B. Related Work
To deal with the increased information security threats,
many kinds of security equipments have been used in the
large scale network. These equipments produce lots of
security events. It' s very difficult to obtain the security state
of the whole network precisely when facing too much
warning information. To settle this problem, many
researches had introduced the concept of situation awareness
into internet security system. Bass was the first who
introduced this concept into network and bring forward the