Aspect-Oriented Timing Model For Real-Time Systems In Cyber Physical Systems

Cyber-Physical Systems (CPS) is a research hotspot in recent years. CPS is a system featuring a tight combination of and coordination between the system's computational and physical aspects by communication networks. CPS extensive application prospect, represents a new generation of industrial technology development, get all the attention. At the same time, CPS involves computer science, communication science and control science and other disciplines, is currently facing system theory, design methods, design tools, and many other challenges.Time feature is a key factor in real-time systems, the reliability and quality depends largely on the real-time. However, the time characteristics of scattered in the various functional components of the system where the code bringing the above code to spread confusion and problems, leading to system code hard to read, hard to modify, hard to produce inconsistent, poor reusability and difficult to modify and upgrade a range of issues. Therefore, to make time characteristics as a separate aspect for aspect-oriented modeling has become an ideal method.Aspect-oriented technology as a new technique based on separation of concerns in software development has been a certain application, with a number of relatively mature aspect-oriented programming language, a common technical framework in which some of the aspects of programming has also been better reflected. However, aspect-oriented for modeling, still have not a unified standard or a common way of modeling. The most widely used UML standard nor has the support for aspect-oriented, and only through the expansion mechanism for UML aspect-oriented modeling.For modeling the time characteristics of real-time systems, there are many studies in this area. AOSDM-UML models to real-time with extended formal description, getting the time to construct a separate time, and use the time model to create a more complete model to model the system time, is likely a good method.This paper focus on the CPS. It introduces the basic concepts, related features and its current challenges. Discussing the semantics of time as a new requirement in CPS and introducing some related research. With the time modeling framework in MARTE UML profile, using the extension of UML for aspect-oriented, combined with MARTE framework, the establishment of the timing model based on UML. Decomposing the real-time feature of CPS, using different aspects, we get the establishment of the time characteristics of the corresponding model. First, by the time characteristics of the basic time, time events, timing mechanisms, time service in four areas. Each side can extend the UML for modeling. Second, the CPS for a discrete time, continuous time, mixing time characteristics, characteristics of the time is divided into discrete time, the continuous time, the mixture of timing and the establishment of the appropriate model. Again, the time is divided into deterministic time, stochastic time, ambiguous time and establish the appropriate model. Time characteristics using different methods for different aspects of modeling, and then weaving through the mechanism for the methods needed to integrate these models. Later in this article we also analysis the worst-case execution time, and proposed a level of time synchronization algorithm to achieve clock synchronization.