Risk Assessment Quantification of Ambient Service Fundamental investigation of the risks of cyber-physical systems

摘要

Ambient services have attracted attention as a possible ubiquitous, future intelligent infrastructure. An ambient service automatically provides services suited to the user by making sensors and computers cooperate and by gathering and analyzing information about each user. As such, ambient services are related to cyber-physical systems. However, in the process of managing personal information, ambient services are prone to various risks, such as information leakage. Our previous study analyzed the service provision and service use sides. It used the risk breakdown structure (RBS) and risk matrix, which are typical risk management methods of project management, and identified 40 risk factors faced by ambient services and countermeasures thereof. However, we recognized that it was only a qualitative study and that a quantitative evaluation would be needed to make its countermeasures more practical. Hence, in this paper, the risk factors identified in the previous study are analyzed and quantitatively evaluated. Specifically, the values of the risk factors were calculated by using a risk formula used in the field of information security management systems (ISMS). On the basis of these values, the effect of the countermeasures proposed in the previous study was evaluated quantitatively. It was found that the countermeasures in the previous study could reduce their corresponding risk factors by 18% - 36%. The results herein can be used to promote ambient services in the future.