Science and Development Network (SciDev.Net)
With the rapid development of technology, now a brand new research area-Cyber Physical Systems (CPS) emerges. CPS are integrations of computing, communication and control systems, and it integrates with the physical world closely. Though it has influenced common life a lot, many problems still need to be solved when using the existing theories and technologies. Among the difficulties, the description and analysis of time in CPS is one of the most important issues. This paper aims to specify cyber physical systems by clock theory.