Interdepedency modeling of cyber-physical systems using a weighted complex network approach

This paper introduces a three-dimensional weighted Complex Network Theory (CNT) model to study the dependency and interdependency of cyber-physical systems (CPS) and to identify the most critical and vulnerable components within the coupled network. Based on CNT, the electric power buses within power system and communication routers and multiplexers within communication network are modelled as nodes, while the power lines and communication channels are modelled as edges. The intrinsic properties of electric power system (e.g. power flow) and the communication network (e.g. gross bitrate) are assigned as weights to each edge. A novel CNT-derived index, Vulnerability-weighted Node Degree (VWND), has been developed and applied to assess the dependency/importance of each physical/cyber node to its own and to the other system and such to help identify potentially weak areas of the system. The approach is illustrated on a 14-bus synthetic power distribution network with supporting Information and Communication Technologies (ICT)