Fuzzy modelling of speech interference in noisy environment

In this paper, an attempt has been made to develop a fuzzy model to investigate the effects of noise pollution on speech interference. The speech interference measured in terms of speech intelligibility is considered to be a function of noise level distance between speaker and listener, and the age of the listener. The model has been implemented on Fuzzy Logic Toolbox of MATLAB using both Mamdani and Sugeno techniques. The model results are in good agreement with the survey findings of World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA). The study reveals that for good communication at normal distances ('short' and 'medium') encountered in ambient environment, the noise level should not exceed 65 dB(A) for 'young' and 'middle aged', and 55 dB(A) for 'old' persons. The present effort also establishes the usefulness of fuzzy technique in studying the environmental problems where the cause-effect relationships are inherently fuzzy in nature.