“…With the help of specific systems in which the production process is featured as a multistage link, a lot of studies have been conducted; among these, some typical studies use a two-stage process to detect the realistic individual stage efficiencies and specific inefficient stages [22,23,25,26], which coincides with Section 2, and the basic process is shown in Figure 4. Similarly, for the jth (j = 1, · · · , n) HEI, its inputs, intermediate variables, and outputs are represented by X ij , i = 1, · · · , m, Z f j , f = 1, · · · , g, and Y rj , r = 1, · · · , s, respectively.…”