approach that uses the Empirical Mode Decomposition (EMD) method in order to overcome the previous problem. To illustrate the improvement obtained with the proposed method, an example of its application is presented.
    04/2008;
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    Fernando A. Marengo Rodriguez, Alejandro Federico, Guillermo H. Kaufmann
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    ABSTRACT: When the Hilbert transform method is used to recover the phase distribution in temporal speckle pattern interferometry, the influence of the fluctuations of the bias and the modulation intensities on the calculated phase must be driven heuristically. In this paper we show that the Empirical Mode Decomposition method can overcome these drawbacks and consequently introduces an improvement in the evaluation of the phase distribution. An example is used to illustrate the phase measurement improvement that can be obtained by the application of the proposed approach.
    Optics Communications 01/2007; 275(1):38-41. · 1.44 Impact Factor
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    Fernando A. Marengo Rodriguez, Federico S. Miyara
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    ABSTRACT: Traffic noise at an urban location can be simulated aurally in such a way that its parameters can be carefully controlled. This will prove useful in experiments on noise effects and in traffic noise impact assessment. In order to accomplish this, noise samples of individual vehicles equivalent to what would be recorded at a receptor moving along with the vehicle should be recorded. This is, however, impractical, due to the turbulence noise that would be generated at the microphone, so they must be obtained indirectly from the noise recorded at a fixed position. The main difficulty is, then, that noise immission is distorted by Doppler effect and geometric divergence. In this paper, experimental and computational techiques are developed in order to supress the Doppler and divergence effects. Finally, the performance of the method is assessed aurally by simulating vehicle noise within a virtual open profile urban street.

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