The Extension of Quality Function Deployment Based on 2-Tuple Linguistic Representation Model for Product Design under Multigranularity Linguistic Environment

Table 1

Linguistic labels for rating of criteria and grade of importance.

Linguistic term sets 𝑆1	Linguistic term sets 𝑆2
𝑆^10 = DL: definitely low	𝑆^20 = VL^2: very low
𝑆^11 = VL: very low	𝑆^21 = L^2: low
𝑆^12 = L: low	𝑆^22 = M^2: middle
𝑆^13 = M: middle	𝑆^23 = H^2: high
𝑆^14 = H: high	𝑆^24 = VH^2: very high
𝑆^15 = VH: very high
𝑆^16 = DH: definitely high