Table 4 Algorithm for reduction of attributes using soft rough based on covering

Step 1

Input \(\mathcal {S}=(\mathcal {U},\mathcal {G})\), \(\mathcal {G}=(\mathcal {F},\mathcal {A} )\), \(\mathcal {A}\) is a set of attributes which symbolize table’s information

Step 2

Calculate \(\underline{\mathcal {M}S}(\mathcal {X}_{1})\), \(\overline{\mathcal {M}S}(\mathcal {X}_{1})\), \(BND_{SC}(\mathcal {X}_{1})\) for the of accepted pilots

Step 3

Remove an attribute \(a_{i}\) from the set \(\mathcal {A}\), and generate \(\underline{\mathcal {M}S}(\mathcal {X}_{1})\), \(\overline{\mathcal {M}S}(\mathcal {X}_{1})\), \(BND_{SC}(\mathcal {X}_{1})\) using \(\mathcal {\mathcal{A}}-\{a_{i}\}\)

Step 4

Reiterate step 3 for all attributes of \(\mathcal {A}\)

Step 5

If \(\underline{\mathcal {M}S}(\mathcal {X}_{1})\), \(\overline{\mathcal {M}S}(\mathcal {X}_{1})\), \(BND_{SC}(\mathcal {X}_{1})\) are equal for step 2 and step 3, then the attribute \(a_{i}\) is superfluous and is not important in decision making