Traditionally, the problems in cyber systems and physical systems were largely isolated and investigated by researchers from different research domains. The research on Cyber-Physical System (CPS) emphasizes the integration of computing with physical processes. This has greatly broadened the research scope of the traditional network and embedded system design. By incorporating the novel technology in network and embedded system design, this will also potentially bring tremendous improvement for new and traditional physical systems and applications. For the automobile system, which used to be predominately a physical system, when tens if not hundreds processors located in one single car and more than averagely 90% new innovations coming from its electronic systems, the integrated study of cyber and physical system will no doubt become more and more critical to ensure its safety, security, reliability, and energy efficiency.

To study the physical system as an entirety is challenging as it usually demands knowledge and expert skills crossing multiple (i.e. mechanical, thermal, chemical, and electrical) disciplines. The barriers between the cyber space and physical space would further add another level of challenges in the integrated study of CPS. Our approach to overcome these barriers is to develop a simulation environment that can encapsulate and capture cyber and physical characteristics of the systems in one unified framework. This environment is developed based on an existing multidisciplinary simulation platform, the Virtual Test Bed (VTB) ( VTB is a multi-formalism and multi-physics platform developed at the University of South Carolina in the last ten years with the support of the Office of Naval Research (ONR). VTB uses the resistive companion model (RCM) to model different physical phenomenon from different disciplines, thereby allowing simulation and virtual prototyping of complex multidisciplinary systems in an integrated environment.

We are developing a simulation platform, based on current version of VTB, that can simulate the cyber sub-system and physical sub-system in a coordinated and unified way (as see in Figure 2). The primary purpose of current VTB is to simulate physical system with phenomenon crossing different disciplines. We intend to expand the scope of current VTB by developing appropriate cyber space models such as those for processors, memory/storage, software, network, and operating systems as well as building corresponding simulation kernel and other facilitates to enable the simulation of cyber and physical systems in an integrated environment.

Figure 1   The VTB for Cyber-Physical System Co-simulation