Table 3 Classification criteria and characteristics of coupling degree and coupling coordination degree

High coupling

0.8 < C ≤ 1

Quality coordination

0.90 < D ≤ 1.00

The benign coupling of the two systems becomes stronger and gradually develops in the direction of order and is at a high level of coordinated coupling

Good coordination

0.80 < D ≤ 0.90

Moderate coordination

0.70 < D ≤ 0.80

Moderate coupling

0.5 < C ≤ 0.8

Elementary coordination

0.60 < D ≤ 0.70

The two systems begin to check and match each other, showing benign coupling characteristics

Reluctant coordination

0.50 < D ≤ 0.60

Light coupling

0.3 < C ≤ 0.5

Near-disorder

0.40 < D ≤ 0.50

The two systems interact and strengthen each other, constantly influencing and adapting

Mild disorder

0.30 < D ≤ 0.40

Moderate disorder

0.20 < D ≤ 0.30

Micro coupling

0 < C ≤ 0.3

Serious disorder

0.10 < D ≤ 0.20

Shallow level of coupling of the two systems

Extreme disorder

0.00 < D ≤ 0.10