where si denotes restoration scheme i; i ¼ 1; 2; ... ; m; fj represents
the attribute j with quantitative or qualitative data, j ¼ 1; 2; ... ; n;
fij indicates the performance score of restoration scheme si with
respect to attribute fj.
TOPSIS requires that attributes should be numeric, monotonic
and have commensurable units. Therefore all attributes should
be converted to benefit attributes, and the evaluation method of
attributes has been introduced in Section ‘Identification and evaluation
of attributes’.