Method for quantitative expression of psychological safety and security distance (PSSD) using fuzzy theory

Usually psychological safety and security distance (PSSD) is difficult to express quantitatively as it belongs to the field of social science. This article presents a mathematical approach for the PSSD expression using fuzzy theory. In the building of this method, the rough sets theory is applied to weight the influencing factors concerning the PSSD. The triangular fuzzy theory and the expert fuzzy evaluation method are utilized to address the fuzziness and uncertainty that might arise in assessing the relevant factors of PSSD. Fitting a curve for depicting the relationship between the PSSD and individual psychological factors is carried out using computer software. Also, the procedures of measuring PSSD are summarized as a general method and it is therefore of validity for the quantitative measurement of other relevant qualitative issues.