Research on quantitative conversion of qualitative requirements of product maintainability

Maintainability qualitative requirements are mainly represented by qualitative terms and expressions. In order to make maintainability evaluation objective and simple, it is necessary to describe qualitative requirements as quantitative requirements or parameters, namely, quantitative conversions of maintainability qualitative requirements. Based on the basic expressions and uncertainties of maintainability qualitative requirements in analyzing product, these requirements are recategorized from the perspective of language description, including restricted quantity, fuzzy concept, reasoning rule, and other language etc. The cloud theory and cloud model are used to realize the quantitative conversions of partial qualitative requirements. Other qualitative requirements may not need or be unable to convert into quantitative requirements based on present techniques. This research is crucial to maintainability design task in development process of product, such as maintainability analysis, maintainability demonstration and evaluation.