Abstract:

The level of intermittent transportation noise into the bulding is controlled by activating an intelligent control system to close the window when the noise occurs. This method is a possible solution for conflict between passive noise control and natural ventilation for places with a moderate climate. A knowledge-based control strategy has been implemented to control the position of the window using acoustic feedback. There are three major steps, training, source classification, and control, in which fuzzy logic and rule-based algorithms are implemented. If somebody plays music or speaks near the window, the intelligent window must not react even though the level of the sound may be higher than an approaching aircraft or vehicle. To identify an approaching noise source, centroid of the Wigner--Ville distribution and the peaks of STFT are used. The cross correlation between output data from indoor and outdoor microphones indicates the effect of outdoor transportation noise on the indoor noise level. A training software is considered to update the thresholds of noise classification. The experimental result of a prototype intelligent window is presented. A noise attenuation of more than 10 dB in L[inf eq] and L[inf max] in each single noise events is achieved. [Work supported by RTA of NSW.]