Akinori Hayashi

Comparison of noise environment of residences in Nagoya, Japan and in Beijing, China

Abstract A social survey based on the noise environment at residential sites both in Nagoya, Japan and in Beijing, China has been carried out. Noise levels have been measured during one day and night at house sites and a social survey of the reactions of residents to the living environment has also been made. The surveys in both cities indicate that the distribution of noise levels is almost the same, but the reactions of residents to the noise environment are quite different. The analysis and results of the surveys and discussion on the difference between the reactions of residents in the two cities to their noise environments are given in this paper.

Estimation of equivalent sound level by invoking a neural net

The equivalent sound level Leq for road traffic noise is estimated using two models. One is a nonlinear neural model in which the transformation sometimes becomes analytical when it is expanded to a series. Therefore, the output function of the net is examined, and a means of partitioning the data for learning and evaluation is described. The other model is a prediction equation in which the decay due to distance is added to the unit pattern based on an expression derived from Poisson traffic flow. The variables included in the equation are then selected as inputs to the net, and learning is evaluated. The output of the net is compared with the results of the prediction equation. The neural net learns functional relations with relatively little polarization, and predictions are easily made since the data are partitioned. The degree of prediction errors is approximately the same for both the equation and the neural net.

Reaction to the outdoor noise among inhabitants in Nagoya, Japan and Beijing, China

Inhabitants’ reaction to outdoor noise in Nagoya and in Beijing was surveyed. A questionnaire on noise was conducted with more than 2000 people in Nagoya and more than 1000 in Beijing. They were also asked whether they were sensitive to each of the 37 types of noise sources. The responses of inhabitants to the above questionnaire in Beijing are more sensitive than those in Nagoya to loudness, annoyance, and sleep disturbance. Road traffic noise is the most audible of 37 noise sources in both cities. Sounds of fireworks and sounds from festivals are also highly audible in Beijing. The most annoying noise is one from motorcycle gangs in both cities, and one from construction in Beijing. The annoyance rates in Beijing are higher than those in Nagoya.