Computing minimal hitting sets with CHS-tree method

In model-based diagnosis theory, a Cardinality-based Hitting Set-tree (CHS-tree) method was put forward to compute the whole Minimal Hitting-Sets (MHSs) according to all conflicts. The smallest cardinality set was selected from the current conflict set cluster to be expanded, and the frequency of the element occurrence was considered as an auxiliary condition to decompose the big problem into some sub-problems. All the MHSs of the set cluster which did not contain any element in the expansion set were computed as well. Experimental results showed that the proposed method had easier process and fewer nodes. Compared with the classical HS-tree method, BHS-tree and HSSE-tree method, this method had higher efficiency. In some cases, its efficiency was higher than the current most efficient Boolean method.