Research On Analyzing Software Requirement For Cyber Physical Systems

Integrating computing process with physical process, CPS is a kind of complex hybrid system which includes both physical entities and software entities, and has become a new trend of industry informationization. They will change the way people interact with the world.During operation, software entities monitor the operation of the physical entities, observe the changes of physical process, and affect the physical processes. Finally, a feedback loop in which computing processes and physical processes interact with each other is formed. In this loop, software entities play the roles of monitoring, analyzing and controlling, and locate in the center of CPS. In this case, it is important to analyze the software requirements for CPS to clarify the software entities constituting CPS and the task of the software entities.However, there is still lack of effective methods to analyze software requirements for CPS. The integration of computing process with physical process makes the software requirements analysis for CPS a challenging task. First starting from the desired changes of physical entities, we must derive software requirements based on the understanding of the properties of physical entities. Second, the software requirements analysis for CPS can't regard the software of CPS as a whole and describe its external behavior, we instead need to analyze which software entities and physical entities to be included, why these entities are required, what relationships between them, and what properties each physical entity possesses, and what behaviors each software entity should have. In addition, a unified way to describe the behavior of software entities and the properties of physical entities is required to facilitate the validation of the satisfactions of users' requirements.To solve above issues, we propose a software requirements analysis approach for CPS based on Alloy. The main contributions of this paper are summarized as follows:(1) We propose a software requirements analysis approach for CPS. Starting from the users' requirement on CPS, this approach can help analyze the physical entities, software entities, the properties of physical entities and the requirements on software entities.(2) We verify the validity of the model established for the CPS based on the Alloy, which to detect whether the entities constituting CPS can satisfy the users' requirements.(3) An adaptive cruise control system has been taken as an example to show the feasibility and application process of the approach.