Abstract
Up to now, the psychological impression to acoustic noise by use of fuzzy set theory has been quantitatively studied from the viewpoint that the psychological impression as judged by human beings is a fuzzy event. The membership functions of categorized impression on the noise level universe in the studies played an important role in the discussion of the quantitative relationship between the noise as the objective input and impression as the subjective output. However, this being the beginning stage of the studies the method used to estimate the membership function was very primitive. At the next stage, the system for measuring impression to the noise easily and effectively, and for estimating the membership function, is developed for the purpose of investigating individuality of response to the noise, changes of the function by various kinds of factor and so on. The validity and usefulness of the system are confirmed by applying it to the actual measurement for the functions of four subjects.Finally, several methods for estimating the function proposed before by other researchers are summarized and the differences between the present method and previous ones, and the features unique to the present method, are discussed. It is shown from the discussion that the proposed method is a new one based on the decomposition theorem, and a practical one with a wide application based on a small number of assumptions.Noisiness, Calmness, Individuality, Decomposition theorem
