Cloud model is an effective tool for qualitative and quantitative transform

a specific structure generator is formed by normal cloud model through expectation

entropy and hyper entropy

This particular structure makes the normal cloud model has more general applicability and simply and straightforward completed conversion process between qualitative and quantitative.An intrusion detection methods is proposed based on cloud model and BP Network.The cloud model and BP algorithm are combined.The simulation experiment is compared respectively by KDD99 CUP data set.Experimental results show that the method is not only fast convergence but also has fewer number of iterations.It can improve the accuracy of intrusion detection.