Review of risk assessment approaches in the area of security system

Human society is faced with greater insecurity and challenges with the increasing unconventional emergencies in recent years. In order to response wisely and efficiently, we must first assess the risks of these unconventional emergencies. The risk assessment approaches in the area of security system are investigated in this article. After reviewing the evolution history of risk assessment approaches, we review the assessment approaches of threat, vulnerability, consequence these three factors of risk respectively.