In the measurement and evaluation of actual random phenomena in sound environment systems, the observed data exhibit various probability distribution forms, and often contain fuzziness due to the existence of confidence limitation in measuring instruments, permissible error in experimental data, and the variety of human response to phenomena, etc. In this study, by introducing fuzzy probability theory, two types of state estimation methods based on the fuzzy observations are theoretically

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... ed from both the static and dynamic viewpoints. First, a static method for estimating the probability distribution of a signal in the psychological evaluation for sound environment is discussed theoretically by considering the human noise annoyance scores as observation data with fuzziness. Next, a dynamical estimation method for a signal in sound environment systems based on fuzzy observations is theoretically proposed under the actual situation of existence of an external noise. The validity and effectiveness of the proposed methods are experimentally confirmed by applying the theories to the actual fuzzy data observed in a sound environment