This paper presents a reference architecture know as Virtual-Physical Space (ViPS). ViPS aims at supporting development of CPSS-like applications in various domains. One of the basic functions of the space is to integrate virtual and physical worlds to support the virtualization of physical “things”. The integration function is supported by a component called the Guard system. The architecture of the Guard system and the supporting tools are also presented in this article. The use of guards is demonstrated by a small scenario of the operation of the intelligent agriculture system.