The original naive implementation used the modulus (%) operator, which is wildly inefficient, to check every number from 2 up to the target number itself to determine if it is a factor.
Protection for the operator and passengers will remain a key factor.
尽管如此，对操作人员及旅客安全的保护将始终是首要考虑的因素。
3
The degenerative model is that original image was passed by operator or was acted on degenerative factor, and noise overlap-added, then, degenerated image was formed.