Archives of Acoustics, 23, 2, pp. 179-194, 1998

A trial of evaluation based on multiplicative multivariate model for non-stationary road traffic noise

M. Ohta
Department of Electronic Engineering and Computer Science, Faculty of Engineering, Kinki University Umenobe 1, Takaya, Higashi-Hiroshima, 739-21 Japan

Y. Fujita
Department of Management and Information Science, Onomichi Junior College, Hisayamada-Chou 1600, Onomichi, 722 Japan

Since the non-stationary fluctuation of actual acoustic environment like the road traffic noise within a long time interval is usually caused not by the change of merely additional external noise but by the essential change of internal factors themselves, it is reasonable to give as a mathematical model of this non-stationary fluctuation not an additive model but a multiplicative model. In this paper, mainly from a methodological viewpoint, first, the characteristic function method of Mellin transform type for the above multiplicative model is introduced and a new unified expression form of the probability density function within a long time interval is derived in an expansion form based on the probability density function within a short time interval of local stationary type as its first expansion term with distribution parameters reflecting hierarchically various types linear and nonlinear correlation information.
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