A novel ontology-based service model for cyber physical system

In cyber physical system (CPS), computation, communication and physical processes are tightly integrated. The inherent complexity of CPS challenges its design and implementation. In order to achieve rapid development of CPSs, the well-known SOA technology gradually receives attentions of researchers in the field of CPS. Modeling CPS service is fundamental to further application of SOA technology. In recent years, several CPS service models have been proposed, however, these models still have some drawbacks. First, CPS service integrates operations in both cyber and physical spaces, but in existing models, physical characteristics are not obviously manifested. Second, while almost all existing work points out the necessity of considering context, deep study on context in CPS is hardly done. Therefore, further research on CPS service model is very essential. In this paper, we propose an ontology-based CPS service model, which has three main concepts: physical entity, location and CPS service. We introduce several important physical characteristics, such as operation space, degree of parallelism, operation object flow and running time. In terms of context, we introduce two types of common context information, that is, location and state of physical entity. In the end, we conduct case study and invalidation using an automatic mixed assembly line. The results show that the proposed model is very useful in the practical.