A Hybrid Multiobjective Evolutionary Approach for Flexible Job-Shop Scheduling Problems

Algorithm 3

Procedure of sequence adjustment.

Procedure: Sequence Adjustment

Randomly select a critical operation 𝐼_𝑖.

if  Operation 𝐼_𝑖 is critical block head  then

 Randomly generate an integer 𝑖^′ between the machine successor and job

 successor of 𝐼_𝑖.

 Insert operation 𝐼_𝑖 into the position 𝑖^′, Insert(i, i' ).

end if

if  Operation 𝐼_𝑖 is critical block rear  then

 Randomly generate an integer 𝑖^′ between the job predecessor and ma-

 chine predecessor of 𝐼_𝑖.

 Insert operation 𝐼_𝑖 into the position 𝑖^′, Insert(i, i' ).

end if

if  Operation 𝐼_𝑖 is critical internal block  then

 Randomly create a decimal 𝑑 between 0 and 1.

 if  𝑑≤0.5  then

  Randomly generate an integer 𝑖^′ between the machine successor and

  job successor of 𝐼_𝑖.

  Insert operation 𝐼_𝑖 into the position 𝑖^′, Insert(i, i' ).

 else

  Randomly generate an integer 𝑖^′ between the job predecessor and ma-

  chine predecessor of 𝐼_𝑖.

  Insert operation 𝐼_𝑖 into the position 𝑖^′, Insert(i, i' ).

 end if

end if