[Retracted] An Improved Ant Colony Optimization Approach for Optimization of Process Planning

Table 2

Precedence constraints for the example part.

ID	Features	Operations	Precedence constraints description
1	F1	OP1	𝐶𝑂1 is prior to 𝐶𝑂2
2	F2	OP2	𝐶𝑂2 is prior to 𝐶𝑂4
3	F4	OP4	𝐶𝑂4 is prior to 𝐶𝑂3
4	F5	OP5	𝐶𝑂5 is prior to 𝐶𝑂3